Flooding Caused Greatest Economic Damages In Asia In 2022
Flooding in Sirajganj, Bangladesh, in 2020. Flooding emerged as the leading cause for damages in Asia last year (Photo by Oregon State University/Wikimedia Commons)
The Asian region was battered by extreme events driven by climate change, with flooding emerging as a particularly frequent and damaging threat, a new report by the World Meteorological Organisation (WMO) released at the end of July, shows. India suffered the third highest losses in the region on account of flooding, amounting to over $4.2 billion, the report found.
The warming trend in Asia between the years 1991 and 2022 was almost double the warming trend during the 1961 to 1990 period, says the WMO report. In 2022, mean surface temperatures were either the second or third warmest on record over Asia, at about 0.72 degrees Celsius above the 1991-2020 average and 1.68 degrees Celsius above the 1961-1990 average, which is the WMO’s reference period for assessing climate change.
Global mean surface temperature reached 1.15 degrees Celsius above pre-industrial levels last year. While these rising temperatures have brought with them worsening heatwaves, precipitation, sea level rise and drought over the last year, flooding was the leading cause of death and damage in the region in 2022, according to the report.
The Asian region experienced a total of 81 natural hazard events last year, according to the WMO’s Emergency Events Database, of which over 83% were flood and storm events.
“Normally, high land surface temperatures should pass onto the sea. But because ocean temperatures are also rising at a faster rate, it is causing heat to trap,” explained Abinash Mohanty, an expert reviewer for the IPCC’s sixth assessment report on climate change and Sector Head for Climate Change & Sustainability at IPE Global, an advisory firm working on climate solutions. “This trapped heat is interfering with atmospheric processes, causing more erratic rainfall and cloudburst like events, which is worsening flooding.”
Of the 5000 fatalities resulting from the 81 natural hazard events, 90% were due to flooding. Pakistan bore the brunt of losses due to flooding, amounting to over $15 billion, followed by China (over $5 billion) and India.
Pakistan received 60% of its normal total monsoon rainfall within just three weeks of the start of the monsoon season in 2022, wiping out 1.7 million hectares of agricultural land and 800,000 heads of livestock and leading to food insecurity.
Uneven Precipitation And Drought
Observations of precipitation events across Asia in 2022 show that both, large deficits, and excess rainfall, occurred over the region.
Iraq, the Hindu Kush Mountain range from central to western Afghanistan, the lower course of the Ganges and Brahmaputra Rivers in India and Bangladesh, the Korean Peninsula, and Kyushu (western island of Japan) all experienced a deficit. Unusually high precipitation, on the other hand, was observed in central India and the Western Ghats in India, Siberia, North-East Asia, the eastern Himalayas (Nepal and Bhutan), along the Yellow River (northern China) and in western Tian Shan (the high mountain range in western China), according to the WMO’s analysis.
“In India, heavy rainfall lasting from May to September triggered multiple landslides and river overflows and floods, resulting in casualties and damage. Heavy monsoon rains in particular affected the north-eastern parts of India and Bangladesh. Cumulatively, this flooding caused over 2,000 deaths and affected 1.3 million people, and this disaster event caused the highest number of casualties of any disaster event in 2022 in India,” says the report.
The state of Assam, which is flood prone, had experienced its worst floods in a decade last year after it received rainfall in excess of 60% between March and May.
Apart from climatic factors, flooding is also made worse by landscaping decisions, said Mohanty. “When natural and inland drainage systems are blocked, floods tend to intensify. This is a complex and compounding problem in which climate change plays a role, but so does unsustainable landscape planning,” he explained.
The triple dip La Nina, which began in 2020 and lasted till early 2023, could also have played a role in the heavy precipitation. La Ninas are known to cause excess rainfall over South Asia and drought over Peru and Ecuador.
While parts of South Asia suffered heavy rainfall, other regions reeled under the effects of a drought. The Yangtze River Basin in south-west China experienced the worst drought in the last six decades, for example. Between August and September last year, the Yangtze River flow was about 50% below the average for the previous five years.
“The Yangtze River is an important water supply; it is used for energy production, transportation, and crop irrigation, and the Three Gorges Dam, the largest hydropower plant in the world, is also located along this river. The estimated economic losses from the drought affecting many regions in China in 2022 were over $7.6 billion,” says the report.
Drought was the second leading cause for loss and damage, with the WMO saying in its report that “the economic losses associated with drought in 2022 ($7.6 billion), which mainly occurred in China, exceeded by nearly 200% the 20-year average from 2002 to 2021 ($2.6 billion).”
Glaciers And Sea Surface Temperatures
The year 2022 was also marked by an accelerated melting of glaciers. “Exceptionally warm and dry conditions” across the Altay mountain range, the Tien Shan in Central Asia and the Hindu Kush exacerbated mass loss for most glaciers, says the report, adding that between 2021 and 2022, Urumqi Glacier No. 1 in the eastern Tien Shan, recorded its second most negative mass balance (negative 1.25 metres water equivalent) since measurements began in 1959.
Melting glaciers have also resulted in rising sea levels in some parts of Asia. The northwest, northeast and southeast Indian Ocean saw between 3.8 millimetres (mm) and 4.13 mm rise in levels every year on average from 1993 to 2022. The western tropical Pacific region saw the highest rise, at 4.19 mm, compared to the global mean of 3.4 mm, says the report.
Sea surface temperatures in the Arabian Sea, the southern Barents Sea, the southern Kara Sea, and the southeastern Laptev Sea are warming at an average of 0.5 degrees Celsius per decade. This is more than three times faster than the global surface ocean warming rate of about 0.16 degrees Celsius per decade, the report added.
A study from 2021 had found that warming sea surface temperatures, coupled with greater humidity, has resulted in more frequent and intense tropical cyclones in the Arabian Sea, which are not typical of the region.
The WMO report also noted rising heatwaves across India, China and Pakistan, as well as increasing lightning in India, on account of climate change.
Prevention And Protecting Food Systems
The WMO suggested that close monitoring and risk reduction practices can help soften the blow of climate driven natural hazards, particularly floods.
Giving the example of Pakistan, where floods struck just before the harvesting of key crops, the report warns that “if risks at the producer level are not effectively managed, this can have cascading effects across all components of the food value chain, potentially leading to overall food system failures.”
According to the report, more than 25% of all damage and losses for disasters like floods, droughts, and tropical storms, are associated with the agriculture sector.
“It is estimated that early warning systems provide more than a tenfold return on investment and a dependable multi-hazard early warning system (MHEWS) is the backbone of a comprehensive risk-management programme. Unfortunately, the hydrological and meteorological infrastructure, which is a key component in the early warning information value chain, is costly and underfunded, especially in developing countries,” says the report.
According to Mohanty, regional analysis is helpful to monitor emerging trends as climate change accelerates, but more granular observations are needed to devise meaningful adaptation strategies.
“Risk profiles are fast evolving and changing, and so you need a granular risk assessment to better manage the hazard,” he said, adding, “What’s equally important is communicating these risks in a people centric way.”
(Published under Creative Commons from Mongabay-India. Read the original article here)
