Letter 14 — To Professor Piers Forster
We can no longer bargain with the carbon budget; we can only decide how we respond to its reality. That response is now less about technology than about truthfulness.
Facing limits with honesty and hope
Date: 26 October 2025
Recipient: Professor Piers Forster, Director — Priestley Centre for Climate Futures, University of Leeds
Context
The final letter of Week 2 of One Letter a Day turns to Professor Piers Forster — one of the UK’s leading climate scientists and a long-time adviser to government through the Climate Change Committee. His recent article, “Only Three Years Left,” warns that the window for staying below 1.5 °C of warming is almost closed and that governments are moving too slowly to prevent serious impacts. This letter closes the week’s academic dialogue with a reflection on honesty, accountability and hope in a time of narrowing choices.
Letter
Dear Piers,
I am writing as part of One Letter a Day: a year-long public correspondence to reopen grounded conversations about the climate emergency. Each day I write to someone whose work shapes how we think and act on this crisis, and publish both letters and replies to encourage wider dialogue. This week has been devoted to academics here in Leeds whose work I believe is central to the transition.
Your recent article in The Conversation, “Only Three Years Left,” has stayed with me. It expressed, in clear and direct terms, what so many prefer not to confront: “We need to face this head on: the window to stay within 1.5 °C is essentially shut.” You warned that governments have been too slow to act in the face of mounting evidence and that “the world has already reached the level where it has warmed so much that it cannot avoid significant impacts from climate change. There is no doubt we are in dangerous waters.”
That clarity is what distinguishes your voice. As a scientist you quantify change; as a public servant on the Climate Change Committee you witness how evidence is filtered, softened, and too often ignored. You stand at the junction between what we know and what we do, and that is not an easy place to occupy.
From the outside, it seems increasingly clear that the CCC’s advice is not being treated with the seriousness it deserves. In the UK, as elsewhere, the targets remain intact but delivery is faltering. Policies arrive late or incomplete; timetables drift; and the optimistic narrative of “green growth” often replaces an honest reckoning with environmental limits. The gap between scientific urgency and political pacing has rarely felt wider.
You have advised government directly on climate targets and progress. We are now in a place where the science could not be clearer, yet national action arguably still moves at a fraction of the necessary speed. From your perspective, what kinds of structural or governance change are needed so that these warnings translate into action that genuinely protects people? And where, honestly, should we be looking for hope if politics continues to lag behind the science?
I ask because it feels as though we are entering a new phase. We can no longer bargain with the carbon budget; we can only decide how we respond to its reality. That response is now less about technology than about truthfulness – about whether leaders are willing to speak plainly and whether society is willing to listen. Yet public discourse is drifting away from the climate emergency and with it the sense of proportion the crisis demands.
Your work through the Indicators of Global Climate Change is, in itself, a civic service: a running audit of progress and delay that keeps the science visible when attention wanes. But indicators alone cannot compel action. The question is how to turn such visibility into responsibility, how to make knowledge politically and morally inescapable.
Part of me hopes that small, persistent projects like One Letter a Day might contribute to that task. By showing day after day what people are saying and already doing, perhaps we can help rekindle a shared sense of capacity, even as the window narrows.
You, more than most, understand how thin that window has become. Yet I sense that you have not given up on the possibility of meaningful change – that you still see honesty itself as a form of hope.
With respect and gratitude for your work and your candour,
– Vivien Badaut
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Next week, One Letter a Day turns to culture and imagination — exploring how art, storytelling and civic creativity can re-anchor hope in everyday life.