"We will have to get used to these kinds of summers," says Friederike Otto of the Environmental Change Institute at Oxford University, as countries across Europe swelter in the continent's hottest weather of the past three years.
The effects of climate change mean the world can expect higher temperatures and more frequent heatwaves, climate experts have warned, with poor communities likely to be worst affected.
Heat is neglected because it is both an invisible and hard-to-document disaster that claims lives largely behind closed doors, they said, and because hot weather does not strike many people as a serious threat.
"We will have to get used to these kinds of summers," said Friederike Otto, deputy director at the Environmental Change Institute at Oxford University.
The warning comes as hot weather has swept the northern hemisphere. Britain has sweltered in a prolonged heatwave, with temperatures set to test national records, the country's Meteorological Office said.
"There is no doubt that there is a link to climate change. We need to take heat waves seriously around the world as something that we need to adapt to," Otto told the Thomson Reuters Foundation.
Fires have also caused devastation in Greece, Sweden and the United States.
In Greece, rescuers are searching scorched land and the coastline for survivors three days after a wildfire destroyed a village outside Athens killing at least 82 people.
TRT World's Simon McGregor-Wood has more.
Highest recorded temperature
The past three years were the hottest on record, the United Nations' World Meteorological Organization said in March.
The World Health Organization says heat stress, linked to climate change, is likely to cause 38,000 extra deaths a year worldwide between 2030 and 2050.
Two weeks into Japan's blistering heatwave, at least 80 people have died and thousands have been rushed to emergency rooms, as officials urged citizens to stay indoors to avoid temperatures exceeding 40 degrees Celsius in some areas.
In a heat wave in May, more than 60 people died in Karachi, Pakistan, when the temperature rose above 40C.
Hotter weather linked to suicides
Stanford University researchers on Monday said hotter weather was linked to increases in suicides, after examining decades worth of temperature data against suicide rates in US counties and Mexican municipalities, some dating back to the 1960s.
In 2015, countries signing the Paris Agreement set a goal of limiting a rise in average world surface temperatures to "well below" 2C above pre-industrial times, while "pursuing efforts" to limit rising temperatures to 1.5C.
US President Donald Trump has vowed to pull out of the accord, which would make his country the only one to do so.
Poor to suffer the most
Nearly one in three people around the world are already exposed to deadly heatwaves, and that will rise to nearly half of people by 2100 even if the world moves aggressively to cut climate-changing emissions, a University of Hawaii study found in 2017.
But poorer communities will suffer the most, said Frank Rijsberman, head of the Global Green Growth Institute, which helps developing countries adopt clean energy to boost their economies and reduce carbon emissions.
About 1.1 billion people in Asia, Africa and Latin America are at risk from a lack of air conditioning to keep them cool as global warming brings more high temperatures, the non-profit Sustainable Energy for All said in a study last week.