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Chapter 19 Global Change
Global Climate Change • Global changes are changes that occur in the chemical, biological, and physical properties of the planet • Global climate change are changes in the earth’s climate ▫ Natural (el nino) or anthropogenic (pollution) • Global warming is the human caused warming of our planet • Global warming vs. greenhouse effect vs. climate change
Global Warming • Physical and biogeochemical systems regulate temps and control amounts of gases • Sun’s heat has high energy, so energy that reaches our planet is visible/UV (shortwave) ▫ 1/3 reflected back to space ▫ Some absorbed by atmosphere ▫ About 1/2 absorbed at surface • Planet cooler, so longwave radiation(IR) leaves which does not easily pass through gases in atmosphere • This warming is called greenhouse effect • Greenhouse gases: H 2 O, CO 2, CH 4, N 2 O, O 3 • Greenhouse effect necessary for life
Sources of Greenhouse Gases • A greenhouse gas is a gas that absorbs infrared radiation • Natural sources include volcanic eruptions, digestion, decomposition, denitirification, evaporation, and evapotransporation • Anthropogenic sources include burning fossil fuels, agriculture, deforestation, landfills, and industrial production • 20% of people live in developed world, but they account for 75% of the CO 2
Feedbacks and Climate Change • Positive feedbacks ▫ Higher temps increase biological activity in soil, which increase CO 2 release from soil which enhances temps ▫ As tundra melts, trapped CO 2 release from decomposition • Negative feedbacks ▫ Warmer temps means increased evaporation which means more clouds and less radiation and cooling • Very hard to predict future
• • Consequences of Global Warming on Environment Polar ice caps melting (find more oil) Glaciers melting (aesthetic beauty) Permafrost melting (human structures built on them) Sea levels rising (ice melting and warm water expands) More heat waves and less cold spells Weather patterns shift (crops, erosion) More extreme storms Ocean currents shift (climates and nutrients)
Temperatures will rise globally Projected increases in surface temperature for 2090– 2099 relative to 1980– 1999
Projected changes in precipitation Precipitation will increase at high latitudes and decrease at low and middle latitudes
Consequences of Global Warming on Living Organisms • Growing season for plants extended 6 -14 days. Brings birds and insects earlier • Some organisms may not be able to adapt to more hospitable environment • Humans may have to move further inland • More disease • Economy (places that depend on snow) • Kyoto protocol is a global agreement where countries agreed to reduce greenhouse emissions to certain levels
Global Warming and People • Societies are feeling the impacts of climate change • Agriculture: shortened growing seasons, decreased production, crops more susceptible to droughts ▫ Increasing hunger • Forestry: increased fires, invasive species ▫ Insect and disease outbreaks • Health: heat waves and stress can cause death ▫ Respiratory ailments, expansion of tropical diseases ▫ Disease and sanitation problems from flooding ▫ Drowning from storms
Impacts of climate change The Arctic has suffered the most so far U. S. temperatures will continue to rise
Impacts of climate change will vary
Kyoto Protocol • Kyoto Protocol: An agreement drafted in 1997 that calls for reducing, by 2012, emissions of six greenhouse gases to levels lower than their levels in 1990. Although the United States has refused to ratify the protocol, it came into force in 2005 when Russia ratified it, the 127 th nation to do so.
Problem 1 (Similar to FRQ from 2010, question #4) In recent years many scientific studies have shown the relationship between the global mean atmospheric temperature at Earth’s surface and rising sea levels. The increases in the global mean atmospheric temperature during the past two hundred years have been accompanied by a gradual increase in sea level. The average rate of increase in sea level over the past 200 years is 2. 5 mm/yr. a) Calculate the expected increase in sea level, in meters, for the following lengths of time: 10 years, 100 years, 200 years. Problem 2 Figure 19. 13 on page 530 in the text presents historical CO 2 levels. Use the graph to determine the net change in atmospheric Carbon Dioxide concentration between 100, 000 years ago and present day levels.