Figure 3.6 Water withdrawal ratios by continent During the 20th
century, the world population increased 4.4 times while water withdrawal
increased 7.3 times over the same period. Thus, global water withdrawal
increased 1.7 times faster than the world population.Source: FAO Aquastat, UN
Figure 3.7 Global water use vs. population growth GLOBAL
PROBLEMSFreshwater shortages and water diversion are major global problems.
Water Shortages
The rate of water consumption is growing twice as fast as the population growth
rate. Freshwater shortages that result from this demand can be due to natural
weather patterns that reduce rainfall, rivers changing course, flooding that
contaminates existing supplies, competition for available water, overgrazing and
the resulting erosion, pollution of existing supplies, and competing interests that
reduce water conservation programs. Water is a limiting factor as it limits the
amount of food that can be produced in a region. If food cannot be grown locally
due to water shortages, then food must be imported at additional costs.
CASE STUDY
CALIFORNIA WATER DROUGHT: California’s latest official water
drought (2011–2017) was the driest period in the state’s 163 years of recorded