New Study Reveals Climate Change, Rapid Urbanisation Caused Severe Flooding In West Africa
By Jean-Pierre A. Côte d’Ivoire, Ghana, Togo, and Nigeria recently experienced exceptionally widespread and severe flooding following intense and persistent rainfall, in what scientists have called human-induced climate change, that altered the likelihood and intensity of the heavy precipi
-Pierre A. Côte d’Ivoire, Ghana, Togo, and Nigeria recently experienced exceptionally widespread and severe flooding following intense and persistent rainfall, in what scientists have called human-induced climate change, that altered the likelihood and intensity of the heavy precipitation leading to the severe flooding. Between 20–22 June, the coastal regions of the countries bordering the Gulf of Guinea, experienced heavy rainfall. In several locations, more than 140 mm of rain fell within less than 24 hours, overwhelming natural drainage systems and triggering extensive flash floods. Now a new study published by the World Weather Attribution, finds that the floods affected a very densely populated region where rapid urbanisation and the expansion of formal and informal settlements into floodplains and conversion of natural vegetation to croplands have reduced natural drainage capacity and increased exposure to flooding. The study notes “Population growth is projected to continue its upward trajectory in this region, further increasing exposure in the decades to come. ”The flood impacts extend far beyond the areas directly inundated; the new study released this week finds. According to the study’s main findings, disruptions to infrastructure, livelihoods, and agriculture can worsen food insecurity, and contaminated water and damaged sanitation and hygiene systems increase the risk of water-borne diseases in the coming week and months, particularly for children and people with pre-existing health conditions. This year’s flooding, the study says is part of a pattern of similar floods that periodically occur in this West African region, eroding people’s assets and ability to recover. However, the research says the event [heavy rainfall] is not rare in today’s climate, which is 1. 4°C warmer than it would have been at the beginning of the industrial period. “A 3-day rainfall event of this magnitude is now expected to occur about once every 2-4 years in the study region,” predicts the study. Induced-human climate changeThe study’s results show that observed 3-day rainfall has increased in intensity by about 23 percent over the study region since records began. Equivalently, an event like this is about five times more likely to occur today than it would have in a 1. 4°C cooler climate, noted the study authors. To quantify the role of human-induced climate change, researchers also analyse climate models over the relatively small study region. Overall, the available climate models indicate only a very small increase in the likelihood of an event such as the one under study with about 4 percent increase in intensity. Researchers warn under a future warming scenario where the global temperature is 2. 8°C higher than pre-industrial levels, climate models suggest that even wetter 3-day periods should be expected. The study states research has shown that sea level rise along the Gulf of Guinea coast has exceeded the global average, compounding the impacts of increasingly intense rainfall. “Together, these changes are thus driving greater flood risk along the Gulf of Guinea than would result from rainfall intensification alone, increasing risks to densely populated cities and critical infrastructure,” researchers note. The rainfall at the end of June led to a series of deadly flash floods across the region from Lagos to Monrovia, submerging vehicles and washing away markets. At least 34 people died in Ghana, where June rainfall reached its highest level since 1995, while five fatalities were reported in Togo.