Long-term global cooling ended in 19th century - study

WASHINGTON Mon Apr 22, 2013 10:01pm IST

A general view over a valley in the mountains of south Norway from beside the Lendbreen glacier, March 21, 2013. REUTERS/Oppland county council/Handout/Files

A general view over a valley in the mountains of south Norway from beside the Lendbreen glacier, March 21, 2013.

Credit: Reuters/Oppland county council/Handout/Files

Related Topics

Priyanka Gandhi Vadra, daughter of Congress party chief Sonia Gandhi, adjusts her flower garlands as she campaigns for her mother during an election meeting at Rae Bareli in Uttar Pradesh April 22, 2014. REUTERS/Pawan Kumar

Election 2014

More than 814 million people — a number larger than the population of Europe — are eligible to vote in the world’s biggest democratic exercise.  Full Coverage 

WASHINGTON (Reuters) - A global long-term cooling trend ended late in the 19th century and was followed decades later by the warmest temperatures in nearly 1,400 years, a sweeping study of temperature change showed.

The study, by a consortium of 78 authors in 24 countries, said its 2,000 years of data made it harder to discount the impact on higher temperatures of increased greenhouse gases due to human activity.

"Global warming that has occurred since the end of the 19th century reversed a persistent long-term global cooling trend," the National Science Foundation, one of the study's sponsors, quoted the report as saying.

Researchers found that various factors, including fluctuations in the amount and distribution of heat from the Sun and increases in volcanic activity, fed an overall change in temperature patterns.

The researchers were part of 2K Network of the International Geosphere Biosphere Program's Past Global Changes (PAGES) project. The research was published online on Sunday by the Nature Geoscience journal.

The National Science Foundation and the Swiss National Science Foundation jointly support the PAGES office. The U.S. agency called the study the most comprehensive evaluation of temperature change on the Earth's continents over the last 1,000 to 2,000 years.

The PAGES study relied mainly on analysis of tree growth rings, pollen, skeletons of coral that register sea surface temperatures, polar and glacier ice samples and lake sediments, the National Science Foundation said.

The 20th century ranked as the warmest or nearly the warmest century on all the continents except Antarctica. Africa lacked enough data to be included in the analysis.

An abstract of the report on the Nature Geoscience website said that reconstructions of temperature showed generally cold conditions between 1580 and 1880. The trend was punctuated in some areas by warm decades in the 18th century.

From 1971 to 2000, the weighted average temperature was higher than any other time in nearly 1,400 years, it said.

(Reporting by Ian Simpson; Editing by Greg McCune and Dan Grebler)

FILED UNDER:
Comments (0)
This discussion is now closed. We welcome comments on our articles for a limited period after their publication.

  • Most Popular
  • Most Shared

REUTERS SHOWCASE

Iran Oil Payment

Iran Oil Payment

India to make May-July oil payments to Iran - sources  Full Article 

Ferry Tragedy

Ferry Tragedy

Children's corpses in Korean ferry reveal desperate attempts to escape.  Full Article 

Ukraine Crisis

Ukraine Crisis

Russia says it will respond if Ukraine interests attacked.  Full Article 

Reassuring Allies

Reassuring Allies

Obama seeks to ease Asian allies' doubts during visit to Japan.  Full Article 

Moyes Speaks

Moyes Speaks

Sacked Moyes thanks Ferguson for Man Utd opportunity.  Full Article 

Mobile Ads

Mobile Ads

Google extends reach into mobile apps with new ad feature.  Full Article 

Allegations Denied

Allegations Denied

Allegations of teen sex abuse by three Hollywood execs denied.  Full Article 

Need for Speed

Need for Speed

United must move fast with vital window looming.  Article 

Reuters India Mobile

Reuters India Mobile

Get the latest news on the go. Visit Reuters India on your mobile device.  Full Coverage