Wednesday, December 02, 2009

Climate Change skeptics - what about the last 10 years?

This figure was created by Robert A. Rohde from publicly available data. Click here for a full sized graph.

AGW skeptics and deniers frequently claim that global temperatures are lower over the last 10 years.

I have found a valuable resource at Climate4you here, which shows a variety of recent temperature readings.

It is clear that there is a sinuous line, with a notable peak in 1998, and generally since then, a flattish line with an sharp upturn in the lat 12 months.

This is consistent with the red line in the graph shown above, which has a fairly regular variation of about 10 years. The peak of 1998 is shown, and since then the line should fall before the upturn, which we can see on the Climate4you graphs.

It is tiring, but necessary, to meet all these claims of the skeptics. There is a consistent pattern in their arguments: pick one item out of the hundreds or thousands available in the field, and extrapolate from that item to draw the conclusion that we should do nothing that might damage the bottom line of the oil companies' account sheets.

Climate change FAQs.


Anonymous said...

How did you get a 5 year average to run to only 2 years on the graph?

DocRichard said...

Sorry, not quite sure what you are asking.

I am looking at the rhythm of the ~10 year wave. To my eye, it looks as if we are now towards end of the downward half of the wave.

Is that what you mean?

Steve Horsfall said...

Do you know anything about a scientist called Qin Bin Lu, who claims that the main human-generated greenhouse gas was CFCs, which we more or less stopped producing years ago, and that therefore the globe is now colling again? Some deniers I know online keep referring to him, but I can't find anything online to rebut them with.

DocRichard said...

Hi Steve
There is a mention of him here:
"His conclusions are based on observations that from 1950 up to now, the climate in the Arctic and Antarctic atmospheres has been completely controlled by CFCs and cosmic rays, with no CO2 impact."

His article is here:

It does seem to be about the (Ant)arctic climate, so the sceptics are extrapolating as per usual.

I hope to god he's right, or at least has a blim of rightness in his contribution.

Steve Horsfall said...