An analysis of the flooding, which killed
more than 400 people in Durban and surrounding areas in the eastern part of the
country, found that the intense two-day storm that caused it had a 1 in 20
chance of occurring in any given year. If the world had not warmed as a result
of human-caused emissions of greenhouse gases, the study found, the chances
would have been half that, 1 in 40. The study, by a loose-knit group of climate
scientists, meteorologists and disaster experts called World Weather
Attribution, is the latest in a string of analyses showing that the damaging
effects of global warming, once considered a future problem, have already
arrived. And extreme events like this one are expected to increase as warming
continues. “We need to drastically reduce greenhouse
gas emissions and adapt to a new reality where floods and heat waves are more
intense and damaging,” one of the study’s authors, Izidine Pinto, a climate
scientist at the University of Cape Town, said in a statement issued by World
Weather Attribution. The flooding and related mudslides caused
more than $1.5 billion in damage and were “the biggest tragedy that we have
ever seen,” President Cyril Ramaphosa said at the time. Bridges and roads were
destroyed, and thousands of homes, many of them in makeshift settlements, were
swept away or damaged. The disaster led to sharp criticism of the
government for not fulfilling pledges to improve infrastructure to handle heavy
downpours and to tackle a long-standing housing crisis. World Weather Attribution conducts its
analyses within days or weeks of an event, while it is still fresh in the
public’s mind. This one looked at the two-day storm that hit eastern South
Africa beginning April 11 and produced rainfall totals of nearly 14 inches in
some areas, half or more of the area’s annual total. The work has yet to be
peer-reviewed or published, but it uses methods that have been reviewed
previously. This includes using observational data and
two sets of computer simulations, one that models the world as it is, about 2
degrees Fahrenheit (1.1 degrees Celsius) warmer than it was before widespread
emissions began in the late 19th century, and a hypothetical world in which
global warming never happened. The finding that the likelihood of such an
extreme rainstorm has increased with global warming is consistent with many
other studies of individual events and broader trends. A major reason for the
increase is that as the atmosphere warms, it can hold more moisture. The study noted that from a meteorological
perspective, a storm that has a 1 in 20 chance of occurring in any given year,
while not common, is hardly a rare event. So the researchers looked at other
factors that could have contributed to the disaster’s high toll in deaths and
damage. Among these, they wrote, were legacies of
policies instituted during the apartheid era. In 1958, for example, the Durban
City Council adopted a measure that forced nonwhites into less desirable and,
in many cases, more flood-prone, areas. The researchers also cited the rise of
makeshift settlements as a result of rapid urban growth and a lack of
affordable housing. About 22% of Durban’s population, or 800,000 people, live
in such settlements, which usually lack services and proper infrastructure. In
the April flooding, the study noted, about 4,000 of the 13,500 houses that were
damaged or destroyed were along riverbanks in these types of settlements, and
most of the deaths were in these areas as well. “Again we are seeing how climate change
disproportionately impacts the most vulnerable people,” said Friederike Otto, a
founder of World Weather Attribution and a climate scientist at Imperial
College London.   ©2022 The New York Times Company