SUSTAINABLE DEVELOPMENT TASK 1 PDF

🌿 SUSTAINABLE DEVELOPMENT TASK 1 What were/are the critiques on the conventional model of development? Conventional model of development focuses on economical growth, es. Rostow’s model - different stages of economical growth. Different critique on this model (such as it’s not applicable for every country), to summarise it’s on the weakness of this approach to preserve nature and sustainable development, prioritising the economical growth, and not considering the non replaceability of natural resources and that the exploitation of them caused underdevelopment in the Third World. The model ignores the loss of biodiversity, the exploitation and that there are limits to economical growth, carrying capacity e.g. ability of biosphere to absorb the effects of human activities. The post-World War Il experience of economic growth and prosperity was both: Exceptional -> it cannot be replicated across space (from the West to the global level) or across time (into the future). —> (NOTE: this contradicts with Rostow's view) Contingent-> depending upon a short-term perspective, the prioritisation of one region of the globe over another, and upon giving preference to one species (humans) over the system as a whole. In this critical context the sustainable development has gained traction. Kuznet’s curve: when the society arrives at a certain income, it’s willing to sacrifice a bit the economical growth to reagin the better quality of the environment. (Per reference Capitolo 1 pagine 3-5) SUSTAINABLE DEVELOPMENT 1 Rostow’s model What is the Brundtland report and the definition of sustainable development? It’s a report made in 1987, it’s revolutionary because puts development (traditional economical and social growth goal) with sustainability (ecological goal) together, and before this two goals were conflicting. Another important point of this report is the importance that gives to future generations, to allow them and give them the possibility to use natural resources. This reports come in a particular historical moment, just after Chernobyl’s explosion. The main object is giving to everyone the opportunity to satisfied human needs and aspirations, while achieving an economical growth, it’s also very positive about technology and the use of it to find solutions. There are some environmental limits (where we should stay within) implied to the Brundtland report tho, not real limits but limitations imposed by the present state of technology and society and by the ability of the biosphere to absorb the effects of human activities. Baker argues that the notion of limits is linked to other/later concepts and approaches like ecological footprint and planetary overshoot → global focus (concentrating also on the poors). The Brundtland Report laid the groundwork for the convening of the Earth Summit in Rio de Janeiro in 1992. Brundtland report also laid foundations for the three pillars of sustainable development: social, economic and environment. The report recommends urgent action on 8 key issues: Population and human resources Industry Food security Species and ecosystem Urbanisation SUSTAINABLE DEVELOPMENT 2 Managing the commons Energy Conflict and environmental degradation So why is was this report so successful? Besides the points already explained before (so putting together the economical and social goal with the environmental one and having an optimistic outlook for solution, especially technological one), also important is the global focus about satisfying the needs of the world’s poor and the reduction in the wants of the world’s rich. It’s still very anthropocentric, nature should be preserved for the humans not for the environment. “To meet the needs of the present without compromising the ability of future generations to meet their own needs” (For reference box 2.4-2.5 Capitolo 2) What are the different views on sustainable development (weaker approach, stronger approach, other approach)? The main point of sustainable development is to integrate environmental, economical and social consideration into a new development paradigm, promoting non achieving sustainable development, as it’s a ongoing process. The ladder of sustainable development organises many different interpretations and relate them to specific policy imperatives (anthropocentric and ecological approach, it’s not wise to make a too sharp distinction with the two approaches as they are interrelated one with another). Pollution control: nature seen only in relation to its use to human beings —> nature has use-value - exploitation of resources Weak approach: sustainable development becomes a challenge to develop a more environmentally friendly approach to planning and resource management —> substitution of natural capital with human- made capital Strong approach: nature is allowed to set the parameters of economic behaviour so that sd becomes an externally guided development model, based on planetary limits —> maintenance of critical natural capital Ideal approach: green philosophy, sustainable development is views as managerial interface with nature and her natural cycles —> nature has intrinsic value Weak vs strong: the key point is the substitutability Weak approach postulates the full substitutability of natural capital; only thing that matters is the total value of the aggregate stock of capital, which should be at least maintained or ideally increased for the sake of future generations Strong approach demonstrates that this substitutability should be severely seriously limited due to the existence of critical elements that natural capital provides for human existence and well-being (=critical natural capital). IMPORTANT: natural capital is a set of complex systems consisting of evolving biotic and abiotic elements that interact in ways that determine the ecosystem's capacity to provide human society directly and/or indirectly with a wide array of functions and services Type of development Ideal model: simplicity; meeting needs not wants; environmental limits guide development (local self- sufficiency) Strong SD: also changes in consumption (demand- side): shift to non-material aspects; necessary development in Third World Weak SD: decoupling; reuse, recycling, repair; product life cycling management (supply-side) Pollution control: exponential market-led growth (globalisation, global market) SUSTAINABLE DEVELOPMENT 3 What are the SDGs (content and development process)? In 2000 the UN adopted the Millennium Development Goals (MDGs) with a deadline by 2015. SDGs are universal goals, targets and indicators that UN member states should adapt to by 2030, from human well-being to economic prosperity and environmental protection. They were born after Rio+20 (2012 duh), to develop global sustainable development. Contrary to the MDGs, the SDGs were formulated in a broad participatory process (11 thematic and 83 national consultations). This whole process culminated with the adoption of the 2030 Agenda for sustainable development, with 17 SDGs and 169 target in September 2015, into force in January 2016. While the MDGs where melted only for poor countries, the SDGs are a global agenda, it is intended as holistic framework (ending poverty has to go side to side with health and education improvement). They are not legally binding, but governments are expected to establish national and regional plans. Holistic framework is a new way off thinking, basically every goal is somehow connected and depend on each other (es. climate change will negatively affect other SDGs as hunger, poverty ecc). Evaluate the current policies in your own country; are they mostly guided by the conventional model of development or by sustainable development? To answer this question, I read the political program of the Brothers of Italy, the right-wing party currently in power. I was quite surprised by how unsustainable and environmentally unfriendly their underlying ideology is. They dismiss the concept of strong sustainability as a left-wing ideological bias and clearly state their intention to prioritise economic development over environmental sustainability. Furthermore, they advocate for unsustainable practices in various sectors. For instance, in agriculture, they express the need to oppose the production and sale of synthetic meat and to protect agricultural workers from environmental regulations. The document states: 'the eco-fanaticism of the Green Deal, drafted by the European left, condemns us to a miserable decline. It definitely follows a conventional model of development giving priority to economic growth, focusing on the individual or local dimension, seeing only the extrinsic value of nature and its resources and ignoring planet's capacity. What is your view on the Brundtland report? First of all, the Brundtland Report has been published in 1987 by the World Commission on Environment and Development. The Brundtland Report puts “development” a traditional economic and social goal and SUSTAINABLE DEVELOPMENT 4 “Sustainability” an ecological goal, together to devise a new development model, the Sustainable Development. It’s a model of societal change that, in addition to the traditional development objectives, has the objective of maintaining ecological Sustainability. This differs from the previous IUCN approach which linked the environment to conservation, not to development. In addition, the Brundtland Report, made it explicit that social and economic factors, especially processes operating at the international level, such as trade, influence whether or not the interactions between society and nature are sustainable. The Brundtland concept of sustainable development is global in its focus and makes the link between the fulfilment of the needs of the world's poor and the reduction in the wants of the world's rich. What key issues/concepts do you think the Brundtland report really added to the policy discussions about our future society/planet? The Brundtland definition of sustainable development is “development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Brundtland report is also important because formulates the societal goals, came in an important environmental delicate moment and supported developing countries in their pursuit of their