Featured Research

from universities, journals, and other organizations

Earth's Recent Warming Trend Is Truly Global, University Of Michigan Researchers Conclude

Date:
April 12, 2002
Source:
University Of Michigan
Summary:
A team of Michigan and Canadian researchers has found that over the past half-century, the rocks of Earth's continental crust have warmed significantly, similar to the warming of the oceans, atmosphere and ice reported by other investigators last year. Showing that the continents have warmed along with the other principal components of Earth's climate system indicates that the warming of our planet has been truly global, the researchers say.

ANN ARBOR --- A team of Michigan and Canadian researchers has found that over the past half-century, the rocks of Earth's continental crust have warmed significantly, similar to the warming of the oceans, atmosphere and ice reported by other investigators last year. Showing that the continents have warmed along with the other principal components of Earth's climate system indicates that the warming of our planet has been truly global, the researchers say.

"Our findings remove any last doubt that this is anything other than a global phenomenon," says Henry Pollack, U-M professor of geological sciences, who collaborated on the work with U-M assistant research scientist Shaopeng Huang, U-M graduate student Jason Smerdon, and Hugo Beltrami of St. Francis Xavier University in Nova Scotia. The researchers report their work in the April 15 issue of Geophysical Research Letters, a leading geology journal.

"Until recently, the story of global warming has been built up primarily on the basis of temperature measurements at the surface of the land and oceans," says Pollack. "These measurements have been painstakingly acquired and put together, and there has been enough information to reconstruct a temperature history for the Earth's surface for the past 140 years. But it's all based on surface measurements." That approach was augmented about a year ago when another group of researchers determined how much heat had been gained during the last half of the 20th century throughout the atmosphere, the depths of the oceans, and the cryosphere (the portion of Earth's surface where water is in solid form such as sea ice, snow cover, glaciers, ice caps and permafrost). However, their analysis left out one major component of the climate system: continental rock, which covers almost 30 percent of the planet's surface.

Now, Pollack, Beltrami and colleagues have completed the picture by determining how much the continental rock has warmed in recent centuries. The scientists based their analysis on temperature readings taken by lowering sensitive thermometers into holes drilled from Earth's surface into rock formations on six continents (Africa, Asia, Europe, North America, South America, and Australia). These readings can reveal how temperatures have changed in the past, because the heat that surface rocks absorb from the atmosphere travels slowly downward into subsurface rocks, leaving a distinct signature in the rocks. Signals from short-term daily or seasonal variations penetrate only a few meters, and Earth quickly "forgets" them, but temperature changes that take place over hundreds of years are preserved in deeper rock.

The researchers' calculations, based on data from 616 bore holes, found evidence of an increase in the heat content of the continents over the past 500 years, with more than half of that heat gain occurring during the 20th century and nearly one-third of it since 1950.

"The magnitude of the warming we estimate is very similar to that which has come from the studies of the ocean, atmosphere and ice," says Pollack. "We believe it makes a persuasive case that the warming has been truly global."


Story Source:

The above story is based on materials provided by University Of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan. "Earth's Recent Warming Trend Is Truly Global, University Of Michigan Researchers Conclude." ScienceDaily. ScienceDaily, 12 April 2002. <www.sciencedaily.com/releases/2002/04/020412075120.htm>.
University Of Michigan. (2002, April 12). Earth's Recent Warming Trend Is Truly Global, University Of Michigan Researchers Conclude. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2002/04/020412075120.htm
University Of Michigan. "Earth's Recent Warming Trend Is Truly Global, University Of Michigan Researchers Conclude." ScienceDaily. www.sciencedaily.com/releases/2002/04/020412075120.htm (accessed September 3, 2014).

Share This



More Earth & Climate News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands of Fish Dead in Mexico Lake

Raw: Thousands of Fish Dead in Mexico Lake

AP (Sep. 2, 2014) — Over 53 tons of rotting fish have been removed from Lake Cajititlan in western Jalisco state. Authorities say that the thousands of fish did not die of natural causes. (Sep. 2) Video provided by AP
Powered by NewsLook.com
Raw: Iceland Volcano Spewing Smoke

Raw: Iceland Volcano Spewing Smoke

AP (Sep. 2, 2014) — The alert warning for the area surrounding Iceland's Bardarbunga volcano was kept at orange on Tuesday, indicating increased unrest with greater potential for an eruption. Smoke is spewing from the volcano, and lava is spouting nearby. (Sept. 2) Video provided by AP
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) — The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Halliburton Reaches $1B Gulf Spill Settlement

Halliburton Reaches $1B Gulf Spill Settlement

AP (Sep. 2, 2014) — Halliburton's agreement to pay more than $1 billion to settle numerous claims involving the 2010 BP oil spill could be a way to diminish years of costly litigation. A federal judge still has to approve the settlement. (Sept. 2) 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