Extreme heat

Extreme heat

Heat does not damage the building. It slows down the people who work in it or around it: past a certain heat and humidity, a worker can only sustain a fraction of normal effort. Extreme heat prices Business interruption only (% of annual revenue), as lost labour productivity. It does not price cooling cost or equipment stress.

What the map shows

• Today: the CHELSA design temperature, the mean daily maximum of the warmest month, for the 2011-2040 climatology (sheet).
• Projected: one band per scenario at 2035, 2050 and 2080, under the low, intermediate and high emissions settings. Each band adds a CMIP6 warming change to the same current field, so every horizon reads against one today.

How the loss is computed

The engine reads the design temperature at the site's point and converts it to a wet-bulb globe temperature (WBGT) at an assumed 50 % relative humidity. The ILO / Kjellström work-capacity curve, set by the work intensity of the site type, turns WBGT into a share of work capacity lost, weighted by the share of the year spent near that heat. Air conditioning sets the indoor WBGT, with a chance of cooling failure that rises with outdoor heat. A site can state whether it is air-conditioned; otherwise its type carries a presumption. Heat is tagged Built. See Damage functions: Extreme heat and Climate risks.

Heat is measured as a slow drift. Its level is booked like every other hazard, and the Exclude slow-drift baselines switch sets its baseline to zero so that only the change counts.

Sources

• CHELSA v2.1 (Karger et al.) bio5, GCM ensemble mean (GFDL-ESM4, MPI-ESM1-2-HR, MRI-ESM2-0). CC0 1.0.
• Multi-origin C3S Atlas CMIP6 daily maximum temperature, ensemble median, for the warming change. CC BY 4.0.
• Damage curve: ILO / Kjellström work-capacity loss on WBGT.

Limits

• Humidity is fixed at 50 %. No humidity layer is read, so a site in a humid climate is under-read.
• The cooling-failure envelope and the warm-season weight are Darwin proposals, uncalibrated.
• Only unmanned sites read zero. A cooled site's figure is an order of magnitude, not a precise value.