When the sea ice is gone
|Peter Wadhams Sc.D., Professor of Ocean Physics|
and head of the Polar Ocean Physics group at the
University of Cambridge, U.K., researching effects
of global warming on sea ice, icebergs and oceans
- Summer sea ice disappears, except perhaps for small multiyear remnant north of Greenland and Ellesmere Island, by 2015-2016.
- By 2020 the ice free season lasts at least a month and by 2030 has extended to 3 months.
- September sea surface temperatures are already elevated by 6-7 °C over continental shelves of Arctic. As shrink back continues, the newly exposed surface water over abyssal depths warms up less in a single summer (say 2-3 °C) because of deeper surface water layer (150 m) than over a shelf (50 m).
- The 6-7 °C warming over the shelves causes offshore permafrost to shrink back and vanish over about 10 years. During this time there is elevated methane emission from offshore and from onshore warming, and global warming rates increase by about 50%.
- Result is that bad effects forecast for end of century (4 °C warming worldwide, 10 °C in Arctic) actually occur by about 2060. Speed of change is catastrophic for agriculture; warfare and population crashes ensue.
- Late in the day, the rapidly disintegrating civilised world tries desperate technofixes for warming and resource depletion, e.g. widespread use of nuclear power (thorium cycle), geoengineering. This may work, and bring us back from the brink of destruction after heavy losses.