Climate change activist Greta Thunberg reacts during a news conference during COP25 climate summit in Madrid, Spain, December 9, 2019. (Photo by Juan Medina/Reuters)

A woman reacts as she joins around a thousand New Year swimmers, many in costume, braved freezing conditions in the River Forth in front of the Forth Rail Bridge during the annual Loony Dook Swim on January 1, 2013 in South Queensferry, Scotland. Thousands of people gathered last night to see in the New Year at Hogmanay celebrations in towns and cities across Scotland. (Photo by Jeff J. Mitchell)

Hardy Dutch swimmers brave the icy North Sea on January 1, 2012 in Scheveningen, Netherlands. A record number of 10,000 people took the plunge in this year's traditional New Year's dip. The high turnout was attributed to the mild weather with a sea temperature of 8 degrees compared to 4 degrees last year. (Photo by Jasper Juinen/Getty Images)

Workers attach 288 new Waterford Crystal Triangles on the 2012 Times Square New Year's Eve Ball at One Times Square on December 27, 2011 in New York City. (Photo by Jason Kempin/Getty Images)

Spectators pass through security screening ahead of the New Year's Eve celebration in Times Square in New York, on Sunday, December 31, 2017. (Photo by Peter Morgan/AP Photo)

Revellers enjoy themselves during Hogmanay celebrations in Edinburgh, Scotland on December 31, 2017. (Photo by Russell Cheyne/Reuters)

In this Saturday, March 21, 2015 photo, a porter rests carrying supplies for the upcoming climbing season, near the Everest Base camp, Nepal. Nepal has cleared more than 300 mountaineers to climb Mount Everest after they had to abandon last year's efforts when an ice avalanche killed 16 guides in the mountain's deadliest disaster, an official said on March 20. The three-month climbing season for Everest, the world's tallest mountain, begins in March. (Photo by Tashi Sherpa/AP Photo)

Fireworks light up the London skyline and Big Ben just after midnight on January 1, 2012 in London, England. Thousands of people lined the banks of the River Thames in central London to see in the New Year with a spectacular fireworks display. (Photo by Peter Macdiarmid/Getty Images)