Earth Could Hit Critical Climate Threshold in Next Five Years

In December 2015, the Paris Agreement on climate change set 2.7 degrees Fahrenheit (1.5 degrees Celsius) of warming above pre-industrial levels as a key target for limiting the negative consequences of human-caused climate change. Now, a new report suggests annual global temperatures could breach that threshold for the first time within the next five years, report Nadine Achoui-Lesage and Frank Jordans for the Associated Press.

There is roughly a 20 percent chance that one of the next five years will see Earth’s yearly average rise to at least 2.7 degrees Fahrenheit higher than pre-industrial levels, according to the report issued by the World Meteorological Organization (WMO). The odds of striking this grim milestone of climate change in the next five years will “increase with time,” the report specifies, adding that there is a 70 percent chance that one or more months in the next five years will crest 2.7 degrees Fahrenheit.

To be clear, hitting or even exceeding this threshold for a month or a single year is not the same thing as 2.7 degrees Fahrenheit of warming becoming the planet’s new normal, but Maxx Dilley, director of climate services at the WMO, tells the AP that, “it shows how close we’re getting to what the Paris Agreement is trying to prevent.”

Earth’s average temperature has already risen 1.8 degrees Fahrenheit above the pre-industrial era (1850-1900) and the last five years were collectively the warmest half-decade ever recorded, reports Ron Brackett for Weather.com.

Limiting the planet to just 2.7 degrees Fahrenheit of warming was the more ambitious of two targets laid out by the 2015 Paris Agreement. Participating countries agreed to hold the rise in global average temperature “well below 2 degrees Celsius [3.6 degrees Fahrenheit] above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius [2.7 degrees Fahrenheit].”

In 2018, the Intergovernmental Panel on Climate Change (IPCC) released a landmark report detailing the impacts of 2.7 and 3.6 degrees Fahrenheit of warming. Even the more aspirational goal of halting planetary warming at 2.7 degrees Fahrenheit comes with serious consequences.

As Brad Plumer and Nadja Popovich reported for the New York Times in 2018, global average temperatures 2.7 degrees Fahrenheit above pre-industrial levels would expose an additional 350 million people to severe drought. By 2100, 31 to 69 million additional people would be subject to flooding from sea level rise. Meanwhile, coral reefs would experience mass mortality events similar to those seen recently on Australia’s Great Barrier Reef “very frequently.” At an increase of 3.6 degrees Fahrenheit, these predictions become even more dire.

"Limiting warming to 1.5 C [2.7 F] is possible within the laws of chemistry and physics," Jim Skea of Imperial College London, one of the authors of the 2018 IPCC report, told NPR’s Christopher Joyce in 2018, "but doing so would require unprecedented changes."

The graphic below, produced by the Carbon Brief in 2019, illustrates the increasingly precipitous drop in global carbon dioxide emissions required to stave off 2.7 degrees Fahrenheit of planetary warming.

UNEP: 1.5C climate target ‘slipping out of reach’ | @hausfath @robbie_andrew https://t.co/dGUfgnegzf pic.twitter.com/feXQTVyuNM

— Carbon Brief (@CarbonBrief) December 30, 2019

The models the WMO used to create its five-year climate forecast did not incorporate the reductions in carbon emissions associated with the coronavirus pandemic, per the AP. But the temporary drop in emissions associated with the lockdown measures aimed at curbing the virus’ spread are unlikely to significantly alter Earth’s climate future.

"Due to the very long lifetime of CO2 in the atmosphere, the impact of the drop in emissions this year is not expected to lead to a reduction of CO2 atmospheric concentrations which are driving global temperature increases," says WMO Secretary-General Petteri Taalas in a statement. "WMO has repeatedly stressed that the industrial and economic slowdown from Covid-19 is not a substitute for sustained and coordinated climate action."

Taalas adds that despite the immediacy and severity of the COVID-19 pandemic, “failure to tackle climate change may threaten human well-being, ecosystems and economies for centuries.” He urged global governments to, “use the opportunity to embrace climate action as part of recovery programs and ensure that we grow back better.”

Alex Fox | | READ MORE

Alex Fox is a freelance science journalist based in California. He has written for the New York Times, National Geographic, Science, Nature and other outlets. You can find him at Alexfoxscience.com.