Much of Europe is getting hit with a record-setting heat wave. The World Meteorological Organization is concerned not just because of the temperatures, but because the summer heat is a month earlier than usual and more intense. It is likely another sign of climate change.
Europe is wilting from the warm air masses coming from Africa, bringing with them Saharan heat and, in some cases, Saharan dust.
The World Meteorological Organization said temperature records have been broken this week in France, Spain, Germany, Austria and Switzerland.
On Friday, France issued red alerts for four areas in the south as temperatures reached an all time high of 45.1 Celsius (113 Fahrenheit).
While this spate of new maximum daytime records is of concern, WMO spokeswoman Claire Nullis said the increasing number of minimum overnight temperature records is particularly worrisome.
"I stress the overnight records are important because night time is when our bodies recover,” Nullis said. "It is when plants and animals recover. So, if we are seeing minimum overnight temperatures of 25 degrees C (77 Fahrenheit) as we have done in some places, it is not good news."
Heat events kill thousands of people every year. They often trigger secondary events such as wildfires and electrical grid failures.
The WMO said the number of people exposed worldwide to heat waves rose by an estimated 126 million between 2000 and 2016.
The World Health Organization warns high temperatures affect the health of many people. It said heat can trigger exhaustion or heat stroke, and can worsen existing conditions such as cardiovascular, respiratory and kidney diseases.
Nullis said this heat wave was predicted, so nations were able to plan for it and head off the worst. She said early health warnings and measures to help people in distress have prevented the huge numbers of deaths seen in previous years.
She said it is premature to attribute the unusually early heat wave in Europe to climate change.
"But it is absolutely consistent with what we expect from climate change,” Nullis said. “Heat waves will become more intense. They will become more drawn out. They will become more extreme. They will start earlier, and they will finish later."
The WMO reports the Earth is set to experience the five warmest years on record from 2015 to 2019. It said the warming of the planet will increase greenhouse gas concentrations, fueling global warming.
That, it said, will cause ice melt, glacier retreat, sea level rise, ocean heat and extreme weather for generations to come.