Arctic sea ice has declined rapidly in all seasons, with an increasing decline since 2000. The sixth assessment report of the International Panel on Climate Change predicts that the Arctic will be virtually ice-free on average in September.
The results suggest that the human impact on declining sea ice in the Arctic can be observed year-round and can be largely attributed to increased greenhouse gas emissions. But the contribution of aerosols and natural factors (such as solar and volcanic activity) turned out to be much smaller.