By 2071, nearly half of the 204 fresh water basins in the United States may not be able to meet the monthly water demand. These model projections, recently published in the journal Earth’s Future, are just one preliminary component of the upcoming Resources Planning Act (RPA) Assessment expected to be published next year. In 1974, congress required that this assessment of US renewable resources be published every 10 years.
Conducted by the U.S. Forest Service, the research describes two causes for the projected shortages. The first is that the U.S. will simply have more people. Despite that the average American is using less water, population growth is still expected to increase water demand across most of the country.
Second, the water supply itself is expected to decrease. Projected climate change affects both rain patterns and temperatures. While rainfall is expected to increase in some parts of the US, the southern Great Plains and parts of the South won’t be so lucky. The water basins rely on rainfall to feed the rivers and tributaries that flow into them. Separately, more water will evaporate from reservoirs and streams as the climate gets warmer, further chipping away at the water supply. Around 50 years from now, many U.S. regions may see water supplies reduced by a third of their current size, while demand continues to increase.
The water shortages may especially impact U.S. agriculture. Irrigated agriculture often accounts for around 75% of the annual consumption of water from these basins. The authors point out, though, that this also makes agriculture a clear area for reducing water use. Up to 96 fresh water basins are projected to face shortages. Reducing water use for irrigation by just 2% could prevent shortages in a third of these basins. For others, though, the reduction must be greater – often over 30%. The authors say it’s unlikely that agriculture will be the only facet of society to adapt. Still, the agricultural sector “is likely to face serious challenges.” Accordingly, the findings raise concerns about both future water security and food security in the U.S.
Managing Correspondent: Jordan Wilkerson
Original Report: Adaptation to Future Water Shortages in the United States Caused by Population Growth and Climate Change. Earth’s Future
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