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

US Firms Concerned About China's New Cyber Regulations

New rules would require technology companies doing business in financial sector to hand over their source code, adopt Chinese encryption algorithms More

WHO Focus on Ebola Shifts to Ending Outbreak

Focus to be less on building facilities and more on efforts to find infected people, manage their cases, engage with communities and ensure proper burials More

US Scientist Who Conceived of Groundbreaking Laser Technology Dies

Charles Townes, Nobel laureate, laser co-creator paved way for other scientific discoveries: CDs, eye surgery, metal cutters to name a few technologies that rely on lasers 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.
Super Bowl Ads Compete for Eyes on TV, Webi
X
January 29, 2015 9:58 AM
Super Bowl Sunday (Feb. 1) is about more than just the NFL's American football championship and big parties to watch the game. Viewers also tune in for the world famous commercials that send Facebook and Twitter abuzz. Daniela Schrier reports on the social media rewards for America’s priciest advertising.
Video

Video Super Bowl Ads Compete for Eyes on TV, Web

Super Bowl Sunday (Feb. 1) is about more than just the NFL's American football championship and big parties to watch the game. Viewers also tune in for the world famous commercials that send Facebook and Twitter abuzz. Daniela Schrier reports on the social media rewards for America’s priciest advertising.
Video

Video Theologians Cast Doubt on Morality of Drone Strikes

In 2006, stirred by photos of U.S. soldiers mistreating Iraqi prisoners, a group of American faith leaders and academics launched the National Religious Campaign Against Torture. It played an important role in getting Congress to investigate, and the president to ban, torture. VOA's Jerome Socolovsky reports.
Video

Video Freedom on Decline Worldwide, Report Says

The state of global freedom declined for the ninth consecutive year in 2014, according to global watchdog Freedom House's annual report released Wednesday. VOA's William Gallo has more.
Video

Video As Ground Shifts, Obama Reviews Middle East Strategy

The death of Saudi Arabia’s king, the collapse of a U.S.-friendly government in Yemen and a problematic relationship with Israel’s leadership are presenting a new set of complications for the Obama administration and its Middle East policy. Not only is the U.S. leader dealing with adversaries in Iran, the Islamic State and al-Qaida, but he is now juggling trouble with traditional allies, as White House correspondent Luis Ramirez reports.
Video

Video MRI Seems to Help Diagnose Prostate Cancer, Preliminary Study Shows

Just as with mammography used to detect breast cancer, there's a lot of controversy about tests used to diagnose prostate cancer. Fortunately, a new study shows doctors may now have a more reliable way to diagnose prostate cancer for high risk patients. More from VOA's Carol Pearson.
Video

Video Smartphones About to Make Leap, Carry Basic Senses

Long-distance communication contains mostly sounds and pictures - for now. But scientists in Britain say they are close to creating additions for our smartphones that will make it possible to send taste, smell and even a basic touch. VOA’s George Putic reports.
Video

Video NASA Monitors Earth’s Vital Signs From Space

The U.S. space agency, NASA, is wrapping up its busiest 12-month period in more than a decade, with three missions launched in 2014 and two this month, one in early January and the fifth scheduled for January 29. As VOA’s Rosanne Skirble reports, the instruments being lifted into orbit are focused on Earth’s vital life support systems and how they are responding to a warmer planet.
Video

Video Saved By a Mistake - an Auschwitz Survivor's Story

Dagmar Lieblova was 14 when she arrived at Auschwitz in December 1943, along with her entire Czech Jewish family. All of them were to die there, but she was able to leave after several months due to a bureaucratic mix-up which saved her life. Now 85, with three children and six grandchildren, she says she has a feeling of victory. This report by Ahmad Wadiei and Farin Assemi, of RFE/RL's Radio Farda is narrated by RFE’s Raymond Furlong.

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More

All About America

AppleAndroid