Forget about climate geoengineering, says Professor Debra Roberts, just leave fossil fuels in the ground.

South African climate scientist Professor Debra Roberts didn't mince her words when she was asked to comment on the best way to slow down the global climate crisis.

"We need to leave fossil fuels in the ground," Roberts replied bluntly.

She was responding to a question on whether humanity should resort to elaborate geoengineering experiments, carbon capture schemes or massive tree-planting projects to reduce soaring carbon dioxide and greenhouse gas emissions.

Roberts, a senior member and scientific author of the United Nations' Intergovernmental Panel on Climate Change (IPCC), was speaking in her home city of Durban during a municipal climate change workshop at the International Convention Centre on 30 June 2023.

Roberts' direct response on ending fossil fuel dependence was in stark contrast to the more guarded language she used in the same venue 12 years ago, when she fielded similar questions in her former capacity as Durban's climate protection manager and member of the South African government negotiating team at UN climate change meetings.

Roberts, who is in line to become the first woman from Africa to chair the UN's scientific advisory panel, noted that the IPCC had produced a series of detailed reports over the past few...