News & Features

The heating imbalance in Earth's oceans reached a new record high in 2017. From 1993–2017, the ocean has accumulated 0.36–0.40 watts of heat per square meter in the top 700 meters and another 0.19–0.35 watts per square meter at depths between 700–2,000 meters.

2017 will likely be the 38th year in a row that, on average, glaciers worldwide have lost ice mass. Cumulative mass losses have accelerated since 2000.

In 2017, land areas recorded more than 60 days of extreme daytime heat worldwide, nearly double the 1961-1990 average. 

Large areas of severe or extreme drought affected every continent except North America in 2017. Extreme drought conditions affected at least 3 percent of the global land area in every month of 2017.

Global mean sea level in 2017 was the highest in the satellite record—3 inches (77 millimeters) higher than it was in 1993—and the rate of increase has been accelerating. 

Global temperature in 2017 was the warmest of any non-El Niño year in the instrumental record. Since 1901, the planet’s surface has warmed by an average of 0.7–0.9° Celsius (1.3–1.6° Fahrenheit) per century, but the rate of warming has nearly doubled since 1975 to 1.5–1.8° Celsius (2.7–3.2° Fahrenheit) per century.

As part of the State of the Climate in 2017 report, experts describe a record three-year-long episode of mass coral bleaching at tropical reefs worldwide. Previous global bleaching events required the presence of El Niño, but the devastating 2014–2017 event began before El Niño emerged and continued long after it ended—implicating human-caused global warming in the mass die offs.

The State of the Climate in 2017 report includes a summary of the devastation in Puerto Rico from Hurricane María, describing damage so widespread and severe that thousands of residents of the Caribbean island moved to the U.S. mainland in the aftermath. 

In a sidebar to the State of the Climate in 2017 report,  experts describe how human-caused climate change is leading to longer, more damaging fire seasons in the evergreen-dominated boreal forests of Alaska, Canada, and Eurasia. 

See highlights from the 2017 issue of the planet's most comprehensive annual physical, the American Meteorological Society's State of the Climate report.