by Judith Curry and Peter Webster
The 2010 Pakistan floods began in July 2010 following following a series of heavy monsoon rains in the northern part of the country.
As the flood waters extended across the country, as much as 20% of Pakistan’s total land area was under water at the flood peak. While the impacts of the floods are still being assessed, the following impacts have been gleaned from the Wikipedia. It is estimated that over two thousand people have died and over a million homes have been destroyed, and more than twenty million people are injured or homeless as a result of the flooding. Officials estimate the total economic impact to be as much as USD $43B, with structural damages estimated to exceed USD $4B. It is estimated that floods have damaged 2,433 miles of highway and 3,508 miles of railway, and Pakistan’s power infrastructure has sustained substantial damages. Floodwaters destroyed and estimated 700,000 acres of cotton, 200,000 acres each of rice and cane, 500,000 tons of wheat, 300,000 acres of animal fodder, and 200,000 herd of livestock. In addition, household effects, farming equipment and stock seed were lost. Many farmers will be unable to meet the fall deadline for planting new seeds in 2010, implying a massive loss of local food production in 2011. Flood victims are at risk from gastroenteritis, diarrhea, and skin diseases, and flooding compounds the problem of cholera. Mines and artillery shells have been flushed downstream by the floods and scattered in low-lying areas, posing a future risk to returning inhabitants. The destruction wrought by the 2010 floods could set Pakistan back years or even decades, weaken its struggling civilian administration and add to the burdens on its military, distracting from their efforts to keep the Taliban in check.
The short-term issues are humanitarian, but the longer-term issue presents a global security imperative. Can the international climate community offer something to help Pakistan, other than a debate over whether global warming contributed to the floods and a mistake in the IPCC AR4 regarding the melting of the Himalayan glaciers?
Attribution to global warming?
Most of the response of the climate research community to this catastrophe has focused on the attribution of the floods, i.e. whether greenhouse warming played any role in causing the floods. As summarized by AOL News, the following statements have been made by UN representatives:
IPCC chief Rachendra Pachauri stated that while it would be scientifically incorrect to link any single set of events with human-induced climate change,
“the floods of the kind that hit Pakistan may become more frequent and more intense in the future in this and other parts of the world.”
The World Meteorological Organization (WMO) made the following statement:
“While a longer time range is required to establish whether an individual event is attributable to climate change, the sequence of current events matches IPCC projections of more frequent and more intense extreme weather events due to global warming.”
WMO director Ghassem Asrar said that higher Atlantic Ocean temperatures contributed to the intense monsoon rains that precipitated the flooding in Pakistan:
“There’s no doubt that clearly the climate change is contributing, a major contributing factor.”
Kevin Trenberth has gone further, to state:
“What we can say is that certain events would have been extremely unlikely to have occurred without global warming, and that includes the Russian heat wave and wildfires, and Pakistan, Chinese and Indian floods.”
The Islamic Bloc has been forthright in blaming the Pakistan floods on global warming. The Secretary General of the Organization of the Islamic Conference (OIC) stated:
“We have to act instantly and decide on the best way forward to support Pakistan which has been struck by the effects of global warming and climate change. Indeed, the Islamic World is paying a heavy price, resulting from the negative repercussions of climate change.”
Christiana Figueres, head of the U.N.’s Framework Convention on Climate Change, stated
“All these events are constant reminders to governments that they need to deal in a consummate manner together to address climate change.”
Apart from the issue of whether or not we can attribute a portion of a particular extreme weather event to global warming (this will be the topic of a future post), exactly what is the point of even trying to do so? Suppose for the sake of argument that an attribution study determined that 5% of Pakistan’s floodwaters could be attributed to global warming. Well, 95% of a catastrophe is usually still a catastrophe, unless that 5% was the proverbial straw that broke the camel’s back. Not only is the attribution exercise pointless in our opinion, but it is actually counterproductive in that it distracts from the reality at hand and diverts the efforts of the meteorological and climate communities from actually doing something that might be helpful.
A closer look at the causes of the catastrophe
During an active phase of the monsoon through July 2010, three periods of intense rainfall covered north and northwest Pakistan. Heavy monsoon rains exceeded 10 inches in some locations over the period July 27-30. However, Pakistan water experts believe that poor land management, outdated irrigation systems, and logging are at least as much to blame as the rainfall.
Illegal logging supported by the Taliban in the northwest province of Khyber-Pakhtunkhwa has felled as much as 70% of the forest in some districts. The lack of trees, combined with overgrazing by livestock, reduces the soil’s ability to hold water and leads to soil erosion. Flash flooding in the northern, mountainous areas then sends silt downstream, reducing the amount of water the river channel can hold. Diverting the Indus through irrigation channels has encouraged people to build closer to or even in the river channel. Many of the irrigation channels are built using techniques from the 18th century.
