Hot, But Not All Bad

Last year was the hottest on record in Australia, with temperatures about one degree Celsius warmer than the 1961-1990 average, which is the reference period for the Australian Bureau of Meteorology.

According to the Bureau, a full degree increase in temperatures in southern Australia is equivalent to moving towns about 100 kilometers north.

But the temperature increase was not uniform across Australia, with parts of Western Australia recording a cooler than average year in 2005, while central western Queensland was on average more than two degrees warmer.

Information on temperatures from around the world is compiled at The National Aeuronautics and Space Administration (NASA) in the US.

NASA reports that, globally, temperatures have increase on average by 0.6 degrees in the past three decades and 0.8 degrees when measured over the last 100 years.

Interestingly, globally, 2005 was not the hottest year on record.  According to NASA 2005 was a "dead heat" with 1998, the warmest previous year.

Again the temperature increase has not been uniform across the globe.

While parts of Antarctica have been cooler than usual, it was more than two degrees hotter across much of the Arctic than it was during the 1951-1980 period, which is the reference period for NASA.

As a consequence of the warming in the Arctic it has been reported that Greenland's ice sheets are melting and glaciers retreating.

Interestingly, while Greenland has been thinning at the margins, measurements show the island has also been getting taller -- that's right taller.

Satellite measurements showed that more snow has been falling on Greenland and as a consequence the island's icecaps are growing at a rate of approximately five centimeters a year.

According to the Norwegian Centre for Global Ocean Studies and Operational Oceanography, this thickening is consistent with theories of global warming because warmer air, even if it is still below freezing, can carry more moisture.

While the often quoted CSIRO scenario modelling suggests that it could get drier in Australia with global warming, in contrast some Australian climatologists have predicted that as it gets warmer there will be more cloud cover and more rain.

The hypothesis that it will get wetter as it gets warmer is consistent with the observation that Greenland is getting taller because more snow is falling.

So global warming might not be all bad news.  Indeed, last year, the warmest year on record in Australia, was also the year the drought broke for many farmers.

I hope that 2006 is warm, but not too warm, and wet, but not too wet!  Happy New Year!

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