A large-scale, drought-induced famine occurred in Africa's Sahel region and many parts of the neighbouring Sénégal River Area from February to August 2010. It is one of many famines to have hit the region in recent times. The Sahel is the ecoclimatic and biogeographic zone of transition between the Sahara desert in the north of Africa and the Sudanian savannas in the south, covering an area of 3,053,200 square kilometres. It is a transitional ecoregion of semi-arid grasslands, savannas, steppes, and thorn shrublands. The neighbouring Sénégal River Area contains various vegetation types and covers parts or all of Mauritania, Mali, Senegal and Guinea. It has also had very low rainfall over the last year according to the UN, NGOs and the Senegal River Basin Development Authority. Sudan set a new temperature record of 49.7 °C (121.3 °F) on 22 June, in the town of Dongola. Overview Famine and food shortages were present in the following Sahelian countries during 2010 after heavy rains hit the region in late 2009, followed by a heat wave: Sudan, the Niger, northern Nigeria, northern Cameroon, Chad, Senegal, Burkina Faso, Mauritania, Mali, as well as in parts of the neighbouring Sénégal River Area. In December 2009, both USAID and several NGOs predicted an increased food insecurity situation in more of the southern districts of Mali as compared to the same time the previous year. Possible causes Environmental problems The Western donor nations once theorised that the drought in the Sahel primarily was caused by humans over-using natural resources in the region through overgrazing, deforestation and poor land management. In the late 1990s, climate model studies suggested that large-scale climate changes were also triggers for the drought. In the early 2000s, after the phenomenon of global dimming was discovered, some speculatively suggested, that the drought was likely caused by air pollution generated in Eurasia and North America. The pollution changed the properties of clouds over the Atlantic Ocean, disturbing the monsoons and shifting the tropical rains southwards. Global dimming, the blocking of sunlight by man-made particulates, has been identified as one culprit for a decades-long drought across sub-Saharan Africa. A 2006 study by NOAA scientists Rong Zhang and Thomas L. Delworth suggests that the Atlantic Multidecadal Oscillation/(MAO) plays a leading role. An AMO warm phase strengthens the summer rainfall over Sahel, while a cold phase reduces it. The AMO entered a warm phase in 1995 and, by