Coal-Burning in the U.S. and Europe Caused a Massive African Drought

A drought in the '60s and '70s that killed thousands was previously attributed to bad farming practices. The real cause is even worse.
Sahel-banner.jpg
Starving cattle are shown wandering in the Sahel district of Senegal where, as in the other African states, entire populations died from hunger following a catastrophic drought, in this May 17, 1973 photo. (AP)

A famine ravaged North Africa's Sahel region from the mid-1960s through the early 1980s, killing 100,000 people and leaving 750,000 more dependent on food aid. Between 1972 and 1974, the U.S. shipped 600,000 tons of grain to the region, which accounted for about half of the total relief at the time. But even as they worked to save Africans from starvation, what Westerners at the time didn't know is that the United States and Europe played a big role in the drought itself.

New research from the University of Washington shows that air pollution from the Northern Hemisphere indirectly caused reduced rainfall over Africa's largely arid Sahel region, causing Lake Chad, a major local water source, to dry up, and leading to widespread crop failures.

Originally, the drought was blamed on overgrazing and poor land management, but a forthcoming study in Geophysical Research Letters shows that the environmental catastrophe was partly the result of factory emissions in the Western world. As the University of Washington puts it:

Aerosols emanating from coal-burning factories in the United States and Europe during the 1960s, '70s and '80s cooled the entire Northern Hemisphere, shifting tropical rain bands south. Rains no longer reached the Sahel region, a band that spans the African continent just below the Sahara desert.

Burning coal generates sulfate aerosols, particles that create hazy air and reflective clouds that cool the climate around them. Meanwhile, the world overall was getting warmer, thanks to rising greenhouse gas emissions, so the net temperature felt normal to Northern Hemisphere-dwellers at the time, the authors wrote.

precipmap.jpg

This graphic shows global precipitation change between 1931-1950 and 1961-1980. The African Sahel, center, is much drier, while east Africa and east Brazil are wetter. (Dargan Frierson/University of Washington)

This cooling disrupted normal rainfall: Other areas near the same latitude as North Africa, like some northern parts of India, also saw reduced precipitation during those decades. As further proof, the researchers found that the normal rain patterns were restored soon after clean-air laws were passed in Europe and the U.S.

sahelrain.jpg

These days, it appears the trend is being reversed: The Northern Hemisphere is warming faster than the Southern Hemisphere, a trend that's shifting tropical rainfall northward.

"To some extent, science messed this one up the first time around," the study's co-author, UW associate professor of atmospheric sciences Dargan Frierson, said. "People thought that a large part of that drought was due to bad farming practices and desertification."

While it's satisfying to have an explanation for this phenomenon (and to exculpate Sahelian farmers), in some ways the real answer is even more unsettling than the previously-held, wrong one.

Presented by

Olga Khazan is a staff writer at The Atlantic, where she covers health.

The Best 71-Second Animation You'll Watch Today

A rock monster tries to save a village from destruction.

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register.

blog comments powered by Disqus

Video

The Best 71-Second Animation You'll Watch Today

A rock monster tries to save a village from destruction.

Video

The Case for Napping at Work

Most Americans don't get enough sleep. More and more employers are trying to help address that.

Video

A Four-Dimensional Tour of Boston

In this groundbreaking video, time moves at multiple speeds within a single frame.

Video

Who Made Pop Music So Repetitive? You Did.

If pop music is too homogenous, that's because listeners want it that way.

Video

Stunning GoPro Footage of a Wildfire

In the field with America’s elite Native American firefighting crew

More in Global

Just In