SIO25 Study Guide-2 PDF

Week 1: Climate: Long term average and variability, usually time spans of 30 years Weather: Short-term atmospheric conditions Climate Normals + How are they made?: Climate Normals are 30-year averages for climate variables like temperature and precipitation. They are made by taking the 30 year ave...

Week 1: Climate: Long term average and variability, usually time spans of 30 years Weather: Short-term atmospheric conditions Climate Normals + How are they made?: Climate Normals are 30-year averages for climate variables like temperature and precipitation. They are made by taking the 30 year average of weather data from a specific location 5 Major Components of the Climate System?: the atmosphere, the hydrosphere, the cryosphere, the lithosphere, and the biosphere How is Weather Measured/Monitored: It is monitored at point location through temperatures, precipitation, humidity, wind, cloud cover, snow cover, lake, river and snow levels, date of spring blossom, arrival of migrating birds, ocean temperatures, salinity, and sea ice concentrations Remote Sensing by Satellite: global coverage, global measures such as incoming and outgoing radiation Climate Forecasts: A prediction about average or extreme climate conditions for a region in the long-term future (Seasons to decades) Climate Variability: The actual changes in climate that fall within the normal range of extremes for a particular region. Drivers of climate variability include the El Nino Southern Oscillation and other phenomena What Factors Determine Climate Zones? Name a Few Examples: Climate zones are defined by factors like latitude, average annual temperatures, total precipitation, and seasonal extremes What is the Definition of Climate Change? How are humans impacting the climate?: Climate change is a significant and persistent change in the mean state of the climate or its variability. Human activities such as greenhouse-effect/gasses and the burning of fossil fuels. Projections - Mercator/Orthographic: Mercator projection flat surface, Orthographic projection world from space What is a biome? Give a few examples of biomes. How are biomes related to climate zones?: A biome is a region of the Earth’s surface characterized by specific plant and animal communities. A few examples are rainforests, Savanna, Desert. Biomes and climate zones are related as climate zones and its plants and animals make up a biome. Week 1 Units: What is 1 calorie and how does it relate to energy? What is the SI unit for energy? What is power and what are its units?: 1 calorie = When the temperature of 1 g of H2O is raised by 1 deg C. The SI unit for energy is Joules. The SI unit for power is Watts. Know the different temperature scales: Kelvin, celsius, and Fahrenheit, and how they relate to one another: Kelvin: Scientific unit of temperature Celsius: Obtained by subtracting 273.15 temperature expressed in Kelvin Fahrenheit: Older temperature scale in use in the US. What is atmospheric pressure? How do the units bar, hectoPa, and Pa relate?: Pressure = Force per unit area At sea level, P = 1 atmosphere / 1.013 bar SI Units = N/m^2 = Pascal 1 hectoPascal = 100 Pa = 1 mbar What is vapor pressure? What is relative humidity? What is the relationship between relative humidity and temperature?: Evaporation - Liquid water becomes vapor Condensation - Water vapor becomes liquid water Saturation vapor pressure - liquid water is evaporating at the same rate that water vapor is condensing Relative Humidity : Vapor pressure divided by saturation vapor pressure Relation between Humidity and temperature : When temperature increases, relative humidity decreases. What is latent heat? What is the lapse rate? How do they relate to one another?: Latent heat: The energy released or absorbed during a phase transition Lapse Rate: Change in temperature with altitude Relationship between both: When water vapor condenses and releases latent heat, it slows down the rate at which rising parcel of air cools, resulting in a smaller lapse rate. What is the heat index?: The combination of air temperature and relative humidity that reflects how hot it feels Steps of the hydrologic cycle? How does warming affect the cycle?: Steps: Evaporation, Condensation, Precipitation, Transpiration. Warming accelerates the hydrological cycle. Difference between the heat capacity of air and the heat capacity of water. How do the differences in heat capacity contribute to climate regulation?: Heat Capacity of air: 1J Heat Capacity of Water: 4.2 J Water has more heat capacity than air Differences in heat capacity contribute to climate regulation by allowing large bodies of water to absorb and release heat slowly. Week 1: The Atmosphere How is solar energy concentrated on Earth? Solar Energy is concentrated at the equator. It is concentrated through mirrors or lenses with tracking systems. What are the different layers of the atmosphere? What are global wind patterns driven by? What is the Coriolis Effect and what does it affect? Objects in motion on the Earth’s surface feel a force perpendicular to their direction of motion. Its force is greatest at the poles and