Average temperatures across the Sahel have risen by around one degree Celsius over the past 40 years, according to a study identifying potential climate 'hotspots' in the region. The report, published by the UN Environment Programme (UNEP), analysed historical climate trends across the Sahel, and aimed to identify potential hotspots and the impact on livelihoods in the region. Half of the 17 West African nations mapped experienced a temperature increase of 0.5–1 degree Celsius between 1970 and 2006, while 15 per cent of the region - in far eastern Chad and northern Mali and Mauritania - saw a rise of more than one degree Celsius.