Monday, August 19, 2013

With the forthcoming IPCC report, the contrarians finally agree we are changing the climate

John Abraham and Dana Nucitelli in "Climate Consensus- The 97%" blog in the Guardian (UK): We are weeks away from the much-anticipated release of the 5th climate report from the Intergovernmental Panel on Climate Change (IPCC). This organization has worked very hard to summarize the latest science on climate change, with thousands of donated hours from scientists around the globe. Although there are many other climate reports that synthesize the science, the IPCC is the largest and most comprehensive.

...So, what will the report say? I will admit that I have not read the report (it hasn't been released). Early drafts have been leaked, primarily by people trying to disrupt the process. These early drafts allow us to predict what will be contained within the report. An alternative approach is to review the immense body of literature from which the report is drawn. Based on the literature I've reviewed, I will predict the central themes of the IPCC report.

First, readers will likely find that this report is very similar to the last report (which was released in 2007). There will be slight changes to our confidence in certain observations. Climate models will have improved slightly, particularly in how they handle atmospheric particulates and cloud formation. A major effort since the last report has been the use of climate models to predict changes at the regional level. The report will likely say that this endeavor has had mixed success.

The new report will describe how climate changes are continuing without abatement. In particular, temperatures are rising, oceans are heating, waters are rising, ice is melting, the oceans are acidifying, heat is even moving to the deepest parts of the oceans. Just as importantly, the report will show that these changes are largely human-caused.

Some items are worse than we thought. In the last report, ice loss, particularly from Greenland, was a minor issue. Now, it is clear that not only Greenland, but also Antarctica are melting and this melt is raising sea levels. Furthermore, Arctic sea ice is being lost faster than previously reported.

The new report will likely have continued questions. For instance, how will hurricanes change in a warming world (the most powerful hurricanes are becoming even more powerful, but the change in frequency is not known) is still an open question....

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