least at the equator. It affects Know where the different circulation cells are located and their respective trade winds. There are three different circulation cells, Hadley cells, Ferrel Cells, and Polar Cells. Polar cells are near the poles : Located on the top of the Southern and Northern Hemisphere Ferrel Cells are in the mid-latitudes : Located near the 30° - Westerlies Hadley cells are near the equator : Located on the 60° of the equator - Easterlies What are the Earth’s precipitation patterns? High rain near the equator What are jet streams? In what direction do they move and what do they influence? Jet streams are bands of strong wind that blow from west to east. They impact weather, air travel How are clouds formed and what are they classified by? Know what the suffixes and prefixes of cloud names mean. Clouds form when the invisible water vapor in the air condenses into visible water droplets or ice crystals. They are classified by their cloud type (low,middle, high, vertical) , cloud appearance and cloud base. High Clouds: Cirrocumulus - Small, white puffs | Cirrus - thin, wispy | Cirrostratus - often producing a halo Middle Clouds: Altostratus - gray layer cloud with ‘watery sun’ | Altocumulus - gray, puffy Low Clouds: Stratus - uniform grayish cloud; low blanket of gray | Cumulus - puffy, floating ‘ cotton’ with flat base | Stratocumulus - larger cloud elements with lower cloud base Cloud with Vertical Development: Cumulonimbus - thunderstorm with anvils | Nimbostratus - dark gray with light rain How do solar energy distribution and atmospheric circulation affect global circulation? Week 2: The Ocean How is the ocean stratified? What are the different layers and how does temperature change between them? The ocean is stratified due to differences in density, with warmer, lighter, less salty water layering on top of heavier, colder, saltier water. Layers: Buoyant (warm,fresh) waters near surface (mixed layer) Denser (Colder, more saline) waters below (deep ocean) Euphotic Zone ~ 100m the surface heated How does the thermocline vary with latitude? Thermocline, seawater temperature decreases with depth, less pronounced at high latitudes How do salinity and temperature affect density? What latitudes have fresher water and what latitudes have saltier water? Understand how all of this relates to thermohaline circulation. The warmer the water, the more space it takes up, and the lower its density. The equator and high latitudes (near the poles) tend to have fresher water, while mid-latitudes have saltier water. How does wind affect ocean circulation? What are gyres? What type of currents are associated with gyres? Gyres are circular patterns caused by wind patterns. Types of Currents: Western Boundary Current, Eastern Boundary Current, Trade Wind Driven Current, Westerly Wind Driven Current How does global warming affect the ocean? The hydrological cycle? How is the ocean warming? Ocean is warming from top down, consistent with heating from the atmosphere and ocean circulation Intensification of the hydrological cycle causes more evaporation and salinity in regions that already have high salinities Week 2: The Changing Climate What are temperature anomalies? What do they suggest? Temperature anomaly is a departure from a long-term average Positive anomaly suggests that the observed temperature was warmer than the reference value Negative anomaly indicates that the observed temperature was cooler than the reference value How is the cryosphere changing? Decreasing snow cover, melting glaciers, shrinking sea ice extent and thickness, thawing permafrost and overall mass loss from polar ice sheets. What is sea level rise? Why is it happening? Sea level rise: The rise of average height of ocean’s surface. It is caused by the melting of glaciers and ice sheets due to climate change. What is the effect of climate change on weather? How does the effect of the sun ( solar irradiance) compare to anthropogenic activities? The impact of human activities, primarily greenhouse gas emissions, is significantly larger and considered the primary driver of recent climate change, while natural variations in solar irradiance have much smaller influence on current warming trends. Week 2: Paleoclimate What are paleoclimate proxies? Know the different examples and what each proxy tells us. Long term climate: Ocean Sediments: Millions of years Ice Cores: 800,000 years Recent Climate: Tree Rings: 10,000 years Corals: Thousands of years Written historical records: 1,000 years How do CO2 levels affect Earth’s climate? CO2 dominant driver of climate. It acts as a greenhouse gas, which traps heat from the sun in the atmosphere, causing the plant to warm. Know the main extinction events covered in class ( End-Permian, Cretaceous-Paleogene, Paleocene-Eocene) When/how did these occur? What was the impact? Which one of these events is considered the closest historical analog to current anthropogenic climate change due to fossil fuel burning? End-Permian: Largest mass extinction in Earth’s history, occurred around 252 million years ago, Earth experienced global warming, ocean deoxygenation, ocean acidification