goals of economic and social improvements. Review Box 2.4 in Chapter 2 from the textbook by Baker: which of these issues do you think are still relevant today and how do these issues compare to the SDGs? In the box 2.4 are enounced the Brundtland development paradigm, there are some these that could be relevant nowadays. In my opinion all of these issues remain relevant today as they are interconnected and influence each other. Addressing them requires integrated approaches that balance economic, environmental, and social dimensions of sustainability. Continued focus on these areas is essential for achieving long-term sustainable development and addressing the challenges of the 21st century. In relationship with SDG’s concepts I think that the 17 SDG’S point express the same meaning of Brundtland Report more specifically. In fact we can divide the SDG’S objectives in different macro-groups and they’re the 8 Issues argues by the Brundtland Report. Weak or strong approach? Brundtland report and paper by Griggs et al Sustainable development is a very sensitive topic that has been debated over the years with different approaches and thoughts, as well as different theories such as pollution control and the ideal approach, although a sharper division can be observed in the weak and strong approach of sustainability. The Brundtland report, created in 1987, was revolutionary in many ways, as it linked for the first time the goal and the growth of the economy and the society, to an environmental growth, creating a connection that would always be considered from there on. The importance that this report places on future generations and their right in using natural resources, combined with the positive outlook towards technology can clearly define that this report aligns more with a weak approach towards sustainable development, as it recognises the importance of natural capital, but leaves room for the idea that economic and social development can compensate for the loss of natural resources, as long as it is managed in a way that does not compromise the needs of future generations. According to the Brundtland report, therefore, a substitution of natural capital with human-made capital is possible. Another point that demonstrates that this report aligns more with a weaker sustainability vision is, as previously mentioned, an optimistic expectation towards technology. On the other hand, regarding Griggs' paper “Sustainable development goals for people and planet,” it can be observed that it pays attention to the environment in a more similar way to strong sustainable development, as it accentuates the importance of setting planetary limits and respecting them, linking them with the SDGs, and finally emphasising the importance of natural resources, suggesting that a cost should be placed on their use, as happens with carbon pricing. All these points are in fact shared by strong sustainable development , which claims that natural resources are not replaceable by human-made resources. It’s mostly a conceptual difference Differences: natural resources - limits to development - social change - needs based approach - it’s not black and white it’s a spectrum SUSTAINABLE DEVELOPMENT 5 What are the SDGs (content AND development process)? I agree with the criticism that the term ‘sustainable development’ is vague. The vagueness starts, in the first place, from the multitude of definitions and interpretations surrounding the concept itself. Over time, numerous associated terms have been coined such as ‘sustainable cities’, ‘sustainable architecture’, ‘sustainable culture’ and ‘sustainable growth’. Each of these terms apply the concept of sustainability to different sectors, but risk generating ambiguity and confusion due to the lack of a solid definition. Moreover, the concept of ‘sustainable development’ is based on three fundamental pillars: social, economic and ecological. This tripartition makes the concept extremely complex and dynamic, as it requires a balance between dimensions. SUSTAINABLE DEVELOPMENT 6 Even the definition of sustainable development provided by the Brundtland Commission in 1987, according to which ‘sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs’, leaves room for multiple interpretations. This vagueness of the concept of sustainable development is both a strength, as it allows its application in different contexts, and a weakness, as it risks becoming a generic concept with no clear operational direction. I believe that the Sustainable Development Goals (SDGs) provide a more structured and clearer framework for the operationalization of sustainable development. Their main purpose is to serve as a blueprint, a strategic plan, to promote peace and prosperity for people and the planet. With their 17 goals and 169 associated targets, the SDGs address a wide range of issues critical to global well- being. They cover topics such as poverty, health, education, through to reducing inequality, sustainable economic growth, climate action and the protection of ecosystems. This broad thematic coverage makes the SDGs framework particularly powerful, as it recognizes the interconnection between different dimensions of development and the need to address them in an integrated manner. Moreover, the structure of the SDGs, with its specific goals and measurable targets, facilitates the practical implementation of sustainable development policies. TASK 2 What was the main message of: · Leopold in a Sand County Almanac? In “A Sand County Almanac”, Leopold’s central theme is the idea of a “land ethic”, which underscores the deep connection between humans and the natural world, land is the where human and nature interact. He calls for a transformation in the way people perceive and interact with nature, advocating for ethical responsibilities that extend beyond human relationships to include the land, water, wildlife, and ecosystems. Leopold insists that humans must recognise themselves as members of a broader ecological community, taking on the role of responsible caretakers rather than dominators. This land ethic encourages a harmonious relationship with nature, emphasising the importance of respect, sustainability, and conservation. He also critiques society's violence towards nature driven by a conquest ethic. He hopes that humans will adopt the "land ethic," shifting from being conquerors of the land-community to becoming ordinary members and citizens within it. Leopold further expresses deep concern that our educational system is leading us away from a deep awareness and connection with the land. SUSTAINABLE DEVELOPMENT 7 · Rachel Carson in Silent Spring? In “Silent Spring”, Rachel Carson’s main message is a powerful warning about the harmful effects of pesticides, on the environment, human health, and wildlife. She highlights how the ignorant use of chemical pesticides disrupts ecosystems, contaminates the soil and water, and leads to the death of birds, fish, and other wildlife, creating a "silent spring" where nature’s voices are absent. Carson advocates for a more responsible and sustainable approach to pest control, urging society to recognise the interconnection of all living things and the long-term risks posed by chemical pollution. She calls for stricter regulations, increased environmental awareness, and a shift toward non-chemical, biological methods of pest management. These methods include introducing natural predators to control pest or weed growth, using naturally occurring attractants to trap insects, reducing insect populations by introducing sterilised insects, or using ultrasound to eliminate pests. Many of these practices have since been embraced by the organic farming movement. She also questioned the philosophical belief that man was destined to exert control over nature and she accused the government of uncritically accepting the chemical industry’s claims of safety, this lead to the creation of the Environment Protection Agency in 1970 and DDT was banned in 1972. · Lovelock in his work on the Gaia-hypothesis? James Lovelock's central message in the "Gaia Hypothesis" is that Earth operates as a self-regulating, complex system in which living organisms and their non-living surroundings interact to maintain the conditions essential for life. The hypothesis proposes that Earth functions much like a living organism, with its biological, chemical, and physical components collaborating to sustain a stable environment. Lovelock argues that life on Earth actively influences the atmosphere, oceans, and climate to achieve a state of balance or homeostasis over time. This regulation includes managing factors like temperature, atmospheric composition, and ocean salinity to preserve life-friendly conditions. The Gaia Hypothesis challenges conventional views of nature as passive, emphasising the dynamic role of living organisms in shaping and stabilising the environment. It also underscores the significance of understanding the interconnection of all life forms and Earth's systems, which is crucial for promoting environmental responsibility and sustainability. For Lovelock the system is dynamic, self-regulation through feedback processes, this system reacts to external influences and acts as a living organism. Daisy world model is an hypothetical planet orbiting a sun SUSTAINABLE DEVELOPMENT 8 that increases in intensity reducing the environment to a single variable, temperature, and the biota to a single species, daises, self-regulating of temperature via albedo and feedback Black daisies: low albedo —> absorb solar energy, warming the planet White daisies: high albedo —> reflecting solar energy, cooling the planet We can collegate it at a post-normal science Very important for all three is INERTIA many consequences depend on exposure over time, effects are delayed. What are ecosystem services and what kind of ecosystem services can be identified? The main report about ecosystem services is the Millennium Ecosystem Assessment (2005), asses that consequences of ecosystems changes for human-being. It identifies options that can better achieve core human development and sustainability goals, all countries and communities are grappling with the challenge of meeting growing demand of food, clean water, health