For the second straight summer, a deadly heat wave has gripped Japan, killing an estimated 57 people and hospitalizing 18,347 more over the past week, according to the Japan Times. 

More than half of those hospitalized were over the age of 65, highlighting the risks faced by elderly people when temperatures climb to dangerous levels. The country’s capital, Tokyo, counted the most hospitalizations, and deaths were reported in 24 of Japan’s 47 prefectures. 

After a mascot died in a 35-pound costume, theme parks and other outdoor venues have shut down or curtailed events, according to the BBC. 

This is the second extreme heat wave in Japan this year, with the first taking place unseasonably early in May, forcing authorities to issue travel warnings to tourists. 

The latest heat wave comes at the end of the hottest July in recorded history, which was preceded by the hottest June in recorded history. Unprecedented heat waves have recently hit parts of Europe and the Arctic.  

Meanwhile, 18 of the 19 hottest years on record have happened after the year 2000. 

Read More: A 'Climate Apartheid' Is Right Around the Corner, UN Warns

While the heat wave in Japan has yet to be definitively linked to climate change, it’s likely that it was a contributing factor. As greenhouse gases accumulate in the atmosphere, they trap more heat on Earth, leading to higher general temperatures, and stoking extreme heat events.

The 2018 heat wave in Japan, which killed more than 1,000 people, “could not have happened without human-induced global warming,” a study found in May.

The oceans, which absorb the majority of excess heat on the planet, have also begun to intensify heat waves in recent years because they no longer exert as much of a cooling pressure on the global jet stream. 

Read More: Record-Setting Heat Wave in Europe Bears 'Signature of Climate Change'

Scientists predict that catastrophic heat waves will become much more common in the decades ahead and that future heat waves will be unlike anything ever experienced before. In the US, these mega heat waves could kill tens of thousands of additional people every time they strike. 

In countries facing water shortages that also lack air conditioning systems, future heat waves will be especially gruesome. 

The best way to prevent heat waves from getting worse is to curb greenhouse gas emissions in accordance with the United Nations’ Paris climate agreement.