Cretaceous-Paleogene: Occurred 66 million years ago, most recent mass extinction, Was caused by a massive asteroid, wiped out nearly all non-avian dinosaurs, Impact site: Yucatan Peninsula Paleocene-Eocene: A period of global warming that occurred around 56 million years ago. Characterized by a rapid increase in carbon dioxide in the atmosphere. The PETM lasted for over 170,000 years The Paleocene-Eocene Thermal Maximum is considered the closest historical analog to current anthropogenic climate change due to fossil fuel burning. What are the impacts of volcanic eruptions? A rapid release of CO2 due to them. How is CO2 related to extinction events? Know the cooling trend of the last 55 million years. What was this caused by? The cooling trend was due to a decrease in atmospheric carbon dioxide levels. What are Milankovitch Cycles? The changes in the intensity of solar radiation received at the Earth were affected by three factors, eccentricity, obliquity, precession. What happened during the Pleistocene Ice Ages? When did it happen? During the Pleistocene Ice Ages, which spanned roughly 2.6 million to 11,700 years ago, large ice sheets repeatedly covered vast areas of the Earth causing significant climate changes with altering periods of glacial (cold) and interglacial (warmer) phase. What are meltwater pulses and how do they affect sea level? Meltwater pulses refer to a period of rapid sea level rise caused by a large volume of meltwater from glaciers and ice sheets quickly entering the ocean. Meltwater pulses can lead to significant and rapid sea level increases. What is the younger dryas period? When did it happen? What was it caused by? The Younger Dryas Period: A period of extreme climate change that occurred between 12,900 and 11,700 years ago. Scientists believe that the Younger Dryas Period was caused by a reduction in the strength or shutdown of the AMOC. What is the Atlantic Meridional Overturning Circulation? How does it relate to the Younger Dryas? How does it relate to today’s climate? The AMOC is a system of ocean currents that circulate water and distribute heat, nutrients, and moisture around the globe. It is related to the Younger Dryas period because scientists believe a weakening or shutdown of the AMOC occurred. The AMOC plays a crucial role in regulating today’s climate by transporting heat from the tropic toward the North Atlantic. Week 3: Radiation and Energy Balance What is the primary energy source for Earth, and how is energy transferred to the planet? The primary energy source for Earth is the Sun. Energy is transferred from the Sun by electromagnetic waves. What is blackbody radiation, and how do the Sun and Earth differ as blackbody emitters? Blackbody radiation: Emitted by a body that emits or absorbs equally well at all Wavelengths. The difference is that the Sun, with a much higher temperature, emits most of its radiation in the visible light spectrum, while the Earth, being cooler, emits primarily infrared radiation due to its lower peak wavelength of emission according to its temperature. What is the electromagnetic spectrum, and which portions are most relevant to Earth's energy balance? The complete range of all types of radiation that has both electric and magnetic fields and travels in waves. How do Wien’s Law and the Stefan-Boltzmann Law describe radiation emission from black bodies? Wien’s Law tells you at which wavelength a blackbody emits the most radiation based on its temperature, while Stefan-Boltzmann Law tells you the total amount of energy a black body emits across all wavelengths. What is the composition of Earth’s atmosphere, and which gases are considered greenhouse gases? How do greenhouse gases absorb infrared radiation, and what distinguishes them from non-greenhouse gases? Greenhouse gasses absorb infrared radiation by causing their molecular bonds to vibrate when they encounter infrared photons at specific wavelengths. How does the atmosphere influence outgoing terrestrial radiation? Why does the Earth radiate energy in the infrared spectrum, and what factors influence this radiation? Week 3: Simple Climate Model How do the processes of absorption, emission, transmission, and reflection impact the Earth's energy balance? It determines how much solar radiation from the sun is captured by the Earth’s surface and atmosphere, and how much is reflected back into space. How does the Earth's energy balance operate when there is no atmosphere? Without an atmosphere, the Earth’s energy balance would be significantly colder. What is the greenhouse effect, and how does it influence Earth's temperature? The greenhouse effect is a natural process where certain gases in the Earth’s atmosphere, known as greenhouse gases, trap heat from the sun, warming the planet’s surface by absorbing infrared radiation that would otherwise escape into space. Does a one-layer greenhouse model explain the Earth’s surface temperature? Yes What factors determine the energy balance on other planets like Venus and Mars? Solar flux, albedo, surface temperature and layer greenhouse Venus - runaway greenhouse Mars - Not enough greenhouse Why is heat energy transferred from the equator to the poles? Heat energy is transferred from the equator to the poles because the Earth receives significantly more direct sunlight at the equator Week 4: Impacts on Extreme Weather How has climate change influenced the frequency and intensity of heat waves? What are the main health and societal impacts of heatwaves, as seen in recent events like Europe 2022 and California 2022? Loss of agricultural productivity, labor productivity, higher rates of mortality for older, 60,00 heat-related deaths in Europe in 2022. What are the main causes and impacts of the ongoing Amazon River Basin drought? How does climate change influence flooding events, and what factors affect flood Severity? Due to climate change and El Nino but the drought severity currently being experienced is largely driven by climate change. What role does climate change play in increasing wildfire risks? It creates warmer, drier conditions that dry out vegetation, lengthen fire seasons, and make it easier for fires to ignite and spread rapidly. How has the intensity of hurricanes changed with rising global temperatures? Hurricane intensity has been increasing as global mean surface temperatures have increased What is extreme event attribution, and how does it connect climate change to specific weather events? Extreme event attribution is a method used to determine how much human activity has influenced the likelihood or intensity of an extreme weather event. Week 4: Impacts on Ice/Snow What are the primary ice sheets on Earth, and why are they significant? The two primary ice sheets on Earth are Greenland and Antarctica. They are significant because they hold ~ 99% of Earth’s freshwater and contain enough ice to raise sea level by an estimated 67 meters if they melted entirely. What is the positive feedback mechanism in ice sheet elevation-mass balance? The positive feedback mechanism in ice sheet elevation-mass balance gives threshold for the equilibrium line What makes the West Antarctic Ice Sheet particularly vulnerable? It is vulnerable to sea level rise because the grounding line is below sea level. What is the potential impact of the melting Greenland ice sheet on the Atlantic Meridional Overturning Circulation (AMOC)? Freshwater from melting ice sheets and rain could make the North Atlantic less salty and less dense, which can slow or stop AMOC. Week 5: Impacts on Sea Level What are the key methods for measuring sea level, and what are their advantages and limitations? Tide-gauges: Positive - long-term observations, Negative - local factors can bias the readings Satellite date: Positive - near-global coverage, high precision, Negative - short observation records. What factors contribute to global sea level rise? Melting glaciers, groundwater use, greenland and Antarctic ice sheets, thermal expansion of seawater How does isostatic rebound influence local sea level changes? Why is sea level rise a critical issue for coastal populations? Higher population and GDP along coast lines compared to their nation’s average are at higher vulnerability. Which areas of the United States are most vulnerable to sea level rise? Primarily along the Gulf Coast and the mid-Atlantic to South Atlantic States including Florida. What strategies can mitigate the risks of sea level rise? Reducing greenhouse gas emissions would reduce the rate, although there is a long-term ‘commitment’ to sea level due to the inertia of the system. Week 5: Impacts on Ocean Acidification How does atmospheric CO₂ contribute to ocean acidification? CO2 dissolves in seawater, carbonic acid is produced which then the carbonic acid dissociates, releasing hydrogen ions and bicarbonate. This increases the hydrogen ion concentration causing an increase in acidity. What are the primary impacts of ocean acidification on marine organisms? It makes it difficult for creatures such as corals, oysters, and other shellfish to build and maintain their shells and skeletons. What is coral bleaching, and how is it linked to ocean acidification? Coral bleaching is when corals, under stress, expel their symbiotic, algae-like protozoa, which leads to a lighter or completely white appearance. Ocean acidification causes the dissolution of the calcium structure that makes up the cora. How does ocean acidification affect economically important marine species? It makes it difficult for them to build and maintain their shells and skeletons. Week 5: Impacts on Vegetation and Agriculture How does climate change impact global vegetation patterns? What role do forests play in mitigating climate change, and how does deforestation contribute to it? Forests cover 30% of Earth’s land, which absorbs carbon. This reduces atmospheric CO2 and slows down climate change. Deforestation has contributed to 30% of CO2 emissions since 1850. What are the main challenges for agriculture due to climate change? Floods, droughts, sea level rise, and increased salinity of coastal aquifers threaten food production. How does agriculture contribute to global greenhouse gas emissions? How do livestock contribute to climate change, and what strategies exist to reduce This? Livestock produce methane, and soils, fertilizers, and manure emit nitrous oxide. Livestock is the largest single source of methane. What is permafrost, and why is its thawing a potential tipping point for climate Change? Permafrost is ground that remains frozen for two or more years, covering 15% of Northern Hemisphere land. It thawing creates thermokarst lakes and can destabilize several meters of soil quickly which can cause landslides and infrastructure damage. Week 6: Carbon Cycle What are the Earth’s major reservoirs of carbon? Atmosphere, land biosphere, ocean, and lithosphere. How does the ocean act as a carbon sink, and what is the role of the biological Pump? Carbon dioxide from the atmosphere is absorbed by marine plants at the ocean surface through photosynthesis, then transported to the deep ocean through sinking and mixing of organic matter. How does the weathering of silicate rocks remove CO₂ from the atmosphere? Acid Rain dissolves silicate rock to make sand and carbonate rock and remove CO2 from the atmosphere What are the turnover times for carbon in various reservoirs, such as the atmosphere, plants, soil, and oceans? Atmosphere: A few years Plants: Several years to decades Soil: Decades to centuries Ocean: Thousands of years How have human activities perturbed the carbon cycle? By releasing large amounts of carbon dioxide into the atmosphere. What are the primary sources of methane emissions, both natural and Anthropogenic? Wetlands, agriculture, fossil fuels, landfills, wastewater treatment. Swamps, termites, grow rice in flooded fields, ruminant animals, and the fossil fuel industry. Week 6: Forcing Feedback What is radiative forcing, and how does it affect the Earth's climate system? Radiative forcing measures how specific forcing perturbs the climate system. If it is a positive forcing, it leads to warming, if it is a negative forcing, it leads to cooling. What role do aerosols play in radiative forcing, and how do they contribute to Cooling? The overall effect of all aerosols is a negative radiative forcing, and it is estimated to cool the surface of the planet. The larger the concentration of aerosols the more effective their absorption and scattering of radiation. What are the main positive feedback mechanisms in the climate system? A positive feedback exists if an initial forcing is amplified by other changes through the system. How does the ice/snow albedo feedback accelerate warming? Higher temperatures melt ice and snow, which makes a less reflective earth surface so the albedo decreases, making the earth warmer by absorbing more sunlight. Why is cloud feedback one of the least understood components of climate Sensitivity? The large global-mean LW and SW cloud feedback cancel, leaving a small net cloud feedback that is unconstrained in sign. What is equilibrium climate sensitivity (ECS), and what is its estimated range? Equilibrium climate sensitivity is defined as the change in temperature with a doubling of CO2, 1.5 to 4.5 deg C is the range. Week 7: Why Changing How do plate tectonics influence the carbon cycle, and why can’t they explain recent warming? Plate tectonics affect CO2 levels through volcanoes, but they can’t explain recent warming because their impact is too slow. What is the Early Anthropogenic Hypothesis, and how does it link agriculture to early climate impacts? The Early Anthropogenic Hypothesis is the idea that human activities began to significantly impact Earth’s climate and ecosystems around 8,000 years ago. How does solar variability compare to CO₂ in explaining recent warming trends? Warming from increased levels of human-produced greenhouse gases is actually many times stronger than any effects due to recent variations in solar activity. What role do carbon isotopes play in identifying human contributions to CO₂ Increases? It shows fossil fuels, which are depleted in carbon-13, are the primary source of the extra CO2 in the atmosphere. How do atmospheric oxygen levels provide supporting evidence for human-driven climate change? It is because we burn fossil fuels, which consist of carbon, we consume oxygen from the atmosphere to create carbon dioxide which results in measurable, small decline in overall oxygen levels. Week 7: Predictions How have climate models evolved since the First Assessment Report (FAR) of the IPCC? They have become more detailed, accurate, and better at simulating climate processes and future scenarios. What are the key components included in modern climate models? Modern climate models include components like the atmosphere, oceans, land surfaces, ice sheets, and greenhouse gases. What are Representative Concentration Pathways (RCPs), and how do they guide climate predictions? RCPs are scenarios that represent different greenhouse gas concentration levels in the future, and they give climate predictions by showing how varying emission levels could impact global temperatures. Why is model resolution important, and what are its trade-offs? Model resolution is important because higher resolution improves accuracy in simulating climate details, but it requires more computing power and time, limiting