and employment, bring knowledge about interdependencies between ecosystems, human development and sustainability. It’s better to understand the trade-offs in decisions and align the response options with the level of governance where they can be most effective. Ecosystem is a dynamic complex of plant, animal and microorganism communities and the nonliving environment interacting as a functional unit, where humans are an integral part of it, ecosystem provide a variety of benefits to humans (ecosystem services). Biodiversity is the variability among living organism from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part. “Ecosystem services are the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfil human life. They maintain biodiversity and the production of ecosystem goods, such as (sea)food, forage, timber, biomass fuel, natural fibre, and many pharmaceuticals, industrial products and their precursors.” · Provisioning services are the products people obtain from ecosystems · Regulating services are the benefits people obtain from the regulation of ecosystem processes. · Cultural services are the nonmaterial benefits people obtain from ecosystems. · Supporting services are those that are necessary for the production of all other ecosystem services SUSTAINABLE DEVELOPMENT 9 SUSTAINABLE DEVELOPMENT 10 What is meant with the Anthropocene? The Anthropocene is a proposed geological epoch that highlights the significant impact humans have had on Earth's ecosystems, climate, and geology. This term suggests that human activities, especially since the Industrial Revolution, have altered the Earth so profoundly that they may warrant recognition as a new epoch, distinct from the Holocene, which began around 11,700 years ago after the last Ice Age. Key features of the Anthropocene include: Environmental Changes: Widespread deforestation, soil degradation, and urbanisation. Climate Change: The rise in global temperatures due to the burning of fossil fuels and increased greenhouse gas emissions. Biodiversity Loss: The extinction of species at accelerated rates due to habitat destruction, pollution, and other human activities. Pollution: The introduction of plastic waste, chemicals, and radioactive materials into the environment. Geological Evidence: Layers of human-created materials like concrete, plastics, and radioactive isotopes are becoming embedded in the Earth’s strata. While the Anthropocene is not yet officially recognised as a formal epoch by the International Commission on Stratigraphy, it is widely used in scientific, cultural, and environmental discussions to highlight the transformative role humans now play in shaping the planet's future. Why do you think that that Leopold’s book ‘A Sand County Almanac’ can be considered a milestone in our changing perception on the environment? Leopold’s “A Sand County Almanac” it is one of the most respected books about the environment ever published. It can be considered a milestone in our changing perception of the environment because it fundamentally reshaped the way we view our relationship with nature. Leopold has come to be regarded by many as the most influential conservation thinker of the 20th century. The book was written while there was already a consumeristic model. Several key aspects make it a transformative work: Leopold's idea of the “land ethic”: It changed the way we think about our responsibility towards nature, expanding it to include all living things—plants, animals, soil, and water. This new way of thinking encouraged people to respect nature more, instead of seeing land as just a resource to use for our own benefit. SUSTAINABLE DEVELOPMENT 11 1. Land is a system of interdependent parts, best regarded as a community, not a commodity; 2. Humanity is a member, not the master, of the land community; 3. We can understand and appreciate our place in nature only by understanding nature as a whole; and 4. Our duty is to preserve the integrity, stability and beauty of the biotic community. Idea of “Land Pyramid”: He shows how everything in nature is connected, helping people understand that what we do affects the environment in big ways. It promoted a view of nature as a web of interconnected parts, highlighting how changes in one part can impact the whole system. Call for Conservation: At a time when conservation largely focused on managing resources for human benefit, Leopold argued for a more ethical approach that prioritised sustainability and preservation for nature’s own sake. Violence: 'The less violent the man-made changes, the greater probability of successful readjustment in the pyramid. Violence, in turn, varies with human population density; a dense population requires more violent conversion.' His solution to this violence is to adopt a land ethic which changes the role of homo sapiens from conqueror of the land-community to plain member and citizen of it. Call for Education: Leopold further expresses deep concern that our educational system is leading us away from a deep awareness and connection with the land Through these ideas, Leopold’s work contributed to a broader cultural shift that moved society from a dominion-driven perspective of the environment to one of interdependence, ethics, and long-term sustainability, making it a landmark in environmental thought. It is a milestone yes and no. We are losing nature, he critics the new generation. Land health connected with the resilience of ecosystem Why do you think that Rachel Carson’s book ‘Silent Spring’ can be considered a milestone in our changing perception on the environment? I’m sure that we can consider Rachel Carson’s book “Silent Spring” as a milestone in our changing perception on the environment because she was the first one to warns society about the harmful effects of chemicals, especially pesticides, on the environment and human health. Carson focused especially on DDT, a very dangerous pesticide, highlighting example such as a clear lake in California, where DDT moved through food chain, from the insects to birds. The writer argues that pesticides do more harm than good, killing every kind of insects also the beneficial insects. Notice that Carson wasn’t against pesticide use, she advocates for careful, informed application and promotes natural pest control methods, such introducing predators, using sterilised populations, and employing natural attractants. In my personal opinion this is a very modern view. She always ignored the critiques, before her other people already declared the danger of DDT, but she addressed them in a good way, she made explicit why everybody should care about this topic. Yes it was a milestone, since she changed not only the vision but also the regulation about DDTs, but mainly in the US. Example where DDT in California from plants to insects, to arrive at birds → food chain Why do you think that Lovelock’s work on the Gaia hypothesis can be considered a milestone in our changing perception on the environment? Lovelock's work on Gaia generates a view in which life happens on a planetary scale and each element, characteristic, organism is a part of a geo-physiological system. This ideology (supported by the concept of homeostasis - the capacity of the Earth to control its chemical composition) leads to recognise the intrinsic value of nature, that is to say that nature has value itself, regardless its impact on human life. I believe this theory transcends the simple definition of nature's intrinsic value. Indeed, one could affirm the latter while simultaneously acknowledging humanity's external position relative to the natural world. However, Lovelock clearly states that all organisms are part of the geo-physiological system and contribute to its life ("Would we mine our livers for nutrients? Would we raze our hair and plant our scalps with tomatoes?") This leads to a systemic view and to an alteration of the Darwinian model of evolution. SUSTAINABLE DEVELOPMENT 12 Daisy world is a response to the critique, he invents a planet Daisy, where there are the black and the one daisies, they can survive only with sun, there is a continue competitiveness between white and dark daisies. Light daisies can germinate only when it’s hot, dark daisies only when temperatures are cooler, but temperature is not linear, so white one die than dark one too and then they born again. Rabbits eat, but then rabbits die (why?), and daisies can grow again. Grey daisies have a function, they regulate the temperature. That’s his idea of system. When we cross the tipping points the equilibrium shifts and destabilised, humans changed the system but we all depend from nature Why do you think that the concept of ecosystem services (as discussed in the Millennium Ecosystem Assessment) can be considered a milestone in our changing perception on the environment? The concept of ecosystem services represents an important change in how the environment is understood and valued, being revolutionary in many ways, as it connects the health of ecosystems with human well-being in four major categories, it assigns an economic value to the natural processes creating a common language between ecologist and economist, and encourages an holistic approach to sustainability, by using a system- thinking approach. Furthermore, it also leads to more inclusive decision-making processes, taking into account different stakeholders’ opinions and ideas and especially focusing on long-term sustainability by making decisions for the sake of the future and not only regarding the problems of the present. I believe that ecosystem services provide an approach for more sustainable decision-making, as they help the decision-making process in many ways, such as taking into consideration the importance of the natural capital, incentivising the conservation of natural habitats, encouraging the cooperation of different stakeholders including the trade-offs of every decision, coming from different opinions and interests. But we can also say that is not a milestone, since we haven’t reached yet that vision of nature, especially the importance of natural capital. In conclusion, the Millennium Ecosystem Assessment has marked a turning point in how we value and manage the environment, leading to more sustainable