Catastrophic Floods are the new normal in Pakistan [View all]

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Catastrophic floods: the new normal in Pakistan
In Pakistan, where at least 207 people died in the past weeks' flooding, crippling and catastrophic floods have become the new normal. The past four consecutive monsoon seasons--2013, 2012, 2011, and 2010--have all seen top-five most expensive flood disasters in Pakistani history. The worst came in 2010, when the second heaviest monsoon rains of the past 50 years triggered rampaging floods that inundated one-fifth of the country, killing 1,985 people and causing a staggering $9.5 billion in damage--4% of the nation's GDP--according to the International Disaster Database, EM-DAT. Part of the reason for the increase in destructive flooding is due to poor flood control infrastructure, combined with a rising population and ineffective government policies.


Heavy monsoon rainfall events are increasing
A warming climate loads the dice in favor of heavier extreme precipitation events. This occurs because more water vapor can evaporate into a warmer atmosphere, increasing the chances of record heavy downpours. In a study published in Science in 2006, Goswami et al. found that the level of heavy rainfall activity in the monsoon over India had more than doubled in the 50 years since the 1950s, leading to an increased disaster potential from heavy flooding. Moderate and weak rain events decreased during those 50 years, leaving the total amount of rain deposited by the monsoon roughly constant. The authors commented, "These findings are in tune with model projections and some observations that indicate an increase in heavy rain events and a decrease in weak events under global warming scenarios." However, a 2011 study by Ghosh et al., "Lack of uniform trends but increasing spatial variability in observed Indian rainfall extremes", cautioned that the observed increase in heavy precipitation events in India had a very complicated pattern that was not easily quantified. In general, we should expect to see an increased number of disastrous monsoon floods in coming decades if the climate continues to warm as expected. Since the population continues to increase at a rapid rate in the region, death tolls from monsoon flooding disasters are likely to climb dramatically in coming decades. However, my greater concern for India is drought. The monsoon rains often fail during El Niño years, and more than 4.2 million people died in India due to droughts between 1900 - 2012. Up until the late 1960s, it was common for the failure of the monsoon rains to kill millions of people in India. The drought of 1965 - 1967 killed at least 1.5 million people. However, since the Green Revolution of the late 1960s--a government initiative to improve food self-sufficiency using new technology and high-yield grains--failure of the monsoon rains has not led to mass starvation in India. It is uncertain whether of not the Green Revolution can keep up with India's booming population, and the potential that climate change might bring more severe droughts. Climate models show a wide range of possibilities for the future of the Indian monsoon, and it is unclear at present what the future might hold. However, the fact that one of the worst droughts in India's history occurred in 2009 shows that serious droughts have to be a major concern for the future. The five worst Indian monsoons along with the rainfall deficits for the nation:

1) 1877, -33%
2) 1899, -29%
3) 1918, -25%
4) 1972, -24%
5) 2009, -22%



Figure 1. A temple is partially submerged in floodwaters in Jammu, India, Saturday, Sept. 6, 2014. (AP Photo/Channi Anand)

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