4th to 5th of July 2016 at University of Florence, Florence, Italy

Workshop in Florence on HEAT-SHIELD heat indices

In the historic and picturesque meeting venue at the University of Florence, members of the HEAT-SHIELD project were gathered on the 4th to 5th of July 2016 to discuss and decide an appropriate heat stress index to be used for the forthcoming development of the weather warning system and predictions of future heat stress scenarios over Europe.

Simone Orlandini welcoming all participants to the meeting in the Aula Magna

Group photo with all the participants – representing MeteoSwiss (Sven Kotlarski and Ana Casanueva), University of Ljubljana (Lučka KAJFEŽ BOGATAJ and Igor Mekjavic), University of Florence and CeRIMP (Simone Orlandini, Alberto Baldasseroni, Alessandro Messeri, Miriam Levi and Marco Morabito), CETRI (Tord Kjellstrom), University of Copenhagen (Lars Nybo) and Loughborough (George Havenith)

From the left: George, Tord, Miriam, Lars, Igor, Lucka, Sven, Ana, Alessandro, Simone, Marco, Alberto

Consensus statement

Summary of the part of the meeting related to heat indices

The impact of environmental thermal stress on humans relies both on the surrounding climate and human factors such as the individual thermoregulatory capacity, work intensity, clothing and other behavioral strategies. More than 160 indices are described in the literature, but it is clear that no perfect index may cover all heat stress scenarios.

The HEAT-SHIELD project has decided to use the WBGT index and will provide it both for open (in sun – non-sheltered) and shadowed-sheltered conditions for the prolonged predictions and for the short-term warning of environmental heat-stress conditions. The index is chosen because it is simple and may be calculated (estimated) from standard climate service data as well as measured locally e.g. at workplaces. The purpose of using the WBGT index is for general environmental warning whereas more sophisticated/complex indices may be used for evaluating specific work conditions (when individual factors such as clothing, metabolic heat production, age, gender and acclimatization status is known) and future analyses should indeed also utilize other indices (returning to the original climatic data – temperature, humidity, radiation and wind) to identify the best input parameter for predicting health or productivity impact of a given heat-stress condition and such analyses should also evaluate if the mean, max or minimum daily values provides the greatest impact.

The WBGT-index is considered to fulfill the purpose for general warning (with individualized limits for different populations and industries) and for identifying long-term effects of importance for impact on policy making and comparison of current and future heat-stress scenarios in Europe with other parts of the world experiencing major heat stress.