Carbon Dioxide Has Never Been Higher

Illustration for article titled Carbon Dioxide Has Never Been Higher
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It happens every year, but it doesn’t make it any less shocking: Humanity has once again set a new high-water mark for carbon dioxide in the atmosphere.


Carbon dioxide levels average 417.1 parts per million for the month of May at Mauna Loa Observatory, the gold standard for carbon measurements. That bests last year’s peak of 414.7 ppm, which bested the 2018 peak of 411.2 ppm and, well, you get the point. These levels are all unprecedented in human history. With each passing year that the world continues to rely on fossil fuels, the higher and more dangerous the levels of carbon pollution will get.

This is the type of story I hate writing. On the one hand, it’s news and we have to bear witness to the state of the atmosphere, since our fate is tied to it. On the other hand, the story writes itself.

The state of carbon dioxide in the atmosphere follows a seasonal pattern, swinging up from the northern hemisphere’s late fall and into spring when plants die off and release carbon into the atmosphere as they decompose. From summer into early fall, plants leaf out and suck that carbon back out of the atmosphere. That’s become a jagged pattern, though, due to human activities that emit more carbon than plants, the ocean, and other sinks can take up.

Record keeping at Mauna Loa goes back to the late 1950s, a time when humans were well into the act of burning fossil fuels. Every year of the record has coincided with a new peak, and the pace has quickened as fossil fuel use has accelerated. The past 20 years account for 40 percent of all carbon emissions tied to human activities alone.

The result is an atmosphere out of whack, pushed outside the constraints of conditions that have allowed society to flourish. You’d have to go back much, much deeper in time to find an atmosphere like the one the world has created today. In fact, the last time atmospheric carbon dioxide was this high was 3 to 5 million years ago, on a version of this world we would find unrecognizable today. Sea levels were up to 65 feet (20 meters) higher, all sorts of weird animals roamed the Earth, and it was up to 5.5 degrees Fahrenheit (3.6 degrees Celsius) warmer than pre-industrial temperatures. Oh, and no humans.


Now, we have that atmosphere again. While it takes the Earth time to adjust to any shoves to the climate system, make no mistake that it is responding to the blast of carbon dioxide pumped into the atmosphere. The planet has already warmed 1.8 degrees Fahrenheit (1 degree Celsius), and we’ve seen sea levels creep up, weather become more intense, and seas turn acidic. The climate will continue to destabilize and contort in ways that will put more stress on society, particularly the poorest among us.

While this year has seen carbon emissions drop due to the coronavirus and ensuing economic slowdown, it’s not enough to turn the tide—nor is it how we should be going about cutting emissions anyway. Even with the dip, the world will still set a new carbon dioxide record next year. Only when emissions hit zero will the records cease coming. So you can watch this space for the same basic story, slightly different flavor, around this time next year.


Managing editor at Earther, writing about climate change, environmental justice, and, occasionally, my cat.


Dense non aqueous phase liquid

How about some public data? Our scientists at NOAA/ESRL recently updated (spring 2020) its Annual Greenhouse Gas Index (AGGI) and nicely explains the whole kit and kaboodle here:

NOAA/ESRL (Earth Systems Research Laboratory) has a kickass website. I highly recommend spending time on it. Its data presentation tools are truly awesome. USA! USA! USA!

Up and to the right, the whole lot of ‘em (greenhouse gases in atmosphere - except some of the banned refrigerants)

We’ve turned up the warming potential by 45% from 1990 to 2019 due to continuously dumping more GHGs in the atmosphere. The baseline of 1990 was chosen because that’s when the Montreal Protocol was signed:

Cool graph showing that we’re really at around 500 ppm, all things (GHGs) considered. That would be the black line. The powdered blue line is just CO2. The red line is the Annual Greenhouse Gas Index (AGGI) plopped onto the graph, with its own vertical axis to the right.