-Lord Julian Hunt is visiting Professor at Delft University, and former Director-General of the UK Met Office. The opinions expressed are his own.-
The unusually large rainfall from this year’s monsoon has caused the most catastrophic flooding in Pakistan for 80 years, with the U.N. estimating that around one fifth of the country is underwater. This is thus truly a crisis of the very first order.
Heavy monsoon precipitation has increased in frequency in Pakistan and Western India in recent years. For instance, in July 2005, Mumbai was deluged by almost 950 mm (37 inches) of rain in just one day, and more than 1,000 people were killed in floods in the state of Maharashtra. Last year, deadly flash floods hit Northwestern Pakistan, and Karachi was also flooded.
It is my clear view that this trend is being fueled both by global warming (which also means extremes of rainfall are also a growing world-wide trend), and indeed potentially by any intensification of the El-Nino/La-Nino cycle.
To understand the reasons why global warming is playing a role here, one needs to look at the main climatic trends in South Asia. In addition to more extreme rainfall events, there is also a decreasing thickness of ice over the Tibetan plateau and changing patterns of precipitation, with less snow at higher levels, plus more rapid run off from mountains.