ES+1%2C+F24%2C+Class+5%2C+10.15+ (Change Wrap Up & Climate Causes) PDF

Our Planet Our universe is 13.8 billion years old. Most physicists believe that it began with a “Big Bang.” The 2nd Law of Thermodynamics states that total entropy, or disorder, will always increase in a closed system. The Peaceable Kingdom, by Edward Hicks, a classic artistic example of the balan...

Our Planet Our universe is 13.8 billion years old. Most physicists believe that it began with a “Big Bang.” The 2nd Law of Thermodynamics states that total entropy, or disorder, will always increase in a closed system. The Peaceable Kingdom, by Edward Hicks, a classic artistic example of the balance of nature idea. YET Beginning around 1800 and continuing to today, research on geology, evolution, climate, ecology, and other fields has shown that directional—not just cyclical— environmental change is inherent and universal. Geology This engraving depicts an “unconformity” in the sedimentary layers near Jedburgh, Scotland. Published in James Hutton’s Theory of the Earth Volume 1 (1795), it suggested that this bucolic region had experienced major upheavals during its long geologic history. Geology Meteor Crater, AZ Grand Canyon, AZ Uniformitarianism Catastrophism Earth history is shaped by rare, The same slow processes that have unpredictable, transformative events always shaped life on earth continue (Georges Cuvier). to do so today (Charles Lyell). Evolution These words appeared in Alfred Russell Wallace’s journal around 1855. Wallace was the coauthor, along with Charles Darwin, of the first paper that introduced the theory of evolution by natural selection. By the mid-19th century, most naturalists embraced a more dynamic view of nature. They knew environments changed, but still they did not know why, how, or over how long a time. Evolution Phyletic Gradualism Darwin believed that large changes occurred through the accumulation of many smaller changes over long periods of time. Versus Punctuated Equilibrium In the 20th century, scholars such as Stephen J. Gould pointed out that rare events may lead to rapid and drastic changes after long periods of relative calm. These two models in evolutionary biology depict different rates and patterns of change; they also imply different underlying processes and causes. Climate Gaia Hypothesis Chaos Theory Five Atmospheric Indicators: Two Initial Conditions: Negative feedbacks tend toward Positive feedbacks tend toward convergence and equilibrium. divergence and change. Earth’s atmosphere and biosphere Future outcomes depend on comprise a stable, self-regulating conditions today; the climate is prone system that has endured for millions of to unpredictable changes (Edward years (James Lovelock). Lorenz).  Ecology Succession Disturbance North Woods, New England: Coast Ranges, California: New England’s forests have regrown Fires reshape California ecosystems, and are an essential part of the landscape. since the 19th century. Disturbed ecosystems pass through Disturbance is the norm in most predictable stages, reaching a final ecosystems, and can result in “climax” state determined by climate unpredictable, even irreversible shifts and soils (Frederick Clements). at certain tipping points. Today, we know that there are many causes of environmental change that work together in (remember) -Extraterrestrial impacts - Planetary orbital cycles - Geologic (tectonic) processes - Evolutionary change - Climatic cycles - Random weather events - Population dynamics Summary: Why do environments change? And how do we know it? People have always understood that environments change. Until the 18th century, however, most Western thinkers believed that environments tended toward a “balance of nature.” We now know that change is an intrinsic property of our planet, of life on earth, and even the universe itself. Change is not always easy to understand. But we do know that human activities are greatly accelerating environmental change and moving it in new and often worrisome directions. By the 1990s, these insights led to the development of a new interdisciplinary field called Earth System Science (ESS) ESS studies our planet as a complex, dynamic, and non- linear “system of systems.” By the 1990s, these insights led to the development of a new interdisciplinary field called Earth System Science (ESS) Earth System Science (ESS) is an interdisciplinary field that studies the Earth as an integrated system of interacting physical, chemical, biological, and human components. It looks at how different parts of the Earth—such as the atmosphere, Geosphere, lithosphere, and biosphere— interact and affect each other. ESS studies our planet as a complex, dynamic, and non- linear “system of systems.”  Forces of anthropogenic environmental change - Migration - Agriculture - Urbanization - Industrialization - Resource extraction - Pollution - Domestication - Interactions with wild species - Etc.  Forces of anthropogenic environmental change I = PAT Where: I = Impact (environmental) P = Population (births - deaths + immigration - emigration) A = Affluence (consumption) T = Technology  Human population as a force of environmental change The Malthusians - Population growth will outpace food production and resource availability - This will lead to conflict, disease, hunger, and other “negative checks” - Technology and affluence can alter the rate of change, but not affect the outcome - Malthus got it wrong, but mainly because he was looking backward Thomas Malthus instead of forward! (1766-1834)  Forces of anthropogenic environmental change I = PAT Where: I = Impact (environmental) P = Population (births - deaths + immigration - emigration) A = Affluence (consumption) T = Technology (for the next several slides, refer back to the de Sherbinin et al. reading from week two) Human population as a force of environmental change Carrying