Icebergs – Global Warming or Local Cooling?

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In the southern spring of 2009, hundreds of icebergs drifted from the Antarctic toward New Zealand.  This had occurred only twice before – in 1931 and 2006.  The event prompted a sombre warning from an Australian glaciologist on 23 November 2009.

Scientist Neal Young said more than 100 icebergs — some measuring more than 200 metres (650 feet) across — were seen in just one cluster, indicating there could be hundreds more. He said they were the remains of a massive ice floe which split from the Antarctic as sea and air temperatures rise due to global warming.  He also said that he expected to see more icebergs in the area if the Earth’s temperature continues to increase. “If the current trends in global warming were to continue I would anticipate seeing more icebergs and the large ice shelves breaking up,” he said.

That’s rather breathless hype for a scientist, if that’s what a glaciologist is.  Global warming?  In 1931 as well, eh?  Looks like a candidate for a very high Penn & Teller rating!

As a southern hemisphere glaciologist, Neal Young should be well aware that Antarctic sea ice has grown since the 1970s at a rate of 100,000 square kilometres a decade.  (Some scientists who believe in Anthropogenic Global Warming put that down to the hole in the ozone, which supposedly limits the greenhouse effect caused by man-made CO2).

Young should also be well aware of the nature of Antarctic sea ice.  In the Arctic, some sea ice persists for years, but almost all Antarctic sea ice melts away and reforms annually.  That means that the massive ice floes break up every year.  Because every year (at least since mankind became aware of Antarctica), the waters around it have been warm enough in summer to melt almost all of the Antarctic sea ice.  And because it happens every year, the breakup of Antarctic ice floes therefore clearly has sod-all to do with Global Warming!  Every year, there is a greater area of ice shelf waiting to break up into ice floes.   The destination of the remnants (icebergs to you) is up to the winds and currents at the time, and how long they last depends on the temperature of the waters in which they float.  At best, claiming that icebergs getting close to New Zealand is because of Global Warming is nothing but chicken-licken-style poppycock.  And poppycock of that nature can only cause alarm – or is that the real point of it?

It leaves me with two questions:

  • What sort of agencies fund Australian glaciology
  • Have some or all of the funding agencies any connections with the IPCC?

P.S.  Like Neal Young, I also expect to see more icebergs and more large ice shelves breaking up.  But not because of Global Warming.  In fact, quite the opposite – local Antarctic cooling!  Each decade, there are 100,000 square kilometers more winter sea ice in Antarctica – that’s nearly half the area of New Zealand.  100,000 square kilometres more to break up in the summer.  That’s a hell of a lot of icebergs.

2 Comments

  1. Do we know if the increase in sea ice attributed to the flow of glaciers or is the sea ice formation unrelated to glaciers?

  2. JJ says:

    On the face of it, they are unrelated, in the sense that the glacial flow is ice formed by compressed snow. Glacial flow is related to snowfall over a period of years, for that is the source of glaciers. Sea ice forms when the sea is cools enough for it to form – simple as that. In the Arctic, where the North Pole is in the middle of the sea, sea-ice can persist for years. The South Pole is close to the middle of Antarctica, an island continent nearly as big as Australia, and the sea-ice around the rim is almost wholly seasonal. Most of it disappears in the summer and it reforms in the winter. As it warms and thins in the summer, wave-motion cracks it and it breaks up into vast floes. Unlike glacial icebergs, which calve off the face of glaciers as they reach the sea, the floes are flat. The icebergs seen off the coast of NZ last year are of this type – huge ice floes.

    Having said that, the presence of thick sea-ice at the mouth of a glacier can inhibit calving for years, so that the glacial flow juts out from the mouth, sometimes so consolidated that it survives the summer melt of the sea-ice. When it finally calves, either from its own weight or from the impact of a floating iceberg, it can create a super-iceberg. That is the type of iceberg reported this year.

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