Why are there historical heat waves?

(CNN Spanish) — From America to China, through Europe, The world is burning: High temperatures are already claiming hundreds of lives and flames are consuming thousands of hectares. Why have heat waves reached these historic dimensions? The long-awaited answer by scientists: the climate change factor.

“Our way of life – based on producing, consuming, discarding and polluting – has led to the planetary emergency we face. It’s time to change our relationship with nature.” Antonio Gutierrez wrote this TuesdayUN Secretary-General calls for “credible commitments” on climate matters

His message puts rising temperatures as a result of greenhouse gas emissions as the root cause of extreme weather events. How is it specifically affected? Here we explain the factors that need to be taken into account to understand the current heat waves.

Two pressure settings in the game

When looking at the cause of extreme heat in the US and Europe, two weather systems are at play.

In Europe, a strong high pressure ridge has allowed temperatures on the continent to rise in recent days. On Tuesday, an area of ​​low pressure moved off the coast, helping to push extreme heat north towards England.

In the United States, a strong dome of high pressure has settled over the Southern Plains and Mississippi Valley. Instead of sending heat from the south, it builds steadily as the sun warms through cloudless skies.

The link between heat waves: climate change

The connection between heat waves on both sides of the Atlantic Ocean is clear to scientists: it is the impact of greenhouse gas emissions and the base temperature of the planet, which increases. Increasingly.

Stephen Belcher, chief scientist at the UK Met Office, said on Tuesday that heatwaves were “almost impossible” in the country in “unperturbed weather”.

“But climate change driven by greenhouse gases has made these temperatures possible, and we’re actually facing that possibility now,” he said.

What does science say? Global temperatures have already risen 1.1°C above pre-industrial levels. Under these conditions, extreme heat waves are already five times more likely to occur, according to a major report by the Intergovernmental Panel on Climate Change. UN Climate Change Released in 2021.

The future of America and England is red hot

An outlook for the future is key.

Belcher said that in the UK, if greenhouse gases continue to be released at current levels, such a heat wave is likely to occur every three years.

And in America? “It’s very difficult to predict exactly when and where, but we can say that they will be more intense, longer, more frequent and in more places,” Dr. Andrew Pershing, director of the National Climate Center, told CNN recently.

Recent history records the Dust Bowl era of the 1930s, Like bad droughts and heat waves.

Summer 2021 Incorporated in 1936 For higher temperatures. And, Pershing says, “It’s not going to be long before we see events of that magnitude again.”

According to a report by the UN Framework, if the temperature rises by two degrees, the probability of heat waves increases by 14 times.

And they’re not the only ones likely to happen: with a two-degree rise, maximum temperatures in heat waves could rise by nearly three degrees.

A heat wave in Portugal has intensified an existing drought and fueled wildfires in the center of the country, including the town of Memoria in the municipality of Leiria. (Credit: PAULO CUNHA/EPA-EFE/Shutterstock (13027640ab)

“Time to learn to live with fire”

Thousands of hectares of land have already been ravaged by fires in Spain, France, Portugal and Greece. In Spain, for example, they have destroyed more than 70,000 hectares so far this year, almost double the average of the past decade, according to Prime Minister Pablo Sánchez.

This year, Report of the UN project For the environment, UNEP warned that it is time to “learn to live with fire” and adapt to the increased frequency and intensity of forest fires, which will inevitably endanger more lives and economies.

According to the report’s analysis, the number of severe wildfires will increase by 14% by 2030. By 2050, the increase will be 30%. Even the most ambitious efforts to reduce emissions have short-term effects.

Global warming, more land encroachment and policies to suppress fires while ignoring forest management explain the shift in fire regimes, the UN says.