21 september 2016

Stuck on record warm: Earth has unprecedented 16-straight warmest months

By Andrew Freedman, Mashables, 21 September 2016

When it comes to Earth's climate, even the records themselves are breaking records now. Earth just experienced its hottest August on record, according to NASA and the National Oceanic and Atmospheric Administration (NOAA).

This means the planet has set a record warm monthly temperature record during every month for the past 16 consecutive months — an unprecedented warm streak, according to NOAA. The year-to-date is also record warm, as was the June through August period, known as meteorological summer in the Northern Hemisphere.

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According to NOAA findings released Tuesday, the globally averaged surface temperature for August was 0.92 degrees Celsius, or 1.66 degrees Fahrenheit above the 20th century average of 15.6 degrees Celsius, or 60.1 degrees Fahrenheit.

This surpassed all other Augusts in temperature data going back to 1880, beating August of 2015 by 0.05 degrees Celsius, or 0.09 degrees Fahrenheit. Unlike NASA, however, NOAA did not find that August tied July for the title of the hottest month on record.

Based on NOAA's analysis, August was slightly cooler than July, compared to average.

The record warm streak has featured months that have shattered previous milestones, with 14 of the 15 highest monthly temperature departures from average occurring since February 2015, NOAA found.

For the year-to-date, global average surface temperatures beat out the previous record warm January through August period, which occurred just last year, by 0.16 degrees Celsius, or 0.29 degrees Fahrenheit. Both land and ocean surface temperatures were record warm for the year so far.

Record warmth during the first eight months of the streak occurred across much of the globe, NOAA found, including western Canada, northern South America, central and southern Africa, Indonesia, northern and southern Asia and Australia. Not a single land area saw cooler-than-average conditions during the January to August period, NOAA said.

"Something that gets lost in the monthly updates to this streak of record-breaking months is the magnitude of change compared to just a couple decades ago," Derek Arndt, chief of climate monitoring at NOAA’s National Centers for Environmental Information, told Mashable via email.

"Sure, we've broken the record 16 consecutive months, that is evidence that we are in a warm surge following decades of warming. But the magnitude is immense: twenty years ago, in 1996, no year had poked above half a degree Celsius warmer than the 20th century average. Now, we're at a degree above the average. We've doubled that difference in half a generation."

For the oceans, the only area that was record cold for the year-to-date was the stormy Drake Passage off of South America.


The extraordinarily warm year of 2016 has brought flood disasters to the U.S. — the most recent of which devastated parts of Louisiana — as well as in China.

Typically hot locations, such as India, Kuwait and Iraq, set new benchmarks for what constitutes their hottest days. Meanwhile, the world's oceans have been suffering through the longest-lasting global coral bleaching event on record, which is now expected to last into 2017.

Meanwhile in the Arctic, both the Northwest and Northeast Passages were open for navigation, with a massive cruise ship passing through the Northwest Passage for the first time, carrying more than 1,000 passengers and crew.

Arctic sea ice hit the second-lowest level on record, which continues the long-term trend toward a seasonally ice-free Arctic.

Warmest year?

While NASA has said that it is virtually certain that 2016 will be the warmest year on record, beating the milestone set just last year, NOAA is hedging on that prediction a bit more.

The agency published a graph showing different scenarios in which 2016 could end up being the second-warmest year. For example, if each month from September through December matches the 1998 monthly values, NOAA scientists found, the year would end up behind 2015 by 0.06 degrees Celsius, or 0.11 degrees Fahrenheit.

The 1998 comparison is apt, since that year also saw an El Niño event at the start of the year, followed by much cooler conditions in the tropical Pacific as the year went on.

Global average surface temperature anomaly horserace for 2016 compared to previous warmest years. Triangles show scenario involving 1998 monthly average temperatures, while circles follow scenario in which September to December match 21st century monthly average temperatures..

While part of the warmth is due to an El Niño event in the tropical Pacific Ocean, which tends to boost global average temperatures, that event has subsided, yet warm records have continued to topple. This illustrates the influence of human-caused global warming, which has been driving temperatures upward at a faster pace in recent decades.

Without a La Niña event to dampen global average temperatures slightly, it's possible that more monthly temperature records will be set before 2016 is over.

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