A tanker airplane drops fire retardant on a wildfire on September 1, 2011 in Graford, Texas. More than 6,500 acres and more than 45 homes in the area have burned since Tuesday as wildfires sweep through parts of Texas and Oklahoma. (Photo by Tom Pennington/Getty Images)

Sinabung mount spews ash to the air during an eruption near from Karo, North Sumatra on January 7, 2014. An Indonesian volcano that has erupted relentlessly for months shot volcanic ash into the air 30 times on January 4, forcing further evacuations with more than 20,000 people now displaced, an official said. (Photo by Sutanta Aditya/AFP Photo)

Wounded people walk after clashes with riot police in central Kiev February 18, 2014. Ukrainian riot police advanced on the heart of 12-week-old protests against President Viktor Yanukovich on Tuesday and security forces set a deadline to end disturbances after at least five protesters were reported killed in a day of clashes. (Photo by Vlad Sode/Reuters)

A woman on a bicycle rides past the remains of an Audi sedan set afire by an arsonist recently in Zehlendorf district in a street where two more cars were torched on August 23, 2011 in Berlin, Germany. Police have so far made no arrests in a series of arson attacks that have destroyed at least 70 cars within the last week and show no signs of abating. In recent years several hundred cars have been torched annually and police suspect left-wing radicals. The recent series of attacks, averaging about 10 a day, has been particularly severe. (Photo by Sean Gallup/Getty Images)

A boat paddles behind a fence near a plane sitting on the flooded tarmack of the closed Don Muang airport November 3, 2011 in Bangkok,Thailand. The airport was used as a domestic terminal and was formerly the International airport. Thailand is experiencing the worst flooding in over 50 years and has affected more than nine million people. Over 400 people have died in flood-related incidents since late July according to the Department of Disaster Prevention and Mitigation. (Photo by Paula Bronstein/Getty Images)

Performers wearing traditional outfits demonstrate the Coopers' Dance on Marienplatz square on January 7, 2012 in Munich, Germany. The Coopers' Dance, known in German as the Schaefflertanz, is performed only every seven years and dates back to 1702. (Photo by Johannes Simon/Getty Images)

Workers carry sacks of coffee beans at a warehouse at the Nogales farm in Jinotega, Nicaragua January 7, 2016. Soaring temperatures in Central America due to climate change are forcing farmers to pull up coffee trees and replace them with cocoa, spurring a revival in the cultivation of a crop once so essential to the region's economy. (Photo by Oswaldo Rivas/Reuters)

A CRH train is seen passing through Nanjing South Railway Station, which is part of the Beijing-Shanghai High-Speed Railway Line, on March 27, 2011 in Nanjing, Jiangsu Province of China. The High-Speed railway line is 1,318 kilometres long, running between Beijing and Shanghai. The line will open on June 10, 2011. (Photo by ChinaFotoPress/Getty Images)