photo: Sarah McD via flickr
Regardless of what methods are used, from hard geoengineering artificial CO2 scrubbers to softer methods like reforestation projects, actively removing carbon from the atmosphere will likely require a decades or centuries-long commitment if it is to really reverse global warming. That's the word from scientists from the Carnegie Institute. Here's why:
The researchers found that removing all human-emitted carbon dioxide from the atmosphere caused temperatures to drop, but it offset less than half of CO2-induced warming. Why would removing all the extra carbon dioxide have such a small effect? The researchers point to two primary reasons. First, slightly more than half of the carbon dioxide emitted by fossil-fuels over the past two centuries has been absorbed in the oceans, rather than staying in the atmosphere. When carbon dioxide is removed from the atmosphere, it is partially replaced by gas coming out of ocean water. Second, the rapid drop in atmospheric carbon dioxide and the change in surface temperature alters the balance of the land carbon cycle, causing the emission of carbon dioxide from the soil to exceed its uptake by plants. As a result, carbon dioxide is released back into the atmosphere. (Science Daily)
According to the simulations run by the team--which didn't focus on any one method for removing and storing CO2--each 100 billion tons of carbon removed would reduce average global temperatures by 0.16°C.
In terms of policy implications of the scale of active CO2 reduction and the long-term commitment required for it to be effective, even after reducing carbon emissions to zero, the researchers suggest, "a more prudent plan might involve preventing carbon dioxide emissions now rather than trying to clean up the atmosphere later."
More on Global Warming Solutions:
Reforestation & Biochar: Two Geoengineering Methods That Won't Cause More Harm Than Good
5.2°C Temperature Rise by 2100: New Business-as-Usual Climate Change Scenario Presented by MIT
IPCC Chairman Personally Backs 350ppm CO2 Targets, Holding Temperature Rise to 1.5°C
90% Chance Global Temperature Rise Held to 2°C - If Nations Spend 2% of GDP On The Problem