Damian Carrington Environment editor Guardian
‘Silver bullet’ to suck CO2 from air and halt climate change ruled out
Scientists say climate targets cannot be met using the technologies, which either risk huge damage to the environment or are very costly. Ways of sucking carbon dioxide from the air will not work on the vast scales needed to beat climate change, Europe’s science academies warned on Thursday.
From simply planting trees to filtering CO2 out of the air, the technologies that some hope could be a “silver bullet” in halting global warming either risk huge damage to the environment themselves or are likely to be very costly. Virtually all the pathways laid out by the UN’s Intergovernmental Panel on Climate Change (IPCC) to reach the targets in the Paris agreement require huge deployment of so-called negative emissions technologies (NETs) in the second half of the century. This is because cuts in CO2 are expected to be too slow to hit zero emissions quickly enough, so the overshoot has to be recaptured later by NETs. The IPCC calculates that about 12bn tonnes a year will need to be captured and stored after 2050 – the equivalent of about a third of all global emissions today.
“You can rule out a silver bullet,” said Prof John Shepherd, at the University of Southampton, UK, and an author of the report. “Negative emissions technologies are very interesting but they are not an alternative to deep and rapid emissions reductions. These remain the safest and most reliable option that we have.” The new report is from the European Academies Science Advisory Council (EASAC), which advises the European Union and is comprised of the national science academies of the 28 member states. It warns that relying on NETs instead of emissions cuts could fail and result in severe global warming and “serious implications for future generations”.
The report assesses the range of possible technologies, including “bioenergy with carbon capture and storage” (BECCS), on which the IPCC scenarios rely heavily. BECCS involves growing trees, which take CO2 from the atmosphere, and then burning them to produce electricity while capturing the emissions and burying them. Marine examples included
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