Top Leaderboard, Site wide
October 24, 2014
Truthdig: Drilling Beneath the Headlines
Sign up for Truthdig's Email NewsletterLike Truthdig on FacebookFollow Truthdig on TwitterSubscribe to Truthdig's RSS Feed

Get Truthdig's headlines in your inbox!








Truthdig Bazaar more items

 
Report

Global Warmth Trend Hides Local Variants

Email this item Email    Print this item Print    Share this item... Share

Posted on May 10, 2014

Photo by Atmospheric Infrared Sounder (CC BY 2.0)

By Tim Radford, Climate News Network

This piece originally ran on Climate News Network.

LONDON—US scientists have studied the obvious and found some surprises. The average rise in global temperatures because of rising levels of greenhouse gases is just that, an average – but it masks some unexpected variations.

Zhaohua Wu and colleagues at Florida State University report in Nature Climate Change that they looked at 100 years of data about land surface temperatures in every continent except Antarctica.

And they found that when global warming began to announce itself, it did so in different regions at different times, and some places even got cooler. The overall result was global warming, but new statistical analysis revealed a changing mosaic of temperature differences.

“Global warming was not as understood as we thought,” said Wu. The first clear pattern of warming emerged around the Arctic Circle and the sub-tropical regions in both hemispheres. The largest accumulated warming so far has been in the mid-latitude regions of the northern hemisphere.

Advertisement

Square, Site wide
Cooling Andes

The match of old data and new techniques enabled the researchers to make a series of world maps, offering “snapshots” of local average temperature increases at 10-year intervals from 1950 to 2009.

These reveal a pattern of warming that began in Labrador, Greenland, Scandinavia and eastern Siberia, with blotches of unexpected cooling in the western Sahara, inland Brazil and the Chilean Andes.

Over the following six decades, Asia, Europe and North America warmed conspicuously, and the southern hemisphere unevenly: by 2009 the only region that seemed to have actually grown cooler and stayed that way was in the Andes.

Consistent

In one sense, the research confirms what meteorologists and climate scientists and geographers have known all along: that the world is a complicated place.

Atmospheric circulation patterns in the two hemispheres are different, and atmospheric mixing is slow; oceans and atmosphere and land interact in ways that produce local temperature variations that have nothing in particular to do with anthropogenic global warming.

But the study could also help other researchers begin to tease out more precisely the differences between local and regional natural cycles of warming and cooling and the overall impact of greenhouse gas emissions, and help economists, politicians and planners prepare a little better for climate change.

And, the scientists warn, the trend they observe “seems to be consistent with the slowly increasing carbon dioxide in the atmosphere.”


New and Improved Comments

If you have trouble leaving a comment, review this help page. Still having problems? Let us know. If you find yourself moderated, take a moment to review our comment policy.

 
Right 1, Site wide - BlogAds Premium
 
Right 2, Site wide - Blogads
 
Join the Liberal Blog Advertising Network
 
 
 
Right Skyscraper, Site Wide
 
Join the Liberal Blog Advertising Network
 

A Progressive Journal of News and Opinion   Publisher, Zuade Kaufman   Editor, Robert Scheer
© 2014 Truthdig, LLC. All rights reserved.

Like Truthdig on Facebook