A severe drought suffocated much of the northern hemisphere this summer, from China to Europe to the western United States. Scientists say climate change is at least partly responsible.
Climate change has increased the risk of drought in the hemisphere 20-fold, according to new study from the World Weather Attribution research consortium, specializing in the links between climate change and extreme weather events.
Focusing specifically on Europe, which experienced one of its driest summers in decades, climate change may have made drought three to four times more likely to occur.
The study was published on Wednesday, just weeks after the end of the summer.
This is the latest in a series of “rapid attribution studies” from World Weather Attribution, which this summer examined the role of climate change on heavy rains in brazil, UK record heat and devastating floods in pakistan.
In this case, the researchers conducted two analyses: one focusing on most of the northern hemisphere, excluding the tropics, and the other looking specifically at central-western Europe. Europe experienced its hottest summer on record this year, and it experienced its driest conditions since 1950.
Drought can be defined in a variety of ways, ranging from low rainfall to low river flows. In this study, researchers looked at soil dryness, a critical factor in plant growth. Low soil moisture is sometimes referred to as agricultural or ecological drought.
They found that in both study regions – in Europe and in the northern hemisphere in general – the drought this summer was about one event in 20 years. It is an event with about a 5% chance of occurring in any given year.
By examining historical data, the researchers found that the risks of these types of severe droughts had increased over the past century. The researchers then used climate models to determine if global warming was part of it.
Models suggest that climate change has, in fact, played a role. Warming has made this summer’s level of drought about three to four times more likely to occur in Europe, and up to 20 times more likely in the Northern Hemisphere.
These are the best estimates, based on the model results. That said, there is a lot of uncertainty around these numbers. This is partly because drought is a fairly complex weather phenomenon compared to other events like heat waves or extreme rainfall, and soil moisture is also relatively difficult to observe, quantify and reproduce in models.
Although the exact numbers are up for debate, researchers strongly conclude that climate change played a major role.
“There’s no doubt that climate change has played a big role here,” said Friederike Otto, a climatologist at Imperial College London and co-lead of World Weather Attribution. “The exact quantification of this role is more uncertain for soil moisture than, for example, when we look at heavy rainfall.”
The study also uses climate models to project into the future. The world has already warmed by around 1.2 degrees Celsius and if the planet reaches 2°C, the risk of severe drought will increase even more. In some parts of the northern hemisphere, the probability could be multiplied by 15.
“This means that the current event, which happens once every 20 years, will happen almost every year,” said Dominik Schumacher, a scientist at the Swiss Federal Institute of Technology in Zurich and one of the authors of the study. ‘study.
Reprinted from E&E news courtesy of POLITICO, LLC. Copyright 2022. E&E News provides essential information for energy and environmental professionals.