Here’s All the Climate Science You Missed So Far This Year

By Eric Roston | April 6, 2021

In early January the high atmosphere above the Arctic warmed abruptly, which happens about six times a decade. That warming gradually weakened the jet stream below, causing frigid air to spill down across North America. Texas froze, and tragedy ensued. Some evidence points to a link between the quickly heating Arctic and cold spells to the south, but not everyone agrees, and it’s become a bit of a stalemate. Two things are certain: Winter is the fastest-warming season, and Texas missed warnings.

Scientists are much clearer about humanity’s role in more common extreme weather events. Some 40,000 people evacuated their homes in New South Wales in March after biblical rainfall. Aspects of Australia’s climate make parsing the climate influence of any precipitation event more complicated, but new work affirms that more greenhouse gas means more heat, a wetter atmosphere, and more extreme rainfall. It’s not only about more or less precipitation—the timing of the seasons is changing almost everywhere, with California’s rainy season now starting a month later than it did 60 years ago.

Global heating has also slowed down the Gulf Stream, the vast Atlantic circulation system that directly affects climate in Africa, the Americas, and Europe, to its lowest level in 1,000 years. This deceleration is a long-predicted and long-feared development, and scientists say a better understanding of it “is urgently needed.”

Keeping the temperature rise below 1.5°C seems like a better and better idea, even as it’s becoming harder and harder to achieve. With heat comes more humidity, a potent combination that can push a human body to its breaking point. Halting climate change below 2°C would dramatically cut the risk to people in the tropics of conditions that push the body past “the survival limit.”

A quarter of the CO₂ pollution we emit every year washes into the ocean, and some falls to the floor as sediment, where it stays safely away from the atmosphere for millenniums. Except when industrial fishing trawlers run over 1.3% of the ocean floor every year, releasing as much as 20% of the atmospheric CO₂ that the oceans absorb annually. The good news: The creation of protected marine areas would help keep down this carbon, while improving both fisheries and marine life, according to a new study. The authors included Jane Lubchenco, a university distinguished professor at Oregon State University, who’s since taken the White House’s highest-ranking climate-science adviser position.

Like marine sediment, soil is an amazing place to hide carbon from the atmosphere. It’s supposed to be a twofer: Plants suck down CO₂, and when they shed leaves or die, the stored carbon becomes a part of the soil. That process is now called into question by research suggesting that as plants soak up soil nutrients, microbes wake up and feast—with their metabolism releasing stored CO₂ back into the atmosphere. The more plants grow, the less the soils hold on to. The discovery may require changes to important models.

There’s a downside to earlier springtime and later winter: more time for plants to kick out allergens. Allergy season is 20 days longer than it used to be in North America, with pollen concentrations growing by 21%. Meanwhile across the pond, scientists trying to give Europeans better tools to prepare for allergies found that seasonal severity may rise an additional 60% in the decades ahead. And if that’s not too much to inhale, researchers in Colorado found that the energy required to grow cannabis indoors produces 1.3% of the state’s emissions.

Somehow there’s still good news—the adoption of renewables and electric vehicles, oil-industry introspection, even sweeter peaches (drought stress raises sugar production). With sustained effort, we might see the most important measures of planetary health improve. Global CO₂ emissions from energy rose by 0.9% a year from 2010-18, less than a third of the annual growth in the previous decade. The pandemic year knocked down annual CO₂ emissions by an historic 7%, but economic engines have restarted, and December 2020 emissions were already higher than the same month in 2019. It adds up: Last year tied 2016 as the hottest year on record, and the hottest seven years in the last 141 have all occurred since 2014.

About the photo: A car is seen half submerged in the flood on March 24, 2021 in Sydney, Australia. Recovery and flood clean up begins for parts of Western Sydney following days of continuous rain leading to dozens of communities declared disaster zones. (Photo by Flavio Brancaleone/Getty Images)

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