The rapid growth of sea ice on the southern hemisphere alone goes a long way to explain why, over the past three months, surface air temperatures have not been much higher than they used to be, both globally and in the Arctic, as illustrated by above NOAA image. What has also contributed to warmer temperatures around latitude 60 on the northern hemisphere is the fact that methane has accumulated in the atmosphere at that latitude, as discussed in earlier posts. Arctic SST far exceed anything ever seen in human history So, does the sea ice on the southern hemisphere constitute a negative feedback that could hold back global warming? It doesnt. It may temporarily keep surface temperatures close to what they used to be, as the sea ice reflects lots of sunlight back into space, but at the same time ocean temperatures are rising strongly, as the sea ice also prevents heat from radiating out of the waters around Antarctica. The latter also helps explaining the colder surface temperatures over those waters. Much of this additional ocean heat has meanwhile been transported by the great ocean conveyor belt to the northern hemisphere. No time before in human history has such a huge amount of ocean heat accumulated in the North Atlantic and the North Pacific. This heat is now threatening to invade the Arctic Ocean and trigger huge temperature rises due to methane eruptions from the seafloor. arctic-news.blogspot.sg/2014/09/antarctica-linked-to-arctic.html
Posted on: Mon, 08 Sep 2014 09:51:43 +0000
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