decision-making. There are tho some pro and cons about them, such as Critiques of the Ecosystem Services Concept: Commodification of Nature Simplification and reductionism Equity and justice issue Policy instrument limitations Counter arguments in defence of services concept: Recognition of human-nature relationships A tool for policy and decision-making Flexibility and adaptability Potential for inclusive approaches There are two moral ways to look at ecosystem services: Utilitarian perspective: exploitation ecosystem services Non utilitarian perspective We have to give out some habits to gain the type of sustainability that we want to reach. The one thing that is missing in ecosystem services can be that there is not a calculation for the future, also having disadvantage from the ecosystem (e.g. floods, temperature rising). Human-nature in an interconnected way and system thinking (make a bigger answer about this two fundamental points, be cause could be a question in the exam, keywords: antropocentric view - trade off - we depend on nature - global and local scale). Look at the table in the previous question about ES SUSTAINABLE DEVELOPMENT 13 Why Anthropocene can be considered a milestone in our changing perception on the environment? The Anthropocene highlights that humans are now having an impact on the planet. This is a big change in the way we think. Before, we thought only natural events could shape the Earth on a geological scale. Now, we realise that human activities like industrialisation, pollution, and deforestation are permanently altering the Earth’s systems. We humans saw ourselves separate from nature, controlling and using it for resources. The Anthropocene challenges this by showing that humans and nature are interconnected. We’re no longer just influencing nature, but are part of the environmental systems we’re affecting. This shift in thinking encourages us to see ourselves as responsible of the Earth, rather than “ruling” over it. The Anthropocene makes it clear that many of the changes we’ve made to the environment are long-lasting or even permanent. For example, we can’t easily reverse the loss of biodiversity or stop the long-term effects of climate change. This highlights the importance of thinking about the future, since our actions today will have major consequences for generations - ethical to come. In the past, environmental issues were often seen as local problems, like air pollution in a city or deforestation in a specific area. The Anthropocene shows us that environmental changes are global—what happens in one part of the world, like CO₂ emissions, can affect the entire planet. This makes us think of the environment as a global system and pushes us to take responsibility for our actions on a worldwide scale. Are we there already or are we getting there? TASK 3 What are biogeochemical cycles (incl. reservoirs, fluxes, residential time, sink, source)? Biogeochemical cycles are the recycling processes where the Earth, being an open system with regard to energy, but a closed one with regard to matter, so it’s fixed, has to be constantly recycled to make it available for the growth of living organism. At the largest scale only four global reservoirs are distinguished: water, air, land and rocks Bio: active role of living organisms Geo: role of geological processes in the cycle Chemical: recycled elements change in form and compound The key components of biogeochemical cycles are: Reservoirs (or pools): place of storage → water, air, land and rocks Fluxes: flows from one place of storage to the other Sink: when the influx of a element into a reservoir is larger than the out flux SUSTAINABLE DEVELOPMENT 14 Source: when the influx is smaller than the out flux, the reservoir is being impoverished Residence time: when both size of a reservoir and the in- and out flux are known, it equals reservoir divided by flux and represent the time an element on average resides in a given reservoir before moving on to the next one. The shorter the residence time per reservoir, the faster an element is cycled, knowing the residence times helps better understand problems caused by a disturbance of the cycle. What is photosynthesis and what is its role in the carbon cycle? Plant absorb carbon dioxide from the atmosphere and use it to produce more plant material. Photosynthesis is the reaction where carbon dioxide, water and sunlight, combine to produce CH2O and O2. Because CH2O is a combination of carbon and water, molecules made up of this unit are generally referred to as carbohydrates. This is the main source for the oxygen in our atmosphere, which we breath to survive. At the same time humans, animals and bacteria consume plant material in order to produce energy. SUSTAINABLE DEVELOPMENT 15 What are the main reservoirs and fluxes in the natural phosphorus cycle? Unlike carbon and nitrogen, phosphorus has only a tiny gaseous component and no biotic pathway that brings new phosphorus into ecosystems. Most phosphorus historically came from organic sources and is an essential nutrient often in short supply. The largest reservoir are marine and freshwater sediments and terrestrial soils account for most phosphorus on Earth’s surface. Phosphorus cycle is a sedimentary cycle, so is slower compared to the “gaseous” carbon and nitrogen cycles. Most of this store is not directly accessible to the biota but occurs primarly in insoluble forms such as calcium or iron phosphate. Most organic phosphorus is in plant or microbial mass. Recycling of that organic matter when it dies is the major source of phosphorus that is directly avaiable to organisms. The physical transfer of phosphorus is mainly through wind erosion and runoff of particulates in rivers and streams to the ocean. The major flux in the global phosphorus cycle is via hydrologic transport from land to the ocean. In the ocean, some of those phosphorus containing particulates are recycled by marine biota and the rest is buried in sediments. Because there is no atmospheric link from the ocean to land, the flow is one- way on short time scale. On geological time scales (hundreds of millions of years), phosphorus containing sedimentary rocks are exposed and wealthered, resupplying phosphorus to the biosphere. SUSTAINABLE DEVELOPMENT 16 What are the main reservoirs and fluxes in the natural nitrogen cycle? The majority of nitrogen reservoir is the atmosphere (78% N2), with small parts in the ocean, rocks and sediments. It’s biologically unavailable (very stable molecule, most organism cannot use this N2 directly), is transformed to biologically avaiable forms via nitrogen fixation by bacteria in soils and aquatic systems, or living in association with plants. Nitrogen fixation is needed: fixation refers to the conversion of atmospheric N to a biologically available form, required for the biosynthesis of all nitrogen-containing organic compounds, such as amino acids Biological nitrogen fixation (bacteria) and non-biological nitrogen fixation (lighting) Free-living bacteria in soils or aquatic systems, or bacteria living in association with plants Fixed nitrogen=inorganic nitrogen compounds usable by plants Role of bacteria To make nitrogen available for plants/organism: N2-> nitrates Step 1: nitrogen fixating bacteria (nitrogen fixation): atmospheric N2 is converted into ammonia Step 2: nitrifying bacteria (nitrification): biological oxidation of ammonia to nitrite followed by the oxidation of the nitrite to nitrate Step 3: assimilation; nitrate is assimilated by plants via their roots and converted into organic nitrogenous compounds. Animals derive their nitrogen requirement from the plant proteins To return. The nitrogen from organic forms to the atmosphere as N2 Step 1: decomposition of plants, animals, metabolic waste/excretion (ammonification): converts organic forms of nitrogen into inorganic form Step 2: denitrifying bacteria (denitrifying), nitrate is converted into N2 Some nitrogen-fixing bacteria are free-living, while others are symbiotic nitrogen-fixers → require a close association with a host to carry out the process. These hosts are called nitrogen-fixating plants. Explaining the image: Nitrogen fixation: Human activities increase nitrogen inputs through fertilizer production, planting of nitrogen- fixing crops, and combustion of fossil fuels (next page) SUSTAINABLE DEVELOPMENT 17 Human activities also increase emissions of nitrogen trace gases (NOX, N20, NH3) through fossil fuel emissions, land emissions (agriculture, fire, land-use change), and animal husbandry e.g. Chapin about NO2-> Human activities have nearly doubled N20 flux from Earth to the atmosphere, primarily through agricultural fertilization. Other anthropogenic N20 sources include cattle and feedlots, biomass burning, and various e.g. Chapin about Ammonia (NH3): Animal husbandry, fertilizer addition, and biomass burning are the major cause for increased ammonia transport to the atmosphere. Domestic animals are largest global source of ammonia; agricultural fertilization (ammonia flux from cultivated soils to the atmosphere), biomass burning, and human sewage are other important sources What are the main reservoirs and fluxes in the natural carbon cycle? Carbon has 4 major pools (reservoirs): Atmosphere: mainly CO2, is the smallest but most dynamic pool, turn over time about 5 years, mainly removed through photosynthesis and returned by respiration. Ocean: carbon is present in the ocean through dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and particulate organic carbon (POC), which consists of both live organism and dead material. Most of this carbon (98%) is in inorganic form – bicarbonate (90%), the rest is carbonate. The carbon in marine biota has a turnover time of 3 weeks. The ocean’s surface waters that interact with the atmosphere has a similar quantity of CO2 as the atmosphere. The capacity of the ocean to take up carbon, so the surface exchange rate, depends on wind speed, surface temperature and the CO2 concentrations of surface waters. Surface waters are a small pool that exchanges relatively slowly with deeper ocean layers because the warm, low-salinity surface water is less dense than deeper layers. Carbon that enters surface waters is transported slowly to