Climate

We Just Lived In The Hottest Year On Record

CREDIT: NASA

NOAA and NASA have announced that 2015 was by far the hottest year on record globally. In fact, NOAA reports that “2015 is Earth’s warmest year by widest margin on record.” 2015 set the record for setting records!

While global temperature records are normally measured in hundredths of degrees Fahrenheit, NOAA reports 2015 crushed the previous record just set in 2014 by nearly three tenths of a degree, or 0.29°F (0.16°C) above the previous record, which was set in 2014.

NOAA 2015

Last month was not just the hottest December on record, blowing out the previous record (set in 2014) by a staggering half degree — 0.52°F (0.29°C). NOAA reports “The December temperature departure from average was also the highest departure among all months in the historical record and the first time a monthly departure has reached +2°F from the 20th century average.”

The NOAA and NASA findings are consistent with other key global surface temperature datasets. For instance, Berkeley Earth — originally funded in part by deniers like Charles Koch to disprove global warming — reported last week that “2015 was unambiguously the hottest year on record.”

The blowout record warmth of 2015 erases the notion of a so-called pause in warming. NASA and Columbia University climatologists explain that “the updated global temperature record makes it clear that there was no global warming ‘hiatus’.” Similarly, Berkeley Earth’s Scientific Director Richard Muller, says 2015 “confirms our previous interpretation” that “global warming has not slowed.”

Far from slowing down, according to a number of studies last year from NOAA and others, we may well be entering an era of even more rapid global warming. Indeed, the combination of short-term warming from the ongoing El Niño with the long-term human-caused global warming trend mean that “2016 is likely to be at least as warm, if not warmer” than 2015, as UK Met Office research fellow Chris Folland explained in December. NOAA’s Tom Karl and NASA’s Gavin Schmidt told reporters Wednesday that the chances were better than even that 2016 will top 2015.

As for why 2015 was so hot, a recent analysis by Climate Central makes clear that virtually all of the warming — some 95 percent — is due to human activity.

Climate graph

A graph showing how much greenhouse gases dominate global temperatures compared to natural factors like El Niño. Almost all of 2015’s record heat is due to human activity.

The human-caused warming has injected huge amounts of energy into the atmosphere — putting our weather on steroids — and vastly more energy into the oceans, where it can speed up ice melt and supercharge hurricanes. For instance, on October 23, 2015, Hurricane Patricia became a powerful Category 5 storm with 200 mph sustained surface winds, making it “the most intense hurricane ever observed in the Western Hemisphere,” as meteorologist and former Hurricane Hunter Dr. Jeff Masters explained. Similarly, in March, “a tropical cyclone catastrophe of nearly unprecedented dimensions” named Pam devastated the South Pacific island nation of Vanuatu.

The most destructive event of 2015 was Indonesia’s fire, which did cumulative damage of some $16 billion and likely killed over 10,000 adults. All told, the world suffered 29 billion-dollar weather disasters — the fourth-highest since accurate global records started in 1990. The U.S. alone saw ten or eleven billion-dollar weather disasters (depending on how the accounting is done) in 2015, the fourth-highest total since 1980. Masters points out that “billion-dollar events account for roughly 80% of the total U.S. losses for all weather-related disasters.”

Climate Nexus has put together a good video for 2015 of the year in extreme weather:

Since preindustrial times, the planet is now more than now halfway to the 2°C (3.6°F) “defense line” that the world’s top scientists and governments say we must stay well below to avoid catastrophic climate impacts. We have no more time to lose in slashing carbon pollution.