UN: “Cutting carbon emissions not enough; Suck Co2 from the air and bury it”

Carbon emissions need to abruptly drop six or seven percent a year to avoid breaching the Paris climate treaty’s goal of capping global warming at “well below” two degrees Celsius compared to pre-industrial levels

To save the world from the worst ravages of climate change, slashing carbon pollution is no longer enough – CO2 will also need to be sucked out of the atmosphere and buried, a landmark UN report is expected to say on Monday.

If humanity had started to curb greenhouse gas emissions 20 years ago, an annual decrease of two percent out to 2030 would have put us on the right path. Challenging, but doable. Instead, the emissions climbed another 20 percent to more than 40 billion tonnes of CO2 in 2021.

This means an abrupt drop in carbon emissions of six or seven percent a year is needed to avoid breaching the Paris climate treaty’s goal of capping global warming at “well below” two degrees Celsius compared to pre-industrial levels. Staying under the safer aspirational threshold of 1.5C would mean an even steeper decline.

To put that in perspective, the painful 2020 shutdown of the global economy due to Covid saw “only” a 5.6 percent decrease in CO2 emissions. Hence the need for carbon dioxide removal (CDR), or “negative emissions”, is likely to figure prominently in the UN Intergovernmental Panel on Climate Change (IPCC) report.

Even under the most aggressive carbon-cutting scenarios, several billion tonnes of CO2 will need to be extracted each year from the atmosphere by 2050, and an accumulated total of hundreds of billions of tonnes by 2100. As of today, however, CO2 removal is nowhere near these levels. The largest direct air capture facility in the world removes in a year what humanity emits in three or four seconds. There are at least a dozen CDR techniques on the table, with different potentials and costs.

Most of the hundreds of models laying out a game plan for a liveable future reserve an important role for a negative emissions solution called BECCS, or bioenergy with carbon capture and storage. In a nutshell, this is the recipe: grow trees, burn them for energy, and bury the CO2 underground, in an abandoned mineshaft, for example. But what works on paper (or in so-called integrated assessment models), has not materialised in reality.

One of the few commercial-scale BECCS facilities in the world, in Britain, was dropped last year from the S&P Clean Energy Index because it failed to meet sustainability criteria. “I don’t see a BECCS boom,” said Oliver Geden, a senior fellow at the German Institute for International and Security Affairs and an expert on CDR.