Oxford University scientists, after a year of research, have determined the best technology to suck carbon dioxide from the atmosphere and try to reverse global warming.
They considered methods ranging from capturing emissions from factories and power stations to extracting carbon dioxide directly from the air, and adding lime to oceans to increase their absorption of the gas, a study released on Tuesday showed.
None were more promising than planting trees, or baking waste wood to form a type of charcoal that can be added to soil. Relative to other so-called Negative Emissions Technologies, afforestation and biochar are low-cost, have fewer uncertainties and offer other benefits to the environment, the research shows.
Policy makers need to work to increase their use as they are the most encouraging of the possibilities through 2050, the scientists wrote.
The study follows a report by the university in November that also found using geoengineering, like spraying sea salt or sulphate aerosols into the atmosphere to reflect sunlight, won’t provide a “magic bullet” to combat global warming. The United Nations Intergovernmental Panel on Climate Change in April said extracting emissions may become necessary to curb global risks.
Deploying NETs by 2050 could help to draw 2.5 years of CO2 from the atmosphere, almost exclusively using afforestation, biochar and improvements to soil carbon, the university found.
Most other technologies are high cost, need large amounts of energy and have many uncertainties and challenges, it said. Using them isn’t easier than cutting emissions to start with.
Beyond 2050, it’s “conceivable” that NETs will have more potential and investments now are sensible in case they’re needed. Their deployment doesn’t mean “business as usual” and shouldn’t foster continued fossil-fuel use, the research shows.