Wednesday, September 26, 2012

Climate change

There is a lot of talk nowadays about ‘combating climate change’ – an absurd expression which makes it sound like humans can stop the climate from changing. 
To achieve this they would need to control the sun, the earth’s orbit, the earth’s interior, its oceans and their currents, the biosphere, and key processes taking place in the atmosphere. 
It’s remarkable that ‘climate change’ has come to be virtually synonymous with ‘man-made climate change’ – which in turn is usually understood to mean climate change caused by greenhouse gas emissions from fossil fuel combustion 
Though some researchers believe that land-use changes (urbanization, deforestation, etc.) and pollutants such as black carbon (soot), mainly emitted by developing nations, have a greater impact on climate than greenhouse gas emissions. 
The mainstream view, as articulated by the UN’s climate panel (the IPCC), is that ‘most’ of the warming over the past 50 years is ‘very likely’ the result of anthropogenic greenhouse gas emissions. 
And that unless drastic measures are taken to slash emissions and switch to renewable sources of energy, the result will be dangerous, runaway warming. 
As already noted, there are good reasons to gradually reduce our dependence on carbon-based fuels. 
But the claim that this is necessary to save the world from catastrophic global warming is based on shoddy science and hot air (see Climate change controversiesClimategate). 
The earth has generally warmed since the depths of the Little Ice Age three or four hundred years ago, but in fits and starts, and most of the warming has been in night time, winter temperatures in the northern hemisphere. 
During the Medieval Warm Period (c. 950-1300) it was warmer than today, as it was in Roman times and during the Holocene Climate Optimum (3500-6000 years ago). 
During the last major ice age (Pleistocene), each of the last four interglacials, going back nearly half a million years, was several degrees warmer than today.
 David Pratt 

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