Two independent analysis conducted by NASA and NOAA showed that 2015 is the warmest year since 1880 when modern temperature recording began. A previous record was held by 2014, and globally-averaged Earth's surface temperatures in 2015 are estimated higher by 0.13 °C (0.23 °F).
In their study, NASA's scientists have utilized temperature measurements from 6 300 weather stations, ship and buoy borne observations of the sea surface temperature along with temperature records from Antarctic research stations. The data was analyzed with an algorithm taking into account the varied spacing of temperature stations and effects arising from urban heating.
The calculations resulted in the global average temperature difference estimate from a baseline period between 1951 and 1980. The same temperature data over a different baseline period was used to study Earth's polar regions and global temperatures with different techniques.
2015 was the warmest year since modern record-keeping began in 1880, according to a new analysis by NASA’s Goddard Institute for Space Studies. The record-breaking year continues a long-term warming trend. 15 of the 16 warmest years on record have now occurred since 2001. Image credit: Scientific Visualization Studio/Goddard Space Flight Center
Results of the analysis show that a long-term warming trend continues. According to NASA, 2015 was the warmest year with a 94% certainty.
"Climate change is the challenge of our generation, and NASA’s vital work on this important issue affects every person on Earth. Today’s announcement not only underscores how critical NASA’s Earth observation program is, it is a key data point that should make policy makers stand up and take notice - now is the time to act on climate," said NASA Administrator Charles Bolden.
On average, Earth's surface temperature has risen by about 1 °C (1.8 °F) since the late 19th century, and experts think this is largely caused by increased carbon dioxide concentration and other emissions of human origin into the atmosphere. According to the report, the warming mainly happened over the last 35 years. In that period 15 of the 16 warmest years occurred since 2001.
This visualization illustrates Earth’s long-term warming trend, showing temperature changes from 1880 to 2015 as a rolling five-year average. Orange colors represent temperatures that are warmer than the 1951-80 baseline average, and blues represent temperatures cooler than the baseline. Image credit: GSFC Scientific Visualization Studio
It is important to note that El Niño warming weather phenomena was active throughout most of 2015, and has contributed to short-term global average temperature oscillation.
"2015 was remarkable even in the context of the ongoing El Niño. Last year’s temperatures had an assist from El Niño, but it is the cumulative effect of the long-term trend that has resulted in the record warming that we are seeing," said NASA's Goddard Institute for Space Studies (GISS) Director Gavin Schmidt.
Not all parts of our planet have experienced record average temperatures, as different regions are influenced by the local weather dynamics. For example, the 2015 annual mean temperature for 48 neighboring states in the US was the second warmest on record.
Featured image: 2015 was the warmest year since modern record-keeping began in 1880, according to a new analysis by NASA’s Goddard Institute for Space Studies. The record-breaking year continues a long-term warming trend. 15 of the 16 warmest years on record have now occurred since 2001. Image credit: Scientific Visualization Studio/Goddard Space Flight Center