News / Science & Technology

Study: Pollution Led to African Drought

FILE - Through the 1980s, rainfall in the African Sahel declined more than anywhere else in the world, causing increased aridity, as evidenced by this dust storm in Senegal.
FILE - Through the 1980s, rainfall in the African Sahel declined more than anywhere else in the world, causing increased aridity, as evidenced by this dust storm in Senegal.

Related Articles

Unapproved US Wheat Sparks Trade Concerns

Some countries are suspending imports of U.S. wheat after unapproved genetically modified variety turns up in in northwestern state of Oregon

Video South Sudan Hopes New Mining Law Will Unearth Treasures

New nation seeks to attract foreign companies to eastern region to uncover natural resources that could transition country off its oil dependency

Ethiopia: Halting Dam's Construction Unthinkable

Tensions between Egypt, Ethiopia rising after Ethiopia began diverting water of a Nile River tributary to build continent’s biggest hydroelectric power plant
Decades of drought in central Africa may have had a surprising cause, according to new research that challenges the notion that the severe dry weather was triggered mainly by bad agricultural practices and overgrazing.

The research, done at the University of Washington, shows that the drought was at least partially caused by pollution in the Northern Hemisphere.

The researchers said that sulfate-laden aerosols coming from coal-burning factories from the 1960s through the 1980s actually slowed warming in the Northern Hemisphere compared to the Southern Hemisphere. This shifted tropical rain bands south, away from the Sahel region, and led ultimately to the near drying up of Lake Chad, which is used to water crops in surrounding areas.

Africa's Sahel regionAfrica's Sahel region
x
Africa's Sahel region
Africa's Sahel region
“We think people should know that these particles not only pollute air locally, but they also have these remote climate effects,” said the study’s lead author, Yen-Ting Hwang, a University of Washington doctoral student in atmospheric sciences.

Hwang’s co-author, Dargan Frierson, an associate professor of atmospheric sciences at the University of Washington, said “to some extent, science messed this one up the first time around.”

“People thought that a large part of that drought was due to bad farming practices and desertification,” he said. “But over the last 20 years or so we’ve realized that that was quite wrong, and that large-scale ocean and atmosphere patterns are significantly more powerful in terms of shaping where the rains fall.”

Researchers also studied rainfall in other places on the northern edge of the tropical rain band such as northern India and South America. These areas also experienced less rainfall during the 1970s and 1980s. Meanwhile, areas on the southern edge of the tropical rain band, such as northeast Brazil and the African Great Lakes, saw an increase in rainfall.

The researchers also looked at 26 climate models used by the Intergovernmental Panel on Climate Change, and found that nearly all the models showed some southward shift in rainfall and that slowed warming in the Northern Hemisphere was the “primary cause.”

“One of our research strategies is to zoom out,” said Hwang. “Instead of studying rainfall at a particular place, we try to look for the larger-scale patterns.”

There was a silver lining found in the research.

The study showed that steps taken in the United States and Europe in the 1960s and 1970s to reduce emissions and improve air quality began to improve the situation in the Sahel. While the area still suffers short-term droughts, “the long-term drought began to recover in the 1980s” as the rains began to move north again, according to the research.

“We were able to do something that was good for us, and it also benefited people elsewhere,” Frierson said.

It’s a trend that Hwang says is likely to continue.

As the atmosphere gathers higher levels of greenhouse gases, however, Hwang said the Northern Hemisphere will warm more rapidly than the Southern Hemisphere because there is more land.

“It’s not yet crystal clear what will happen,” she said. “There will be some shift in the tropical rains, and most models predict a northern shift.”

You May Like

HRW: Egypt's Trial of Morsi ‘Badly Flawed’

Human Rights Watch says former Egypt leader's detention without charge for more than three weeks after his removal from office violated Egyptian law; government rejects criticism More

Photogallery Lancet Report Calls for Major Investment in Surgery

In its report published by The Lancet, panel of experts says people are dying from conditions easily treated in the operating room such as hernia, appendicitis, obstructed labor, and serious fractures More

Music Industry Under Sway of Digital Revolution

Millions of people in every corner of the Earth now can enjoy a vast variety and quantity of music in a way that has never before been possible More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Study: Insecticide Damaging Wild Bee Populationsi
X
April 24, 2015 10:13 PM
A popular but controversial type of insecticide is damaging important wild bee populations, according to a new study. VOA’s Steve Baragona has more.
Video

Video Study: Insecticide Damaging Wild Bee Populations

A popular but controversial type of insecticide is damaging important wild bee populations, according to a new study. VOA’s Steve Baragona has more.
Video

