Assessing the impact of climate change in African cities. Methodological aspects. Adaptation to Climate Change

The term “climate” relates to the mean values, measured over long periods, and for large and well-defined geographical areas (called “climate zones”), for meteorological parameters (rainfall, temperature, cloud cover, etc.). Observations over 30 years are needed to establish the characteristics of climate. The climate thus differs from “weather”, which corresponds to the conditions at a given time. Weather forecasts are valid only locally and for a short period (no more than a few days). An unusually violent storm is therefore not evidence of climate change. To be certain of climate change, you need to be able to show that the frequency of certain weather conditions has increased significantly in a given region, over a long period.