capacity is the total population or amount of a thing that can be can be sustained in a given area. sad In this model, population follows a “logistic,” or S-shaped growth pattern, until grows tapers off at the system’s carrying capacity (K). This is a very simple model; most systems do not behave in this way. Human population as a force of environmental change The carrying capacity idea is incomplete because It often fails to include key considerations, like: - cultural adaptation - technological change - globalization and trade - institutional arrangements - resource allocation - gender equity  Human population as a force of environmental change Population take-home points: - Multiple competing theories and ideologies - No simple or straightforward relationship - More complex than simply size and growth - Complex, dynamic, interacting factors - Stories vary over space and time - Gender matters India on Population versus Consumption India, along with other developing countries, has long argued that it should be able to grow its economy without major environmental restrictions because developed nations created most of today’s environmental problems, and because it still has a long way to go to meet its people’s needs. Today, India, is democratic but poor. It has a population of around 1.33 billion people and is one of the world’s largest fossil fuel emitters. But its emissions (per capita) are only a third of the global average and one-tenth of the North American average. Which is more important: Population or consumption? The past or the future?  Forces of anthropogenic environmental change I = PAT Where: I = Impact (environmental) P = Population (births - deaths + immigration - emigration) A = Affluence (consumption) T = Technology (for the next several slides, refer back to the de Sherbinin et al. reading from week two)  Affluence as a force of environmental change Environmental Kuznets Curve Argues that, following an initial period of increased impacts, total environmental impacts decrease with increasing affluence. This may be correct for Impact (Negative) some countries, but it often fails to consider issues like international trade. Highly developed countries may exploit the environments of less developed countries while seeking to protect their own. Affluence (or Time)  Technology as a force of environmental change Technology Scholars also have pointed to technology in general as a driving force of environmental change. Foremost among these is the suite of technologies that has enabled the large-scale exploitation of fossil fuels.  Finally – Impact Forces of anthropogenic environmental change And finally, what do we mean by Impact in the I=PAT equation? - We can measure impact using specific criteria, such as land cover change or carbon emissions - But overall impact is difficult to quantify - Even the idea of “impact” itself is problematic - When considering anthropogenic influences, it is better to think about “interactions” than “impacts” (humans shape the environment and it shapes us) The idea of “human impacts” is never- theless powerful, and has long been at the center of environmental thought. George Perkins Marsh (1801-82) was a 19th century American statesman, scholar, and author whose book, “The Earth as Modified by Human Action,” is seen as a foundational text in environmental studies. For Marsh, whose work was influenced by Darwin and others, humanity was “everywhere a disturbing agent.” Climate Change: The Basic Science Energy from the Sun comes in a spectrum of wavelengths. Some is reflected back into space by the atmosphere; of the energy that reaches the earth’s surface, some is reflected while some absorbed then reradiated as heat. Climate Change: The Basic Science Some molecules in our atmosphere—including CO2 (Carbon Dioxide) and CH4 (methane)—have geometries that enable most light from the sun to pass through them, but then trap infrared radiation, known as heat, reemitted from the earth’s surface. These are called “greenhouse gasses.” Climate Change: The Basic Science This retention of heat energy emitted from the earth is called the “greenhouse effect.” Earth has always had a greenhouse effect—it is what keeps our planet relatively mild— but adding more heat-trapping gasses is increasing the effect’s potency. Climate Change: The Basic Science Since the 18th century, humans have been emitting increasing amounts of greenhouse gases into the atmosphere. The Keeling Curve, shown above, tracks the rise of global atmospheric CO2, from the late 1950s to the present. Climate Change: The Basic Science 33.33% Increase Just in: Carbon dioxide (CO2) is accumulating in the atmosphere faster than ever - accelerating on a steep rise to levels far above any experienced during human existence. The period from 2022 to 2024 has seen the largest two-year jump in atmospheric CO2 concentrations in the NOAA record. Climate Change: The Basic Science To-date, about half of human-caused carbon emissions (CO2, CH4, etc) have ended up in the atmosphere. The other half has been soaked up by forests, grasslands, soils, and oceans. There is reason to be concerned that these systems may not continue to act as such efficient “carbon sinks,” absorbing our emissions at this level into the future. Climate Change: The Basic Science Different greenhouse gases have different capacities to retain heat, and they remain in the atmosphere for different lengths of time—with some persisting for centuries or even millennia. Climate Change: The Basic Science The result is that a greater amount of heat is being retained in the atmosphere, leading to its overall (average) warming. Climate Change: The Basic Science Emissions, both historical and current, are also not equally distributed across the earth. Highly developed countries in North America and Europe have contributed the most emissions, both total and per capita.