Why Europe faces so much heat and fires – 08/22/2023 – Environment

This summer, Europe once again faces scorching temperatures, with fires raging across the continent, from Greece to Spain. Understand below how climate change causes these events in the region.

Hotter and more frequent heat waves

Climate change makes heat waves hotter and more frequent. This is the case for most regions on Earth, as attested by the global group of climate scientists at the United Nations, the so-called IPCC (Intergovernmental Panel on Climate Change).

Since pre-industrial times, greenhouse gas emissions generated by human activities have already caused the planet’s temperature to rise by about 1.2°C. This warmer base temperature leads to higher temperatures during extreme heat events.

Every heat wave being felt today has been hotter and more frequent due to climate change, says Friederike Otto, a climatologist at Imperial College London who leads the World Weather Attribution research group.

But other issues also affect hot flashes. In Europe, atmospheric circulation is an important factor.

Fingerprints of climate change

To find out exactly how much climate change affects a specific heat wave, scientists conduct so-called attribution studies. More than 400 such studies have been conducted since 2004 on extreme weather events, including heat waves, floods and droughts, calculating the extent to which climate change played a role in each event.

The studies involve simulating the modern climate hundreds of times and comparing it to simulations of a climate without man-made greenhouse gas emissions.

For example, scientists from the World Weather Attribution determined that a record-breaking heat wave in western Europe in June 2019 was 100 times more likely to occur now in France and the Netherlands than would have been the case if humans had not changed the climate. .

Heat waves will get worse

On average, on land, heat extremes that without human influence on the climate would have occurred once every ten years are now three times more frequent, according to climatologist Sonia Seneviratne of the Federal Institute of Technology in Zurich.

The temperature will only stop rising if humans stop releasing greenhouse gases into the atmosphere. While that doesn’t happen, the heat waves should get worse. If climate change is not tackled, heat extremes could intensify even more dangerously.

Under the Paris Agreement of 2015, countries committed to reducing their emissions quickly enough to limit global warming to a maximum of 2°C above pre-industrial levels and to aim for no more than 1.5°C to avoid the most dangerous impacts. The policies being followed today will not, however, reduce emissions in a timely manner for either of the two targets to be achieved.

A heat wave that occurred once a decade in the pre-industrial era would occur 4.1 times a decade at 1.5°C of warming and 5.6 times at 2°C, says the IPCC.

Letting warming pass 1.5°C “will mean that most years in the future will be affected by heat extremes,” Seneviratne said.

forest fires

Climate change increases hot and dry conditions that help fires spread faster, last longer and be more intense.

In the Mediterranean, this has helped to make the fire season start earlier and devastate larger areas. Fires that have been burning on the Greek island of Rhodes since mid-July required the evacuation of 20,000 people as the fire reached tourist resorts and seaside towns in the island’s southeast.

The heat also sucks moisture out of vegetation, converting it into dry fuel that helps fires spread.

Drier and hotter weather conditions make fires much more dangerous, says Mark Parrington, senior scientist at the Copernicus Atmospheric Monitoring Service.

Without human-induced climate change, the extreme weather events seen in many parts of the world this summer would have been extremely rare, according to a study by the World Weather Attribution.

The work concluded that human-induced climate change played an overwhelming role in the extreme heatwaves that hit North America, Europe and China in July.

Climate change is not the only factor in wildfires

Forest management and ignition sources are also important factors for fires. In Europe, according to data from the European Union, more than nine out of ten fires are caused by human activities, such as arson, disposable barbecues, power lines or glass scattered on the floor.

Several countries, including Spain, face the challenge of shrinking rural populations due to the exodus of inhabitants to cities, reducing the workforce available to clear undergrowth and prevent the accumulation of fuel for wildfires.

Some actions can help prevent serious fires, such as setting controlled fires that mimic the low-intensity fires of natural ecosystem cycles or clearing forests to prevent fires from spreading quickly over large areas.

But there is a consensus among scientists that without a strong reduction in the greenhouse gas emissions that cause climate change, heat waves, fires, floods and droughts will get much worse.

In a decade or two, when people look back at the current fire season, it will likely look mild compared to what they will be experiencing, said Victor Resco de Dios, professor of forestry engineering at the University of Lleida in Spain. .

_{Translated by Clara Allain}