How is the climate going to change in the future?
What are the projected changes for the 21st century and on the longer term?
Projected changes in temperature for the 21st century
The global average temperature is expected to increase by about 0.2°C per decade over the next two decades. Continuing greenhouse gas emissions at or above current rates would cause a further increase in global temperatures and many other climatic changes during the 21st century.
The best estimates for projected global temperature increases from the 1980s to the end of the 21st century range from 1.8°C (1.1 - 2.9°C) to 4°C (2.4 - 6.4°C) for the IPCC scenarios that do not consider additional mitigation measures apart from those already in place in 2000.
Other projected changes for the 21st century
Global average sea level is expected to rise by 18 to 59 cm by the end of the 21st century. Warming is expected to be greatest over land and at high northern latitudes and smallest over the Southern Ocean and parts of the North Atlantic Ocean. Other projected changes include acidification of the oceans, reduced snow cover and sea ice, more frequent heat waves and heavy precipitation, more intense tropical cyclones, and slower oceanic currents.
Projected changes on the longer term
Warming and sea level rise caused by human activities will continue for centuries, even if greenhouse gas concentrations were to be stabilized. If warming persists over many centuries, it could lead to a complete melting of the Greenland Ice sheet, increasing global sea levels by about 7m.