Why is Climate Change so important?

Average GLOBAL Temperature

Current climate models predict global warming of about 1.4 – 5.8 ºC between 1990 and 2100. These projections are based on a wide range of assumptions about the main forces driving future emissions(such as population growth and technological change) but do not assume any climate change policies for reducing emissions. Even a 1.4 ºC rise would be larger than any century-time-scale trend for the past 10,000 years.

These projections take into account the effects of aerosols and delaying effect of the oceans. Oceanic inertia means that the earth's surface and lower atmosphere would continue to warm for hundreds of years even if greenhouse gas concentration stopped rising in 2100.


 

 

 

 

 

 

 

 

 

 

 

  
Measurement records 
between 1860 and 2000
 
Predicted value 
between 1990 and 2100
0.6 ± 0.4 °C
1.4 ± 5.8 °C

Mean Sea Level

The average sea level is predicted to rise by 9 to 88 cm by 2100. This would be caused mainly by the thermal expansion of the upper layers of the ocean as they warm, with some contribution from melting glaciers. The uncertainty range is large, and changing ocean currents, local land movement and other factors will cause local and regional sea levels to rise much more or much less than the global average.

Slightly faster melting of the Greenland and Antarctica ice sheets is likely to be counteracted by increased snowfall in both regions. As the warming penetrates deeper into the oceans and ice continues to melt, the sea level will continue rising long after surface temperatures have leveled off.

  
Measurement records 
between 1860 and 2000
 
Predicted value 
between 1990 and 2100
10 ~ 20cm
9 ~ 88 cm