Global warming underestimated ?


GLOBAL WARMING of more than 2˚ C is much more likely than many people are prepared to admit, according to American climate expert Professor Matthew Huber.

He told the opening session of the Australian Geoscience Council Convention in Adelaide on Monday, October 15:  “It’s going to get hot, very hot.”

The most recent testing of current models of climate change against the higher temperatures and levels of carbon dioxide (CO2) which we know existed during the miocene era showed that “our climate models are not sensitive enough”, he said.

Recent research in the area suggested that “warmer climates tend to be more sensitive” to increases in CO2.

Professor Huber, based at the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University, Indiana, said it had been assumed since the 1970s that temperatures would rise between 1.5 degrees and 4.5 degrees for every doubling of the amount of CO2. But estimates based on climate data from millions of years ago pointed to increases of more than 2.5 degrees per doubling of CO2. In warmer climates that could be as high as 4.5 degrees.

He said the theory that the cooler tropics in those times acted as a kind of thermostat, mitigating the impact of higher global temperatures, had now been shown to be mostly wrong.

Research had confirmed, however, that the increase in temperatures tended to be much more dramatic at the poles.

The miocene era had temperatures between 5 and 8 degrees warmer than today, with no Greenland ice cap and Antarctica half its current size.  About 15 mln years ago the average  temperature in the arctic was around 20 degrees.

One impact of global warming would be an increase in heatwaves, which have already killed thousands of people in Europe, India and Russia in recent years.

The impact of hotter weather on humans’ ability to work outdoors would be significant.  Research into the impact of heat stress on people indicated that an average temperature increase of 2 per cent could reduce labour capacity in southern Australia by about ten per cent and as much as 30 or 40 per cent in the top end.

BD

15 October 2018

 

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