How Climate Change Contributed to Massive Floods in South Asia

Heavy monsoon rains have caused disastrous floods and left millions displaced in South Asia. Like Harvey, climate change likely played a role.
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Heavy monsoon rains have caused disastrous floods and left millions displaced in South Asia. Like Harvey, climate change likely played a role.
People wade through a flooded street in Mumbai, India, on August 29th, 2017.

People wade through a flooded street in Mumbai, India, on August 29th, 2017.

While most Americans are fixated on Hurricane Harvey, which continues to break rainfall records since making landfall along the coast on Friday, an even deadlier disaster is unfolding in South Asia. Across Nepal, Bangladesh, and India, an exceptionally strong monsoon season has left almost 1,200 dead and displaced or affected tens of millions more. Heavy rains led to unprecedented landslides and floods—as much as a third of Bangladesh is under water—leaving communities cut off as they face food and fresh water shortages and disease threats that will remain long after the water recedes.

"This is not normal," Reaz Ahmed, the director-general of Bangladesh's Department of Disaster Management, told CNN. "Floods this year were bigger and more intense than the previous years."

Climate change appears to be intensifying the region's monsoon rains. Rising sea surface temperatures in South Asia, for example, led to more moisture in the atmosphere, providing this year's monsoon with its ammunition for torrential rainfall—much the same way abnormally high water temperatures in the Gulf of Mexico intensified Harvey before it stalled over Texas.

Rising sea surface temperatures in South Asia led to more moisture in the atmosphere, providing this year's monsoon with its ammunition for torrential rainfall.

Warmer air temperatures in high latitude regions of the globe have also increased glacier melt, which has, in turn, raised the Himalayan rivers' water levels and heightened the risk of flooding. That flooding has proven very costly; some 500 million people live within the flood plains of the Ganges and Brahmaputra rivers in India and Bangladesh. Unchecked urban development has also left many communities in the region without proper drainage systems, which only compounds the problem when a natural disaster strikes. "A lot of the urbanization ... has happened in a largely unplanned matter," Abhas Jha, the World Bank sector manager for Transport, Urban and Disaster Risk Management for East Asia and the Pacific, told CNN in July. "For instance they don't have risks adequately taken into account, they don't invest enough in sustainable drainage."

The same has been said of Texas' hardest hit city. "Houston has been sprawling out into the swamp for decades, largely unplanned and unzoned," Eric Holthaus wrote Monday in Politico. "Now, all that pavement has transformed the bayous into surging torrents and shunted Harvey’s floodwaters toward homes and businesses."

But the man-made contributions to the disasters in both the U.S. and South Asia suggest that there might be man-made solutions as well. Climate scientists have been predicting for years that climate change would lead to more frequent and more extreme weather events; evidence now abounds that they were right. The flooding in Texas and South Asia should be a wake-up call that forces officials to curtail climate change-causing carbon emissions enough to prevent its worst effects—or at least to consider climate change when they begin to rebuild.

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