A flooded street in Miami Beach in September 2015. The flood was caused by a combination of seasonal high tides and what many believe is a rise in sea levels due to climate change. Miami Beach has already built miles of seawalls and has embarked on a five-year, $400 million stormwater pump program to keep the ocean waters from inundating the city. Joe Raedle/Getty Images North America/Getty Images

Sea water collects in front of a home in Tangier, Virginia, in May 2017. Tangier Island in Chesapeake Bay has lost two-thirds of its landmass since 1850. Now, the 1.2 square mile island is suffering from floods and erosion and is slowly sinking. A paper published in the journal Scientific Reports states that "the citizens of Tangier may become among the first climate change refugees in the continental USA." JIM WATSON/AFP/AFP/Getty Images

The Pasterze glacier is Austria's largest and it's shrinking rapidly: the sign on the trail indicates where the foot of the glacier reached in 2015, a year before this photo was taken. The European Environmental Agency predicts the volume of European glaciers will decline by between 22 percent and 89 percent by 2100, depending on the future intensity of greenhouse gases. Sean Gallup/Getty Images Europe/Getty Images

A NASA research aircraft flies over retreating glaciers on the Upper Baffin Bay coast of Greenland. Scientists say the Arctic is one of the regions hit hardest by climate change. Mario Tama/Getty Images

A wooden pole that had been driven into the ice the year before now stands exposed as the Aletsch glacier melts and sinks at a rate of about 10-13 meters per year near Bettmeralp, Switzerland. Sean Gallup/Getty Images Europe/Getty Images

In the Mississippi Delta, trees are withering away because of rising saltwater, creating " Ghost Forests ." John Rubenstahl/CNN Air

A street is flooded in Sun Valley, Southern California in February 2017. Powerful storms have swept Southern California after years of severe drought, in a "drought-to-deluge" cycle that some believe is consistent with the consequences of global warming. David McNew/Getty Images North America/Getty Images

The carcass of a dead cow lies in the Black Umfolozi River, dry from the effects of a severe drought, in Nongoma district north west from Durban, in November 2015. South Africa ranks as the 30th driest country in the world and is considered a water-scarce region. A highly variable climate causes uneven distribution of rainfall, making droughts even more extreme. MUJAHID SAFODIEN/AFP/AFP/Getty Images

A gigantic cloud of dust known as "Haboob" advances over Sudan's capital, Khartoum. Moving like a thick wall, it carries sand and dust burying homes, while increasing evaporation in a region that's struggling to preserve water supplies. Experts say that without quick intervention, parts of the African country -- one of the most vulnerable in the world -- could become uninhabitable as a result of climate change. AFP/Getty Images

Low tide reveals the extent of accelerated erosion shown by the amount of exposed beach rocks on Maafushi beach in the Maldives. This is the world's lowest-lying country, with no part lying more than six feet above sea level. The island nation's future is under threat from anticipated global sea level rise, with many of its islands already suffering from coastal erosion. Aishath Adam/Getty Images AsiaPac/Getty Images

Los Glaciares National Park, part of the third largest ice field in the world, on November 27, 2015 in Santa Cruz Province, Argentina. The majority of the almost 50 large glaciers in the park have been retreating during the past 50 years due to warming temperatures, according to the European Space Agency (ESA). Mario Tama/Getty Images South America/Getty Images

A boy from the remote Turkana tribe in Northern Kenya walks across a dried up river near Lodwar, Kenya. Millions of people across Africa are facing a critical shortage of water and food, a situation made worse by climate change. Christopher Furlong/Getty Images Europe/Getty Images

An Indian farmer in a dried up cotton field in the southern Indian state of Telangana, in April 2016. Much of India is reeling from a heat wave and severe drought conditions that have decimated crops, killed livestock and left at least 330 million people without enough water for their daily needs. NOAH SEELAM/AFP/AFP/Getty Images