Friday, December 31, 2010

It's snowing! It's snowing! The world's going to freeze!

On January 23rd 2010 Anthony Watts, fearless independent climatologist, posted this graph from the Danish Meteorological Institute, chortling over just how low and how rapidly Arctic temperatures were dropping. Clearly that's all deniers need to disprove the multiple lines of proof of climate science: three weeks worth of data. Note that Watts described the green line as 'normal' — a meaningless statement without some sort of context, and a strange term to use when the deniers claim that 'climate is always changing'.

Even as the gloating amongst his followers commenced, the data started moving back up again. Watts then posted this updated version:

What did his remarkable insight, his knowledge of climate, atmospherics, geology and politics suggest as a hypothesis that might explain this? What would follow? Watts didn't know, merely asking rather hopefully "will it oscillate back?" Comments on the post ceased on January 28th.

EoR decided to check to see whether it had 'oscillated' back or not. Here is the full graph for 2010 (the green line, rather than being 'normal' represents daily mean temperatures for the period 1958-2002).

Not only did it not 'oscillate' back, it was for most of the year above the averaged mean, and the greatest variations were also largely in the warmer rather than the colder range.

Arctic sea ice extent, as graphed by the National Snow and Ice Data Center is also low.

While the average monthly Arctic sea ice extent continues its inexorable decline.

But surely we're entering a new Ice Age? Isn't the world currently being blanketed by unprecedented amounts of snow? James Hansen at NASA notes

Back to the cold air in Europe: is it possible that reduced Arctic sea ice is affecting weather patterns? Because Hudson Bay (and Baffin Bay, west of Greenland) are at significantly lower latitudes than most of the Arctic Ocean, global warming may cause them to remain ice free into early winter after the Arctic Ocean has become frozen insulating the atmosphere from the ocean. The fixed location of the Hudson-Baffin heat source could plausibly affect weather patterns, in a deterministic way — Europe being half a Rossby wavelength downstream, thus producing a cold European anomaly in the trans-Atlantic seesaw. Several ideas about possible effects of the loss of Arctic sea ice on weather patterns are discussed in papers referenced by Overland, Wang and Walsh.

However, we note in our Reviews of Geophysics paper that the few years just prior to 2009-2010, with low Arctic sea ice, did not produce cold winters in Europe. The cold winter of 2009-2010 was associated with the most extreme Arctic Oscillation in the period of record. Figure 3, from our paper, shows that 7 of the last 10 European winters were warmer than the 1951-1980 average winter, and 10 of the past 10 summers were warmer than climatology. The average warming of European winters is at least as large as the average warming of summers, but it is less noticeable because of the much greater variability in winter.

In Canada, "the Hudson Bay region of Canada had monthly mean anomalies greater than +10°C." It's interesting that this isn't receiving the same amount of coverage that the snowstorms in Europe and the US are. Or the flooding in the Balkans, Central America and Australia (unless you happen to be in one of those areas). And the World Meterological Organisation reports:

The year 2010 is almost certain to rank in the top 3 warmest years since the beginning of instrumental climate records in 1850, according to data sources compiled by the World Meteorological Organization (WMO). The global combined sea surface and land surface air temperature for 2010 (January–October) is currently estimated at 0.55°C ± 0.11°C1 (0.99°F ± 0.20°F) above the 1961–1990 annual average of 14.00°C/57.2°F. At present, 2010’s nominal value is the highest on record, just ahead of 1998 (January-October anomaly +0.53°C) and 2005 (0.52°C)2. The ERA-Interim3 reanalysis data are also indicating that January-October 2010 temperatures are near record levels. The final ranking of 2010 will not become clear until November and December data are analysed in early 2011.

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