Floods in Pakistan ‘were made 50% worse by global warming’ | Climate crisis


Intense rains that caused devastating floods across Pakistan have been made worse by global warming, which has also made future floods more likely, scientists have found.

Climate change could have increased the most intense rainfall by around 50% over a short period in the most affected areas, according to a study by an international team of climatologists.

The floods were a once-in-a-100-year event, but similar events are likely to become more frequent in the future as global temperatures continue to rise, the scientists said.

Scientists have not been able to quantify exactly how more likely flooding has been made by the climate crisis, due to the high degree of natural monsoon variability in the region. However, they said there was a 1% chance of such rainfall occurring each year, and an event such as this summer’s floods would likely have been much less likely in a world without greenhouse gas emissions. of human origin.

Friederike Otto, a senior lecturer at the Grantham Institute for Climate Change and the Environment at Imperial College London, said the “fingerprints” of global warming could be clearly seen in the floods in Pakistan, which were consistent with what climatologists had predicted for extreme conditions. Weather report.

“We can say with great confidence that [the rainfall] would have been less likely to happen without climate change,” she said. “The intensity of the precipitation has increased a lot.” Historical records have shown that heavy rainfall has increased dramatically in the region since mankind began dumping greenhouse gases into the atmosphere, scientists have found.

Otto added: “Our evidence suggests that climate change played an important role in the event, although our analysis does not allow us to quantify the magnitude of this role. Indeed, it is a region with very different weather patterns from year to year, making it difficult to see long-term changes in observed data and climate models.

About a third of Pakistan has been affected by the floods, with water covering more than a tenth of the country after more than three times the average rain fell in August. Nearly 1,500 people died and 33 million people were affected, with 1.7 million homes destroyed.

For the country as a whole, it was the wettest August since 1961, and for the two southern provinces of Sindh and Balochistan, the wettest on record, with about seven to eight times more rain than habit.

Although the increase in precipitation has been influenced by climate change, local factors have also played a role in the floods and their impacts. For example, forests in the region have been cut down for many decades and mangroves removed, while man-made dams, irrigation and other watercourse alterations have also impacted natural water regimes. flood. Poor infrastructure, such as precariously built houses in flood-prone places, has also caused more people to suffer as a result of the floods.

Ayesha Siddiqi, Assistant Professor in the Department of Geography at the University of Cambridge, said: “[Flooding] touched places where local socio-ecological systems were already compromised enough. This disaster is the result of a vulnerability built up over a number of years and should not be viewed as the result of a single event.

Pakistan faces a cost of at least $30 billion in damage, with the loss of food crops alone amounting to around $2.3 billion, a particularly heavy burden at a time of rising commodity prices. food in the world. Around 18,000 km2 of cultivated land was destroyed, including around 45% of the cotton crop, one of Pakistan’s main exports, and around 750,000 head of cattle were killed.

The Pakistan flood report comes from World Weather Attribution, a group of scientists around the world trying to discern the influence of human-induced climate change on extreme weather events. They analyze these events in real time to produce quick answers on whether climate change has influenced extreme weather, a process that used to take years.

Previous studies have shown that climate change exacerbated heat waves in India, Pakistan and the UK earlier this year, and floods in Brazil. WWA found last year that the heat wave in the Pacific Northwest region of the United States would have been “virtually impossible” without climate change.

A recent Guardian analysis revealed how the climate crisis is ‘supercharging’ weather events, with devastating consequences.

Otto said countries meeting in November for the UN Cop27 climate conference in Egypt should take note of the extreme weather conditions the world has experienced this year and in recent years. “The lesson is that it will become more likely, probably much more likely. Becoming more resilient is very important.

theguardian Gt

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