Scientists have long agreed that the highest level that might possibly be safe for humans is 350 ppm, which we exceeded in 1988. We passed 400 parts per million (ppm) in 2016 for the first time in millions of years. We are now at 410 ppm (March 2019), and at the current rate of growth, we could reach 500 ppm within 50 years.

Removing atmospheric CO2 is critical because we are currently at a level not seen since before humans evolved. For about 800,000 years, until the Industrial Revolution, global CO2 levels were, on average, 280 ppm. That’s the level at which our species and civilization evolved, and the optimal level needed to cement a healthy future for our planet. That level of CO2 should also be the stated goal of the Green New Deal (GND).


There are two primary categories of CO2 removal methods. The first one is using technology to capture CO2 directly from the air or from the exhaust from power plants. The next step would be either to pump it underground or turn it into products.

Companies tackling this challenge have developed technologies that can take CO2 directly from the air, and they’re improving in efficiency every year. In order to finance the removal of CO2, they usually convert it into commercial products, although, with one exception, they don’t have markets large enough to finance the removal of significant amounts of CO2. Moreover, when these companies insert captured CO2 into products such as fizzy drinks, enhanced oil recovery (EOR), and green fuels, the CO2 is released back into the atmosphere. To make a real impact on the climate, we must permanently sequester the carbon.


The second category of removal involves natural strategies, such as leveraging photosynthesis in the oceans and on land. Forests in the U.S. already store and sequester carbon, but at a rate of 3 metric tons of carbon for every acre per year, this process is a drop in the bucket.

Similarly, certain crops grown for human consumption (such as grasses and grains) sequester carbon in their roots. The advantage of these methods is that they are relatively inexpensive; the obvious downsides are that the roots rot over a few years — we are already fighting global deforestation — and there is simply not enough available (unused) land to grow the number of plants needed to sequester and store carbon at the requisite level.

Marine plants such as kelp, eelgrass and other sea vegetation naturally sequester carbon by sinking to the depths of the ocean, where the gas stays sequestered for hundreds to millions of years. Per acre, marine plants can remove up to 20 times more CO2 from the atmosphere than forests can on the land. Yet, like much of our marine life, flora in our seas is disappearing. Rising temperatures are decreasing seaweed communities and fish populations; productivity at some fisheries has been reduced by 15% to 35% over the past eight decades, a trend likely to accelerate as the oceans continue to warm. Technologists and entrepreneurs are working on ways to harness this natural process in order to absorb more CO2 and slow ocean acidification.

Having the technology to remove CO2 from the atmosphere and sequester it safely underground or underwater is only one side of the equation. The critical part is finding paying customers for the byproducts of CO2 removal.