depth by the biological pump (exchange of orfanic carbon between upper and deep ocean) and the solubility pump (exchange of dissolved carbon between upper and deep ocean). Once carbon reaches the deep waters, it’s stored for hundreds to thousands of years before returning to the surface through upwelling. Most of the ocean carbon (97%) is in the intermediate and deep waters. SUSTAINABLE DEVELOPMENT 18 Land: is the largest biological reservoir of carbon. There is nearly as much as carbon in land as in the atmosphere, with 2-3 more organic carbon in soils than in the atmosphere. Permafrost also contains a large carbon pool that, until recently, turned over very slowly. Land plant carbon has a turnover time of 11 years, compared to 3 weeks in the ocean. Soil carbon turns over on average every 25 years. Photosynthetically fixed carbon turns over in seconds, leaves and roots are replaced in weeks to years and wood is replaced from decades to centuries. Also components of soil organic matter has different turnover times (humus can take thousands of years) Sediments/rocks: it accounts for 99% of Earth’s carbon, both organic and inorganic, including fossil fuels. This pools cycles are extremely slow, with turnover time of millions of years. Factors that are associated with the rock cycle include the movement of continental plates, volcanism, uplift and weathering. Human activities are now a significant component of global carbon cycle, human carbon emissions from combustion of fossil fuels increased 40% from 1990 to 2008, land conversion has a huge impact on the carbon cycle too. These anthropogenic fluxes are about 15% of the carbon cycled by terrestrial or by marine production, making human carbon emissions the 3rd largest biologically controlled flux of carbon to the atmosphere. Changes in Atmospheric CO2: Geochemical processes determine variation in amtosmperic CO2 on geological time scales. These includes the weathering of silicate rocks (consumes CO2), burial of organic carbon in sediments and volcanism (releases CO2). Biological processes influence geochemical cycling in many ways, e.g. increasing weathering rates, but in a slow rate compared to human action consequences. Some examples are the concentrations of CO2 related to the glacial-interglacial cycles (CO2 declined during glacial periods and increased during interglacial periods). Overall the concentration of CO2 has always been relatively stable, until the entering of Anthropocene. Marine sinks for CO2: Ocean removes CO2 from the atmosphere through dissolution in seawater and photosynthesis by marine organisms, the dissolution produces acidity, this results in 30% increase in ocean acidity and has two important consequences: It tends to dissolve the carbonate shells of marine invertebrates and altering the functioning of marine ecosystems It reduces the rate at which CO2 dissolves in the ocean, making the ocean a weaker sink for CO2, resulting in more CO2 in the atmosphere Terrestrial sinks for CO2: Land-use change, CO2, fertilization, nitrogen deposition and various climate effects contribute to the terrestrial sink for CO2. Climate change affect carbon storage through their effects on carbon inputs and outputs, plant respiration acclimatizes to temperature, so ecosystems respiration increases less in response to warming than might be expected from short-term measurements. As for the ocean, also the strength of terrestrial sinks is weaking, suggesting that the various sink mechanism are beginning to saturate and may remove less CO2 from the atmosphere, the only solution is reducing anthropogenic emissions. Fluxes (how carbon moves between the atmosphere, ocean, land biosphere, and rocks on the Earth?) · Atmosphere-land biosphere exchange: photosynthesis and respiration · Atmosphere-ocean carbon exchange: carbon dissolution, photosynthesis and respiration (between atmosphere and mixed layer), biological and solubility pump (between mixed layer and deep ocean) · Atmosphere-rock exchange: volcanic eruptions and weathering → natural carbon sequestration Can you explain the formation of acid rain in the Carbon cycle? CO2 (carbon dioxide) combines with water as raindrops fall through the atmosphere, later this acid dissolves rocks (from atmosphere to litosphere). Emissions of CO2 were distributed between 3 Earth system components: 23% taken up by the ocean 31% stored by vegetation in terrestrial ecosystems SUSTAINABLE DEVELOPMENT 19 46% accumulated in the atmosphere Explaning the image: The ocean takes up part of the additional atmospheric carbon via dissolution in the seawater and via photosynthesis by marine organisms. Hence, 24% of the flow from the atmosphere into the ocean is now human-made (see figure for percentage). This subsequently also affects the flux from the ocean into the atmosphere, which is 21% human made (see figure for percentage) Figure: Comparing the amount of carbon moving into the ocean from the atmosphere (92 Pt per year) and the amount of carbon moving carbon the other way around (91Pt per year), -> the ocean is a carbon sink. Surface water contains 900Pg carbon; 2% human contribution Land sink in this image is 100% human made Enhanced photosynthesis: The land takes up part of the additional atmospheric carbon via enhanced photosynthesis. CO2 fertilization: higher carbon dioxide levels (due to human activities) stimulate plant growth. However, this CO2 fertilization effect is limited due to the limited availability of other important nutrients needed for plant growth (e.g. nitrogen, phosphor) ‘Nitrogen deposition/additions’: Humans have added fertilizers to stimulate plant growth; this also stimulates the uptake of carbon by plants. Atmospheric deposition of nitrogen due to burning fossil fuels can also stimulate plant growth (nitrogen is a key nutrient for plant growth. Land use change that results in carbon uptake bio terrestrial biosphere: Forest regrowth abandoned agricultural land has enhance carbon storage (In Europe and north America) Suppression of wild fires (mid-lattitudes) reduces fire-emissions and allows woody plant to encroach into grassland (which enhance carbon storage). What kind of ecosystem services are the biogeochemical cycles? Biogeochemical cycles provide supporting ecosystem services, as they involve essential nutrients as carbon, nitrogen, phosphorus and water through the Earth’s ecosystem. They are fundamental for the nutrient cycling (regulating the presence of nutrients in soil, water and air enabling plants and all the organism to SUSTAINABLE DEVELOPMENT 20 grow), soil formation, through processes like decomposition and primary production, supporting photosynthesis. E.g. of supporting services in biogeochemical cycles: photosynthesis, nutrient cycling, soil formation. How have humans altered the carbon cycle and what are the consequences of the disturbance. Much of the increased concentration of CO2 will remain in the atmosphere for hundreds to thousands of years. If allanthropogenic emission ceased today, about 50% would be absorbed by lands and ocean in 30 years, about 30% of it would remain in the atmosphere for several centuries and the remining 20% for thousand of years. CO2 concentrations will disappear slowly from the atmosphere (hundreds to thousands of years) due to: o The weakening efficiency of land and ocean sinks o The slow equilibration of the deep ocean with the surface ocean and atmosphere o Stabilising feedbacks that limit changes in carbon storage within ecosystems o The slow weathering of silicate rocks, which serve as the largest long-term terrestrial CO2 sink These processes contribute to continued global warming Human activities are also responsible for increasing methane concentrations in the atmosphere. Two main factors that alterate it Fossil fuels combustion, burning them it releases carbon dioxide and this can’t be taken away. Land also like agriculture and deforestation, because burning them CO2 goes from biosphere to atmosphere and we don’t have any more trees that absorb CO2 Consequences: Weakening of the sink: CO2 being absorbed by ocean water, that became saturated (concentrate on ocean acidification, leads to the release of CO2 in the atmosphere evaporating) that’s from where acid rain come from. Ocean acidification leads to loss of biodiversity. SUSTAINABLE DEVELOPMENT 21 How have humans altered the nitrogen cycle and what are the consequences of the disturbance? Most of the nitrogen important to biogeochemistry is found in the atmosphere, with smaller amounts in the ocean, rocks, and sediments. Nitrogen becomes biologically available through nitrogen fixation, a process carried out by bacteria in soils and aquatic systems or in association with plants. Historically, the amount of nitrogen entering the biosphere through fixation was roughly balanced by its return to unavailable forms through processes like denitrification and burial in sediments. During glacial periods, the amount of nitrogen in the ocean decreased, while during interglacial periods, denitrification outpaced nitrogen fixation. Denitrification is the process that converts nitrate to nitrogen gas, thus removing bioavailable nitrogen and returning it to the atmosphere. Due to human-made nitrogen fixation, there is also an increase in denitrification. Human activities, particularly those related to agriculture, have drastically altered this balance. Agriculture is the primary source of increased ammonia emissions, which contribute to air pollution and the formation of aerosols. Ammonia also acts as the main acid-neutralizing agent in the atmosphere, raising the pH of rainfall, cloud water, and aerosols. About 60% of global nitrogen flux is returned to Earth through precipitation. SUSTAINABLE DEVELOPMENT 22 Overall, human activities have increased nitrogen flux to the atmosphere by six to seven times, mainly through fossil fuel combustion. The deposition of this nitrogen affects various ecosystem processes. After long-term nitrogen inputs, ecosystems may become nitrogen-saturated, where nitrogen supply exceeds the needs of plants and microbes. In these cases, nitrogen losses to streams, groundwater, and the atmosphere increase, eventually matching nitrogen inputs. Additionally, nutrient imbalances can shift