Global warming and El Nino: a review of the current knowledge.

The observations of temperature from meteorological networks, as independen t observations or indicators (paleoclimatic, snow cover; sea-ice and glacie rs extensions, sea level), tend towards a surface global warming, which has been more intense during the last decades. Several studies converge on the attribution of part of the most recent warming to human activities. The El Nino event (and its companion La Nina) of climate variability, induces cli mate anomalies which can be distributed all over the globe. The forecasting of these events, several season in advance, became foreseeable a few years ago. These forecasts, as climate change predictions, can be used as input to impact studies on the occurrence and extension of infectious diseases. I t appears important that the corresponding methodologies account for the un certainties of the climatic forecasts and predictions. (C) 1999 Elsevier, P aris.