Ocean Heat
The Global Ocean Monitoring and Observing Program conducts long-term ocean observations that help us better predict and prepare for the impacts of hotter seas, including rising coastlines, changing fisheries, coral bleaching, and more frequent storms.
About the Program
The global ocean is getting warmer.
NOAA is dedicated to understanding how much and how fast the ocean will warm, and what the ripple effects will be. Measuring changes in ocean conditions, producing datasets and tools that are accessible for a range of users, and improving model projections are a few ways that we are empowering leaders and communities across the globe to make informed marine management decisions.
Use slider to view the 2013 vs. 2024 ocean temperatures.
What happens in the ocean doesn’t stay in the ocean.
Increasing ocean temperatures affect people on land, atmospheric processes, glaciers and ice sheets, and living organisms everywhere.
Ocean Heat and Weather
The ocean and atmosphere exchange gases which affect things like how much heat or moisture the air can hold. This, in turn, influences weather across the globe. Warmer ocean waters are connected to changes in day-to-day weather, stronger storm events, like hurricanes, and influence longer-term climate events such as El Nino and La Nina.
Ocean Heat and Ice on Land
Ice sheets at the north and south poles may seem far away, but the interactions between those frozen masses and increasingly hotter ocean waters have impacts worldwide. In places like the Arctic, sea ice concentrations are rapidly decreasing each year in response to a warming ocean.
Coastal communities worldwide are already living with the impacts of sea-level rise, driven in part by the melting of polar ice sheets by warm ocean currents. Warmer water molecules are also larger than cooler ones, and this thermal expansion also contributes to global sea-level rise.
Why is global sea level rising?
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Coastal and Marine Impacts
From the surface to the seafloor, in the deep ocean and the coasts, marine ecosystems are living with the impacts of a warming ocean. Both warm and cool-water fish species are affected by a warming ocean, like the shifting migratory patterns of east-coast tuna and the declining abundances of east Pacific salmon. The reduction of Arctic sea-ice extent due to ocean temperatures has ripple effects through the entire marine ecosystem, impacting zooplankton distribution and, by extension, availability of food for several whale species. This threatens not only food availability but cultural practices that local and Indigenous populations have long depended on.
Tropical coral reef systems provide habitats for many economically-important fish species, and are yet another ecosystem that is suffering from a hotter ocean. While coral restoration efforts, like those spearheaded by NOAA researchers at the Atlantic Oceanographic and Meteorological Laboratory, offer a promising pathway to increase resilience of these delicate ecosystems, they are not a long-term solution against rising ocean temperatures.
Excess heat is stored by the ocean.
As the concentration of gasses like carbon dioxide and methane in Earth’s atmosphere continues to increase, predominantly as a result of human activities, so does the amount of solar energy (or heat) trapped by the Earth’s climate system. Much like a greenhouse, the amount of heat that enters into the atmosphere is greater than what escapesback out into space, leading to an overall increase in temperatures. The global ocean absorbs up to 91% of the excess solar energy that cannot be reflected back into space.
Why the Ocean?
Have you ever chosen to wear a light-colored shirt in the summer instead of a dark one, knowing it would keep you cooler? Dark objects, like your t-shirt and the ocean, have a low albedo – meaning they retain more heat than they reflect. Not only does ocean water have a low albedo, but it also covers over 70% of our planet, making it a natural storage space for excess heat.
Between 1993 and 2022, the amount of heat energy absorbed by the ocean is equal to >800 times the total electricity consumed by the United States in 2022 (the year with the highest energy use recorded).
Understanding the impacts and drivers of these changes, and improving our predictions of future change, are fundamental in building a climate-ready nation. Learn more about how NOAA is leading these efforts through sustained observing and modeling of our global ocean below.
How NOAA is monitoring and predicting impacts of ocean heat.
"The lack of long-term measurements of the global ocean and changes in the observing system over time makes documenting and understanding change in the oceans a difficult challenge."
-IPCC AR5
Measuring the pulse of the oceans
It’s hard to measure how something is changing with only a couple of unconnected data points. How can you tell what is “normal?” By maintaining networks of ocean observing systems, in each ocean basin, over multiple decades, we are checking the pulse for what is “normal,” and can detect when ocean conditions stray from that baseline.
The Global Ocean Monitoring and Observing program (GOMO) funds a variety of devices that measure ocean temperature, and other important ocean properties like salinity and carbon dioxide, in each of the planet’s ocean basins. These long-term and widespread observations allow us to measure changes in ocean heat and better predict future climate impacts.
Through GOMO, NOAA measures ocean heat using a variety of ocean observing instruments. Learn more by clicking below:
Ships
Research vessels are crucial in getting scientists to sea to deploy and recover ocean observing instruments. Programs like GO-SHIP, PIRATA, and others have been collecting valuable ocean data for years. Ships themselves also collect data while they sail!
CTD
A CTD (conductivity, temperature, and depth) measures changes in temperature and salinity from the sea surface to the seafloor. They often have big bottles attached, which allow for sampling of ocean water at different depths, too!
Argo Floats
Over two million ocean profiles have been taken by autonomous Argo floats. Since the program’s inception in 1999, Argo floats have been modified specifically for deep ocean ( to 6,000m) measurements, while others feature sensors that take biological and chemical measurements.
Surface Drifters
More than 1,300 satellite-tracked surface drifting buoys currently drift with ocean currents, collecting data on sea surface temperature, currents, atmospheric pressure, winds, waves, and salinity.
Gliders
Autonomous underwater ocean gliders typically operate for a few months per mission, collecting data on temperature, salinity, currents, and biological conditions.
Autonomous Surface Vehicles
Autonomous surface vehicles (e.g. saildrones) sail across the ocean collecting data such as ocean heat and atmospheric and surface ocean CO2 measurements.
Moored Buoys
Buoys are fixed to the seafloor and float at the ocean surface. They feature sensors and gauges that measure precipitation, wind conditions, and more
Tide Guages
Tide gauges around the world measure how sea level is rising, which is often a direct impact of ocean warming.
eXpendable BathyThermographs (XBTs)
Beginning in the 1960s, XBTs have been deployed from research vessels and Ships of Opportunity (SOOP) to collect temperature observations of the upper 1km of the global ocean. Currently approximately 10,000 XBTs are deployed annually.
More ocean observations supports more reliable weather and climate predictions
NOAA labs and offices across the country are leading efforts, in the field and in the lab, to advance our understanding of the changes in the ocean. The ocean data we collect improves the accuracy of climate and weather predictions. Click on the lab location to learn more about how NOAA labs collect and use ocean heat data.
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