2016 was the hottest year on record -- again

2016: The hottest year on record
2016: The hottest year on record


    2016: The hottest year on record


2016: The hottest year on record 01:22

Story highlights

  • 2016 set a global heat record for the third year in a row
  • A record El Niño played a role in pushing the planet's temperatures higher
  • Scientists say humans are the main cause for the warming

(CNN)Last year was officially the Earth's warmest since record-keeping began in the 1880s, the World Meteorological Organization announced Wednesday morning.

    And the pollution certainly is behind the long-term trend toward warming, scientists say.
    "(T)he spate of record-warm years that we have seen in the 21st century can only be explained by human-caused climate change," said Michael Mann, director of the Earth Science Center at Pennsylvania State University.

    Humans are contributing to warming

    A record El Niño lasting from 2015 into 2016 played a role in further pushing the planet's temperature higher. El Niños are weather phenomena that warm the Pacific Ocean and pump lots of excess heat into the atmosphere, raising global temperatures.
    The science behind El Niño
    The science behind El Niño


      The science behind El Niño


    The science behind El Niño 01:26
    And climate scientists say it is a relatively small one when compared to the role that humans are playing.
    "The record is due to a combination of the (natural) strong 2015-2016 El Niño (warming of the tropical Pacific Ocean surface) and the strong global warming trend that has continued from 1970 to the present," James Hansen, former director of the NASA Goddard Institute for Space Studies, told CNN.
    But "the human-caused, long-term warming trend is the bigger contributor," he added.
    To come up with its figures the WMO combined different global temperature datasets from various sources, including NOAA, NASA, the UK Met Office and the European weather and climate center, ECMWF.
    Despite using different methods to compile and analyze the temperatures, all those agencies reached the same conclusion -- that 2016 "continued the long-term trend of warming we have seen since the 1970s ... and have not paused in any way," said Gavin Schmidt, director of NASA's Goddard Institute for Space Studies.

    Arctic is warming faster

    While the warming for the planet was just over 1 degree Celsius, the Arctic continued to warm much faster, with temperatures more than 3 degrees Celsius -- 5.4 degrees F -- above what they were in previous decades.
    "The Arctic is warming twice as fast as the global average" according to the WMO Secretary-General Petteri Taalas, and "we have also broken sea ice minimum records in the Arctic and Antarctic."
    The polar warmth is not just a problem for the polar bears, it lead an entire village in Alaska to vote to relocate.
    And the impacts extent much further.

    What about 2017...and beyond?

    Many scientists believe 2017 is unlikely to break the record for a fourth consecutive year.
    That's because El Nino, a natural phenomenon that creates more warming, may not be present this year.
    That doesn't mean climate change has stopped, though.
    Humans continue to pump greenhouse gases into the atmosphere, warming the planet in the long term.
    And Schmidt said on Wednesday that 2017 is still likely to be "a top-5 year" for global temperatures.
    "Though some years will be warmer than others, the overall trend over multiple decades will inevitably be upward as long of concentrations of CO2 in the atmosphere keep increasing," said Gerald Meehl, a senior scientist at the National Center for Atmospheric Research.
    Climate models consistently show that if CO2 continues to be released into the atmosphere at the current rate, temperatures will continue to climb well above 2 degrees Celsius, according to the latest from Intergovernmental Panel on Climate Change.
    That creates real consequences, from rising sea levels -- threatening low-lying islands and cities like Miami Beach, Florida -- to searing droughts and mass-extinction in the natural world.
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    Politics of record heat

    Meanwhile, it seems unlikely the world's second-biggest climate polluter, the Untied States, will shift away from fossil fuels soon. As news of the hottest year on record circulated the Internet, President-elect Donald Trump's pick to head the US Environmental Protection Agency, Scott Pruitt, testified on Capitol Hill.
    Pruitt expressed doubt about the certainty and seriousness of human-caused climate change, despite overwhelming evidence. Research shows 97% of climate scientists -- almost all of them -- conclude people are warming the planet.
    Trump has called for the United States to scrap the Paris Agreement on climate change, which aims to "green" the world's economy; and the Clean Power Plan, which aims to clean up power plants in the United States.
    The American public, meanwhile, favors more action on this issue.
    According to a poll released Wednesday by the Yale Program on Climate Change Communication and the the George Mason University Center for Climate Change Communication, nearly 7 in 10 Americans support US involvement in the Paris Agreement; and almost 80% want to tax or regulate global warming pollution.
    Critically, the poll found 60% of Americans realize climate change already is affecting the weather.
    So the Trump Administration may find itself out of step both with the science -- and the public.