Extreme Heat Model

Overview

The maximum daily near-surface air temperature is used to model Extreme Heat. Extreme heat may cause damage to some materials and archetypes, such as roads and asphalt, however the temperatures needed are very high and are not normally a trigger for damage to commercial or residential property. Therefore, the Climate Risk Engines manage probabilities of damage and failure separately. Extreme temperatures can cause the failure of various systems that an asset needs to function. For example, a smartphone exposed to direct sunlight may overheat and shut down, but once it cools it should operate normally. Additionally, rail lines can overheat meaning trains can’t run at their intended speed, power lines become less efficient and air conditioners can stop working above 45 °C, leading to closure of shopping centres or factories. Hence, heat extremes are assumed to be associated with asset failure and disruption rather than damage.

Baseline Hazard Data

Baseline data for the statistical distribution of local temperatures comes from the nearest weather station with sufficient data quality and temporal depth to meet Climate Risk Engines requirements.

Climate Change Projections

Climate projections are used to determine how the return frequency of an asset threshold failure temperature changes over time. The key parameter is the annual maximum of the daily maximum temperature. That is, the system seeks the hottest temperature during the hottest day of each year from the climate model being analysed. These are then smoothed to establish a trend. In general, climate models are either selected based on being at the upper end of warming for an ensemble or as a percentile within the ensemble distribution.