Global Warming to Make Monsoons Worse
The monsoon rains have unleashed their fury over India and Nepal last week, flooding vast swathes in the north and causing immense landslides. So far, more than 150 people have died in the Himalayan state of Uttarakhand in India. The number is only likely to climb as some 62,122 people are stranded, according to the latest government figures.
The Indian government is racing to reach the survivors, many of whom had been visiting the temple town of Kedarnath, which is one of the most auspicious sites for Hindus. The temple is situated high in the Himalayas and close to the Mandakini River, which swelled its banks.
The region has received 385 millimeters of rainfall, much higher than the average of 71 millimeters seen in previous years, according to the Indian Meteorological Department. The flooding provided dramatic video footage in Indian media of waters sweeping away homes and bridges.
The monsoon is the cornerstone of the South Asian summer providing 80 percent of the annual rainfall to the region. When it fails, Indian farmers lurch toward food insecurity and the drought drives up prices for more than a billion people in India. When the skies open up, as it has this year, it often leads to flooding.
Of course, forecasting the severe weather associated with the monsoon would help governments plan ahead, and perhaps stop pilgrims from venturing into the Himalayas at a bad time. But such forecasting is notoriously difficult because meteorologists do not have a good model to simulate the monsoon’s behavior. The government can say if a year will have above or below average rainfall, and that’s about it.
Experts say that predictions of weather events associated with the monsoons will only get more difficult with climate change. As we pump more carbon dioxide into the air, the increasing temperatures will shift weather systems that are tied into the monsoon. These include the El Niño Southern Oscillation, sea surface temperatures, and even aerosols, which are tiny particles of soot and black carbon our industries emit, according to a 2009 study published in Nature Climate Change.
The unknowns could make the monsoon’s future floods even harder to predict, the author of that study told the New York Times.
The World Bank looked at the effect of climate change on the monsoon in a report this week. It considered two scenarios – a world warmer by 2 degree Centigrade (35 degree Fahrenheit), which could happen by 2030, and a world that is 4 degrees Centigrade (39 degree Fahrenheit) warmer by the end of the century. There are many models out there, but little consensus among them beyond the basics.
Some models suggest that rainfall could increase, and it will come in intense bursts, more likely to trigger flooding. When the world is 4 degrees Centigrade warmer, the intensity of the monsoon would increase by 10 percent and the amount of rainfall would swing between high to dry across years.
“Taken together, these changes imply that an extreme wet monsoon that currently has a chance of occurring only once in 100 years is projected to occur every 10 years by the end of the century,” the report states.
IMAGE: Indian farmers participate in a bull race at a paddy field during a monsoon festival in Altekhali village, some 110 km south of Kolkata, on June 20, 2013. More than a hundred bulls from nearby villages participated in the two-day event. (Dibyangshu Sarkar/Getty Images)