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ch9Lecture

9.0-9.1

  • Earth's climate is warming

    • Yearly average temperatures increased in the Arctic twice as fast as the tropics and temperate areas

    • 90% of Arctic glaciers are retreating at fast rates

    • Sea ice has been declining

    • Permafrost is melting during summers

    • Fires are more common

    • Animal populations are decreasing

  • Public perceptions on climate change

    • In the U.S. 2016 study, only 48% believe climate change is caused by humans

    • Opinion is political and financial

  • International and scientific consensus on climate change

    • Based on "facts" that support agendas, in some cases

    • 2015 Paris Agreement is flawed and limited in its scope

  • Long-term climate patterns

    • Earth's climate has been dynamic over the past millions of years

    • In the past 10,000 years, Earth has grown warmer with ups and downs

    • Pleistocene period: Earth cycled between colder and warmer periods

    • Holocene period: Earth in a warm interglacial period, with shifts in climate

9.2

  • Measuring global warming

    • Earth has warmed significantly since the Industrial Revolution

    • Difficult to measure global annual surface air temperature

    • Models, sampling stations, and examining patterns are used

  • Causes of natural climate variation

    • Solar forcing

    • Regional variation in annual temperatures (land vs. water)

    • El Niño/Southern Oscillation, which changes ocean currents and alters weather patterns

    • Volcanic eruptions cool the atmosphere

9.3

  • Causes of global warming

    • Temperature of Earth's atmosphere affected by the amount of solar radiation, Earth's orbit, and human influences

    • Human influences include the chemical composition of the troposphere, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)

  • Greenhouse effect

    • Gas molecules absorb heat, known as greenhouse gases

    • Water vapor (H2O) is the most abundant naturally occurring greenhouse gas

    • Other greenhouse gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)

Page 4

  • Human impacts on global warming

    • Anthropogenic (human-caused) increases in greenhouse gases, such as CO2

    • Deforestation, fossil fuel use, and synthetic greenhouse gases like chlorofluorocarbon (CFC) compounds

  • Impact of anthropogenic greenhouse gases

    • Global warming potential (GWP) measures the long-term impact and capacity to absorb infrared light/retain heat

    • Gases like CO2, methane (CH4), and nitrous oxide (N2O) trap heat from Earth's surface

  • Sources of greenhouse gases

    • Total greenhouse emissions expressed in carbon dioxide equivalents (CO2e)

    • Burning fossil fuels and industrial processes contribute to greenhouse gas emissions

Page 5

  • Consequences of global warming

    • Climate patterns are changing, leading to drier and wetter conditions

    • Melting glaciers and ice sheets, with over 80% of Earth's glaciers retreating

    • Rising sea levels due to thermal expansion and glacial meltwater

  • Changing populations and ecosystems

    • Climate plays

MS

ch9Lecture

9.0-9.1

  • Earth's climate is warming

    • Yearly average temperatures increased in the Arctic twice as fast as the tropics and temperate areas

    • 90% of Arctic glaciers are retreating at fast rates

    • Sea ice has been declining

    • Permafrost is melting during summers

    • Fires are more common

    • Animal populations are decreasing

  • Public perceptions on climate change

    • In the U.S. 2016 study, only 48% believe climate change is caused by humans

    • Opinion is political and financial

  • International and scientific consensus on climate change

    • Based on "facts" that support agendas, in some cases

    • 2015 Paris Agreement is flawed and limited in its scope

  • Long-term climate patterns

    • Earth's climate has been dynamic over the past millions of years

    • In the past 10,000 years, Earth has grown warmer with ups and downs

    • Pleistocene period: Earth cycled between colder and warmer periods

    • Holocene period: Earth in a warm interglacial period, with shifts in climate

9.2

  • Measuring global warming

    • Earth has warmed significantly since the Industrial Revolution

    • Difficult to measure global annual surface air temperature

    • Models, sampling stations, and examining patterns are used

  • Causes of natural climate variation

    • Solar forcing

    • Regional variation in annual temperatures (land vs. water)

    • El Niño/Southern Oscillation, which changes ocean currents and alters weather patterns

    • Volcanic eruptions cool the atmosphere

9.3

  • Causes of global warming

    • Temperature of Earth's atmosphere affected by the amount of solar radiation, Earth's orbit, and human influences

    • Human influences include the chemical composition of the troposphere, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)

  • Greenhouse effect

    • Gas molecules absorb heat, known as greenhouse gases

    • Water vapor (H2O) is the most abundant naturally occurring greenhouse gas

    • Other greenhouse gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)

Page 4

  • Human impacts on global warming

    • Anthropogenic (human-caused) increases in greenhouse gases, such as CO2

    • Deforestation, fossil fuel use, and synthetic greenhouse gases like chlorofluorocarbon (CFC) compounds

  • Impact of anthropogenic greenhouse gases

    • Global warming potential (GWP) measures the long-term impact and capacity to absorb infrared light/retain heat

    • Gases like CO2, methane (CH4), and nitrous oxide (N2O) trap heat from Earth's surface

  • Sources of greenhouse gases

    • Total greenhouse emissions expressed in carbon dioxide equivalents (CO2e)

    • Burning fossil fuels and industrial processes contribute to greenhouse gas emissions

Page 5

  • Consequences of global warming

    • Climate patterns are changing, leading to drier and wetter conditions

    • Melting glaciers and ice sheets, with over 80% of Earth's glaciers retreating

    • Rising sea levels due to thermal expansion and glacial meltwater

  • Changing populations and ecosystems

    • Climate plays

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