Science

President Donald Trump talks with reporters falling his speech at the World Economic Forum, Tuesday, Jan. 21, 2020, in Davos, Switzerland. (AP Photo/ Evan Vucci)

Pedestrians wear protective masks as they walk through a shopping district in Tokyo Thursday, Jan. 16, 2020. Japan's government said Thursday a man treated for pneumonia after returning from China has tested positive for the new coronavirus identified as a possible cause of an outbreak in the Chinese city of Wuhan. (AP Photo/Eugene Hoshiko)

FILE - In this Jan. 4, 2020, file photo, a health surveillance officer monitors passengers arriving at the Hong Kong International airport in Hong Kong. On Friday, Jan. 17, 2020, the U.S. Centers for Disease Control and Prevention officials said they will begin screening airline passengers at three U.S. airports who traveled from Wuhan in central China, for a new illness that has prompted worries about a new international outbreak. (AP Photo/Andy Wong, File)

FILE - In this Nov. 1, 2019, file photo, flames from a backfire consume a hillside as firefighters battle the Maria Fire in Santa Paula, Calif. The decade that just ended was by far the hottest ever measured on Earth, capped off by the second-warmest year on record, NASA and the National Oceanic and Atmospheric Administration reported Wednesday, Jan. 15, 2020. (AP Photo/Noah Berger, File)

Properties at Nerrigundah, Australia, Monday, Jan. 13, 2020, are damaged and destroyed after a wildfire ripped through the town on New Year's Eve. The tiny village of Nerrigundah in New South Wales has been among the hardest hit by Australia's devastating wildfires, with about two thirds the homes destroyed and a 71-year-old man killed. (AP Photo/Sam McNeil)

FILE - In this Jan. 4, 2020, file photo, a health surveillance officer monitors passengers arriving at the Hong Kong International airport in Hong Kong. A preliminary investigation into viral pneumonia illnesses sickening dozens of people in and around China has identified the possible cause as a new type of coronavirus, state media said Thursday, Jan. 9, 2020. In Hong Kong, 15 patients with symptoms of respiratory illness were being treated as of Sunday. (AP Photo/Andy Wong, File)

In this undated photo provided by the California National Primate Research Center, rhesus monkeys are seen in their outdoor enclosure at the California National Primate Research Center in Davis, Calif. A group of the animals exposed to wildfire smoke as infants have developed lungs that are about 20 percent smaller than other rhesus monkeys. (CNPRC/Univeristy California Davis via AP)

This image released by Twentieth Century Fox shows Kristen Stewart in a scene from "Underwater." (Alan Markfield/Twentieth Century Fox via AP)