According to the Government Actuary's Department, climate and risk specialists from GAD and the Institute and Faculty of Actuaries convened a cross-government roundtable during London Climate Action Week. Representatives from eight government organisations attended to compare current practice and consider how climate scenarios can be used more systematically in policy-making, risk planning and long-term investment appraisal. The discussion was framed as a practical exercise in public decision-making rather than a general debate about climate policy. The central question was how departments should make durable choices when future climate conditions are uncertain, but the consequences for assets, services and public spending may be significant.
GAD said departments increasingly recognise climate risk as an issue that reaches beyond environmental policy. In its summary of the event, the department pointed to possible effects on economic performance, infrastructure, public services and national security, placing climate risk within mainstream government planning. The Institute and Faculty of Actuaries opened the session by setting out the distinction between scenarios and forecasts. For policy officials, that distinction matters. A forecast tests a central expectation; a scenario tests whether a decision remains workable under severe but plausible future conditions. That makes scenario analysis especially relevant where government is dealing with long asset lives, hard-to-reverse investment choices or uncertain future demand.
According to GAD, many departments already use scenario-based tools for horizon scanning and strategic risk planning. The issue raised at the roundtable was not whether such methods exist, but whether they are being applied consistently enough to shape policy design and capital appraisal across government. The IFoA also drew on its contribution to HM Treasury's Green Book discount rate review. That work considered whether long-term, transformational and highly uncertain decisions should be appraised differently from routine investments. For departments responsible for estates, infrastructure and resilience planning, that is a material question, because conventional appraisal methods may not always capture the value of avoiding future disruption or heat-related adaptation costs.
GAD said participants then examined where climate uncertainty is already being considered well and where it can still be missed in routine decision-making. The discussion appears to have focused on whether climate risk enters the process early enough, before options are narrowed, business cases are settled and funding assumptions become fixed. The roundtable also explored barriers to wider use. While GAD's published account does not identify each departmental position in detail, it records a shared interest in improving the conditions for effective use of climate scenarios. That points to a familiar policy problem: analytical methods may be available, but they are less useful if governance, commissioning and decision timetables do not support their use.
To illustrate the point, GAD referenced separate work with the Ministry of Justice on overheating risk across the prison estate. That case study examined how rising temperatures could affect the estate over time and how scenario analysis can be used to assess long-term risk and test possible interventions. The policy value of that example is clear. It shows how climate scenarios can move from high-level risk language into operational choices about buildings, service continuity and investment timing. For departments managing complex estates, the method offers a way to compare options under uncertainty rather than waiting for a single projected future to become more certain.
The timing of the event reinforced the message. Matt Gurden, Deputy Government Actuary, said the roundtable was moved to a hybrid format after a Met Office red heat alert during a period of extreme heat. In GAD's account, that served as an immediate reminder that climate risk is already affecting how organisations work today, not only how they plan for later decades. The published conclusion from the session was measured but important. GAD said participants showed a shared interest in strengthening the use of climate scenarios across government through better governance, improved analytical tools and closer collaboration between organisations. For policy professionals, the direction of travel is significant: climate scenario analysis is being treated less as a specialist exercise and more as part of the standard machinery of long-term public decision-making.