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FROZEN HEAT
66
In the East Siberian Arctic Shelf (ESAS, Fig. TB-3.2.1), methane
concentrations in the surface waters exceed typical seawater
values and far exceed the atmosphere’s equilibrium methane
concentrations (Shakhova
et al.
2010a). Shakhova
et al.
(2010b)
suggest methane is released into the atmosphere at an annual
rate of about 8 Tg of carbon (.008 GtC) for the ESAS alone,
Box 3.2
Methane release along the East Siberian Arctic Shelf
comparable to the rate expected for the rest of Earth’s oceans
combined. The present-day ESAS methane release rate is nearly 2
per cent of the nearly 450 Tg of methane carbon (.45 GtC) annually
released to the atmosphere from all sources globally (IPCC, 2007). A
current research challenge is to predict whether methane release rates
will increase significantly in response to ongoing climate change.
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Barents Sea
Kara Sea
Chukchi
Sea
0
100
1000
2000
3000
5000
Depth, metres
Source: adapted from NOAA
Arctic Ocean
East Siberian
Sea
NORTH POLE
East Siberian Arctic Shelf
EAST SIBERIAN
ARCTIC SHELF
Figure TB-3.2.1:
East Siberian Arctic Shelf (ESAS). The ESAS makes up a quarter of the Arctic shelf area (Shakhova
et al.
2010a), with an
average depth of only 58 metres (Jakobsson 2002) and significant riverine input.
East Siberian Arctic Shelf