The recent rainfall in West Asia was made 10-40 per cent heavier by warming, according to the WWA
Extremely heavy rainfall events, like the one that caused floods in many countries across West Asia in the second week of April 2024, have become 10-40 per cent heavier according to a rapid attribution study by the World Weather Attribution (WWA) group.
WWA is a global consortium of climate scientists who study the role played by human-induced climate change in the occurrence, frequency and intensity of extreme weather events such as heatwaves, droughts, cold spells, extreme rainfall, floods and storms. Such studies come under the purview of attribution science.
Scientists from universities, research organisations and meteorological agencies in Saudi Arabia, Switzerland, Sweden, the Netherlands, Germany, the United Kingdom and the United States, were involved in the study.
“While the researchers could not precisely determine how much of the increase is due to human-caused climate change, they find that warming, caused by burning fossil fuels, is the most likely explanation for the increasing rainfall,” noted a statement from WWA.
The scientists also highlighted that the excessive rainfall could have been caused due to the El Nino conditions prevalent in the equatorial Pacific Ocean. They said most of the previous record rainfall events have occurred during El Nino years.
El Nino is the warmer than normal phase of the El Nino Southern Oscillation phenomenon that occurs in the equatorial Pacific Ocean and is generally responsible for heavier than usual rainfall in West Asia, especially during March and April.
Dubai received more than a year and a half’s worth of rainfall in 24 hours on April 14-15 that submerged the city, including its airport and most the freeways. Four people lost their lives because of the flooding.
The Al Ain weather station in the United Arab Emirates (UAE) recorded 254 mm of rainfall, the highest in 75 years, when records began, according to the National Center of Meteorology of UAE. In Oman, 20 people were killed due to flash flooding related incidents. There was also heavy rainfall in Bahrain and parts of Saudi Arabia.
Read DTE Coverage: Dubai Floods 2024
The scientists analysed observations of single day heavy rainfall events in a world that is 1.2°C warmer than pre-industrial times and found the current event, that occurred due to a low pressure system over the region, to be 10-40 per cent heavier than a world that is 1.2°C cooler.
Further, to characterise and quantify the exact role of human-induced climate change in enhancing the rainfall, the study authors used climate models. But the available climate models could not arrive at a trend as the results are highly uncertain because of the high year-to-year variability in rainfall over the region.
The scientists can be sure about the role of climate change when the observational data analysis matches with the trend results from the climate models. Which is not the case for this particular event.
“The disagreement between model results and observations prevents us from concluding with certainty that human-induced climate change is the main driver making this event more likely,” said the authors in the summary of findings.
“However, while multiple reasons could explain the absence of a trend in our model results, we have no alternative explanation for a trend in observations other than the expectation of heavy rainfall increasing in a warmer climate,” they further added.
The study also talked about the lack of early warnings for people travelling in both UAE and Oman as many people died trapped in their cars. The cities in both countries are highly vulnerable to flooding events.
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The analysis flagged that 80 per cent and 85 per cent of the total populations in Oman and the UAE respectively, live in flood-prone and low-lying areas that are highly exposed.
“Because of various challenges to their abilities to respond to flood risk, particularly vulnerable groups tend to include older adults, individuals with disabilities, women with caregiving responsibilities, racial/ethnic minorities, migrant workers, and lower-income groups,” added the research.
The study authors also listed the presence of surfaces with “limited permeability and absorptive capacity” because of urban development, extremely arid soils and lack of drainage as the other reasons for the floods, apart from the extreme rainfall. They also found cloud seeding operations to have had no involvement in the cause or intensity of the rainfall event.
“Model uncertainties meant we couldn’t complete the last step of the analysis to precisely quantify how much of the increasing rainfall is due to climate change,” said Mariam Zachariah, researcher at the Grantham Institute — Climate Change and the Environment, Imperial College London, in the statement.
“However, multiple lines of evidence point to climate change as the most likely explanation for the increasing rainfall,” she added.
“While we can’t stop El Nino, we can stop climate change. The solution is to stop burning fossil fuels, to stop deforestation,” said Friederike Otto, senior lecturer in climate science at the Grantham Institute — Climate Change and the Environment, Imperial College London.
“At COP28 in Dubai, the world agreed to ‘transition away’ from fossil fuels. Nearly half a year later, countries are still opening new oil and gas fields,” she added.
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