species dominance, reducing ecosystem biodiversity. Excess nitrogen can also transfer from terrestrial ecosystems to aquatic ones, leading to high concentrations in surface and groundwater. Exchange biosphere - atmosphere and ocean The production and application of fertilisers while burning fossil fuels nitrogen was also realised - legume crops (legume plants have a lot of bacteria, that they are the one needed, called nodules, when cows eat a lot of legume crops), fossil fuels and fertilisers. Concentrate on how happened and which are the consequences! They are very important indicators of air pollution, factories are the main. How have humans altered the phosphorous cycle and what are the consequences of the disturbance? Human activities have significantly altered phosphorus cycling, mainly through mining phosphorus-rich deposits, which speeds up the natural release of phosphorus from rocks. Agriculture, particularly the production of phosphorus fertilisers since the mid-1800s and its increase after the Green Revolution, has also SUSTAINABLE DEVELOPMENT 23 accelerated the loss of phosphorus from ecosystems. This has increased the global movement of phosphorus, leading to potential negative effects on aquatic ecosystems and society. The phosphors mines are mainly in Morocco, it’s linked to the food crises in the world, because it is an essential nutrient for plant growth and agricultural productivity. Phosphorus is a core component of fertilizers, particularly in the form of phosphate. Modern agriculture relies heavily on chemical fertilizers to increase crop yields and meet the demands of growing populations. Without phosphorus, crops cannot efficiently convert sunlight into energy through photosynthesis or develop strong roots and seeds. As such, global food production would be significantly reduced without sufficient phosphorus. Eutrophication of Water Bodies: Excess phosphorus from fertilizer runoff enters rivers, lakes, and oceans, leading to the overgrowth of algae in these water bodies. This process, called eutrophication, can cause harmful algal blooms, which: Deplete oxygen levels in the water (hypoxia), creating dead zones where aquatic life cannot survive. Disrupt aquatic ecosystems, killing fish, and reducing biodiversity. Contaminate water supplies, making it unsafe for human consumption and harming local communities that rely on these water bodies for drinking water or fishing. The absorbency of phosphorus when we apply fertilisers is very low, plants don't absorb phosphorus. Do you think that this definition can be considered a weak or strong approach to sustainable development (YouTube video)? “Sustainability is the capacity of our human society to continue indefinitely within these natural cycles” - can be strong because takes into account a lot of researches from different people. It acknowledges that we have to follow the biogeochemical cycles, the supporting services also cannot be replaced by humans. What is the relationship between turnover time and feedbacks? For example the weakening of the land sink and ocean sink will enhance the turn-over time of carbon in the atmosphere Tip: try to draw the diagrams so we can remember them better, what’s the biggest and the smallest flux and reserves. In the exam they’ll ask how these cycles work TASK 4 What is radiative forcing and why is this concept important for understanding climate change? The radiative forcing is an imposed change on the energy balance on Earth, after the imposition of the specific change in the climate but before the climate has changed in response. In response to a radiative forcing, the Earth’s temperature adjusts so that energy balance is re established. It’s in the change E in - E out. Positive RF: warms the climate SUSTAINABLE DEVELOPMENT 24 Negative RF: cools the climate The main factors that have an influence on RF are: Greenhouse gasses Aerosol and parcels Deforestation, urbanisation ecc Variation in the solar radiation The main way to understand how fast and how the climate it’s changing it’s analysing the variation of RF. Abundance based forcing → based on the abundance of greenhouse gases or aerosols in the atmosphere. Human-caused net positive radiative forcing causes an accumulation of additional energy (heating) in the climate system (mostly absorbed by the oceans), partly reduced by increased energy loss to space in response to surface warming! Hence, the earth has already responded to the positive forcing by increasing the earth’s surface temperature in order to restore the balance between in-coming and outgoing energy again.. The observed average rate of heating of the climate system: 0.50 W/m2 for the period 1971–2006 0.79 W/m2 for the period 2006–2018 Explain the (natural) greenhouse effect. The sun emits shortwave radiation, which passes through the Earth’s atmosphere and it’s absorbed by the surface, this - once warmed - emits long wave radiation back toward space. Certain gasses in the atmosphere (greenhouse gasses - carbon dioxide CO2, methane CH4, water Vapor H2O and nitrous oxide N2O) absorb some of this outgoing radiation, trapping them in the atmosphere, and re-emit them in all directions. This trapped heat warms the lower atmosphere and the Earth’s surface, keeping the planet at an average temperature of about 15°C, without this effect, Earth’s average temperature would be arounfg -18°C. Of course this process is modified by the human influence: burning fossil fuels - deforestation - agricolture - industrial processes. SUSTAINABLE DEVELOPMENT 25 What are climate feedbacks (including examples). Climate feedbacks are interactions in which a perturbation in one climate quantity causes a change in a second, the change leads to an additional change in the first. Negative feedback: initial perturbation is weakened by the changes it causes e.g Negative Feedback: Increased Plant Growth (Carbon Sink) - a negative feedback reduces the initial change. Initial Change: Higher levels of carbon dioxide (CO₂) in the atmosphere lead to global warming. Feedback Mechanism: Higher CO₂ concentrations can stimulate plant growth, as plants use CO₂ for photosynthesis. Consequence: Increased plant growth means that more CO₂ is absorbed from the atmosphere, reducing the overall concentration of this greenhouse gas. Result: The removal of CO₂ from the atmosphere slows down the rate of global warming, counteracting the initial rise in temperature. In this case, the feedback helps stabilize the system by reducing the magnitude of climate change. Positive feedback: initial perturbation is enhanced e.g Melting Arctic Ice - a positive feedback amplifies the original change. Initial Change: Global temperatures increase due to higher levels of greenhouse gases. Feedback Mechanism: Higher temperatures cause Arctic ice to melt. Consequence: Ice is highly reflective (high albedo), so when ice melts, the darker ocean water (which has lower albedo) is exposed. This darker surface absorbs more sunlight, leading to even more warming. Result: More warming causes even more ice to melt, further accelerating the process. This creates a self-reinforcing loop, where melting ice leads to more heat absorption, which leads to more melting, etc. It’s the Earth response to a climate forcing that either reinforces (P) or counteracts (N) the forcing. The main difference between climate feedbacks and radiative forcing is that: Feedbacks are processed that respond to changes in the surface temperature SUSTAINABLE DEVELOPMENT 26 Forcings are unrelated to the surface temperature, they affect the climate but aren’t affected by it Fast feedbacks occur rapidly in response to a change in surface temperature that will play an important role in the evolution of climate change. Slow feedbacks include processes that response slowly to increasing surface temperature, so they require long period of warmth before they significantly alter energy in or out, they are much more uncertain than fast feedbacks. An example of fast feedback is the water vapour feedback (positive and fast), as it cannot freely vary, but it’s determined by the temperature of lower atmosphere and surface. It will rises when the T rises, since it’s the most potent greenhouse gas, it becomes stronger as the surface becomes warmer —> greater warming. An example of slow feedback is the ice albedo feedback (positive and slow), the melting of the land ice sheets (e.g. Greenland - Antartica) will take long time, but it results in a decreasing albedo. It could also have a negative feedback on surface temperature, as the entire Earth will continue to warm, but the atmosphere will warm more slowly because more of the heat will be trapped in the ocean. Another example of slow feedback could be the carbon-cycle feedback relating to changing carbon sink function of the terrestrial biosphere and ocean (e.g. carbon sotred in the ground - permafrost, is released or weakening of the ocean sink) Important examples: Ocean temperature- CO2 feedback: warmer oceans release CO2 in the atmosphere → resulting in more warming Ice albedo feedback: melting ice decreases the albedo → resulting in more warming Water-vapor feedback: warmer atmosphere can hold more water vapor → resulting in more warming What is the IPCC? The IPCC is the intergovernmental panel on climate change, is the United Nations body for assessing the science related to climate change established in 1988. It has 195 states members, in fact it’s important to remember that, yes it’s the UN, but in reality the real members are the countries. SUSTAINABLE DEVELOPMENT 27 What changes in our climate system have already been observed? Warming of the global surface temperature and the ocean, ocean acidification, melting of ice sea and the rising of greenhouse gases and of the sea level are just some of the effects that are being observed in our climate system, mostly caused by humans. We can also look at the loss of biodiversity, the presence of more extreme weather events and the thawing of permafrost. Does the figure about the energy flows (see task description) show a state of radiative balance? What would happen to the energy flows (in the short term and in the longer term) if we would add more greenhouse gasses to the atmosphere in this figure? SUSTAINABLE