Final answer:
The most significant increase in demand over the last 50 years has been observed in water, food, and energy due to rising populations and higher standards of living. Agriculture uses around 70% of freshwater, and the expansion of agricultural land for both food and biofuel crops as well as the need for more fish products continue to stress these resources.
Step-by-step explanation:
In the past 50 years, there has been a significant increase in the demand for water, food, and energy. The growth in global population, which is anticipated to rise from 6 billion to between 8-10 billion by 2050, exerts pressure on these resources. As standards of living improve worldwide, so does the demand for a higher quality of food, including meat which requires more water and land to produce. Additionally, the need for agricultural land for bioenergy crops used in the production of biofuels has grown.
The increase in water demand is notable as it has outpaced population growth, with a sixfold increase in comparison to the population tripling during the 20th century. Agriculture alone uses about 70 percent of freshwater, significantly affecting both quantity and quality of water. Moreover, as much as 70 percent of the rainforests that have been cut down are utilized for grazing livestock, a practice that contributes to water pollution.
Regarding energy, the drive for improved goods and services leads to higher water and land utilization. Furthermore, marine fisheries face overfishing, with 25 percent being fished at their maximum productivity and 35 percent overfished, signaling an increasing demand for fish that might be addressed partially by aquaculture, known for its environmental costs.