Cloud Mystery Solved: Global Temperatures to Rise at Least 4°C by 2100

Global average temperatures will rise at least 4°C by 2100 and potentially more than 8°C by 2200 if carbon dioxide emissions are not reduced according to new research published in Nature.  Scientists found global climate is more sensitive to carbon dioxide than most previous estimates.

The research also appears to solve one of the great unknowns of climate sensitivity, the role of cloud formation and whether this will have a positive or negative effect on global warming.

The key to this narrower but much higher estimate can be found in the real world observations around the role of water vapor in cloud formation.

Observations show when water vapor is taken up by the atmosphere through evaporation, the updrafts can either rise to 15 km to form clouds that produce heavy rains or rise just a few kilometres before returning to the surface without forming rain clouds.

When updrafts rise only a few kilometres they reduce total cloud cover because they pull more vapor away from the higher cloud forming regions.

Cloud Mystery Solved: Global Temperatures to Rise at Least 4°C by 2100