Featured Research

from universities, journals, and other organizations

Missing monsoon lead to 'years without a summer'

Date:
February 13, 2014
Source:
University of Bern
Summary:
Why do cold, rainy summers in Europe follow intense volcanic eruptions in the tropics? A research team may have found the answer: volcanic emissions in the atmosphere block sunlight and can thereby affect the amount of precipitation in other parts of the world.

Intense volcanic eruptions in the tropics lead to a weakening of monsoons and further result in rainy summers in parts of Europe (schematic figure).
Credit: Stefan Brönnimann

Why do cold, rainy summers in Europe follow intense volcanic eruptions in the tropics? A research team based at the University of Bern may have found the answer: volcanic emissions in the atmosphere block sunlight and can thereby affect the amount of precipitation in other parts of the world.

Related Articles


Historical records provide evidence that strong volcanic eruptions in the tropics are often followed by a cold and rainy summer in Central Europe. These "years without a summer" often lead to catastrophic famines; the last time in 1816 after the eruption of the Tambora volcano in Indonesia when even in Switzerland many people starved to death. Although it is known that volcanic eruptions lead to a cooling of the climate, it has until now been unclear where the additional rain comes from.

A newly published study from the international team of the Oeschger Center for Climate Change Research at the University of Bern brings light to this issue: "We believe that oscillations in the African monsoon may be responsible for the rainy European summers," says Stefan Brönnimann, principal investigator of the study from the Oeschger Center.

Less sunlight allows precipitation zones to shift

Brönnimann and his team are researching the effects of 14 intense tropical eruptions of the last 400 years on the climate of Europe and monsoon regions. The eruptions inject large amounts of aerosols into the stratosphere, where these microscopic particles reflect incoming sunlight. The decreased incoming solar radiation following volcanic eruptions leads to a cooling that is more pronounced over the continents than over the ocean. As a result, the summer monsoons in Africa and Asia are weakened.

According to the study, this not only leads to droughts in the Sahel, but also to a southward shift of the Atlantic low-pressure systems as well as enhanced thunderstorm formation. This process can, in turn, explain the increased precipitation over southern Central Europe and the northern Mediterranean, which was characteristic for the case of the year 1816.

Volcanic eruptions threaten food security

"The study shows, once again, how regions separated by great distances can affect each other climatically," says Stefan Brönnimann. The findings of the study therefore hold a very practical relevance for today, as the researcher states: "Cyclic rainfall regimes like the monsoon are important for food security in many parts of the world. Although large volcanic eruptions are quite rare, they help us better understand the monsoon systems."

As noted by Brönnimann, a better understanding of the connection between volcanic eruptions and precipitation can even prove to be useful in the fight against climate change. The suggestion of slowing down warming using so-called geoengineering techniques -- for example by artificially injecting particles into the stratosphere that reflect sunlight -- can be seen in a new light, as even this could influence monsoon systems.


Story Source:

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


Journal Reference:

  1. Martin Wegmann, Stefan Brönnimann, Jonas Bhend, Jörg Franke, Doris Folini, Martin Wild, Jürg Luterbacher. Volcanic influence on European summer precipitation through monsoons: Possible cause for “Years Without a Summer”. Journal of Climate, 2014; 140211144028000 DOI: 10.1175/JCLI-D-13-00524.1

Cite This Page:

University of Bern. "Missing monsoon lead to 'years without a summer'." ScienceDaily. ScienceDaily, 13 February 2014. <www.sciencedaily.com/releases/2014/02/140213103405.htm>.
University of Bern. (2014, February 13). Missing monsoon lead to 'years without a summer'. ScienceDaily. Retrieved March 29, 2015 from www.sciencedaily.com/releases/2014/02/140213103405.htm
University of Bern. "Missing monsoon lead to 'years without a summer'." ScienceDaily. www.sciencedaily.com/releases/2014/02/140213103405.htm (accessed March 29, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, March 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Antarctic Ice Is Melting Faster Than Ever

Antarctic Ice Is Melting Faster Than Ever

Newsy (Mar. 27, 2015) — A new study of nearly two decades of satellite data shows Antarctic ice shelves are losing more mass faster every year. Video provided by Newsy
Powered by NewsLook.com
Raw: Homes Near Landslide in Washington

Raw: Homes Near Landslide in Washington

AP (Mar. 27, 2015) — Aerial footage from KOMO shows several homes near a landslide in Washington. KOMO reports that at least one of the homes has been damaged. (March 27) Video provided by AP
Powered by NewsLook.com
Clean-Up Follows Deadly Weather in Okla.

Clean-Up Follows Deadly Weather in Okla.

AP (Mar. 26, 2015) — Gov. Mary Fallin has declared a state of emergency for 25 Oklahoma counties after powerful storms rumbled across the state causing one death, numerous injuries and widespread damage. (March 26) Video provided by AP
Powered by NewsLook.com
At Least Four Dead After Floods in Northern Chile

At Least Four Dead After Floods in Northern Chile

Reuters - News Video Online (Mar. 26, 2015) — At least four people have been killed by severe flooding in northern Chile after rains battered the Andes mountains and swept into communities below. Rob Muir reports. Video provided by Reuters
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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