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Is it warm in here or is it just me?. An overview of global warming Matthew J. Essery. What to stay awake for:. What is Global Warming? Causes of Anthropogenic Global Warming Is Global Warming Natural? Recent History Effects of Global Warming. What is Global Warming?.
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Is it warm in here or is it just me? An overview of global warming Matthew J. Essery
What to stay awake for: • What is Global Warming? • Causes of Anthropogenic Global Warming • Is Global Warming Natural? • Recent History • Effects of Global Warming
What is Global Warming? In the 20th century the Earth’s average near surface air temperature has risen 1 degree Fahrenheit (0.6 degrees Celsius). Stories of grandparents walking through feet of snow to get to school (up hill both ways) might be true. . .
General Scientific Opinion Most of the warming during the last 50 years is due to anthropogenic activities . . . HUMAN ACTIVITY.
Anthropogenic Causes of Global Warming • Increasing concentrations of greenhouse gases in the atmosphere and the greenhouse effect. • Agriculture, deforestation and the removal of large carbon sinks from the environment.
How do humans produce greenhouse gases? • Humans like to burn stuff. When organic (carbon and hydrogen containing molecules) are burned they release heat and carbon dioxide, water and any impurities (carbon monoxide, sulfure dioxide, etc.). • Industry loves to burn stuff and produce volatile chemicals (vapor forming at normal pressure and temperature) • Internal combustion engine • Power Plants
How does the greenhouse effect work? • Greenhouse gases allow high frequency radiation from the sun through them (visible light, ultraviolet light, etc.) • The radiation hits the earth and is converted into heat. • Greenhouse gases absorb heat instead of letting it escape into space. The atmosphere heats up.
Plants and CO2 • Plants are a natural sink for carbon dioxide. • Photosynthesis uses carbon dioxide 6H2O + 6CO2 ------> C6H12O6+ 6O2 Water + carbon dioxide -----> Glucose + Oxygen • Sink means a storage place. Plants store carbon from the atmosphere by converting it into glucose. • Less plants = less carbon dioxide taken in which leads to more in the atmosphere which leads to more greenhouse effect.
Where did all the plants go? • Agriculture • Human habitation • Industrial and Commercial “development”
“Growth for the sake of growth is the ideology of a cancer cell.” Edward Abbey
Climate is affected by human action. Everything affects everything else.
Is Global Warming Natural? • Geologic history shows natural warming and cooling trends. • In the last 1,000,000 years, every 100,000 years or so there are cooling and warming periods. • Some warming trends are slow, some are quick.
Ice Ages • 150,000 y.a. Very Cold and Dry, Many Glaciers • 130,000 y.a. Warmer and moister than today • 110,000 y.a. Cold Again • 100,000 y.a. Cooler than today but warming up • 95,000 y.a. Cold Again
More Ice Ages • 90,000 y.a. Getting Milder • 70,000 y.a. Darn Cold and Glacial • 60-25,000 y.a. Cooler and drier than today • 25-15,000 y.a. Freakin’ Cold (Last Glacial Maximum) • 14,500 y.a. Earth starts warming up rapidly • 13,500 y.a. Nearly as warm and moist as today
Another Ice Age? • 12,800 y.a. Sudden Cooling • 11,500 y.a. Sudden Cooling Suddenly Ends • 9,000 y.a Warmer and Moister than today • 8,200 y.a. Sudden Cooling Again • 8,000 y.a. Warmer and Moister than today • 4,500 y.a. Mild Cooling. Similar to today
How do scientists know what temperature it was before written history? • Ice cores. • Bubbles trapped in ancient ice show trace gas composition. • Isotopes in ice cores reflect temperature changes, vapor pressure and other climate data. • Huge wealth of info. trapped in ice.
According to one geologist: “the earth's climate is a capricious beast; instead of taking its threat seriously, we have been poking it with a sharp stick."
1897-1904 • Swedish scientist Svante Arrhenius studies anthropogenic carbon dioxide in atmosphere. • Small percentage changes in atmospheric carbon will have an effect several centuries later. • Good for plants. Good for vacations.
1950s • Geophysicist Roger Revelle, with the help of Hans Suess, demonstrated that carbon dioxide levels in the air had increased as a result of the use of fossil fuels. • Fossil Fuels cause carbon dioxide change? They knew this in 1950?
1965 • 1st government level publication about Global Warming (Roger Revell). • Most people don’t think humans can significantly change the atmosphere.
1977 • National Academy of Sciences releases “Energy and Climate” study which recommends more studies and not to panic at the possibility of global warming • Carbon dioxide is identified as a major greenhouse gas. 2/3rds of CO2 increase is from fossil fuels. 1/3 is from forest clearing
1980’s • Congress discusses global warming • Roger Revell reports on shrinking glaciers and ice melting • NASA scientists predict that global warming should be observable in the 1990’s
1990’s • Lots of countries start meeting to talk about Global Warming • 1997. First Kyoto meeting. • 1997. Senate says it will not ratify anything that might harm U. S. economy. • 1999. U. S. and Australia don’t sign Kyoto pact.
2004 • Eight Arctic nations finish long term study on effects of Global Warming on the Arctic. • The Arctic shrank almost 30% since 1970s. • Polar Bears will be extinct within 50-100 yrs. • 250 scientists from 8 nations worked on study. • Bush administration disagreed.
Rising Seas • Loss of coastal areas where most human habitation is.
Extreme Weather • Heat rising off of oceans causes much of the weather. • Including hurricanes.
Massive ecosystem change • Even slight changes in temperatures can lead to species extinction, changed migrations, behavioral changes, etc. • Desertification of drier areas • Flooding of coastal areas.