IPCC Chair Urges Clear Message: Humans Are Driving Warming as Scientists Begin Next Major Assessment

IPCC Chair: Be Clear About Human Role To Counter Climate Denial

Jim Skea, a Scottish professor and chair of the Intergovernmental Panel on Climate Change (IPCC), told AFP that the UN's climate science body must present the human contribution to global warming "in a very clear way." His comments come amid high-profile scepticism, including public statements by US President Donald Trump calling climate change a hoax.

New assessment cycle launches near Paris

The IPCC opened a five-day meeting this week in a Paris-area skyscraper to begin drafting its next comprehensive assessment. More than 600 scientists from around the world attended the session, which concludes on Friday and starts a process that will lead to a major report due in 2028 or 2029.

What if 1.5°C is crossed before the next report?

Skea warned it is "almost inevitable" that the world could cross the 1.5°C warming threshold. He said the IPCC must be clear about what would be required to return to that level: rapid, significant emissions reductions from both land use and energy sectors, and exploration of large-scale carbon dioxide removal to pull CO2 from the atmosphere. He also stressed that considerable knowledge gaps remain about the feasibility, scale and risks of some removal approaches.

Political support and public communication

France offered visible, high-level backing during the meeting: President Emmanuel Macron and three senior ministers publicly supported the IPCC, which Skea said bolstered scientists' morale and confidence. He emphasised the need for sustained, plain-language communication to cut through misinformation: "It is unequivocal that human beings are causing the climate change that we are already seeing," he said, urging the IPCC to keep repeating that clear message and to support it with multiple lines of evidence.

US participation and approval process

Although the US federal government is not funding American academics' participation, Skea noted a robust US scientific presence — nearly 50 US authors attended with support from philanthropies after being nominated by US observer organisations. He acknowledged that approval sessions, where governments and scientists agree line-by-line on summaries for policymakers, are always challenging. Historically these sessions have been navigated successfully; only once — in 1995 — was a summary deferred to a subsequent session.

Timing the next assessment

Governments are debating whether the assessment should be published in 2028, in time for the COP33 climate summit in India, or in 2029. Skea said the schedule is ultimately a governmental decision but urged that the timetable must allow sufficient time for a rigorous, evidence-based assessment — neither rushed nor unnecessarily delayed.

Final message

"Wait with bated breath for what we are going to come out with in roughly three years' time. There are new areas of research and new knowledge gaps to explore, including whether it is possible to limit warming to 1.5°C in the long term."

lt/np/jj — Reporting by AFP; summary of comments by IPCC Chair Jim Skea at the Paris-area meeting.