“We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.”
James Hansen, Former NASA researcher
A few weeks ago, I wrote about solar geoengineering, one of the two main strategies of intervening in the environment to try to cool the planet. Today I’m diving into the other, and unheating the controversy over carbon dioxide removal.
The planet is getting warmer because too much CO2 is trapped in our atmosphere. To make matters worse, it hangs around for a really long time. So wouldn’t it make sense to try to remove some? In theory, yes, we should reduce CO2 emissions while simultaneously sopping up some of what is already up there.
What is carbon dioxide removal (CDR)?
Some CO2 is removed from the air naturally by plants, trees, wetlands, and the ocean. CDR refers to geoengineering strategies that suck CO2 from the atmosphere or the oceans. While researchers have been working on these technologies for years, progress had been slow until recently. Lately, with the help of government and private funding, several startups (like this) are racing to improve and scale the process.
One approach is called direct air capture (DAC), where CO2 is sucked from the air and either used, or stored permanently. There are currently 27 sites operating around the world, with another 130 being developed. Other strategies include carbon mineralization, biochar, and soil carbon sequestration.
What is the controversy?
Critics argue CDR is simply too expensive to scale to the point of being helpful. For example, right now it costs around $600 for DAC to sequester one ton of CO2, but would need to be under $100 per ton in order to be economically feasible. There are also concerns about environmental impacts, and the huge amounts of land and energy the plants require. Probably the biggest argument against CDR is it diverts funding and attention away from scaling up proven emissions reduction technologies.
Controversy, unheated
Unquestionably, our main focus needs to be on shutting off the CO2 emissions tap, but the reality is, reductions alone won’t get us to net-zero fast enough to keep the warming at bay. CDR has the potential to complement emissions reductions and help reduce the damaging effects of climate change. So, it seems reasonable to at least make some investments in these technologies to try to close the gap.
Let’s do something about climate change. Learn about it. Think about it. Talk about it.