As temperatures rise, major cities around the world are contending with climate flips from wet to dry extremes, or vice versa, while others contend with deadly swings between extremes known as “climate whiplash,” according to a new report.
Commissioned by NGO WaterAid, the report analysed the climate patterns in the world’s 100 most populous cities, as well as 12 selected ones, for changes over the last 40 years. A staggering 95 percent showed a distinct trend toward wetter or drier weather, marked by worsened floods or droughts, threatening access to clean water, sanitation and food, spreading disease and displacing communities.
Globally, more than 4.4 billion people live in cities and those swelling numbers strain water supply, sewage and flood protection, while a changing climate renders existing infrastructure outmoded and makes building new infrastructure even harder.
“Our study shows that climate change is dramatically different around the world,” study co-author Professor Katerina Michaelides, at the UK’s University of Bristol told the Guardian. While Europe, the Arabian Peninsula and much of the US contended with ever drier weather, cities in south and southeast Asia are experiencing extreme rains and flooding.
Professor Michael Singer at Cardiff University, Michaelides’ co-author on the WaterAid report, told the UK paper, “Most places we looked at are changing in some way, but in ways that are not always predictable.”
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More than one in five cities analysed are experiencing a reversal in climate extremes, becoming significantly wetter or drier. Warmer air is perfectly suited to creating these extremes, absorbing more water from the soil during hot dry periods, then releasing that abundance in intense downpours. Cairo, Madrid and Riyadh showed the sharpest flips from wet to dry conditions, with Hong Kong also landing in the top 10.
Where prolonged droughts can lead to water shortages, disrupt food supplies and trigger blackouts in areas reliant on hydropower, as was seen during Brazil’s record-breaking drought last year, floods are just as dangerous, fouling drinking water supplies, inundating crops and killing livestock, and wiping out critical infrastructure.
Cities experiencing climate whiplash experience the worst of both worlds, as Michaelides and Singer witnessed firsthand during their time in Nairobi, Kenya. After years of struggling with no water, failed crops and dead livestock, intense rains triggered flash flooding that led to death, displacement and loss of livelihoods.
The wildfires that ravaged Los Angeles in January were also a tragic example of a whiplash event, as ample vegetation spurred by a wet period turned into tinder in the hot, dry period that followed, fuelling wildfires that killed at least 29 people and damaged or destroyed over 18,000 structures.
Both Nairobi and Los Angles are among the 15 percent of cities surveyed that have been hit by whiplash, a group which also includes Baghdad, Bangkok, Melbourne, Jakarta and Hangzhou. Rapid shifts between extremes make it difficult for these cities to prepare and recover, increasing the impacts on residents’ livelihoods and quality of life.
