Climate models

Scientists can use historic and current data to create a computer simulation of how the world's may change in the future. This is called a .

Scientists created two climate models using data on carbon dioxide level increases:

The second model better matched the observed temperature changes.

This adds to the evidence that the observed warming of the Earth is because of human activities changing the composition of the .

Scientists can also use computer models to predict the impacts of climate change.

What is affected	Impact
Ice	Melting of the Antarctic ice sheet and melting of glaciers in the Northern Hemisphere.
Sea levels	Likely to increase due to melted ice and expansion as temperatures increase.
Ocean temperature	An increase in ocean temperature could change ocean currents and the climate of countries bordering these currents (like the UK).
Extreme weather	Greater differences in weather, for example, more intense droughts and floods and more extreme temperatures (both hot and cold).
Impact on crops	Low lying farmland may be flooded. In areas where there is less rainfall droughts may make it difficult to grow crops. If there is extreme rainfall then crops could get flooded and washed away.

What is affected	Ice
Impact	Melting of the Antarctic ice sheet and melting of glaciers in the Northern Hemisphere.

What is affected	Sea levels
Impact	Likely to increase due to melted ice and expansion as temperatures increase.

What is affected	Ocean temperature
Impact	An increase in ocean temperature could change ocean currents and the climate of countries bordering these currents (like the UK).

What is affected	Extreme weather
Impact	Greater differences in weather, for example, more intense droughts and floods and more extreme temperatures (both hot and cold).

What is affected	Impact on crops
Impact	Low lying farmland may be flooded. In areas where there is less rainfall droughts may make it difficult to grow crops. If there is extreme rainfall then crops could get flooded and washed away.

The evidence for climate changeClimate models