Fires serve up stark lesson on planet's fate

The summer wildfires that tore across many parts of the world may have shocked millions with their intensity, but there's worse to come according to scientists placing the blame on climate change.

In southern Europe, scorching heat and drought ushered in the fires that devastated forests and destroyed homes in countries such as Greece, Italy, Turkey and France. Surrounding regions also burned. And where the flames didn't reach, the floodwaters sometimes did.

In Sicily, the mercury hit a European record 48.8 C, which, if confirmed by the World Meteorological Organization, will surpass the 48 C logged in Athens in 1977.

Experts say the intense heat waves and fires are linked to climate change and that extreme weather－including floods－will only get worse in the coming years.

"Our carbon emissions have caused global heating and that has changed weather patterns, making these extremes more intense and more frequent," said Deirdre McKay, professor of sustainable development at Keele University in Staffordshire in the United Kingdom.

"So, in the northern hemisphere, in the summer, we are seeing these persistent heat domes, like the one that has been stuck over the northwestern United States and Canada."

A heat dome is an area of high pressure that stays over a large part of a region for days or even weeks, trapping very warm air underneath.

McKay noted that a heat dome had also appeared over Europe.

While August is normally hot and dry in the Mediterranean region, the World Meteorological Organization said the temperatures in the summer were extreme.

"The reason you get heat domes is ocean warming over the previous winter," said McKay, adding that heat domes are fairly common in temperate zones but they're getting more regular and more intense.

A heat dome over Greece, Italy and Turkey was responsible for many of the wildfires last month, she said.

"That's because the jet stream in the atmosphere shifts seasonally and right now it's dipped south across Western Europe. That dip created a ridge of high pressure over the southeast of Europe," she said.

"Warm air moving up from the Sahara which is carrying dust has contributed to a big hot air mass that's been parked over southeast Europe, making the temperature 10 to 15 C hotter than average."

This year, some of the heat waves are unprecedented in parts of the Northern Hemisphere, including the Canadian province of British Columbia that saw a record temperature of 49.6 C.

Peter Stott, the lead on climate attribution of the Meteorological Office, the United Kingdom's National Weather Service, predicts even higher temperatures to come.

Extreme temperatures

"The chances each summer of seeing really extreme temperatures are pretty high now," Stott said. "We can't say exactly when it is likely to happen, but Europe will need to prepare for the eventuality of further records being broken with temperatures above 50 C being possible in Europe in future, most likely close to the Mediterranean where the influence of hot air from North Africa is strongest."

The global temperature is around 1.1 degrees above the 1850-1900 preindustrial period level, but some regions have seen average temperatures increase by greater amounts.

Climate change has also driven heavy rainfall and flooding, wreaking havoc in parts of Europe.

The World Meteorological Organization said climate change has made extreme rainfall events similar to those in July that led to floods in Germany, Belgium, the Netherlands and Luxembourg between 1.2 and 9 times more likely to happen.

That's according to a study by an international team of climate scientists, World Weather Attribution group, which also found that such downpours in the region are now 3 to 19 percent heavier because of human-caused warming.

Some 220 people were killed in the floods in Belgium and Germany when extreme rainfall hit Western Europe. More than 90 millimeters of rain was recorded in a single day around the Ahr and Erft rivers in Germany.

"These floods have shown us that even developed countries are not safe from severe impacts of extreme weather that we have seen and known to get worse with climate change," said Friederike Otto, associate director of Environmental Change Institute at the University of Oxford and co-lead of the World Weather Attribution group. "This is an urgent global challenge and we need to step up to it. The science is clear and has been for years."

McKay said extreme weather conditions combined with large areas of intensely human modified landscapes had contributed to the flooding in Europe.

"You have more paving and that means greater volumes of runoffs in extreme rainfall events," she said. "That's because there is just less exposed soil or vegetation to absorb the water. In some places you have rain that's falling on uplands which are already suffering from deforestation."