Bio-climatological aspects of summer 2003 over France

The extreme heat wave of the first two weeks of August 2003 occurred during the hottest summer period (June to August) of the last fifty years and followed a six-month period of drought. Moreover, this heat wave was outstanding in duration (lasting for two weeks) and in geographic extension (over all parts of the country, including mountains and coastal regions) with absolute temperature records in 70 out of 180 stations. Its tragic health impacts, with 15,000 excess deaths, were probably strongly intensified by the persistently high night temperatures on the one hand, by high levels of pollution on the other hand : in Paris, with serial data files since 1873, morning temperatures on the 11th and 12th August were the highest ever registered, with 25.5°C (previous record : 24°C in 1976). Ozone (O3) peaks were strong and frequent, accompanied with some NO2 unusual peaks, probably due to the absence of bracing wind. Nevertheless this unique heat wave is consistent with climate change projections and more heat waves can be expected in the next few years or decades. This heat wave affected most parts of Europe, yet France was the most strongly affected with Andalusia and Portugal, due to unusually thick hot air masses coming from North Africa and settling over Western Europe. Météo-France issued a press release on 1st August announcing a progressive climb in temperatures for the following days over the whole country. On 4th August Metéo-France offered on its website simple health advice and a revue of historical deadly heat waves. A further press release on 7th August included a health warning, especially directed towards elderly and sick persons. The progressive ending of the heat wave was announced on the 13th August. In response to the heavy toll of this summer heat an early Heat Health Warning System is being established with French public survey agencies along with a common scheme for Cold Spells Warnings (previously running). This response includes a first announcement forecast for Health and Social Services professionals 4 to 7 days before the event, a warning forecast 1 to 3 days before the event for the media and general public, and an enhanced warning on a four colours warning scale (green, yellow, orange and red) in case of pollution, strong summer humidity or strong winter winds. The inclusion of other bio- meteorological warnings, such as UV index, pollen and pollution concentrations is also being considered.