Deforestation must decrease by 95 per cent in a 1.5 °C world

Measures within the land sector could contribute about 30 per cent, or 15 billion tonnes of carbon dioxide equivalent (GtCO₂e) per year, of the global mitigation needed by 2050 to deliver on the 1.5 °C target, according to a recent article in Nature and Climate Change.

The researchers based their roadmap on more than a hundred top-down modelled 1.5°C pathways from other studies, as well as bottom-up assessments of the mitigation potential of 24 land-based activities.

Land-based emissions need to be halved each decade (85% decrease by 2050) and carbon removal (sinking) needs to increase tenfold between 2030 and 2050. This would make the land sector net carbon-zero by 2040 and a net sink of approximately 3 GtCO2e per year by 2050.

The greatest contribution will come from reducing deforestation, which must fall 70 per cent by 2030 and 95 per cent by 2050.

“The roadmap foresees a phased approach where first actions to avoid emissions are prioritised. This means concentrating on avoiding deforestation in hotspot geographies such as Brazil and Indonesia,” explains Michael Obersteiner, one of the study authors.

Afforestation and reforestation will also be important. The roadmap suggests that more than 320 Mha of new or restored forests will be needed. This can be compared to the 43 Mha that so far have been pledged in national climate plans (NDCs).

Restoration of peatlands and wetlands, reduced methane and nitrous oxide emissions, shifting to plant-based diets, reduced food waste, improved forest management and agroforestry, and enhanced soil carbon sequestration will also contribute to the emission reductions according to the road map. To achieve negative emissions the researchers have also included moderate use of bioenergy with carbon capture and storage (BECCS), that will contribute 7 per cent of the annual emission reductions by 2050.

Nature and climate change, 21 October 2019 https://doi.org/10.1038/s41558-019-0591-9

IIASA press release 21 October 2019, https://www.iiasa.ac.at/web/home/about/news/191021-roadmap-for-carbon-ne...