CARBON DIOXIDE REMOVAL MAY CARRY SIGNIFICANT RISKS
ALLOWING the global temperature to temporarily exceed or “overshoot” 1.5ºc would mean a greater reliance on techniques that remove carbon dioxide from the atmosphere to return global temperature to below 1.5°C by 2100.
“The effectiveness of such techniques are unproven at large scale and some may carry significant risks for sustainable development,” says the new IPCC report.
Its landmark report cites how there are a number of carbon dioxide removal methods, “each with different potentials for achieving negative emissions, as well as different associated costs and side effects”.
One example in the demonstration phase is a process called Bioenergy with Carbon Capture and Storage (BECCS), in which atmospheric CO² is absorbed by plants and trees as they grow, and then the biomass is burned to produce bioenergy.
“The CO² released in the production of bioenergy is captured before it reaches the atmosphere and is stored in geological formations deep underground on very long timescales. Since the plants absorb the CO² as they grow and the process does not emit CO², the overall effect can be to reduce atmospheric CO².”
But David Hallowes, a local groundwork researcher, says: “Some of the IPCC pathways rely on carbon removal through BECCS in the second half of the century. This is a kind of scientific fairy story and the IPCC is clearly unconvinced by it.
“Governments should not make carbon removal with BECCS an alibi for not reducing emissions now.
“It is particularly dangerous for Africa. It would require growing trees and other crops on vast areas of land and it may be predicted that the land would be grabbed from poor people in the third world.” | Sheree Bega