Global Warming

Climate change 1

Current Evidence of Climate Change

• • • • Precipitation increased 1% in last century.

Artic sea ice thinning.

Alpine glaciers retreating.

Coral reefs bleaching.

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Facts and Figures

• Global warming, or climate change: Over the past century, the Earth has increased in temperature by about .5 degrees Celsius and many scientists believe this is because of an increase in concentration of the main greenhouse gases : carbon dioxide, methane, nitrous oxide, and fluorocarbons .

• Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880.

• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004. 3

• • The effects of climate change are evident today and nowhere is this more true than in the Arctic. Melting sea ice leaves polar bears and other arctic wildlife species treading water without their critical habitat. Alaska’s ecosystems are being dramatically altered by rising sea levels, devastating wildfires, and melting permafrost.

• • • • Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier.

Polar bears and indigenous cultures are already suffering from the sea-ice loss. Glaciers and mountain snows are rapidly In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later. 5

• • • Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching —or die-off in response to stress—ever recorded in 1998 , with some areas seeing bleach rates of 70 percent.

Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise. • An upsurge in the amount of extreme weather events, such as wildfires , heat waves , and strong tropical storms , is also attributed in part to climate change by some experts. 6

• Industrialization, deforestation, and pollution have greatly increased atmospheric concentrations of water vapor, carbon dioxide, methane, and nitrous oxide, all greenhouse gases that help trap heat near Earth's surface. • Humans are pouring carbon dioxide into the atmosphere much faster than plants and oceans can absorb it . 7

Energy and the Greenhouse Effect

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Solar Radiation

 Solar energy not evenly distributed over the globe.

 Of solar energy reaching outer atmosphere: 25% reflected 25% absorbed 50% reaches earth’s surface 8

Green House Effect • The greenhouse effect is the natural process by which the atmosphere traps some of the Sun's energy, warming the Earth enough to support life or The "greenhouse effect" is the heating of the Earth due to the presence of greenhouse gases.

Green house gases • Greenhouse gases naturally blanket the Earth and keep it about 33 degrees Celsius warmer than it would be without these gases in the atmosphere.

• It is named this way because of a similar effect produced by the glass panes of a greenhouse.

• • Shorter-wavelength solar radiation from the sun passes through Earth's atmosphere, then is absorbed by the surface of the Earth, causing it to warm.

Part of the absorbed energy is then reradiated back to the atmosphere as long wave infrared radiation.

• Most mainstream scientists believe a human driven increase in "greenhouse gases" is increasing the effect artificially.

• These gases persist in the atmosphere for years, meaning that even if such emissions were eliminated today, it would not immediately stop global warming . 11

Conventional Pollutants

• US Clean Air Act designated seven major ( conventional or criteria) pollutants for which maximum ambient (Air around us) air levels are mandated. EPA sets allowable limits for concentrations of these pollutants:  Sulfur Dioxide  Carbon Monoxide  Particulates  Hydrocarbons  Nitrogen Oxides  Photochemical Oxidants  Lead 12

Human-Caused Global Climate Change

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IPCC (Intergovernmental Panel on Climate Change (2001)

released report stating “recent changes in the world’s climate have had discernable impacts on physical and biological systems.”  Concluded human activities must be at least partially responsible.

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Controlling Greenhouse Emissions

• • • Switch to renewable energy sources such as solar, wind, biomass etc.

CO 2 is lives longer in the atmosphere than Methane and other greenhouse gases.

Capture and Store CO 2 :  Increase plantations of trees and farmland  Inject CO 2 into underground strata or deep ocean (Read pg 208 for details).

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CLEAN AIR LEGISLATION

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Clean Air Act (1963)

- First national air legislation pollution control.

Clean Air Act (1970)

rewrote original Act.

 Identified critical pollutants.

 Established ambient air quality standards mainly:

Primary Standards

health – to protect human

Secondary Standards

–to protect materials, environment, and comfort.

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Clean Air Act

• Since 1970 the Clean Air Act has been modified & amended: Revision in1990 and have addressed principal problems :  Acid Rain  Urban Smog  Toxic Air Pollutants  Ozone Protection  Marketing Pollution Rights  Fugitive emissions of volatile organics  Ambient ozone, soot, and dust.

 NO x emissions (Nitrogen oxides) 16

International Climate Negotiations

• Kyoto Protocol (1997) signed in Japan as a follow up of the earth’s summit(1992) in Rio de Janeiro  160 nations agreed to roll back carbon dioxide, methane, and nitrous oxide emissions about 5% below 1990 levels by 2012.

  Also included 3 other green house gases to be reduced: hydrofluorocarbon (CFC), perfluorocarbon and sulphur hexafluoride.

The protocol sets different limits for different countries, depending on their output before 1990,however poorer countries like China and India were exempeted from their emission limit to allow thse countries to develop.

 They also argued that wealthier countries created this mess and they should sort out this problem.

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• how global warming works • http://environment.nationalgeographic.com/e nvironment/global-warming/gw-overview interactive.html?fs=video.nationalgeographic.

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