Current carbon dioxide levels are unprecedented in human history and could reach a level unseen in millennia if their rates continue at this pace, a new report out Tuesday warns.
Research published in Nature Communications finds that if fossil fuel use continues unabated, the atmosphere could revert « to values of CO2 not seen since the early Eocene (50 million years ago), » a time when humans did not exist, by the middle of the 21st century.
Dana L. Royer, a paleoclimate researcher at Wesleyan University and co-author of the study, told Climate Central, « The early Eocene was much warmer than today: global mean surface temperature was at least 10°C (18°F) warmer than today. There was little-to-no permanent ice. Palms and crocodiles inhabited the Canadian Arctic. »
Because carbon dioxide stays in the atmosphere for centuries, climate change would continue to impact the planet even if humans miraculously dropped emissions to zero after hitting that mid-century peak, Royer said.
Indeed, global warming may have already locked in the Antarctic ice sheet for unstoppable melting—driving sea level rise and threatening coastal communities worldwide.
The authors continue, « If CO2 continues to rise further into the twenty-third century, then the associated large increase in radiative forcing, and how the Earth system would respond, would likely be without geological precedent in the last half a billion years. »
The report comes as the Trump administration turns its back on climate regulations, issuing an executive order last week that aims to undo Obama-era policies keeping a lid on greenhouse gas emissions.
« Aside from provoking a large-scale nuclear war, it is hard to imagine an American president taking an action more harmful to the U.S. than [President Donald] Trump’s effort to accelerate greenhouse gas emissions, » David J. Arkush, managing director of Public Citizen’s Climate Program, said at the time.
« This day may be remembered as a low point in human history—a time when the world’s preeminent power could have led the world to a better future but instead moved decisively toward catastrophe, » Arkush added.
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