Paper for "Nature Climate Change" warns negative emissions must remain secondary to severe reduction of greenhouse gas.
There are significant constraints to large-scale deployment of negative emissions technologies in the future to reach climate change targets, according to a new study, including research of Jan Minx and the Mercator Research Institute on Global Commons and Climate Change (MCC).
Published today in Nature Climate Change, it demonstrates the potential environmental, economic, and energy impacts of negative emission technologies for addressing climate change. The study comes at a time when UN climate negotiators currently meet in Paris at the world climate summit COP21 and emphasizes that greenhouse gas emissions must be reduced aggressively and immediately.
"At the current state of play in climate diplomacy, negative emission technologies will have to be part of the policy solution. Therefore, we need to study them much more carefully", said Jan Minx from the Hertie School. "The more successful we are in the short-run to reduce global greenhouse gas emissions, the less we will depend on their risky large-scale deployment in the long-run. So all eyes on Paris, really."
Negative emission technologies aim to remove carbon dioxide (CO2), a major driver of climate change, from the atmosphere. They include relatively simple options like planting more trees to lock up CO2 as they grow, or crushing rocks that naturally absorb CO2 and spreading them on soils so that they remove CO2 more rapidly. Other higher-tech options include using chemicals to absorb CO2 from the air, or burning plants for energy and capturing the CO2 that would otherwise be released, then storing it permanently deep below the ground, called bioenergy with carbon capture and storage (BECCS).
The study confirms and warns that future use of negative emissions should not be interpreted as a fall-back option. This would be risky, as continuing to cumulate emissions would entail lower chances of stabilizing climate change at less than two degrees Celsius. "Plan A" must be to reduce greenhouse gas emissions aggressively now. A failure to initiate such aggressive emissions cuts may leave us with no "Plan B" to stabilize the climate within the two degree target, as the deployment of these technologies will likely be limited due to any combination of the environmental, economic or energy constraints examined in the study.
Reference of the cited article:
Pete Smith (et al.) (2015): Biophysical and economic limits to negative CO2 emissions. Nature Climate Change. DOI: 10.1038/nclimate2870