Warming Ocean

A Warming Ocean

Did You Know?

  • The average global sea surface temperature has increased about 1.5oF since 1901, an average rate of 0.13oF per decade.
  • The average global sea surface temperature has been consistently higher during the past three decades than at any other time since reliable records began in 1880.

Oceans cover more than two-thirds of the earth’s surface and play a very important role in regulating the earth’s weather and climate. Currently, oceans absorb more than 90% of the heat that is trapped in the atmosphere from increasing levels of greenhouse gases, which raises the temperature of the water at the sea surface.

Since the oceans continually interact with the atmosphere through the water cycle, an increase in the average global sea surface temperature can have profound impacts on climate and weather systems. A higher sea surface temperature has led to an increase in the amount of water vapor over the oceans, increasing the risk of heavy rain and snow events. This higher temperature also has the potential to shift storm tracks and contribute to droughts in some areas. 

A warming ocean temperature also causes sea levels to rise through thermal expansion, the distribution of many marine species to shift due to their dependence on specific water temperatures and nutrient availability, and changes the circulation patterns of deep ocean currents that transport warm and cold water around the globe.

Learn More

The graph below shows how the average global sea surface temperature has changed from 1880 to 2015. 

Average Global Sea Surface Temperature, 1880-2015

What You Can Do


  • EPA. 2016. "Climate Change Indicators: Ocean Heat." Accessed August 16. https://www.epa.gov/climate-indicators/climate-change-indicators-ocean-heat 
  • EPA. 2016. "Climate Change Indicators: Sea Surface Temparature." Accessed August 16. https://www.epa.gov/climate-indicators/climate-change-indicators-sea-surface-temperature 
  • National Climate Assessment. 2014. "Report Findings: Oceans." Accessed August 16, 2016. http://nca2014.globalchange.gov/highlights/report-findings/oceans 
  • NOOA Climate Program Office. 2016. "The Sustained Global Ocean Observing System for Climate." Accessed August 16. http://cpo.noaa.gov/ClimatePrograms/ClimateObservation/OceanClimateObservation.aspx