Whereas prominent Pakistani politicians, TV anchorpersons, and Punjab water engineers have stated that the catastrophe would not have occurred had the Kalabagh dam had been built, the Climate Himalaya Initiative argues that engineering structures and human error may have played a major role in the catastrophe. There are a substantial number of barrages (dams) on the Indus River that support irrigation and hydropower. The flood occurred when the rising river bed (owing to the huge silt deposition in the upstream areas) was trapped by the Taunsa barrage, obstructing the water flow. These heavy silt loads were then transported through western tributaries of the Indus River. Construction of protective levees and dykes has also contributed to raising the riverbed and the sedimentation of upstream areas; moreover, the rising riverbed levels have rendered protective levees ineffective. A rehabilitation project raised the crust level of the barrage by one foot so that silt entry into the right bank canal could be controlled; however the protective embankments were also to be raised by a foot but this was not done. Further, local accounts and media reports suggest that the barrage staff has failed to properly operate the newly installed motorised hoisting system. It has been reported 10 gates were not fully opened; the Climate Himalaya Initiative argues that this human failure, if true, could have been the main cause of the flood disaster.
Clearly, the situation is complex and further investigations are required to sort all this out.
Pakistan Meteorology
The summer of 2010 produced Pakistan’s worst flooding in 80 years. A perspective on this flood in the context of other natural disasters striking Pakistan can be found here. Severe floods were also seen in 1988, 1992 and 1995. Pakistan’s Flood Forecasting Division was established in 1978 with the support of the United Nations Development Programme (UNDP). An observational system supports measurement of discharge in the canals and also measurements of rainfall and snow melt in the catchment areas of the Indus. Quantitative precipitation measurement is supported by two precipitation radars in key locations of the catchment. A river routing model tracks river discharge and two day flood forecasts are provided each day. On June 21, the Pakistan Meteorological Department’s monsoon forecast cautioned that urban and flash flooding could occur from July to September in the north parts of the country. The initial flooding in the north was not predicted, although the subsequent downstream flooding was forecast a day or two in advance by the river routing model.
Challenges facing Pakistan
The events of the last two months not withstanding, Pakistan’s primary challenge has been drought and inadequate water resources. Pakistan frequently experiences droughts, along with most of southwest Asia. A severe drought at the national scale occurred during the period 1999-2002. Pakistan’s worst regional droughts have been: Punjab Province in 1899, 1920 and 1935; North-West Frontier Province in 1902 and 1951; and Sindh Province in 1871, 1881, 1899, 1931, 1947 and 1999. The most severe drought at the national scale ocurred during the period 1999-2002.
Water resources in Pakistan are exacerbated by its large population, which exceeds 170M, making it the world’s sixth most populous country. Pakistan’s population growth rate peaked around 1960, and has since declined to an annual growth rate of about 1.55% owing to declining fertility and birth rates; nevertheless Pakistan’s population is expected to exceed 200M by 2020. Water from the Indus is withdrawn for agriculture, industry and daily living to such an extent that the river is all but dry by the time it reaches the Arabian Sea.
A combination of lessening water flow, increasing population and economic development are contributing to a pending water crisis in Pakistan. The availability of water in Pakistan has declined from 5,000 cubic meters per capita 60 years ago to 1,200 cubic meters per capita in 2009. By 2020, the availability of water is estimated to diminish to about 800 cubic meters per capita. Transboundary water disputes with India have exacerbated these concerns.
Under the 1960 Indus Water Treaty, India is not permitted to build dams for the purpose of water storage on the Indus, Chenab, and Jhelum rivers, but it is allowed to make limited use of their waters in developing hydroelectric power projects. While the two countries have maintained cooperation for the past 40 years, bilateral talks between the two countries are increasingly focused on water disputes associated with dams being built by India. In 2008 Pakistan accused India of stopping Pakistan’s water from the Chenab River (a tributary of the Indus). Public debate in Pakistan on this issue raises complicated concerns of national security and traditional rivalry with India. An excellent overview of the situation is provided by Zawahiri (2009). With regard to the recent floods, it has been alleged that India released water from its dams up river because of fears the dams would collapse because of the excessive rainfall, and so exacerbating the problem in Pakistan.
Looking forward
While climate researchers and policy makers ponder whether the flood can be attributed to global warming, it seems to us that this emphasis diverts attention from actually using climate, meteorological and hydrological knowledge and research in the application of pressing current needs in the developing world. Substantial benefits would accrue directly for developing countries, as well as indirectly for other countries concerned with global security, by applying advanced research and technologies to support:
- improved river routing models for major rivers
- advanced techniques for providing probabilistic flood forecasts on timescales exceeding two days and integration of these forecasts into early warning systems, preparedness and contingency plans, and rehabilitation measures
- application of advanced dynamical and statistical methods to assess future risk of floods and droughts, and integrate this information into engineering assessments for future water structures
- improved probabilistic rainfall forecasts on timescales of days to weeks to enable farmers to optimize agricultural decision making regarding planting and harvesting.
Based upon our work in Bangladesh along these lines (see here and here), we have demonstrated that such developments are feasible and can be successfully integrated into national meteorological and hydrological services. We have contacted the Pakistan Meteorological Department and have had discussions with relevant personnel in USAID and UNDP regarding how we might help. The current situation in Pakistan is mired in both national and international politics. However, we hope that the international climate, meteorological and hydrological communities can offer something to help Pakistan other than a debate over whether global warming contributed to the floods and a mistake in the IPCC AR4 regarding the melting of the Himalayan glaciers.