Reducing the amount of greenhouse gas emissions can slow the progress of global warming but only reaching and sustaining net zero global emissions can halt the progress of climate change.
The move to renewable power and the use of electric transport are substantial and essential ways to reduce emissions. But even if these transitions take place on a rapid timescale, they will not eliminate all emissions. Many industrial activities and, especially, agriculture will continue to contribute substantial greenhouse gas emissions. There are efforts to reduce the contributions of these things, but there are no zero-emission substitutes for most of them.
As a result, actually removing CO2 from the atmosphere once it is there is essential to achieve net zero emissions. If greenhouse gas removal can be scaled up sufficiently, it opens the option of going “net negative”, which would be the ideal way to mitigate and, better still, reverse the effects of climate change.
There are multiple approaches to carbon dioxide removal. Some are natural, involving ways of capturing and storing carbon in trees, biochar, and peatlands. Others are technological. An example is the system that has just gone into operation in Iceland that uses fans, chemicals, and heat to capture CO2 and then mineralize it in volcanic rock. Another is a system being tested in the UK that captures CO2 from growing biomass and pipes it to storage under the North Sea.
Much of the attention on carbon capture technology is aimed at trapping the emissions from fossil fuel power plants, but the need to remove carbon dioxide that has entered the atmosphere in other ways is ultimately far greater.
Photo, posted August 17, 2013, courtesy of Joshua Mayer via Flickr.