It’s time for your annual reminder humans have pushed the planet into a state unseen in millions of years.
Carbon dioxide measurements at Mauna Loa Observatory in Hawaii averaged 410.31 parts per million (ppm) in April. That bests last May’s record of 409.65 ppm, is well above the pre-industrial value of 280 ppm, and means the atmosphere of April 2018 was unparalleled in human history. Its reign will be short-lived, as May will almost surely set another record.
Right now, carbon dioxide levels in the atmosphere are higher than they’ve been in the past 2 million years (though it may be quite a bit longer). As long as we keep burning fossil fuels like they’re going out of style, this will keep happening.
If current emissions trends continue, we’ll create an atmosphere that resembles the one from 50 million years ago. Back then, crocodiles patrolled the Arctic, and oceans were dramatically higher. Most importantly, the climate was wildly different from the one that’s allowed humans to thrive.
The 1.8 degrees Fahrenheit of warming since the start of the Industrial Revolution has made heat waves more deadly, wildfires more intense, and storm surge higher. And because the Earth’s climate is a big ship that takes millennia to change course, the impacts of our current glut of carbon dioxide emissions will ripple out into the far future. It already looks like islands atolls may be uninhabitable by mid-century. Beyond that, we may have conscripted the West Antarctic ice sheet to collapse, which could cause seas to rise up to 13 feet over the coming centuries.
The 410.31 ppm mark is a sorry reminder of what we’ve already done. But it’s also a rallying cry that we still have time to cut emissions in an effort to keep starship Earth from veering completely off course and tossing us all overboard.