Severe monsoon-rains and flooding have killed at least 1,033 people, including 348 children, and left 1,527 more injured in Pakistan since mid-June.
The country’s National Disaster Management Authority (NDMA) added that 119 people had died and 71 injured in the last 24 hours alone.
At least 33 million people have been affected by the disaster, Pakistan’s Minister for Climate Change Sherry Rehman said on Thursday. She called the floods “unprecedented” and “the worst humanitarian disaster of this decade.”
According to World Resources Institute, Pakistan is among the top 15 countries exposed to the risk of river floods; climate change is expected to further expand flood-prone areas. Around 715,000 people are affected by floods in Pakistan every year and the number is expected to rise to 2.7 million people by 2030.
Causes of Floods
Pakistan is subject to periodic flooding of rivers. Glacier-melting, monsoon rains, deforestation in watershed, and siltation are among the principal divers of riverine floods in Pakistan. In the last few decades, climate change has emerged as an important driving force behind floods in Pakistan, primarily by affecting glacier-melting, and by interfering in summer monsoon patterns.
Glacier-Melting: Himalayan glacier-melting has always been a great source of feeding water into the Indus River system, the lifeline of Pakistan. However, with ongoing climate change, the rate of glacier-melting has exacerbated to the levels of concern. On one hand, we are losing a vital resource, and on the other hand, excessive volume of melt-out water contributes to flooding almost every year.
Monsoon Rains: Summer monsoon rains lasting from June to September are the annual raining season of Pakistan. Water carried by monsoon rains feeds rivers and irrigates croplands. Monsoon rains have become erratic as a consequence of climate change, adding to the odds of flooding in rivers already swollen by glacial melt-out water. According to a ClimateWire investigation, flash floods that devastated the Northern Areas of Pakistan in 2010 were a result of northwesterly shift of monsoon. The volume of water and debris sent downstream by these flash floods, coupled with heavy monsoon in Punjab and Sindh, resulted into the worst floods in the history of Pakistan.
Deforestation in Watershed: Apart from natural causes, a major man-made cause is massive deforestation in watersheds. At the time of birth, Pakistan had 33% of its land covered by forests which has now shrunk to a mere 3-4%. Other than local people, a well-organized “timber mafia” under the shadow support of politicians and forest officers involved in malpractice, is the main culprit behind the loss of essential forest cover.
Siltation: Siltation, another main contributor to riverine flooding, refers to the introduction and deposition of sediments (suspended particles) into a water body. These particles settle to the stream bed, and reduce its water-holding capacity, causing them to sprawl outside their banks even on a mild increase in the volume of water. Sediments also fill up water storage reservoirs resulting in a reduction of their water-storage capacity. Tarbela dam has lost 26% of its storage capacity and the rest of the dams have lost an average 23% because of siltation, thereby compounding flood risks. Deforestation in watershed is the direct cause of increased downstream siltation in rivers and filling up of reservoirs. Massive hill torrents from bare soils carry a huge amount of sediments into water bodies.
How it Turn into a Disaster?
While various natural and man-made forces are contributing to floods, the scale of disaster is intensified by many other factors of utmost concern:
Alterations in flood plains: There are vast inland flood plains in the Punjab and Sindh provinces capable of absorbing floods, and dissipating their intensity. However, since waters of Indus River system have receded in recent decades, the problem of encroachments has intensified. There is a network of land grabbers under the supervision of influential politicians and landlords which brings flood plains under illegal occupation. Thousands of people use flood plains for agriculture and/or housing. As a consequence, the scale of disaster raises many folds; often the loudest cries are from these illegal occupants. Moreover, alterations in flood plains change the natural course of flood water causing more destruction. In Sindh province, flood plains have been most severely altered. There are illegal occupants and permanent structures such as roads and bridges as well.
