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| A break in the clouds on October 29, 2014, allowed scientists the opportunity to fly over Pine Island Glacier—one of Antarctica’s most rapidly changing areas. The flight was part of NASA’s Operation IceBridge, a mission that makes annual surveys of Greenland and Antarctica with instrumented research aircraft. Photo Michael Studinger |
Is Earth headed towards warming of two degrees Celsius this century? If yes, can it be reversed? Should it be? How would it be done?
Two recent publications offer some startling insights. The
first by hockey-stick author Michael Mann estimates when the Earth can be expected to reach a level of 2°C warming
(3.5°F) of the atmosphere.
The answer it seems is very soon. Mann assumes business as usual in carbon emissions,
which are increasing in amount every year, and the effect of the carbon dioxide
(CO2) already in the atmosphere. These numbers are easy to come by, but he has
to come up with a climate sensitivity model to translate the increase of CO2 in
the atmosphere into warming. He determines that an equilibrium climate
sensitivity about midway between estimates of the IPCC best-fit recent climate data.
From this he projects forward and estimates the year Earth’s atmosphere reaches 2°C warming is 2036, twenty-one years
from now. This is much sooner than estimates by the IPCC.
