Climate change drove the unusual Mediterranean heat wave
The news
The early-season heat wave that ravaged parts of Algeria, Morocco, Portugal and Spain last week almost certainly would not have occurred without human-induced climate change, an international team of scientists in an analysis released Friday.
A mass of hot, dry air from the Sahara parked over the western Mediterranean for several days in late April, releasing temperatures more typical of July or August in the region. Mainland Spain put one April record of 101.8 degrees Fahrenheit, or 38.8 degrees Celsius, in the southern city of Córdoba. In Morocco, the mercury climbed to over 106 degrees Fahrenheit in Marrakesh, according to preliminary data, very likely to break that country’s April record as well.
A three-day stretch of such scorching heat in April is already quite rare for the region in the planet’s current climate, with only a 0.25 percent chance of occurring in any given year, according to the new analysis. But it would have been “almost impossible” in a world not warmed by decades of carbon emissions, said Sjoukje Philip, a climate scientist at the Royal Netherlands Meteorological Institute and author of the analysis.
Due to climate change, last month’s hot spell averaged at least 3.6 degrees Fahrenheit warmer than a similarly improbable one in pre-industrial times, the scientists found.
Why it matters: The region is already reeling from drought.
The Iberian Peninsula and North Africa have been struggling with drought for years.
Low rainfall in Morocco has affected wheat yields and increased the country’s imports. Food prices are rising rapidly there. Heat and poor rainfall last year decimated olive production in Spain, the largest producer of olive oil in Europe. The world price of olive oil is the highest in 26 years.
Water scarcity has already had significant impacts on livelihoods in the region, said Fatima Driouech, an environmental scientist at Morocco’s Mohammed VI Polytechnic University and another author of the new analysis. “And the future, unfortunately, is not getting any better,” she said.
Extreme heat can also set the stage for devastating wildfires. Been last year the second most severe in the European Union for forest fires since registration began in 2000. Fires in 2022 burned more than 780,000 hectares of land in Spain, the continent’s worst affected country, and 270,000 hectares in Portugal.
Background: Climate change causes extreme heat worldwide.
Climate scientists have no doubt that global warming is making severe heat more likely and intense on every continent. But to determine exactly how big that influence is for a single weather episode, they have to perform what is called an attribution analysis.
They use computer models to study the same event in what are effectively two alternate histories of global climate: one that responds to the effect of decades of greenhouse gas emissions, and one that is not. Scientists have used this approach to study not only heat waves, but also droughts, storms and cold spells.
The analysis of the April heat was carried out by researchers associated with World weather attribution, a scientific initiative that examines extreme weather events shortly after they occur. The new analysis has not yet been peer-reviewed or published in a scientific journal, although it is based on widely accepted methods.
What’s next: El Niño could soon start raising mercury globally.
Weather forecasters worldwide are gearing up for a major shift. For the first time in three years, the global climate pattern known as El Niño is expected to materialize, likely later this year. It is not yet clear how strong this El Niño will be and how long it will last. But in general, the phenomenon is associated with above-average temperatures on Earth.
On top of the planet’s steady warming from fossil fuel burning, the development of El Niño this year could lead to more record temperatures in many places.