2014 was the hottest year in 135 years of record-keeping.
The year’s average combined global land and ocean surface temperature was 58.24 degrees Fahrenheit. This is 1.24 F above the 20th-century average.
Global average land temperatures were 1.80 F above average, while ocean surface temperatures were 1.03 F above average. Land temperatures alone were only the fourth-warmest on record, but ocean temperatures were the warmest, which helped to make 2014 the warmest year overall.
NOAA and NASA record temperature observations independently, but both agencies confirmed 2014 to be a record-breaking year. The 10 warmest years on record have all been after 1998. 2014 marked the 38th straight year with global average temperatures above the 20th-century average.
May, June, August, September, October and December of last year were all the warmest such months on record.
Watch a NASA animation of five-year global temperature averages, mapped from 1880 to 2014:
The record 2014 temperatures underscore the undeniable fact that we are witnessing the effects of human-caused climate change. It is exceptionally unlikely that we would be seeing a record year, during a record-warm decade, during a multidecadal period of warmth that appears to be unrivaled over at least the past millennium, if it were not for the rising levels of planet-warming gases produced by fossil fuel burning.
Perhaps more important than the global temperature story are the impacts of record regional heat. In places like California, the Southwest U.S. more generally, Australia and parts of Brazil, record heat is exacerbating drought and leading to more stress on our water supplies and forests.
With continued global warming, we’re going to see more and more of these unprecedented regional conditions, and with them will come more and more costs to humans and the things they value. 2014 shows that humans are indeed cooking their planet as they continue to combust fossil fuels.
Along with rising temperatures, atmospheric concentrations of greenhouse gases continue to increase. Carbon dioxide concentrations surpassed 400 parts per million in May 2013, for the first time in at least 800,000 years. CO2 concentrations rise and fall slightly in an annual cycle, but remained above 400 parts per million for several months in 2014 and have already surpassed 400 again in January 2015. The last time carbon dioxide levels were this high, temperatures were up to 11 degrees Fahrenheit warmer than today, and sea levels were dozens of feet higher.
Pretty scary all of this!