Global warming: March update

The so-called warming pause or hiatus since 1998 has generated quite a bit of heat recently.

The Intergovernmental Panel on Climate Change has addressed it, as has two of the most-prominent names in the climate-change community, NASA’s Jim Hansen and Penn State’s Michael Mann.

Since 1998, the year that a record El Nino cooked the atmosphere over the tropical Pacific, data show that the rate of global warming has lost some steam. Dare we call it global lukewarming?

If it is not properly a “pause” or a “hiatus” – it is at least a slowing. Hansen and Mann attribute it to a combination of natural variability and changes in “external” forcing and insist it won’t last.

We promise to keep score.

 The National Climate Data Center publishes monthly global temperature reports based on surface data, as do NASA satellite specialists, based on profiles of the lower atmosphere. Of late, they have tracked closely.

 The NASA report, which came out today, showed that last month’s global temperatures were about 0.3 degrees above the 30-year averages for March.  

In the universe of months starting with January 1998, March ranks in the cooler half.

 However, among all Marches in the satellite dataset , last month was tied for the ninth-warmest, and the eight months ahead of it all have occurred since 1998.

 We expect NCDC’s report later in the week.

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