According to independent analyses by NASA and NOAA, Earth’s average global surface temperature in 2019 was the second warmest since modern record-keeping began in 1880. Globally, 2019’s average temperature was second only to that of 2016 and continued the planet’s long-term warming trend. Rising temperatures are contributing to glacier melt, disappearing snow cover, shrinking sea ice, rising sea level, and changes in rainfall patterns.^[1]

 

NOAA and NASA take slightly different, complementary approaches to interpreting global surface temperature, and work together to produce and communicate an annual update. NASA’s temperature analyses incorporate surface temperature measurements from more than 20,000 weather stations, ship- and buoy-based observations of sea surface temperatures, and temperature measurements from Antarctic research stations. NOAA scientists incorporate much of the same temperature data as NASA, but use a different method of interpreting data from Earth’s poles and other data-poor regions to translate the raw measurements into a global picture of temperature change. Together, the analyses provide a consistent picture of a warming planet. 

 

A 2019 assessment of NASA's record of global surface temperatures found that improved uncertainty analysis, based on source data, suggests that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit. This finding provides greater confidence that past and future research is correctly capturing rising surface temperatures. The assessment of this data product, known as GISTEMP, shows that the resulting annual values (within the 95% confidence interval) are likely accurate to within 0.09°F (0.05°C) in recent decades, and 0.27°F (0.15°C) at the beginning of the nearly 140-year record.

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