The risky promise of ‘negative emissions’: Why we should not assume that land-based measures will save the climate

The document argues that relying on future negative emissions to offset current insufficient climate action is a high-risk strategy. It identifies three primary risks: technological and biophysical infeasibility, unacceptable social and ecological impacts, and the potential for these measures to be less effective than expected due to reversals or irreversible climate tipping points. The authors conclude that while some land-based sequestration is possible, it cannot reach the scales often assumed in climate models without severe trade-offs.

• Climate mitigation models frequently assume the deployment of large-scale negative emissions several decades in the future, with some requiring up to 1,000 Gt CO2 to limit warming to 1.5°C or 2°C.
• The authors identify three sequential risks to negative emission strategies: (1) they may be technologically or biophysically infeasible; (2) they may cause unacceptable social and ecological damage; and (3) they may be ineffective because carbon stocks are prone to reversal or climate impacts become irreversible.
• Bioenergy with carbon capture and storage (BECCS) is considered highly risky because the technology is unproven at commercial scale and its biomass requirements are limited by net primary production (NPP). Reaching the 250 EJ/year bioenergy output often assumed in models would require doubling the current human biomass harvest.
• Land-based negative emissions are land-intensive, with literature estimates ranging from 100 million to nearly 3,000 million hectares. Such large-scale land use could threaten food security, displace indigenous peoples, and conflict with biodiversity objectives, leading to a moratorium on large-scale carbon sequestration by the Convention on Biodiversity (CBD).
• The authors estimate that only 370–480 Gt CO2 of cumulative carbon sequestration is reasonably feasible through forest restoration and reforestation, excluding BECCS entirely due to its unproven nature and resource constraints.
• Limiting warming to 1.5°C or 2°C is still possible without excessive reliance on negative emissions, but this would require immediate global mitigation far exceeding current Paris Agreement pledges and the protection of existing land carbon stocks.

APA

Kartha, S., & Dooley, K. (2016). The risky promise of ‘negative emissions’: Why we should not assume that land-based measures will save the climate. Stockholm Environment Institute. https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-PB-2016-Negative-emissions-land-based-measures.pdf

Chicago

Kartha, Sivan, and Kate Dooley. The risky promise of ‘negative emissions’: Why we should not assume that land-based measures will save the climate. Stockholm Environment Institute, 2016. https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-PB-2016-Negative-emissions-land-based-measures.pdf.

Wikipedia

{{cite report |last1=Kartha |first1=Sivan |last2=Dooley |first2=Kate |title=The risky promise of ‘negative emissions’: Why we should not assume that land-based measures will save the climate |publisher=Stockholm Environment Institute |date=2016 |url=https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-PB-2016-Negative-emissions-land-based-measures.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{kartha2016risky, author = {Kartha, Sivan and Dooley, Kate}, title = {{The risky promise of ‘negative emissions’: Why we should not assume that land-based measures will save the climate}}, institution = {Stockholm Environment Institute}, year = {2016}, url = {https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-PB-2016-Negative-emissions-land-based-measures.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }