Global Warming May Take a Holiday and That's a Problem

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Reuters is reporting that a new article in Nature argues that we can expect global average temperatures to stagnate, or even cool a bit, for the next decade or so. That's right, no global warming for a while. Why do researchers think this will happen? According to Reuters:

Natural climate changes may offset human-caused global warming over the next decade, keeping ocean temperatures the same or even temporarily cooling them slightly, German researchers said on Wednesday.

However, this short-term situation might create a problem if policymakers regarded it as a sign they could ease efforts to limit greenhouse gases or play down global warming.

"The natural variations change climate on this timescale and policymakers may either think mitigation is working or that there is no global warming at all," said Noel Keenlyside, a climate researcher at the Leibniz Institute of Marine Sciences in Germany who led the study.

Climate researchers have long predicted more greenhouse gases in the atmosphere would spur a general warming trend over the next 100 years. The study in the journal Nature is one of the first to take a shorter-term view.

This is useful because natural changes as opposed to human causes may play a bigger role in the short term, Keenlyside said.

His team made a computer model that takes into account natural phenomena such as sea surface temperatures and ocean circulation patterns.

They checked their work by producing a set of forecasts using data recorded over the past 50 years and found the retrospective forecasts were accurate, Keenlyside said.

Keenlyside immediately identified the real problem lurking in his prediction:

"This is important because policies are made in the short term," Keenlyside said. "Our results show we might not have as much change in climate over the next 10 years."

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At the Bali Climate Change Conference in December the world's governments committed to finalizing a new treaty by 2009 to control the emissions of greenhouse gases thought to be warming the atmosphere. At the Bali Conference I was heartened to hear the following prediction from the U.K.'s climate modelers at the Hadley Centre:

"We are now using the system to predict changes out to 2014. By the end of this period, the global average temperature is expected to have risen by around 0.3 degrees Celsius compared to 2004, and half of the years after 2009 are predicted to be hotter than the current record hot year, 1998."

I noted:

Since various temperature records—surface, satellite and weather balloons—have shown a temperature trend that increases at about 0.2 degrees per decade or less, this is a truly bold prediction.

I was heartened by the Hadley Centre prediction because it gives the world a chance to validate the predictions of climate models for future man-made warming in a policy relevant time frame. However, if the new research is correct, there will not be a strong empirical global warming signal in the next few years. That means the world's governments will largely be trusting the outputs of computer models as they try to effect vast changes in how the world's economy is fueled. That's very troubling.

Hat tip to H&R commenter Mick.