According to two separate analyses by NASA and National Oceanic and Atmospheric Administration (NOAA) scientists, 2014 ranks as Earth’s warmest since 1880.
The 10 warmest years in the instrumental record, with the exception of 1998, have now occurred since 2000. This trend continues a long-term warming of the planet, according to an analysis of surface temperature measurements by scientists at NASA’s Goddard Institute of Space Studies (GISS) in New York.
In an independent analysis of the raw data, NOAA scientists also found 2014 to be the warmest on record.
Since 1880, Earth’s average surface temperature has warmed by about 1.4°F (0.8°C).
“This is the latest in a series of warm years, in a series of warm decades,” said GISS Director Gavin Schmidt. “While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases.”
While 2014 temperatures continue the warming trend, scientists still expect to see year-to-year fluctuations in average global temperature caused by phenomena such as El Niño or La Niña. These climate patterns warm or cool the tropical Pacific and are thought to have played a role in the flattening of the long-term warming trend over the past 15 years. However, 2014’s record warmth occurred during an El Niño-neutral year.
Regional differences in temperature are more strongly affected by weather dynamics than the global mean. For example, in the U.S. in 2014, parts of the Midwest and East Coast were unusually cool, while Alaska and three western states – California, Arizona and Nevada – experienced their warmest year on record, according to NOAA.
The GISS analysis incorporates 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 raw data is analyzed using an algorithm that takes into account the varied spacing of temperature stations around the globe and urban heating effects that could skew the calculation. The result is an estimate of the global average temperature difference from a baseline period of 1951 to 1980.
NOAA scientists used much of the same raw temperature data, but a different baseline period. They also employ their own methods to estimate global temperatures.
Click here to see the methodology used to make the temperature calculation.
Source: NASA news release