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 Climate Change Indicators: Sea
Surface Temperature
This indicator describes global trends in sea surface
temperature.
Key Points
Sea surface temperature increased during the 20th century
and continues to rise. From 1901 through 2015, temperature
rose at an average rate of 0.13°F per decade (see Figure 1).
Sea surface temperature has been consistently higher during
the past three decades than at any other time since reliable
observations began in 1880 (see Figure 1).
Based on the historical record, increases in sea surface
temperature have largely occurred over two key periods:
between 1910 and 1940, and from about 1970 to the present.
Sea surface temperature appears to have cooled between 1880
and 1910 (see Figure 1).
Changes in sea surface temperature vary regionally. While
most parts of the world’s oceans have seen temperature rise,
a few areas have actually experienced cooling—for example,
parts of the North Atlantic (see Figure 2). |
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Background
Sea surface temperature—the temperature of the water at the
ocean surface—is an important physical attribute of the
world’s oceans. The surface temperature of the world’s
oceans varies mainly with latitude, with the warmest waters
generally near the equator and the coldest waters in the
Arctic and Antarctic regions. As the oceans absorb more
heat, sea surface temperature increases and the ocean
circulation patterns that transport warm and cold water
around the globe change.
Changes in sea surface temperature can alter marine
ecosystems in several ways. For example, variations in ocean
temperature can affect what species of plants, animals, and
microbes are present in a location, alter migration and
breeding patterns, threaten sensitive ocean life such as
corals, and change the frequency and intensity of harmful
algal blooms such as “red tide.” Over the long term,
increases in sea surface temperature could also reduce the
circulation patterns that bring nutrients from the deep sea
to surface waters. Changes in reef habitat and nutrient
supply could dramatically alter ocean ecosystems and lead to
declines in fish populations, which in turn could affect
people who depend on fishing for food or jobs.
Because the oceans continuously interact with the
atmosphere, sea surface temperature can also have profound
effects on global climate. Increases in sea surface
temperature have led to an increase in the amount of
atmospheric water vapor over the oceans. This water vapor
feeds weather systems that produce precipitation, increasing
the risk of heavy rain and snow (see the Heavy Precipitation
and Tropical Cyclone Activity indicators). Changes in sea
surface temperature can shift storm tracks, potentially
contributing to droughts in some areas. Increases in sea
surface temperature are also expected to lengthen the growth
season for certain bacteria that can contaminate seafood and
cause foodborne illnesses, thereby increasing the risk of
health effects. |
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About the Indicator
This indicator tracks average global sea surface temperature
from 1880 through 2015. It also includes a map to show how
change in sea surface temperature has varied across the
world’s oceans since 1901.
Techniques for measuring sea surface temperature have
evolved since the 1800s. For instance, the earliest data
were collected by inserting a thermometer into a water
sample collected by lowering a bucket from a ship. Today,
temperature measurements are collected more systematically
from ships, as well as at stationary and drifting buoys.
The National Oceanic and Atmospheric Administration has
carefully reconstructed and filtered the data in Figure 1 to
correct for biases in the different collection techniques
and to minimize the effects of sampling changes over various
locations and times. The data are shown as anomalies, or
differences, compared with the average sea surface
temperature from 1971 to 2000. The map in Figure 2 was
developed by the Intergovernmental Panel on Climate Change,
which calculated long-term trends based on a collection of
published studies.
Indicator Notes
Both components of this indicator are based on instrumental
measurements of surface water temperature. Due to denser
sampling and improvements in sampling design and measurement
techniques, newer data are more precise than older data. The
earlier trends shown by this indicator have less certainty
because of lower sampling frequency and less precise
sampling methods.
Data Sources
Data for Figure 1 were provided by the National Oceanic and
Atmospheric Administration’s National Centers for
Environmental Information and are available online at:
www.ncdc.noaa.gov/data-access/marineocean-data/extended-reconstructed-sea-surface-temperature-ersst.
These data were reconstructed from measurements of water
temperature, which are available from the National Oceanic
and Atmospheric Administration at:
https://icoads.noaa.gov/products.html. Figure 2 is an
updated version of a map that appeared in the
Intergovernmental Panel on Climate Change’s Fifth Assessment
Report
https://ipcc.ch/report/ar5/wg1, which gathered data
from a variety of studies that provide the best available
information about climate change.
Technical Documentation
Download related technical information PDF |
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 Figure
1. Average Global Sea Surface Temperature, 1880–2015
This graph shows how the average surface temperature of the
world’s oceans has changed since 1880. This graph uses the
1971 to 2000 average as a baseline for depicting change.
Choosing a different baseline period would not change the
shape of the data over time. The shaded band shows the range
of uncertainty in the data, based on the number of
measurements collected and the precision of the methods
used.
Data source: NOAA, 20166 |
 Figure
2. Change in Sea Surface Temperature, 1901–2015
This map shows how average sea surface temperature around
the world changed between 1901 and 2015. It is based on a
combination of direct measurements and satellite
measurements. A black “+” symbol in the middle of a square
on the map means the trend shown is statistically
significant. White areas did not have enough data to
calculate reliable long-term trends.
Data source: IPCC, 20137; NOAA, 20168 |
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EPA Page |
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This is the
EPA page for this topic. To see if the Trump
administration has changed the EPA page, simply click the
link and compare the information with this page. If you
notice changes were made to the EPA page, please post a
comment. Thanks. |
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Additional Climate Change Information |
Climate Change and Carbon Dioxide
(Beginner - Listening,
reading)
A video lesson to
help with your understanding of climate change
and carbon dioxide.
The English is
spoken at 75% of normal speed.
Great English listening and reading practice. |
Carbon Dioxide and Climate Change
(Beginner - Listening,
reading)
A video lesson to
help with your understanding of carbon dioxide
and climate change.
The English is
spoken at 75% of normal speed.
Great English listening and reading practice. |
Environmental Group Warns Earth's Health at Risk
(Beginner - Listening,
reading)
A video lesson to
help with your understanding of climate change.
The English is
spoken at 75% of normal speed.
Great English listening and reading practice.
A report by the World Wildlife Fund looked at thousands of animal populations
and found they have dropped significantly in 40 years. |
Sea Levels Rising at Fastest Rate in 3,000 years
(Beginner - Listening,
reading)
A video lesson to
help with your understanding of climate change.
The English is
spoken at 75% of normal speed.
Great English listening and reading practice.
A group of scientists say sea levels are rising at record rates. Another group
found that January temperatures in the Arctic reached a record high. |
Capturing CO2 Gas Is Not Easy
(Beginner - Listening,
reading)
A video lesson to
help with your understanding of climate change.
The English is
spoken at 75% of normal speed.
Great English listening and reading practice.
Most scientists agree that carbon-dioxide gas is partly to blame for climate
change: rising global temperatures. But capturing the CO2 gas released by power
stations is costly and difficult. |
Growth, Climate Change Threaten African Plants and
Animals
(Beginner - Listening,
reading)
A video lesson to
help with your understanding of climate change.
The English is
spoken at 75% of normal speed.
Great English listening and reading practice.
Researchers believe Africa may lose as much as 30 percent of its animal and
plant species by the end of this century. |
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