Why Is It So Hot? Climate Expert Says 'This Is the New Normal'

Record-breaking temperatures have caused hundreds of fatalities in a global heatwave.

Deadly wildfires exacerbated by weeks of hot, dry conditions have killed over 80 people in Greece, and devastated areas of California. Scandinavia has also battled wildfires—some, in Sweden, inside the Arctic Circle.

While reports suggest arsonists may be responsible for starting some of these wildfires, record-breaking heat has contributed by drying out fields and trees making it easier for fire to spread.

Dozens of people have died in Japan as temperatures rose to a record-breaking 105.9 degrees Fahrenheit in the city of Kumagaya, near Tokyo.

Wayne Semancik of Trenton, New Jersey pours water on his head to cool himself off July 18, 2006, in New York City. The climate science community has been warning of the effects of human-made climate change from increasing levels of carbon dioxide for years. Michael Brown/Getty Images

"We're seeing this hot weather in different regions for different reasons," Dr. Michael Byrne, a climate scientist at Imperial College London, told Newsweek.

The unusually hot weather over northern Europe can be attributed to a large high pressure system sitting over the area which is providing hot, clear and calm conditions.

Byrne said that usually the jet stream, a core of strong winds around six miles above the earth's surface, provides a combination of high and low pressure systems resulting in some rain over northern Europe. But it is abnormally far north this year which means that low pressure systems are being deflected away.

But there is also a deeper explanation. "The hot weather that's being experienced around the world, we are very confident as a climate science community that this is strongly linked to climate change," said Byrne.

Scientists have been warning about the effects of human-made climate change from increasing levels of CO2 for years.

"We know that the globe has warmed about one degrees celsius [two degrees fahrenheit] since pre-industrial conditions and we're very confident that this increase in global temperature is due to human emissions of greenhouse gases.

"The idea is rooted in very simple physics; when you emit greenhous gases like carbon dioxide into the atmosphere it makes it harder for the earth to cool itself, so that increases the temperature of the earth."

Despite global efforts such as the Paris climate agreement attempting to limit the global temperature increase from 34.7 to 35.6 degrees Fahrenheit, it is likely that temperatures will keep rising.

"We are rapidly approaching the time," Byrne said, "when these heat waves are going to become the new normal. The question is how we mitigate and adapt to those changes."