Featured Research

from universities, journals, and other organizations

Study shows summer climate change, mostly warming

Date:
November 13, 2012
Source:
University of Colorado at Boulder
Summary:
Analysis of 90 years of observational data has revealed that summer climates in regions across the globe are changing -- mostly, but not always, warming -- according to a new study.

Analysis of 90 years of observational data has revealed that summer climates in regions across the globe are changing -- mostly, but not always, warming --according to a new study led by a scientist from the Cooperative Institute for Research in Environmental Sciences headquartered at the University of Colorado Boulder.

"It is the first time that we show on a local scale that there are significant changes in summer temperatures," said lead author CIRES scientist Irina Mahlstein. "This result shows us that we are experiencing a new summer climate regime in some regions."

The technique, which reveals location-by-location temperature changes rather than global averages, could yield valuable insights into changes in ecosystems on a regional scale. Because the methodology relies on detecting temperatures outside the expected norm, it is more relevant to understand changes to the animal and plant life of a particular region, which scientists would expect to show sensitivity to changes that lie outside of normal variability.

"If the summers are actually significantly different from the way that they used to be, it could affect ecosystems," said Mahlstein, who works in the Chemical Sciences Division of the National Oceanic and Atmospheric Administration's Earth System Research Laboratory.

To identify potential temperature changes, the team used climate observations recorded from 1920 to 2010 from around the globe. The scientists termed the 30-year interval from 1920 to 1949 the "base period," and then compared the base period to other 30-year test intervals starting every 10 years since 1930.

The comparison used statistics to assess whether the test interval differed from the base period beyond what would be expected due to yearly temperature variability for that geographical area.

Their analysis found that some changes began to appear as early as the 1960s, and the observed changes were more prevalent in tropical areas. In these regions, temperatures varied little throughout the years, so the scientists could more easily detect any changes that did occur, Mahlstein said.

The scientists found significant summer temperature changes in 40 percent of tropical areas and 20 percent of higher-latitude areas. In the majority of cases, the researchers observed warming summer temperatures, but in some cases they observed cooling summer temperatures.

"This study has applied a new approach to the question, 'Has the temperature changed in local areas?' " Mahlstein said. The study is in press in the journal Geophysical Research Letters, a publication of the American Geophysical Union.

The study's findings are consistent with other approaches used to answer the same question, such as modeling and analysis of trends, Mahlstein said. But this technique uses only observed data to come to the same result. "Looking at the graphs of our results, you can visibly see how things are changing," she said.

In particular the scientists were able to look at the earlier time periods, note the temperature extremes, and observe that those values became more frequent in the later time periods. "You see how the extreme events of the past have become a normal event," Mahlstein said.

The scientists used 90 years of data for their study, a little more than the average lifespan of a human being. So if inhabitants of those areas believe that summers have changed since they were younger, they can be confident it is not a figment of their imagination.

"We can actually say that these changes have happened in the lifetime of a person," Mahlstein said.

Co-authors on the study were Gabriele Hegerl from the University of Edinburgh in Scotland and Susan Solomon from Massachusetts Institute of Technology.

CIRES is a joint institute of CU-Boulder and NOAA.


Story Source:

The above story is based on materials provided by University of Colorado at Boulder. Note: Materials may be edited for content and length.


Journal Reference:

  1. Irina Mahlstein, Gabriele Hegerl, Susan Solomon. Emerging local warming signals in observational data. Geophysical Research Letters, 2012; 39 (21) DOI: 10.1029/2012GL053952

Cite This Page:

University of Colorado at Boulder. "Study shows summer climate change, mostly warming." ScienceDaily. ScienceDaily, 13 November 2012. <www.sciencedaily.com/releases/2012/11/121113122521.htm>.
University of Colorado at Boulder. (2012, November 13). Study shows summer climate change, mostly warming. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2012/11/121113122521.htm
University of Colorado at Boulder. "Study shows summer climate change, mostly warming." ScienceDaily. www.sciencedaily.com/releases/2012/11/121113122521.htm (accessed September 20, 2014).

Share This



More Earth & Climate News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) — An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) — Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) — Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins