An ABC report at the weekend on the Wilkins Ice Shelf being in danger of breaking off from Antarctica sent me scurrying back to look at the data for myself because I had risked being called a climate change sceptic back in June by writing in Crikey that “when you look at the sea ice in the southern hemisphere the evidence for damage from global warming is certainly much harder to see” than you get from looking at pictures of polar bears stranded without ice in the Arctic.
The mistake I was making, several correspondents informed me, was that the evidence I quoted for the ice coverage in the southern hemisphere actually being greater than at any time in the last 30 years did not take account of the fact that while the area might be greater the thickness was left. The evidence produced by the European Space Agency that “a large plate of floating ice shelf attached to Antarctica is breaking up, in a troubling sign of global warming” on which the ABC story was based suggested that I should prepare a mea culpa.
The National Snow and Ice Data Center (NSIDC), part of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder, collates information on ice coverage around both poles gained from satellites and it told me the following story: it’s true that one large section of the Antarctic has a substantially lower concentration of ice than the average over the reference period of 1979-2000. It is shown in blue on the map where the land mass (shown in grey) points towards the tip of South America on the left.
What you will also see are substantial coloured red areas where the ice concentration is higher than normal. The total anomaly is a million more square kilometres covered by ice than the average. If the ice breaking off is caused by global warming, what causes the increased concentration elsewhere?
The NSIDC figures for the extent of ice coverage in June for the last 30 years show the following pattern:
The trend is certainly towards increasing ice coverage. In a probably futile attempt to avoid being dismissed as a sceptical climate change troglodyte, I include the date for the Arctic where the pattern is not only the reverse of down south but the rate of decrease in ice coverage is far greater than the southern increase.
In an attempt to understand the seemingly different behaviour at the two poles, I turned to the NASA’s Goddard Institute for Space Studies (GISS) which uses its satellites to analyse the world’s surface temperatures. Over the last 20 years, it seems, the further north you go, the greater the increase in temperature.
The mean temperature at the South Pole actually has been marginally colder during the years from 1998 to 2007 than in the GISS reference period of 1951-1980 while at latitude 90 degrees North temperatures have got some 1.5 degrees centigrade hotter.
This year has shown a similar pattern in the southern hemisphere to the last 20 years with June being an especially cold month with temperatures at 90 degrees south being four degrees colder than normal.
Don’t ask me what it all means but it does make me think that decisions on climate change are being made on some very uncertain hypotheses.
Please stop confusing people with facts.
But seriously the temperature map of temperature anomalies shows large scale warming over the northern hemisphere – surely that is indicative of a changing climate.
The only real debate is about the vailidity of some of the climate modelling eg Taroh Matsuno of Japan’s Frontier Centre for Global Change, says these models cannot reproduce rainfall patterns in the tropics. The British government’s top adviser on climate, Brian Hoskins of Reading University adds: “Models can’t yet simulate the glacial cycle. Many people won’t believe them until they can.”
Heat rises, right? That’s why it’s going to the top of the world…
I was so incencsed by Farmers inaccurate ramblings I thought I would respond to correct his idiotic conclusions. Thankfully a number of people beat me to it. For the record Richard the International Panel of Climate Change has clearly stated that the Antarctic has not shown any warming and the modelling does not predict any significant warming in the near future based upon the current emissions scenarios. The majority of predictions indicate that the global warming effect is mostly in the northern hemisphere particularly over land masses. Most modelling predicts that the Antarctic sea ice will thin. We should all ve very thankful for small mercies as the Antarctic ice has significant thermal inertia. This (fingers crossed) will delay warming and subsequent melting of the ice for decades and will (hopefully) prevent cataclysmic sea rise. At least in time for the world to get our greenhouse gas emissions down to a ‘no-harm’ level.
Where is the data/graph that correlates salinity levels with ocean surface temp?
Bob
Thanks Chris G., I looked up your reference read it and found one substantive response to it by a climatologist on the blog website itself:
By Jan Lindström:
“I am very disappointed at your series about the climate change myths. Some of then purely speculative, few references and no non- contradicitng references even there are plenty. It would be fair if you stated that this series is biased and does not seek to give a balanced view. Most of your statements can be debunked by other peer-reviewed articles. Some of them very recent. I am a former aerosol researcher myself and find this black and white descriptions very dangerous to the science as a whole. Sooner or later there is a risk there willl be a tremendous back-lash since the science is NOT settled and there is still a good chance that the final outcome will point towards natural variations in the climate system. The next 5-10 yrs will be crucial. If the alarmist side is right the temperatures will start to climb again otherwise we are in for a drop.”
So Chris the real culprit in the climate change debate is the person who tell us ‘how it really is’ rather than telling us the truth: this is my opinion based on the following evidence…
“So here we go again… The reason why the Antarcitc is cooling is because there has been an increase in the strength of circumpolar westerly winds in the Southern Ocean….”blahblah