The "greenhouse effect" refers to the temperature regulation effect that certain atmospheric gases have on the earth. The temperature-regulating gases, called "greenhouse gases" or GHGs, form a blanket around the earth that traps some heat from the sun within the earth’s atmosphere, The Greenhouse gasses keep the planet warm and habitable, and keep the planet some 30 degrees C warmer than it would be otherwise.
There are six types of GHGs covered under global warming policies and in trading programs: Carbon dioxide (CO2), Methane (CH4), Nitrous Oxide (N2O), Sulfur hexafluoride (SF6), Perfluorocarbons (PFCs), Hydrofluorocarbons (HFCs). Greenhouse gases make up only about 1 per cent of the atmosphere.
Source: Chicago Climate Exchange, UNFCCC, TreeFarms
Effects of Climate Change
Higher Sea Levels
New data evaluated by the IPCC shows that losses from the ice sheets of Greenland and Antarctica have very likely contributed to sea level rise from 1993 to 2003. The average global sea level rose at an average rate of 1.8 mm per year between 1961 and 2003, but between 1993 and 2003 it rose by 3.1 mm per year. Sea level rise will continue for centuries due to the time scales associated with climate processes and feedbacks. In its Fourth Assessment Report, the IPCC states that the contraction of the Greenland ice sheet is projected to continue to contribute to sea level rise after 2100. If this contraction is sustained for centuries, that would lead to the virtually complete elimination of the Greenland ice sheet and a resulting contribution to sea level rise of about 7m.
Extinction of Endangered Species
Most of the world's endangered species -- some 25 per cent of mammals and 12 per cent of birds -- may become extinct over the next few decades as warmer conditions alter the forests, wetlands and rangelands they depend on, and human development blocks them from migrating elsewhere.
Severe Weather: Storms, Longer Dry Spells
Trends towards more powerful storms and hotter, longer dry periods have been observed and are assessed in the IPCC’s Fourth Assessment Report. Warmer temperatures mean greater evaporation and a warmer atmosphere is able to hold more moisture -- hence there is more water aloft that can fall as precipitation. There is also observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since about 1970. Similarly, dry regions are apt to lose still more moisture if the weather is hotter; this exacerbates droughts and desertification.
More Drought
Drying has also been observed over large regions, i.e. the Sahel, the Mediterranean, southern Africa and parts of southern Asia. In Africa's large catchment basins of Niger, Lake Chad and Senegal, total available water has decreased by 40 to 60 per cent, and desertification has been worsened by lower average annual rainfall, runoff and soil moisture, especially in southern, northern, and western Africa.
Frequent Floods
The Rhine floods of 1996 and 1997, the Chinese floods of 1998, the East European floods of 1998 and 2002, the Mozambique and European floods of 2000, and the monsoon-based flooding of 2004 in Bangladesh (which left 60 per cent of the country under water), are examples of more powerful storms.
Source: UNFCCC, TreeFarms