its feasibility for long-term projections. Week 8: Growth Social Cost Carbon What is the significance of the discount rate in climate change cost-benefit analysis? The discount rate in climate change cost-benefit analysis affects how how future costs and benefits are valued, influencing the urgency of current climate action What are the strengths and limitations of cost-benefit analysis in evaluating climate change policies? Cost-benefit analysis helps quantify the economic impacts of climate policies but has limitations in valuing long-term and uncertain climate effects, and in addressing equity concerns. What is the social cost of carbon? The estimated economic damage caused by emitting one ton of CO2 into the atmosphere, reflecting its impact on health, agriculture, and the environment. What is the Kaya Identity, and how does it help predict future CO₂ emissions? The Kaya Identity assesses factors governing global CO2 emissions. By projecting the future changes in population, economic production, energy intensity, carbon efficiency, it is possible to make an informed projection of future carbon emissions. What trends in energy efficiency have been observed, and how do they impact CO₂ emissions? Energy efficiency has improved in industries, buildings, and transportation, leading to lower energy consumption and a reduction in CO2 emissions. What are the implications of climate change for developing versus developed Countries? Developed countries are more vulnerable to climate change impacts, such as extreme weather and sea-level rise, while developed countries generally have more resources to adapt and mitigate these effects. Week 8: Adaption What adaptation strategies can mitigate the impacts of future heat waves? Proactive planning and mitigation, ecosystem and resource management, community and economic resilience, innovative solutions and technologies. Give an example of how climate change exacerbates displacement and migration. Rising sea levels due to climate change are displacing communities in low-lying areas, such as the Maldives, forcing people to migrate. What is the relationship between climate change and the spread of disease-carrying mosquitoes? Climate change expands mosquito habitats, increasing the spread of diseases like dengue and Zika. Week 8: Renewables How do photovoltaics and concentrating solar power differ in harnessing solar energy? Photovoltaics convert sunlight directly into electricity. Concentrating solar power harnesses heat energy indirectly through a thermal process. Compare the advantages and challenges of onshore and offshore wind power. Onshore wind power is cheaper and quicker to install and maintain than offshore wind. Its disadvantages are intermittent generation, Community impact, and lower power output. Offshore wind power is located at sea, and benefits from consistent, high-speed winds. Its disadvantage is its higher cost. What role does hydropower play in global energy production, and what are its benefits and limitations? Hydropower is a renewable energy electricity source, offering grid flexibility and storage. It remains more cost-effective than new fossil fuel options. Technology is mature with efficiencies over 85% Hydropower projects disrupt ecosystems and communities. They also emit greenhouse gases when large areas are flooded. How does geothermal energy contribute to renewable energy, and what are its benefits and limitations? Geothermal energy is renewable as it is continuously replenished by Earth’s internal heat. It is reliable and flexible. What are the key benefits and challenges of nuclear power in decarbonization Efforts? Nuclear power plays a role in reducing global CO2 emissions. It has high capital and operating costs, environmental risks including radioactive pollution from reactor accidents and nuclear waste disposal issues. How does Carbon Capture and Storage (CCS) technology work, and what are its current limitations? Carbon Capture and Storage technology is designed to capture CO2 emissions from fossil fuel-based processes in power and industrial sectors. Its limitations include high costs associated with deploying CCS technologies What is Bioenergy with Carbon Capture and Storage (BECCS), and what are its potential benefits and risks? It is a technology that involves generating energy from biomass while capturing and storing the resulting carbon dioxide emissions, effectively removing carbon from the atmosphere and creating a “negative emissions” scenario. Week 9: Carbon Capture and Radiation Management What are the advantages and challenges of afforestation and reforestation as CDR Methods? Afforestation involves the establishment of new forests. Its advantages include reducing soil erosion, improving air quality. Its disadvantages include increased fire risk, potential for invasive species, and altering existing ecosystems. Reforestation: Its advantages include biodiversity, water quality, soil health and reducing greenhouse gases. Its disadvantages include What is direct air carbon capture (DAC), and what are the primary barriers to its Deployment? Direct air carbon capture is a technology that removes