Planet's vital signs are reaching dangerous 'tipping points,' scientists warn

More than a year after the Covid-19 pandemic shut down economies around the world and sharply reduced worldwide travel—sparking speculation among some that emissions would plummet as a result—a coalition of scientists said in a paper published Wednesday that the planet is nonetheless reaching multiple "tipping points," with levels of sea ice melt, deforestation, and other markers revealing that urgent action is needed to mitigate the climate emergency.

"The extreme climate events and patterns that we've witnessed over the last several years — not to mention the last several weeks — highlight the heightened urgency with which we must address the climate crisis," said Philip Duffy, co-author of the study and executive director of the Woodwell Climate Research Center in Massachusetts.

The "World Scientists' Warning of a Climate Emergency 2021" which was published in the journal BioScience, states that 18 out of 31 planetary vital signs have hit record-breaking high or low points in recent years.

The paper detailed how despite fossil fuel use dipping slightly in 2020, levels of carbon dioxide, methane, and nitrous oxide "have all set new year-to-date records for atmospheric concentrations in both 2020 and 2021." The authors emphasized, however, that fossil fuel emissions and the global heating with which they're associated are far from the only indicator that the planet is in danger.

The researchers recorded other tipping points or near-tipping points in levels of ocean heat; ice mass; the deforestation of the Amazon, which serves as a vital carbon sink; ocean acidification, and the amount of ruminant livestock, which now number more than four billion and are a significant source of planet-warming gases.

"We need to stop treating the climate emergency as a stand-alone issue—global heating is not the sole symptom of our stressed Earth system," William Ripple, a distinguished professor of ecology at Oregon State University's College of Forestry and a co-author of the report, said in a statement.

The research was released two months after researchers in Germany and Norway released a study showing Greenland's ice sheet was "at the brink" of reaching a "tipping point," with trillions of tons of ice having flown into the sea.

The paper published Wednesday showed the rate of forest loss in the Brazilian Amazon reached a 12-year high of 1.11 million hectares deforested last year and that the concentration of carbon dioxide in the atmosphere reached 416 parts per million in April 2021—"the highest monthly global average concentration ever recorded," according to The Guardian.

The tipping points recorded in the analysis are all the result of "human overexploitation of the planet," Ripple said.

While emissions from people commuting to work and plane travel went down in 2020 as a result of stay-at-home measures for some, the report still showed "the consequences of unrelenting business as usual," he added.

"A major lesson from Covid-19 is that even colossally decreased transportation and consumption are not nearly enough and that, instead, transformational system changes are required," Ripple said.

To mitigate the rapidly worsening crisis, the authors said, global policymakers must set "a significant carbon price" and link it to financing adaptation measures in the developing world and climate action policies; begin a phase-out of fossil fuel extraction and move towards a ban; and pass policies aimed at restoring and maintaining carbon sinks and natural habitats that support biodiversity, like the Biden administration's recent decision to restore protections like the Tongass National Forest.

"Policies to alleviate the climate crisis or any of the other threatened planetary boundary transgressions should not be focused on symptom relief but on addressing their root cause: the overexploitation of the Earth," the researchers wrote.

One climate action organizer in Minnesota linked the findings to the Line 3 tar sands pipeline, which the Biden administration has so far permitted to continue.

"It's not too late to stop Line 3 and enact a just climate transition," said Andrew Ulasich of the faith-based initiative Isaiah. "But time is short. Now is the time for action."

The paper noted some positive developments, including record-high levels of fossil fuel divestment by cities, financial institutions, universities, and other entities, and a record low level of fossil fuel subsidies.

The research was published as a follow-up to a 2019 paper in which thousands of experts declared the climate emergency, named the planet's vital signs, and called for six courses of action to mitigate the crisis: eliminating fossil fuels, slashing pollution, restoring ecosystems, shifting to plant-based diets, transitioning away from economies that prioritize indefinite growth, stabilizing the human population.

"We're going to have, as we're witnessing, significant human suffering, but if we make the big changes soon, we can limit that suffering," Ripple toldFast Company on Wednesday. "We want to give an update with these vital signs, but we also want to emphasize the importance of moving fast at this point, and thinking big."