Globally, agriculture accounts for approximately 70% of all freshwater withdrawals, with irrigation being the largest user. The amount of water used for irrigation varies greatly from region to region and depends on factors such as climate, soil type, and crop water requirements. In some areas, such as the arid regions of the western United States, irrigation water can account for more than 90% of all water use. In more humid regions, such as the eastern United States, irrigation water use may only account for a small percentage of total water use.

According to the Food and Agriculture Organization of the United Nations (FAO), global water withdrawals for irrigation increased from 192 billion cubic meters (Bm3) in 1950 to 2,760 Bm3 in 2000. This increase in water use has been driven by several factors, including:

* Population growth: The global population has more than doubled since 1950, which has led to an increased demand for food.

* Increased agricultural productivity: In order to meet the demand for food, farmers have increased their use of irrigation and other agricultural technologies, which has led to increased water use.

* Climate change: Climate change is leading to changes in precipitation patterns and increased temperatures, which are both likely to lead to increased water use for irrigation.

The global water crisis is one of the most pressing challenges facing the world today. Agriculture is a major user of water, and it is important to find ways to reduce water use in agriculture. This can be done through the use of more efficient irrigation technologies, the adoption of drought-resistant crops, and the implementation of water pricing policies that encourage water conservation.