Earth's global surface temperatures in 2018 were the fourth warmest since 1880 and the planet will warm further, especially since greenhouse gas emissions are continuing to rise, NASA and the National Oceanic and Atmospheric Administration (NOAA) have said.
That means 2018 was the fourth hottest year recorded in over 100 years.
If it seems like you've heard this before, you have: Eighteen of the hottest 19 years have occurred since 2001.
NOAA said the average temperature for the contiguous U.S.in 2018 was 53.5 degrees Fahrenheit, making it a warmer-than-average year for the 22nd year in a row.
A United Nations report a year ago said the world is likely to breach 1.5 degrees Celsius sometime between 2030 and 2052 on current trends, triggering ever more heat waves, powerful storms, droughts, mudslides, extinctions and rising sea levels.
Increasing temperatures can "contribute to longer fire seasons and some extreme weather events", Nasa also warned.
Most importantly, ice sheet loss from Arctic and Antarctic glaciers lead to sea level rise, which threatens coastal communities around the globe, particularly in developing regions of the world.
The British Met Office, which also contributes data to the WMO, said temperatures could rise to 1.5 degrees Celsius above pre-industrial times, for instance, if a natural El Nino weather event adds a burst of heat.
According to NASA, its temperature analyses incorporates surface temperature measurements from 6,300 weather stations, ship- and buoy-based observations of sea surface temperatures, and temperature measurements from Antarctic research stations.