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The 2010s Were the Hottest Decade on Record. What Happens Next?

The news hasn’t come as a surprise to climate scientists, but all urge immediate action

In 2019, the average temperature across global land and ocean surfaces was 0.95 degrees Celsius (1.71 degrees Fahrenheit) above the 20th century average. (National Oceanic and Atmospheric Administration)
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Another year, another temperature record broken. The decade spanning 2010 to 2019 was the hottest documented since 1880, climate experts say. And 2019 joins the five preceding years at the top of the average annual temperature list, second only to 2016. Fueled by continued greenhouse gas emissions, Earth’s most recent six years have been the most sweltering ones yet, report Henry Fountain and Nadja Popovich for the New York Times.

Arriving on the heels of months of floods, wildfires and melting sea ice, the announcements have unfortunately not come as a surprise. Since late last year, researchers tracking temperature highs around the globe have forecast that warming trends will not only continue, but increase in extremity.

“These announcements might sound like a broken record,” NASA’s Gavin Schmidt tells Damian Carrington at the Guardian. “But what is being heard is the drumbeat of the Anthropocene.”

Climbing global temperatures, one of the best-known symptoms of climate change, spell trouble for the planet and its many residents. Habitats, plant and animal species, and irreplaceable natural resources that support billions of people worldwide are already rapidly disappearing—and should things continue business as usual, such trends are poised to continue.

In a way, these reports represent a sort of planetary health assessment. “We’re seeing that the Earth has a temperature,” NOAA climatologist Ahira Sanchez-Lugo tells Tara Law at Time magazine. “But not only that, we see that there are symptoms.”

A closer look at the numbers

Because dedicated, global-scale temperature monitoring began only in the 1800s, our records don’t capture climate fluctuations from most of Earth’s history. Due in large part to humans’ industrial output in the 20th century, however, the annual rate at which global surface temperatures have been rising has more than doubled since 1981, report Brady Dennis, Andrew Freedman and John Muyskens for the Washington Post. The repercussions of this trend are reflected in statistics at both local and worldwide scales.

Last year also saw the hottest average ocean temperatures yet recorded. Europe and Australia were among the regions that experienced their warmest years in 2019. Zooming in further, Shahdad, Iran, hit its maximum 2019 temperature on July 2, clocking in at a whopping 127.6 degrees Fahrenheit. These numbers aren’t universal, though. In North America, for instance, last year’s temperatures ranked only 14th in the past 140 years, reports Jeff Masters for Scientific American.

anomaly.jpg
Yearly temperature anomalies from 1880 to 2019, with respect to the average from 1951 to 1980. The past decade has been the warmest ever recorded. (NASA GISS/Gavin Schmidt)

On a global scale, however, 2019 temperatures topped those from 2016 by 0.07 degrees Fahrenheit, according to NASA and National Oceanic and Atmospheric Administration reports published yesterday. It also bested the long-term average from 1901 to 2000 by 1.71 degrees Fahrenheit, and the average from 1951 to 1980 by 1.78 degrees Fahrenheit. In separate publications, the UK Met Office, Berkeley Earth and Europe’s Copernicus Climate Change Service came to similar conclusions.

The year’s near-record-breaking global warmth is especially surprising because, all else equal, 2019 shouldn’t have been that hot of a year. From January to December, the sun was at a particularly low point in its activity, sending less toasty radiation our way than usual. 2019 also wasn’t a year with a strong El Niño, which, in 2016, pumped a ton of ocean heat into the atmosphere, Scientific American reports.

How did we get here?

So what does help explain 2019’s temperature spike? Human activity. As humans continue to fell carbon-storing trees and burn fossil fuels for transportation, electricity and more, the atmosphere ends up full of gas that’s eager to store heat—hence the term greenhouse gas. A lot of that gas ends up funneled into the oceans, driving up temperatures both in and out of the water.

The world’s temperature undergoes natural fluctuations due a bevy of factors, including wobbles in our planet’s orbit, dips and spikes in the sun’s activity, and massive volcanic eruptions. But what’s happened to the globe since the beginning of the Industrial Revolution is unprecedented. Since the mid-20th century, human-driven changes to climate have driven jumps in Earth’s temperature that can no longer be explained by natural processes alone.

These skyrocketing heat trends have left their mark. As the Guardian reports, data from ice cores suggest today’s temperatures are unprecedented in the last 100,000 years. And atmospheric sampling shows this much carbon dioxide hasn't filled our skies for many millions of years.

Who’s been most affected?

Climate change isn’t picky. The effects of the heat have been diverse and far-reaching, hitting every corner of the globe.

Residents of Alaska experienced their warmest year on record in 2019, the New York Times reports. Across the northerly state, glaciers have melted, ground has thawed, and sea ice-free waters have begun to encroach on shores. The creeping warmth has driven animals like walruses from the region, imperiling the livelihoods of indigenous Alaskans, reported Madeline Fitzgerald for Time magazine last year.

A hop across oceans reveals similarly dire conditions in southern Africa, where the worst drought in decades has triggered crop losses, food shortages and rapidly declining water levels in the region’s life-sustaining rivers.

In Indonesia, the aftermath has already spilled over into 2020, as monsoon rains and floods, fueled by atypically warm ocean water, displace residents by the thousands. Further south, in Australia, wildfires continue to rage across the landscape, sparked by a hot, dry year that parched native vegetation into a carpet of kindling.

No one is immune to these effects, Katharine Hayhoe, an atmospheric scientist at Texas Tech University, tells USA Today's Grace Hauck and Doyle Rice. “Climate change isn’t just a science issue, or an environmental issue,” she says. “It’s a human issue that matters to all of us living on this planet today, whether we know it or not.”

What’s next?

In October 2018, scientists from around the world issued the world a warning: A temperature rise beyond 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels (circa the 1850s) would leave hundreds of millions of people around the world grappling with drought, flooding, extreme heat and increased poverty.

As of January 2020, the globe stands dangerously close to the precipice. The average temperature in 2019 exceeded the average temperature of the latter half of the 19th century by 1.1 degrees Celsius (2 degrees Fahrenheit). And experts grimly project that the next decade could bring much of the same.

But as environmental economist Zeke Hausfather of Berkeley Earth tells the Washington Post, human intervention could still do some good—and perhaps even help stop or reverse these trends. “If we continue emitting [greenhouse gases] at current levels, we will continue warming at about the same rate,” he says. “What happens in the future is really up to us.”

About Katherine J. Wu
Katherine J. Wu

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University. Previously, she served as a Digital Editor at NOVA Next and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.

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