Climate change, along with rapid urbanization and deforestation, has caused turbocharged floods in Nepal that killed more than 240 people last month, scientists said Thursday.
Nepal was hit by its worst floods in decades in late September after torrential rains fed rivers, flooding the capital Kathmandu and other regions.
The World Weather Attribution (WWA), a network of scientists examining the role of human-caused climate change in extreme weather events, said the link between heavy rainfall and global warming is clear.
“If the atmosphere was not filled with fossil fuels, these floods would not be so powerful, so destructive and so deadly,” said researcher Mariam Zachariah, from Imperial College London.
Their analysis found chronic rainfall, which fell on land in tropical cyclones, was made at least 10 percent more severe and 70 percent due to climate change.
They warned that such “explosions” of rain “will become more severe, with the risk of more devastating floods” if the world does not stop burning fossil fuels.
Rain since September 26 has caused floods and landslides that have killed 246 people and left 18 missing, according to the Nepalese government.
The WWA, which uses modeling to compare climate conditions on our planet and one without human-caused climate change, said there is a high degree of uncertainty in the results because of complex rainfall patterns in the small, mountainous area affected.
However, the results were consistent with the growing scientific evidence of heavier rainfall in warmer climates, where the atmosphere holds more water.
The role of climate change is also compounded by other human-caused problems, they say, including rapid urbanization, and a fourfold increase in built-up areas in Kathmandu since 1990.
That was coupled with massive deforestation that disrupted the natural flow of water, with tree cover reduced by more than a quarter since 1989.
These floods destroyed hydroelectric power plants, washed away homes and tore away bridges. It was the latest catastrophic flood to hit the Himalayan nation this year.
“Climate change is no longer a distant threat,” said Roshan Jha, Researcher at the Indian Institute of Technology in Mumbai.
With every fraction of a degree of warming, the atmosphere can hold more moisture, leading to heavier rains, and catastrophic floods like this one.”
Nepal has started the construction of a large hydroelectric dam, which produces 99 percent of its electricity, and its output has quadrupled in the last eight years.
It has signed agreements to export surplus energy to India’s coal-dependent neighbours.
Earlier this month, the UN’s World Meteorological Organization said increasing floods and droughts are a “distressing sign” of what’s to come as climate change makes the world’s water cycle more unpredictable.
WMO chief Celeste Saulo called water “the canary in the coal mine of climate change”.
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