Leh flood: the climate change nexus

Leh's terrain is not used to heavy rains Photo: Monsoon

From the editor’s desk
As humanitarians help people in the hill town of Leh get back to normalcy after the worst flood in their memory, scientists are wondering if the cloudburst on on 5 – 6 August 2010 that inundated their place was an indicator of climate change.

The cold desert of Leh with an annual rainfall of some 100 mm just cannot take a heavy downpour. A cloudburst that could involve some 100 mm in an hour is a sure way to a disaster. The local geography and infrastructure are not prepared to handle such a sudden fall and flow of water. The town has yet to get back to normal. The cloudburst has claimed at least 175 lives and left over 300 people missing, according to information posted by Indian Red Cross Society in Reliefweb.

Local people have been saying that of late there is less snow and heavy rain. Glaciers that fed their fields have receded – prompting enterprising local people to build their own artificial ones! Some scientists argue that a rising temperature trend can lead to precipitation more in the wet form. Dr M P Sah of the Dehradun-based Wadia Institute of Himalayan Geology has noted that there has been an increase in cloudbursts broadly in the Himalayan area. At the ‘Geomatics 2009’ National Conference held at Dehradun in February 2009 he noted: “This rising temperature trend leads to precipitation more in wet form therefore, in cold desert areas of Himalaya cloud burst and occasional debris flow are reported from Spiti and Ladakh area. The frequencies of cloud burst events are more common from the different parts of the Himalaya in the recent years…”

As it happens this year is going to be one of the warmest as media reports quoting the US National Oceanic and Atmospheric Administration (NOAA) suggest. The trend is continuing as the world is seeing a gradual rise in temperatures thanks to global warming. “We will always have climate extremes. But it looks like climate change is exacerbating the intensity of the extremes,” Omar Baddour, head of climate data management applications at WMO headquarters in Geneva recently told Aister Doyle of Reuters.

The Leh incident – along with floods raging across the border in Pakistan and unusual weather phenonmena elsewhere – is seen by many as part of a pattern, a rise in the frequency of extreme events. For Leh, the rainfall for August is on an average is 15.4 mm as the India Meterological Department (IMD) points out. At the time of the cloudburst an Indian Air Force (IAF) met observatory reported 12.8 mm of rainfall during 05.30 am 5 August to 05.30 August – nowhere near a cloudburst.  Cloudbursts are highly localised events that happen for a short duration. So it is difficult to pinpoint them in time and space – Geoclimatologists study the imprint they leave on ground. People talk about them in folklores. Till we get enough data and scientists can fit it into some pattern it may be tough to explain this unusual phenomenon.

While scientists do believe that climate change shifts the patterns of rainfall that atmospheric processes that lead to precipitation, they caution that it is hard to find a one-to-one connection. Effects of these changing persistent patterns may get more severe as the world get warmer and water cycle gets more vigorous. That is why there are more intense cyclones, extreme rainfall events and more heatwaves in many parts of the world including India these days than they were half a century ago.

To look at the monsoon, more of its rainfall is now becoming extreme events than they used to be. “With global warming, it is expected that frequency of extreme weather events will increase,” Dr M Rajeevan, one of the best-known climate scientists in India recently told the media. “At many places, including over India, such trends are now observed,” said Rajeevan, who is currently a senior scientist at ISRO’s National Atmospheric Research Laboratory (NARL), Tirupati. Scientists, however, insist that no single event can be directly attributed to climate change. As Rajeevan added: “Though it is easier to speculate, Pakistan and Leh events cannot be clearly attributed to global warming. These events can be explained with (other) physical reasons.”

Making a one-to-one connection with climate change may be difficult.  But a disaster is a disaster. People have lost lives and have suffered. It must be recognised that disasters come in a package with environmental changes, economic stress, climatic variations, worsening hazards and poor coping capacities. The dramatic event in Leh should come as an eye opener. And its response should address these various facets that make people’s survival more difficult.