 In about 950 AD a dramatic shift in the regions' climate occurred.A significant drop in annual precipitation in the Titicaca Basin followed as a result, and many cities further away from Lake Titicaca with less access to water sources began to produce less crops, and diminishing surplus food stock to provide to the elites as a result.The immediate area surrounding the capital city and the lake eventually became the last source of substantial agricultural food production for the empire, due to the resiliency of the raised fields to efficiently produce food crops, but in the end even the intelligent design of the fields was no match for the changing climate.