Greenhouse Effect and Global Warming

Greenhouse Gases (Heat trapping property of these gases is undisputed) ä Water vapor (most important gas) ä Carbon Dioxide (next most important gas) ä combustion of fossil fuels ä Methane ä anaerobic bacteria rice fields, cows, sewage ä Nitrous Oxide ä fossil fuels and fertilizers

Carbon Dioxide (CO 2 ) ä ä rapid rise in the use of oil, gas and coal to satisfy the energy demands of today's society ä ä Global deforestation is also a major cause of this increase ä ä Plants and animals release CO 2 as they breath ä ä Decaying organic matter, volcanoes, and forest and grass fires

Methane (CH4) ä ä the break-down of vegetation (rice paddies) ä ä burning, digestion, or rotting without the presence of oxygen (cattle and other grazing livestock) ä ä Wood -burned as fuel and for industrial use in the third world ä ä large tracts of tropical forests are burned to clear land for agriculture.

Nitrous Oxide (N2O) ä ä the use of chemical fertilizers and the burning of fossil fuels ä ä produced naturally by microbes in the soil and bodies of water

CFC ä ä CFCs (chlorofluorocarbons) or freon gases ä ä CFCs are far less abundant that CO2, their effect on climate, molecule for molecule, is about 10,000 more powerful ä ä the blowing agent in the manufacture of foam insulation and padding, as spray can propellants, as coolants in refrigerators, and air conditioners and as solvents for cleaning microchips and other electronic equipment

CFC cont ä ä Montreal Protocol - 24 nations, including Canada, pledged to reduce the use of these chemicals by 50% by 1999 ä ä How is this going?

Ozone (O3) ä ä great benefit in the upper atmosphere ä ä shields us from the harmful ultraviolet rays ä ä major component of urban smog ä damaging crops ä aggravating respiratory problems ä ä 75% of these ozone-forming pollutants come from automobile exhaust, with the remainder originating mainly from coal- burning plants

Balancing ä Forest ä Ocean ä absorb and release large amounts of carbon dioxide ä mechanism are extremely complex and still poorly understood. ä missing carbon sink

Greenhouse effect ä Greenhouse effect is essential for life on Earth ä Without this temperatures would be much colder about 0 o F instead of 57 o F ä Layers of the Earth’s Atmosphere ä Goldilocks Theory ä Venus too close, Mars too far, Earth just right ä Liquid water - hydrated minerals, plate tectonics, recycling of gases from the earth - greenhouse effect

Global Warming ä Is the world’s mean temperature increasing? ä Scientific Evidence ä The Culprits ä Industrial Revolution ä Anthropogenic (human induced) land use ä Potential Outcomes ä Actions

Scientific Evidence ä Study of the ancient ice cores Antarctica ä 160 thousand years of the earth history ä concentrations of carbon dioxide ä Global Mean Annual Temperature ä temperature vs CO 2 levels ä Coral Bleaching

Coral Bleaching

Greenhouse gases are affected by human activity

Global Warming Since the Last Ice Age ä increase in the rate ä about 0.5 o F over the last 40 years ä about 1 o F since the late 19th century ä dramatic shifts in climate ä Loser and winners ä southern US have cooled ä N. America and Eurasia between 40 and 70N increase ä anthropogenic effects

Atmospheric Increase in Global Carbon Cycle ä Emissions from Fossil + fuels ä Net emission from changes in land use ä subtract oceanic uptake ä subtract atmosphere uptake ä what is left missing carbon sink

Potential Outcome ä Rising Temperature ä o F in the next century ä if increase at current rates o F ä Sea Level Rise ä inches in the next century ä as high as 80 inches ä 1 yd will be enough to flood 1% of Egypt, 6% Netherlands, 17.5% Bangladesh, and many islands

cont. ä Intensification of the Hydrologic Cycle ä increasing evaporation will likely result in drier soil ä impact on regional water sources ä Health Effect ä disease such as malaria ä warmer health tougher on body ä Dramatic Effects on Ecosystems ä forest, deserts, mountain regions, lakes, streams, wetlands etc

Impacts ä Extreme temperatures ä several serious diseases ä increase air pollution ä increase ozone ground levels ä ground level ozone vs upper atmosphere ozone ä sea level rising at an average rate of 1 to 2 mm/year over the past 100 years ä El Ninos are not caused by global warming. ä they appear to be more intense

Actions ä Cities and States have prepared greenhouse inventories ä National level - US Global Change Research Program ä Global - firm commitment to strengthening international responses to the risks of climate change ä Alternative energy ä Pumping CO 2 down into ocean forming a clathrate ä What is the Kyoto Treaty?

Greenhouse gas emission factors for fuels