carbon dioxide directly from the atmosphere for CO2, by using chemical processes to trap it from ambient air. The primary barriers to its deployment are its high cost per ton CO2 captured, significant energy requirements needed to operate, and the lack of large-scale infrastructure to store the captured carbon dioxide effectively. What is enhanced terrestrial weathering, and what are its potential benefits and Limitations? Accelerates natural silicate rock decomposition to capture atmospheric CO2, converting it into stable mineral carbonates or bicarbonates, often applied in agricultural settings. It improves oil health, provides plant nutrients, increases biomass production, and can potentially reduce reliance on conventional fertilizers and pesticides Its challenges and limitations are that significant energy is required for rock extraction, production, and transportation. How does stratospheric aerosol injection aim to manage solar radiation, and what risks does it pose? It aims to mimic the cooling effects of large volcanic eruptions by artificially injecting reflective aerosol particles into the stratosphere. It could result in weather disruptions. What is marine cloud brightening and how does it contribute to radiation Management? Marine Cloud Brightening is a geoengineering technique that enhances the reflectivity of oceanic clouds by dispersing small sea salt particles, which increases their ability to reflect sunlight and helps cool the planet, contributing to solar radiation management. What is cirrus cloud thinning, and how does it differ from other radiation management techniques? Cirrus cloud thinning involves reducing the amount of cirrus clouds to allow more heat to escape from the Earth, as these clouds trap heat by reflecting infrared radiation. What are the barriers to using space-based mirrors for radiation management? Barriers to using space-based mirrors for radiation management include high costs, technical challenges in development and maintenance, potential environmental impacts and concerns about governance and ethical implications. Week 9: Mitigation, Carbon Taxes, Cap and Trade What is an externality, and how does it relate to greenhouse gas emissions? Externality is a term used to describe a situation where the actions of individuals, households, or firms result in benefits or costs to others who are not directly involved in the original decisions or transaction. Greenhouse gas emissions are a negative externality because they impose hidden social and environmental costs. What is market failure, and why does it justify government intervention in addressing climate change? Market failure: GHG emission is a historic market failure where firms haven’t accounted for the full costs of their environmental impacts, especially in the long-term. Government intervention is needed to correct for the effects of externalities in the production of GHG. How does a carbon tax work, and what are its key advantages? It imposes a tax on CO2 emissions. Its advantages are that it is cost-effective, market-driven, price stability, simplicity, and its policy flexibility. What is a cap-and-trade system, and how does it differ from a carbon tax? Cap and trade is a set maximum on emissions with trading of emission allowances. Cap-and-trade controls the total level of emissions, while a carbon tax controls the cost of emissions. What are the co-benefits (besides reducing emissions) of carbon pricing strategies? Air quality is improved, health benefits, economic efficiency, What lessons can be learned from successful climate policies worldwide? Price-based instruments work, policy coherence matters Week 10. Climate Science History and Policy What is the Keeling Curve, and how did it revolutionize the study of atmospheric CO₂? The Keeling Curve is a graph that represents the concentration of carbon dioxide in Earth’s atmosphere over time, based on measurements taken at the Mauna Loa Observatory in Hawaii. The Keeling Curve showed the long-term rise in atmospheric CO2, linking it to human activities and highlighting the role of fossil fuels in climate change. What problem did the Montreal Protocol address, and what made it a success? The Montreal Protocol addresses the CFCs deplete Ozone layer. What made it successful was that it was simple to understand threat to human health, simple technical fix that only costs money, no change in behavior, and easy to add new chemicals to the Protocol. Why did the Kyoto Protocol fail to significantly reduce global greenhouse gas Emissions? It did not work because major emitters like the US and China did not participate. What distinguishes the Paris Agreement from previous climate treaties? The Paris Agreement is distinguished by its bottom-up approach, where countries set their own emission targets, lack of penalties for missing targets, and focus on global participation, unlike previous climate treaties. What are the main barriers to the enactment of effective climate policy and progress toward eliminating greenhouse gas emissions? The main barriers consist of political resistance, economic interests, global coordination, public engagement