Sunday, September 22, 2013

John Cook's Climate Change Mythbusters 2

This is part of a series reposting material from John Cook's Skeptical Science website. Although he is a physicist rather than a specialist in climate science, he is a convinced "global warmist" and tries to rebut frequently-raised objections to the theory. However, it is always possible to question the data (e.g. this valuable note about measuring temperature) and the line of argument. Please help advance the debate - with facts and logic.

Solar activity & climate: is the sun causing global warming?
What The Science Says:
In the last 35 years of global warming, sun and climate have been going in opposite directions
Climate Myth: It's the sun
   "Over the past few hundred years, there has been a steady increase in the numbers of sunspots, at the time when the Earth has been getting warmer. The data suggests solar activity is influencing the global climate causing the world to get warmer." (BBC)
Over the last 35 years the sun has shown a slight cooling trend. However global temperatures have been increasing. Since the sun and climate are going in opposite directions scientists conclude the sun cannot be the cause of recent global warming.
The only way to blame the sun for the current rise in temperatures is by cherry picking the data. This is done by showing only past periods when sun and climate move together and ignoring the last few decades when the two are moving in opposite direction.

Figure 1: Global temperature (red, NASA GISS) and Total solar irradiance (blue, 1880 to 1978 from Solanki, 1979 to 2009 from PMOD).

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1 comment:

Sackerson said...

I suggest readers take a look at the NASA GISS website and see how much uncertainty there is: