A zookeeper feeds a hippopotamus with a watermelon in its enclosure in Belgrade's zoo, Serbia, July 20, 2015. Temperatures in Serbia have risen up to 40 degrees Celsius (104 degrees Fahrenheit), according to official meteorological data. (Photo by Marko Djurica/Reuters)

Pigeons cool down at a public fountain on a hot summer day at University Plaza in downtown Bucharest, Romania, 10 June 2020. Temperatures in Bucharest reached 30 degrees Celsius. (Photo by Robert Ghement/EPA/EFE)

A woman takes a selfie picture at the Poklonnaya Hill in western Moscow near the main building of the Moscow State University on June 17, 2020, as the air temperature approaches 30 degrees Celsius. (Photo by Alexander Nemenov/AFP Photo)

Nobby the polar bear cools down as he plays in a lake at the Yorkshire Wildlife Park in Doncaster, England, Friday June 17, 2022. A blanket of hot air stretching from the Mediterranean to the North Sea is giving much of western Europe its first heat wave of the summer, with temperatures forecast to top 30 degrees Celsius (86 degrees Fahrenheit) from Malaga to London on Friday. (Photo by Danny Lawson/PA Wire via AP Photo)

A man in Yakutsk, the capital of the Sakha Republic (Yakutia) in the Russian Far East on November 23, 2021. Located in Tuimaada Valley on the Lena River, Yakutsk is the largest city in the permafrost zone. On 23 November 2021, the daytime temperature ranged between –35 and –31 degrees Celsius in Yakutsk. On the night between 22 and 23 November, the temperature went down to –37 degrees Celsius. (Photo by Vadim Skryabin/TASS)

A frosty sunset is seen through icicles in Peremilovo village, 65 km (40,6 miles) north of Moscow, Russia, Sunday, December 16, 2018. Temperatures in the Moscow region on Sunday dropped to –12 degree Celsius (10 Fahrenheit). (Photo by Alexander Zemlianichenko/AP Photo)

A vendor sells fish at Central Market in freezing conditions of minus 43 degrees Celsius in the city of Yakutsk, Sakha (Yakutia), Russia on December 13, 2020. The winters in Yakutsk are extremely cold and long and the summers short and warm, with temperatures sometimes rising above 30C. (Photo by Yevgeny Sofroneyev/TASS)

A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)