The effects of Global Warming can already be seen
The IPCC's Third Assessment Report finds that in the last 40 years, the global average sea level has risen, ocean heat content has increased, and snow cover and ice extent have decreased, which threatens to inundate low-lying island nations and coastal regions throughout the world.
Effects of global warming already being felt on plants and animals worldwide
Global warming is having a significant impact on hundreds of plant and animal species around the world -- although the most dramatic effects may not be felt for decades, according to a new study in the journal Nature.
"Birds are laying eggs earlier than usual, plants are flowering earlier and mammals are breaking hibernation sooner,"
"Clearly, if such ecological changes are now being detected when the globe has warmed by an estimated average of only 1 degree F (0.6 C) over the past 100 years, then many more far-reaching effects on species and ecosystems will probably occur by 2100, when temperatures could increase as much as 11 F (6 C)."
Global Warming Effects that will happen in the future:
Global warming will have serious impacts on the environment and on society. Higher temperatures will cause a melting of ice in Greenland and Antarctica. This will accelerate the rise of sea level. The speed at which global warming is expected to occur in the 21st century is faster than most plant and animal species will be able to cope with. Some will adapt but others will suffer and may become extinct.
Global warming will affect agriculture. New crops will be able to be grown in areas that are currently too cold to support them. However, more pests and diseases may offset any benefits higher temperatures may have. Water resources will also be affected. Some reservoirs may dry up if temperature increases, especially if rainfall also decreases. Rising sea levels may pollute fresh groundwater supplies with salt water.
Global warming will also affect human health. There may be more heat-related illnesses in hotter summers, and increased breathing problems as higher temperatures increase air pollution in cities, reducing air quality. The malaria mosquito may also be able to spread to other regions of the world where it is currently too cold to survive and breed.
More extreme weather, for example storms, floods and droughts will have severe impacts on the environment and on society. The poorest people in society will unfortunately be those least able to cope with the impacts of global warming.