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This frozen methane is starting to bubble to the surface in some spots in alarming amounts.Methane has been found bubbling up from parts of the East Siberian Sea and Laptev Sea at levels that were 10 times higher than they were in
b) Methane stored in frozen hydrates on continental shelves in the world’s oceans.Methane is able to survive as frozen hydrates because of low temperatures and high pressure.Bacteria digest these frozen hydrates as they melt from warmer ocean temperatures. Methane is generated, then bubbles to the surface, where it is released as a gas into the atmosphere.10C increase in ocean temperatures increases respiration (decay of organic matter) by 10 – 13%. No commensurate increase in photosynthesis results from a 10C increase in temperatures.
Amount of Methane Stored as HydratesThe amount of carbon stored in the hydrates is an estimated 10,000 gigatonnes.This is twice that in the reserves of all other fossil fuels combined.It is also more than enough to dwarf the 750 gigatonnes of carbon stored in the atmosphere as carbon dioxide.If today’s warming continues, deep sea temperatures could cross the threshold at which methane hydrates melt.This could release huge amounts of methane and trigger drastic climate change.
55 Million Years AgoA gradual warming of the oceans preceded a dramatic shift in the amount of carbon in the atmosphere. Methane hydrates were melted in the deep ocean, resulting in vast quantities of methane being released into the atmosphere. Water temperatures continued to rise. Within a few thousand years, sea surface temperatures soared up to 140F (80C), while deep water warmed by 90F (50C).Temperatures remained high for the next 200,000 years. This rise in temperatures did benefit mammals in their evolution and in their spread around the globe.Sea surface temperatures had crossed a certain threshold, releasing all the methane stored in the icy hydrates in a cascade of bursts that caused more warming that, in turn, triggered further releases.
5) West Antarctic Ice SheetThe Antarctic Continent has two ice sheets overlaying it, the West Antarctic and East Antarctic Ice Sheets. The West Antarctic Ice Sheet is particularly vulnerable to a little warming. A little warming could initiate a significant melting of the ice sheet. If the entire West Antarctic Ice Sheet melted, sea level worldwide would rise by 20 feet (6 meters).Recently scientists have discovered that the two ice sheets which have for millennia been attached to each other, have detached. This allows the more vulnerable ice sheet, the West Antarctic Ice Sheet to move faster (propelled by gravity) towards the ocean, where the edges of it are calving off into the ocean at an increasing rate.
6) Ocean Water Warming50 – 55% of the CO2emitted into the atmosphere (because of human activity) is taken out of the atmosphere by vegetation and the surface water of the world’s oceans. But as oceans warm, their ability to absorb atmospheric CO2declines. So more CO2stays in the atmosphere, accelerating warming of both the atmosphere and the world’s oceans.
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