The Medium Ambition scenario, which references the IPR FPS, constitutes our baseline. The IPR FPS was commissioned by the UN-supported Principles for Responsible Investment (PRI) and the climate scenarios were jointly developed by a consortium of technical partners. It receives strong endorsement from the financial sector, which it was designed for.
The IPR FPS represents a high conviction policy forecast scenario and is not a normative scenario. It possesses transparency and granularity with detailed policy and technological assumptions that allows for signposting. We regularly refresh our assessment of the baseline climate scenario to reflect latest developments. Post 31 March 2025, we will be revising the associated temperature of the IPR FPS to reflect the latest developments.
Given that the forecasts and climate sensitivities are subject to considerable uncertainty, we also model two alternative scenarios to simulate the range of plausible outcomes. First, the High Ambition Scenario simulates a net zero outcome, where the more ambitious goal set out in the Paris Agreement, to limit temperature increase to 1.5°C, is achieved. At the other end of the spectrum, the Low Ambition scenario simulates an outcome where climate policy traction is very weak such that global temperature increase rises above 4.0°C.
In our climate scenario analysis, the two climate risk impact channels assessed are physical risk and transition risk.
For physical risk, we apply a top-down approach to assess impact on GDP growth and inflation. This includes assessing acute risks such as extreme weather events and chronic risks such as the consequences of long-term shifts in climate patterns on productivity. For transition risk, we apply top-down and bottom-up approaches. At the country level, we assess the impact of carbon taxes on government revenues and take into account second-order impacts. This includes three-channel fiscal recycling of carbon tax revenues (personal tax cuts, investments, and debt reduction) and monetary policy response to changes in growth and inflation.
Similarly, from a bottom-up perspective, on top of the demand creation and destruction effects that carbon taxes elicit, we consider second-order impacts via company responses. This includes abatement, cost pass-through, and competition effects. The incorporation of second-order impacts enhances the realism of the simulations.
We recognise the trade-off between transition risks in the shorter term and physical risks in the longer term. While greater policy action may increase transition risks in the shorter term, this will reduce the magnitude of physical risks in the longer term. As a result, we adopt differing time horizons for the two categories of risk. For physical risks, we consider up to 2050 as short term and 2050–2100 as long term. For transition risks, we consider a five-year time horizon as short term, a 10-year time horizon as medium term, and a 20-year time horizon as long term. However, as implied by the differing time frames adopted for physical and transition risks, we generally expect the effects of climate-related transition risks to occur across a shorter time horizon, over the next 20 years, and the effects of climate-related physical risks to occur across a comparatively longer time horizon, up until 2100.