Feb. 6, 2019
RELEASE 19-002
2018 Fourth Warmest Year in Continued Warming Trend, According to NASA, NOAA

Earth's global surface temperatures in 2018 were the fourth warmest since 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA).

Global temperatures in 2018 were 1.5 degrees Fahrenheit (0.83 degrees Celsius) warmer than the 1951 to 1980 mean, according to scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York. Globally, 2018's temperatures rank behind those of 2016, 2017 and 2015. The past five years are, collectively, the warmest years in the modern record.

“2018 is yet again an extremely warm year on top of a long-term global warming trend,” said GISS Director Gavin Schmidt.

Since the 1880s, the average global surface temperature has risen about 2 degrees Fahrenheit (1 degree Celsius). This warming has been driven in large part by increased emissions into the atmosphere of carbon dioxide and other greenhouse gases caused by human activities, according to Schmidt.

Earth’s long-term warming trend can be seen in this visualization of NASA’s global temperature record, which shows how the planet’s temperatures are changing over time, compared to a baseline average from 1951 to 1980. The record is shown as a running five-year average.
Credits: NASA’s Scientific Visualization Studio/Kathryn Mersmann
Download high-definition video and still imagery here.

Weather dynamics often affect regional temperatures, so not every region on Earth experienced similar amounts of warming. NOAA found the 2018 annual mean temperature for the contiguous 48 United States was the 14th warmest on record.

Warming trends are strongest in the Arctic region, where 2018 saw the continued loss of sea ice. In addition, mass loss from the Greenland and Antarctic ice sheets continued to contribute to sea level rise. Increasing temperatures can also contribute to longer fire seasons and some extreme weather events, according to Schmidt.

“The impacts of long-term global warming are already being felt — in coastal flooding, heat waves, intense precipitation and ecosystem change,” said Schmidt.

NASA’s temperature analyses incorporate surface temperature measurements from 6,300 weather stations, ship- and buoy-based observations of sea surface temperatures, and temperature measurements from Antarctic research stations.

This line plot shows yearly temperature anomalies from 1880 to 2018, with respect to the 1951-1980 mean, as recorded by NASA, NOAA, the Japan Meteorological Agency, the Berkeley Earth research group, and the Met Office Hadley Centre (UK). Though there are minor variations from year to year, all five temperature records show peaks and valleys in sync with each other. All show rapid warming in the past few decades, and all show the past decade has been the warmest.
Credits: NASA’s Earth Observatory

These raw measurements are analyzed using an algorithm that considers the varied spacing of temperature stations around the globe and urban heat island effects that could skew the conclusions. These calculations produce the global average temperature deviations from the baseline period of 1951 to 1980.

Because weather station locations and measurement practices change over time, the interpretation of specific year-to-year global mean temperature differences has some uncertainties. Taking this into account, NASA estimates that 2018’s global mean change is accurate to within 0.1 degree Fahrenheit, with a 95 percent certainty level.

NOAA scientists used much of the same raw temperature data, but with a different baseline period and different interpolation into the Earth’s polar and other data poor regions. NOAA’s analysis found 2018 global temperatures were 1.42 degrees Fahrenheit (0.79 degrees Celsius) above the 20th century average.

NASA’s full 2018 surface temperature data set — and the complete methodology used to make the temperature calculation — are available at:

https://data.giss.nasa.gov/gistemp

GISS is a laboratory within the Earth Sciences Division of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The laboratory is affiliated with Columbia University’s Earth Institute and School of Engineering and Applied Science in New York.

NASA uses the unique vantage point of space to better understand Earth as an interconnected system. The agency also uses airborne and ground-based monitoring, and develops new ways to observe and study Earth with long-term data records and computer analysis tools to better see how our planet is changing. NASA shares this knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA’s Earth science missions, visit:

https://www.nasa.gov/earth

The slides for the Feb. 6 news conference are available at:

https://www.nasa.gov/sites/default/files/atoms/files/noaa-nasa_global_analysis-2018-final_feb6.pdf
NOAA’s Global Report is available at:


http://bit.ly/Global201812

-end-

Steve Cole
Headquarters, Washington
202-358-0918
stephen.e.cole@nasa.gov
Last Updated: Feb. 6, 2019
Editor: Sean Potter

06 February 2019

Diffusing the methane bomb: We can still make a difference

The Arctic is warming twice as fast as the rest of the planet, causing the carbon containing permafrost that has been frozen for tens or hundreds of thousands of years to thaw and release methane into the atmosphere, thereby contributing to global warming. The findings of a study that included researchers from IIASA, however, suggest that it is still possible to neutralize this threat

…

In their analysis, the researchers quantified the upper range value for natural methane emissions that can be released from the Arctic tundra, as it allows it to be put in relation to the much larger release of methane emissions from human activities. Although estimates of the release of methane from natural sources in the Arctic and estimates of methane from human activity have been presented separately in previous studies, this is the first time that the relative contribution of the two sources to global warming has been quantified and compared.

…

According to the researchers, their findings confirm the urgency of a transition away from a fossil fuel based society as well as the importance of reducing methane emissions from other sources, in particular livestock and waste. The results indicate that man-made emissions can be reduced sufficiently to limit methane-caused climate warming by 2100 even in the case of an uncontrolled natural Arctic methane emission feedback. This will however require a committed, global effort towards substantial, but feasible reductions.

“In essence, we want to convey the message that the release of methane from human activities is something we can do something about, especially since the technology for drastic reductions is readily available - often even at a low cost. If we can only get the human emissions under control, the natural emissions should not have to be of major concern,” concludes Höglund-Isaksson.

…