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What’s on the 5th IPCC Report for West Africa?

The status of knowledge on observed and projected climate change is regularly summarized in the assessment reports of the Intergovernmental Panel on Climate Change. The latest IPCC report (2013) concludes that Africa as a whole is one of the most vulnerable continents due to its high exposure and low adaptive capacity. Here, the major conclusions of the report for Western Africa are summarized. Although there are still large gaps in the available data, evidence of warming over land regions across Africa, consistent with anthropogenic climate change, has increased. Temperature projections over West Africa for the end of the 21st century from global climate simulation range between 3 and 6 °C above the late 20th century baseline depending on the emission scenario. A similar range is produced with regional climate models that are used to downscale global climate simulations. For some regions, unprecedented climates are projected to occur at around 2040. Important progress has been made in the understanding of West African weather systems during the African Monsoon Multidisciplinary Analysis (AMMA; phase 1: 2002–2010, phase 2: 2010–2020) project. For many processes in ecology, agriculture or hydrology, precipitation is one of the most important parameters. In addition to the total precipitation, the onset of the rainy season is of special interest for agriculture. In the past a shift of the rainy season was discussed, but currently a shift cannot be observed for West Africa. However, the length of the Sahelian rainy season reveals an increasing trend of 2–3 days per decade, with a drier phase within. Since the 1950s annual precipitation has tended to decrease in western and eastern parts of the Sahel region, with a very dry period in the 70s and 80s and a slight increase of precipitation afterwards, until today. However, climate projections show a slight increase of total precipitation and a longer rainy season with a drier phase within.