A Whitehall conversation about future climate risk became a live example of it when a Met Office red heat alert pushed a government roundtable into hybrid mode during London Climate Action Week. For Eco Current readers, that detail matters: this is not only a story about modelling the future, but about how heat is already changing the way public institutions work. The event was hosted by the Government Actuary’s Department with the Institute and Faculty of Actuaries, bringing together representatives from eight government organisations to compare methods and ask a practical question. How can climate scenarios shape better policy before disruption becomes routine?

That question is moving up the agenda because departments now recognise that climate risk does not sit in an environmental silo. It reaches economic performance, critical infrastructure, public services and national security, which means decisions on spending, estates and service design can no longer rely on yesterday’s weather assumptions. According to the Government Actuary’s Department, some teams already use scenario tools for horizon scanning and strategic risk planning. The roundtable focused on what happens next: using those tools more consistently, and earlier, in policy and investment choices across government.

One of the clearest points from the day was the difference between a forecast and a scenario. Actuaries are not trying to predict one exact climate future. Instead, they test decisions against several severe but plausible futures to see where plans hold up, where they fail and what changes would improve resilience. That matters in government because a single central case can give false comfort. Public assets and services are expected to last for decades. Planning them against average conditions alone is a costly bet when heat and other climate pressures are becoming harder to ignore.

The Institute and Faculty of Actuaries brought that argument into the Treasury context through its contribution to the Green Book discount rate review. Its actuarial perspective explored whether long-term, transformational and highly uncertain decisions should be appraised differently from routine investments. This may sound technical, but it goes to the quality of public spending. If appraisal methods are built mainly for short-term certainty, projects that protect services and public buildings from future climate stress can look less urgent on paper than they do in daily life.

The most grounded example came from separate Government Actuary’s Department work with the Ministry of Justice on overheating risk across the prison estate. By examining how rising temperatures could affect buildings over time, the case study showed how scenario analysis can test interventions before conditions worsen. That is where the discussion stopped being abstract. Overheating risk is about whether public buildings remain safe and workable in hotter summers, and whether the state acts early enough to avoid disruption, emergency fixes and higher costs later on.

Participants also compared where climate uncertainty is already taken seriously and where it still slips out of view. The discussion pointed to a familiar government problem: some teams have useful methods and live case studies, but they are not always shared widely enough or tied into day-to-day decision-making. The answers raised in the room were practical rather than grand. Officials spoke about the need for better governance, stronger analytical tools and closer collaboration between organisations so that climate scenarios are used with more confidence and less inconsistency.

Matt Gurden, Deputy Government Actuary, said the heat alert was a timely reminder that climate risks are already affecting how people live and work. That gives the roundtable a relevance beyond actuarial method. It suggests climate resilience is starting to move from specialist teams into the machinery of government itself. For readers watching whether public policy is catching up with climate reality, this is a modest but useful signal. A single roundtable will not future-proof public estates on its own, but better scenario work can help government make calmer, earlier and more durable choices before the next heat alert arrives.