Video Data Servers Could Heat Private Homes

As every computer owner knows, when their machines run a complex program they get pretty hot. In fact, cooling the processors can be expensive, especially when you're dealing with huge banks of computer servers. But what if that energy could heat private homes? VOA’s George Putic reports that a Dutch energy firm aims to do just that.
Video

Video Cinema That Crosses Borders Showcased at Tribeca Film Festival

Among the nearly 100 feature length films being shown at this year’s Tribeca Film Festival in New York City are more than 20 documentaries and features with international appeal, from a film about a Congolese businessman in China, to documentaries shot in Pakistan and diaspora communities in the U.S., to a poetic look at disaffected South African youth. VOA’s Carolyn Weaver has more.
Video

Video UN Confronts Threat of Young Radicals

The radicalization and recruitment of young people into Islamist extremist groups has become a growing challenge for governments worldwide. On Thursday, the U.N. Security Council heard from experts on the issue, which has become a potent threat to international peace and security. VOA’s Margaret Besheer reports.
Video

Video Growing Numbers of Turks Discover Armenian Ancestry

In a climate of improved tolerance, growing numbers of people in Turkey are discovering their grandmothers were Armenian. Hundreds of thousands of Armenians escaped the mass deportations and slaughter of the early 1900's by forced conversion to Islam. Or, Armenian children were taken in by Turkish families and assimilated. Now their stories are increasingly being heard. Dorian Jones reports from Istanbul that the revelations are viewed as an important step.
Video

Video Migrants Trek Through Western Balkans to Reach EU

Migrants from Africa and other places are finding different routes into the European Union in search of a better life. The Associated Press followed one clandestine group to document their trek through the western Balkans to Hungary. Zlatica Hoke reports that the migrants started using that route about four years ago. Since then, it has become the second-most popular path into Western Europe, after the option of sailing from North Africa to Italy.
Video

Video TIME Magazine Honors Activists, Pioneers Seen as Influential

TIME Magazine has released its list of celebrities, leaders and activists, whom it deems the world’s “most influential” in 2015. VOA's Ramon Taylor reports from New York.
Video

Video US Businesses See Cuba as New Frontier

The Obama administration's opening toward Cuba is giving U.S. companies hope they'll be able to do business in Cuba despite the continuation of the U.S. economic embargo against the communist nation. Some American companies have been able to export some products to Cuba, but the recent lifting of Cuba's terrorism designation could relax other restrictions. As VOA's Daniela Schrier reports, corporate heavy hitters are lining up to head across the Florida Straits - though experts urge caution.
Video

Video Kenya Launches Police Recruitment Drive After Terror Attacks

Kenya launched a major police recruitment drive this week as part of a large-scale effort to boost security following a recent spate of terror attacks. VOA’s Gabe Joselow reports that allegations of corruption in the process are raising old concerns about the integrity of Kenya’s security forces.
Video

Video Japan, China in Race for Asia High-Speed Rail Projects

A lucrative competition is underway in Asia for billions of dollars in high-speed rail projects. Cambodia, India, Indonesia, Malaysia Thailand and Vietnam are among the countries planning to move onto the fast track. They are negotiating with Japan and the upstart Chinese who are locked in a duel to revolutionize transportation across Asia. VOA Correspondent Steve Herman in Bangkok has details.
Video

Video Scientists: Mosquitoes Attracted By Our Genes

Some people always seem to get bitten by mosquitoes more than others. Now, scientists have proved that is really the case - and they say it’s all because of genes. It’s hoped the research might lead to new preventative treatments for diseases like malaria, as Henry Ridgwell reports from London.
Video

Video Bible Museum Coming to Washington DC

Washington is the center of American political power and also home to some of the nation’s most visited museums. A new one that will showcase the Bible has skeptics questioning the motives of its conservative Christian funders. VOA religion correspondent Jerome Socolovsky reports.
Video

Video Armenia and Politics of Word 'Genocide'

A century ago this April, hundreds of thousands of Armenians of the Turkish Ottoman empire were deported and massacred, and their culture erased from their traditional lands. While broadly accepted by the U.N. and at least 20 countries as “genocide”, the United States and Turkey have resisted using that word to describe the atrocities that stretched from 1915 to 1923. But Armenians have never forgotten.
Video

Video Afghan First Lady Pledges No Roll Back on Women's Rights

Afghan First Lady Rula Ghani, named one of Time's 100 Most Influential, says women should take part in talks with Taliban. VOA's Rokhsar Azamee has more from Kabul.
Video

Video New Brain Mapping Techniques Could Ease Chronic Pain

From Boulder, Colorado, Shelley Schlender reports that new methods for mapping pain in the brain are providing validation for chronic pain and might someday guide better treatment.

VOA Blogs