DEVELOPMENT 28 In the image we can see that there is a slight unbalance between the energy emission, as the Earth is absorbing more energy that is emitting (0.9 W/m2). If we added more greenhouse gases: Short term: it would increase the radiation from the atmosphere to the surface, as GHG trap more outgoing long wave radiation, so it would increased the surface warming and the greenhouse effect would become more strong. Long term: there would be an increased evapotranspiration, more water Vapor in the atmosphere that would enhance the warming, and probably the system would try to create a new equilibrium. What is (the observed) radiative forcing since pre-industrial times and what are the main natural and human drivers? Radiative forcing is an imposed change on the energy balance of the Earth, it’s calculated as the change in energy balance for the planet after the opposition of the specific change in the climate but before the climate has changed in response. The Earth’s temperature adjusts so that the energy balance is reestablished. It’s E in - E out. Between 1750-2019 the radiative forcing was about 2.84W/m2, of which human caused of 2.72 W/m2. The main human factors are: Greenhouse gas emission The increase in carbon diode Increase in methane, nitrous oxide and the halocarbons Ozone in the lower atmosphere has been increasing and resulted in positive radiative forcing (weather becomes warmer) Changes in aerosol concentrations Negative forcing, offsetting half of the positive radiative forcing by carbon dioxide, cooling the temperature. How? Directly by reflecting solar radiation, indirectly through enhancing the could reflectance increasing albedo. Also, due to pollution control the aerosol emissions are expected to decrease (of course this could seem a good effect of aerosol, but it’s only a short term cooling - it remains in the atmosphere for less then CO2 - but there are plenty of negative effects of aerosol: acid rain, air pollution, ice melting (due to black carbon that reduces albedo), environmental and ecological damage such as disruption of natural cycles and ocean acidification. SUSTAINABLE DEVELOPMENT 29 Aerosols are tiny particles or droplets suspended in the atmosphere. They can be naturally occurring (e.g., dust, sea salt, volcanic ash) or result from human activities (e.g., soot, sulfates from burning fossil fuels, industrial emissions). Aerosols affect the climate in two main ways: by scattering or absorbing sunlight and by influencing cloud formation. Depending on their type, aerosols can either cool the climate by reflecting sunlight (e.g., sulfate aerosols) or warm it by absorbing sunlight (e.g., black carbon). Aerosols also modify clouds, potentially increasing their reflectivity and further cooling the climate. How long is the cooling from aeresols felt? A fundamental difference between radiative forcing by aerosols and long-lived greenhouse gases is tied to their atmospheric lifetimes: greenhouse gases have lifetimes of decades to millennia, while the lifetime of tropospheric aerosols is only up to several days. Therefore, climate responds to long-lived greenhouse gases such as CO2 in terms of cumulative emissions, but to aerosols in direct link to its current rate of emissions The change in albedo due to land-use change Deforestation transform forest areas (darker surface) into agricultural area (lighter surface), this increase the land albedo (=more incoming solar radiation is reflected back to space) which has a cooling effects, since the change in land albedo due to deforestation and land-use change is negative forcing. The Earth's albedo changes depending on the reflectivity of different surfaces. A higher albedo (e.g., from ice or clouds) reflects more sunlight, cooling the planet, while a lower albedo (e.g., from oceans or deforested land) absorbs more sunlight, warming the planet. Melting ice is a crucial factor in decreasing albedo, contributing to a feedback loop that accelerates global warming. Albedo refers to the reflectivity of a surface — how much sunlight is reflected versus absorbed. Different surfaces on Earth have different albedos, and changes in these surfaces can alter the planet's climate. For example: High Albedo Surfaces (reflect more sunlight): Snow and Ice: Fresh snow and ice have a high albedo, reflecting up to 90% of incoming solar radiation. This has a cooling effect because less heat is absorbed by the Earth's surface. Low Albedo Surfaces (absorb more sunlight): Forests, Oceans, and Dark Surfaces: These surfaces have a lower albedo, meaning they absorb more sunlight, leading to warming. One of the most significant feedback mechanisms related to albedo and climate change is the ice-albedo feedback: As global temperatures rise, ice and snow melt, reducing the overall albedo of the Earth. Less ice means that less sunlight is reflected, and more is absorbed by the darker ocean or land surface underneath the ice. This absorption of more heat further warms the planet, leading to more ice melt in a positive feedback loop. Human activities also change albedo by modifying the Earth’s surface: Deforestation: Cutting down forests for agriculture or development decreases the albedo of the surface (since forests generally absorb more sunlight than croplands or urban areas). However, it can sometimes have a slight cooling effect, depending on the type of land cover that replaces the forest. Urbanization: Cities, with their asphalt, concrete, and buildings, typically have a much lower albedo than natural landscapes. This contributes to the urban heat island effect, where cities are warmer than surrounding rural areas due to increased absorption of solar energy. Agriculture: Agricultural fields can sometimes have a higher albedo than forests, especially if crops or bare soil are present, slightly reflecting more sunlight. Other humans-made forcing: water vapour in the stratosphere (positive radiative forcing) Regarding the natural factors, we can find them responsible for only the 0.12 W/m2 by solar variations and volcanic eruptions. SUSTAINABLE DEVELOPMENT 30 For exam study the natural and human factors Evaluate the IPCC conclusion that it is unequivocal that human influence has warmed the atmosphere, ocean and land. What is the underlying argumentation by the IPCC for this conclusion? Which Figure or Table from the IPCC would you use to illustrate your answer? The natural processes alone cannot explain the strong rate of warming observed, moreover the dominant effect of human activities is visible not only in the warming of global surface temperature, but also in the pattern of warming in the lower atmosphere and cooling in the stratosphere, warming the ocean, melting of the ice sea etc. I would use this table to demonstrate that it’s unequivocal that human influence has warmed the atmosphere, as it shows that the natural causes making the temperature warmer are the littlest part of the increase. The real problem are the consequences of human actions, such as the greenhouse gases, increased for the majority by people. We expect that it will increase in the years, but we can’t predict it. IPCC conclusion humans influence ocean land make sure you have a connection between DIFFERENT graphs study the graphs FAQ really important for exam!! SUSTAINABLE DEVELOPMENT 31 What is equilibrium climate sensitivity and how is it related to climate feedbacks? Discuss some example feedbacks on how they influence climate sensitivity. Climate sensitivity = forcings (initial warming) + feedbacks Forcings cause the initial change in radiative balance. They affect the climate but are themselves unaffected by the climate and they are unrelated to the changes in the Earth’s climate system, they are the initial trigger. Feedbacks are part of the system response to change in radiative balance. They respond to changes in Earth’s climate system (e.g. change in surface temperature). Forcing do not initiate climate change, but forcings do. Some things can be both feedbacks and forcings -> for example CO2 In the past 200 years: increasing atmospheric CO2 due to human activities is a forcing, but during the end of the ices ages, forcing due to change in earth’s orbit, while increasing atmospheric CO2 (released from warming oceans) acted as a reinforcing feedback. Climate sensitivity is the equilibrium change in global surface temperature that occurs in response to a climate forcing, after increasing CO2 levels, there is an initial warming. In addiction we need to counter in the effect of the climate feedbacks. Climate sensitivity is the outcome of the temperature change associated with the initial forcing + the temperature change associated with the feedbacks. The equilibrium climate sensitivity represents the temperature rise after the Earth’s atmosphere and oceans have equilibrated to this new concentration of CO₂, which could take several centuries. ECS is a central concept in understanding how sensitive the Earth's climate is to greenhouse gas emissions. Without feedback processes climate sensitivity is about 1-1.2 °C An example of positive feedback on climate sensitivity would be the one of water vapor: as the atmosphere warms due to increased CO2, it can hold more water vapor, which is a potent GHG. This feedback amplifies the initial warming, more water vapor is added, more the Earth’s temperature increases, which leads to more water vapor in the atmosphere. This is a fast feedback. Another one is the ice albedo (guarda) slow feedback An example of negative feedback on climate sensitivity is cloud feedback, clouds influence the Earth’s energy balance by reflecting sunlight (cooling) and trapping outgoing infrared radiation (warming). The net effect of cloud feedback is uncertain, but some conditions can lead to positive feedback and others (more low clouds) could reduce warming (negative effect). Fast feedback. How do attribution studies differ from radiative forcing studies in research of climate change? Forcing studies do not look at the actual temperature change/climate change. Only assesses how much forcing can be attributed to natural and anthropogenic factors. Attribution studies assess how much of an observed climate change (e.g. temperature change) is attributable to anthropogenic