For the 12th month in a row, the National Oceanic and Atmospheric Administration has announced record-high global temperatures -- marking a yearlong heat streak that scientists say is grim sign of climate change in action.
April 2016 was the hottest April ever recorded by NOAA since it started tracking global temperatures in 1880, the agency announced Wednesday. This is the 12th consecutive month the agency has identified a monthly global temperature record. That's the longest such streak NOAA has ever recorded.
"The April temperature across global land and ocean surfaces was 1.98°F above the 20th century average of 56.7°F," NOAA announced. "This was the highest for April in the 1880-2016 record, surpassing the previous record set in 2010 by 0.50°F."
Those temperatures are staggering, climatologists say.
Caldas noted that she didn't expect the planet would arrive at this point so quickly.
"I think most climate scientists are surprised at the speed that it's happening," she said. "But at the same time, with emissions peaking again last year... everything was pointing to an increased temperature. It's the amount by which the records are being broken, not the fact that the record's being broken, that's really striking."
While this year's powerful El Niño contributed to the yearlong streak, it's definitely not the root cause, climate scientists emphasized.
"The overall rise in [temperature] is clearly global warming, but punctuated by added spikes from El Niño," Kevin Trenberth, a senior scientist with the National Center for Atmospheric Research, explained in an email.
"We are breaking records by 3 to 4 tenths of degree C, whereas even the largest El Niños... only boost global temperatures by 1 to 2 tenths of a degree C," Michael Mann, a climate scientist and director of Pennsylvania State University’s Earth System Science Center, told The Huffington Post in an email. "Even neglecting the possibility that climate change itself is leading to more monster El Niños... El Niño cannot explain the majority of this record warmth. Climate change is clearly playing a key role in the record warmth."
NASA also recently announced that April 2016 was the hottest April on record, although it considers it to have been the 7th consecutive monthly record, not the 12th. NASA uses slightly different dates than NOAA to determine the long-term average temperatures, and it says that September 2014 was warmer than September 2015 -- a finding that Mann says might be more accurate than NOAA's.
Regardless, neither agency is denying that the past 12 months have been marked by disastrous heat-related climate events.
"I think it is quite clear that climate change has played a key role in several record weather events during the past year, including record strength hurricanes (both the Northern and Southern hemisphere saw their most intense hurricanes on record during the past year), an unprecedented, still ongoing California drought, and raging Canadian wildfires unlike anything we’ve seen so early in the fire season," Mann wrote. "And that’s just a few examples."
Caldas pointed to the floods in Texas and Oklahoma last May.
"They have the signature of climate change," she said, noting that warmer weather allows the atmosphere to hold more moisture. "The heavy downpours are getting heavier."
The recent widespread coral bleaching, she added, has been linked to water temperatures being so high that coral is losing the ability to cope.
International negotiations will be key to mitigating even greater temperature rise in the next 12 months, climatologists say.
"The Paris Agreement needs to be implemented, country by country," Trenberth said. He added that he'd like to see a universal price on carbon implemented globally -- "but politically that will be tough."
Given the United States' critical role in the Paris agreement, it's crucial that the next presidential administration continue taking the lead on climate issues, Mann said.
"We will need to decide in this next presidential election whether we want to continue the progress that the current administration has made, or throw it all away by electing a climate change denier president," he wrote. "The fate of the Earth does quite literally lie in the balance."