The string of hotter-than-average annual temperatures continued in 2018, as Earth experienced its fourth-hottest year on record, according to NASA and the National Oceanic and Atmospheric Administration. Also in 2018, the United States suffered 14 weather and climate disasters with costs surpassing $1 billion during a warmer- and wetter-than-average year, NOAA reports. Global temperatures across land and sea were 1.42 degrees Fahrenheit above the 20th century average, making 2018 the fourth-warmest year since record-keeping began in 1880, NOAA said in a report Thursday. In a separate report, NASA's Goddard Institute for Space Studies said global temperatures were 1.5 degrees above the 1951 to 1980 mean, also the fourth highest going back to 1880.

The impacts of long-term global warming are already being felt — in coastal flooding, heat waves, intense precipitation and ecosystem change. Gavin Schmidt NASA Goddard Institute for Space Studies director

The 2-degrees Fahrenheit increase in global temperatures since the late 19th century has been driven largely by growing carbon dioxide and other greenhouse gas emissions from human activity, said the institute's director, Gavin Schmidt. The conclusion reaffirms NASA's long-established finding that man-made emissions are driving climate change, which President Donald Trump and some senior administration officials frequently challenge.