At the most extreme, lakes such as Lake Chad can dry up in particular years. Impacts of climate change have been found in Lake Baikal, with significant warming of surface waters and long-term changes in the lake's foodweb, and corresponding increases in chlorophyll a and some zooplankton grazers (Hampton et al., In the deep African Rift Valley lakes, such as Lake Tanganyika, climate change has been associated with increases in surface water temperature, reduced vertical mixing of water, reduced primary productivity and reduced fish catch per unit effort, which has driven fishers to other lakes (Verburg et al., In Lake Tanganyika, the surface water temperature has risen over the last century. This has increased the stability of the water column, which along with a regional decrease in wind velocity has contributed to reduced mixing, decreasing deep-water nutrient upwelling and entrainment into surface waters.