factors. They are interlinked Explain what climate feedbacks are, slow and fast and explain the examples and influence on climate sensitivity for exam!! The table (see task description) illustrating the projected surface temperature up to 2100 (in task description) shows a wide range. Explain which factors contribute to the uncertainty range in these IPCC’s model projections of future climate changes? The table shows the climate response to the emission of GHG, the more it will be emitted, the more the temperature will tend to rise. The numbers (1.9-2.6-8.5) are the projected radiative forcing, the different scenarios depends on the quantity of GHG emitted: SSP1-1.9: very low GHG emission, CO2 emission declining to net zero around or after 2050 SSP1-2.6: low GHG emission, negative levels of CO2 emissions SSP2-4.5: intermediate GHG emissions scenario SUSTAINABLE DEVELOPMENT 32 SSP3-7.0: high GHG emissions scenario SSP5-8.5: very high GHG emissions scenario SSP= Shared Socioeconomic Pathways The factors can be: Scenario uncertainties Global political decisions Technological advancements Socioeconomic changes Differents in feedback mechanism Natural activities → climate variations Climate models Study well this table and which factors contribute to the uncertainty range for exam! Evaluate the IPCC conclusion that global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in carbon dioxide (CO2) and other greenhouse gas emissions occur in the coming decades. Which Figures/Tables from the IPCC (SPM or FAQ) would you use to illustrate your answer? To evaluate the IPCC conclusion that global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in carbon dioxide (CO2) I would start with the FAQ’s Figure 1, that shows “How we know humans are causing climate change?” from 1850-2019, showing that the effects of our influence on the climate are serious and they are getting worse day by day, due to mainly greenhouse gases emissions. Another figure I would use its the SPM.2 explaining that observed warming is driven by emissions from human activities, with greenhouse gas warming partly masked by aerosol cooling. Also the SPM.3 “Climate change is already affecting every inhabited region across the globe, with human influence contributing to many observed changes in weather and climate extremes” is another figure that shows hot extremes, heavy precipitation and agricultural and ecological drought. The figure with the biggest impact tho, is the SPM.4 that shows the future anthropogenic emissions will cause future additional warming, with total warming dominated by past and future CO2 emissions. For exam is it possible to stay below 1.5°C? Study all graphs, FAQ SUSTAINABLE DEVELOPMENT 33 SUSTAINABLE DEVELOPMENT 34 SUSTAINABLE DEVELOPMENT 35 TASK 5 Demand and supply Demand refers to how much of a product or service people want and are willing to buy at different prices. Generally, as the price goes down, people are more willing to buy more of it (demand increases). Supply is how much of a product or service is available for sale by producers at different prices. Usually, as the price goes up, producers are willing to make and sell more of it (supply increases). Benefits → demand curve, if the prices of a good/service increases, the consumer demand for the good will decrease Quantity buyers are willing and able to purchase at a given price Maximum price that buyers are willing to pay for a given unit of the good Demand curve = marginal benefit curve Cost → supply curve, if the price of a good/service increases, the suppliers will supply more Quantity suppliers are willing and able to supply at a given price Minimum price that suppliers are willing to receive for a given unit of the good SUSTAINABLE DEVELOPMENT 36 Supply curve = marginal cost curve Market equilibrium price: interaction between consumers and suppliers, that determine the prices Consumer surplus: net benefits the consumer obtain from buying the good (willingness to pay minus the price paid) Producer surplus: benefits suppliers/producers obtain from selling the good (selling price minus production cost) Total benefit: consumer surplus + producer surplus Equilibrium price: quantity demanded is equal to the quantity supplied Imposing a tax will raise the costs for the producer → shift in supply from S0 to S1. This will increase the equilibrium price to $2.55 and will lower the quantity. Consumer and producer surplus will decrease, but there are tax revenues that partly compensates this. However, we see that imposing the tax in a net welfare loss (dead weight loss) (but perhaps you avoid some externality cost of pollution) SUSTAINABLE DEVELOPMENT 37 What are external costs and benefits? Explain how external costs/benefits can result in market failure. Carefully study the tables/figures in the textbook. External costs and benefits refer to the effects of a transaction or activity that affect third parties who are not directly involved in the exchange. These impacts can be either positive (benefits) or negative (costs) and are not reflected in the market price of the good or service being produced or consumed. External costs (negative externalities) occur when an action by individuals or firms imposes a cost on others who are not directly involved in the transaction. These costs are not born by the producer or consumer but by society at large (e.g. pollution). - esempio: fumo una sigaretta, però produco esternalità negativa per il bambino a fianco a me che si becca il fumo passivo They are added to the producer → supply curve (see problem) External benefits (positive externalities) occur when an action provides benefits to others who are not directly involved in the transaction. These benefits are not compensated by the recipient of the benefit (e.g. vaccination). - esempio: faccio ricerca per un vaccino, facendo ricerca scopro altre cose. We want to maximises the benefits Externalities lead to market failure because the market, left to its own devices, does not allocate resources efficiently. Here’s how: Underproduction of Goods with External Benefits (Positive Externalities): When positive externalities exist, the benefits to society exceed the private benefits that individual consumers experience. Because people only consider their private benefits, they may consume or produce less than what is socially optimal. For example, individuals may under-invest in education or vaccination because they do not take into account the benefits to society as a whole. Result: The market produces less of the good or service than is socially desirable, leading to underconsumption or underproduction of beneficial activities (e.g., too few people get vaccinated). Overproduction of Goods with External Costs (Negative Externalities): In the case of negative externalities, individuals or firms do not bear the full cost of their actions. For example, a factory that pollutes does not fully account for the environmental damage and health costs imposed on others. Since the costs are not internalized, firms may overproduce, and consumers may overconsume these goods. Result: The market produces more of the harmful good or service than is socially optimal, leading to overproduction (e.g., too much pollution or traffic). Private cost: the one payed by the consumer or the producer External cost: cost payed by people other than consumer or producer Social cost: cost everyone has to take into - private+external cost SUSTAINABLE DEVELOPMENT 38 Externalities: cost or benefits that fall on people who are not producers or consumers Optimum balance: private (cost and benefits)=social (cost and benefits) What is the Coase Theorem? The Coase Theorem is a principle in economics that suggests that when there are externalities (either positive or negative), private parties can negotiate a mutually beneficial solution to the problem without the need for government intervention, as long as certain conditions are met. “If property rights are well defined, and no significant transaction costs exist, an efficient allocation of resources will result even with externalities. Explain what is meant with optimal pollution? (tip: study figures in text) Do you agree with this concept? Optimal pollutions is the “right” amount of pollution, given current production costs and technologies, but isn’t the right amount of pollution zero? The economists say that, the only way to achieve zero pollution is to have zero production, if we want to produce, there will also be some pollution. Traditional environmental economic theory suggests that the optimal level of a pollution emission occurs when the marginal damage created by the emissions is equal to the marginal cost of reducing the emissions. Optimum pollution is a paradox? If we include all the external costs we still have some pollution SUSTAINABLE DEVELOPMENT 39 Net social benefit: consumer surplus plus balance surplus minus social loss What level of pollution are we ready to accept? If we have an increase in supply, we have a down shit on social costs so optimal pollution increases Normal supply and demand + shift with social optimum Market equilibrium focuses on individual decision-makers (buyers and sellers) and the point where supply meets demand, without necessarily considering externalities or the broader social welfare. Social optimum takes into account the overall well-being of society, which may require interventions (e.g., taxes, subsidies, regulation) to address issues like externalities, market power, or inequality. The social optimum is a condition in which resources are allocated in the most efficient way possible, benefiting society as a whole. This means that the overall wellbeing of society is maximized. In economic terms, social optimum occurs when the total surplus (the sum of consumer and producer surplus) is at its highest achievable level, and no further changes can make anyone better off without making someone else worse off, a concept known as Pareto efficiency. Achieving social optimum often involves addressing market failures and ensuring that private incentives align with the public interest. What is meant with the internalization of externalities? Internalization of externalities refers to the proc

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