Today we expect to have water flowing at our kitchen sink and our food supplied by farms with sufficient water. The 2014 National Climate Assessment, released today, points to opportunities and challenges with the U.S. water resource infrastructure.
This infrastructure must keep pace with a growing population and increased water demand in a rapidly warming world. Take a look at the change in water withdrawals figure that projects a marked increase in most regions of the continental U.S. (except some of the Midwest), when climate change is included on top of population and socioeconomic conditions.
The difference between the projections with climate change and without is primarily due to higher temperatures and potential for evapotranspiration (water is released to the atmosphere from surface water, soil water, and plants).
Weaknesses in existing water law regimes – “stationarity” principle may no longer apply
What is striking about the water resources chapter of the report is the identification of a possible barrier to improving U.S. water systems that are increasingly stressed by future impacts of climate change. Current U.S. water law regimes assume that natural systems fluctuate within an “unchanging envelope of variability” or “stationarity.” With climate change shifting over the lifetime of major water infrastructure projects, this assumption of “stationarity” breaks down.
Water, Climate, and You
Who is stepping up to ensure you have clean water at your tap and enough “virtual water” via the food on your plate? Steps are being taken by some water utilities to ensure drinking water supply projects include climate risks in the design.
A key message from the 2014 National Climate Assessment is that seasonal droughts are expected to intensify in most U.S. regions and longer-term droughts are expected to intensify in large areas of the Southwest, southern Great Plains, and Southeast. This is a huge challenge for improving our water systems to support crops and livestock yields in these regions. The report suggests that as the risk of drought increases, groundwater may be tapped more during periods of drought even though there are limits to this resource given current management and institutional frameworks.
Another key message is “flooding may intensify in many U.S. regions, even in areas where total precipitation is projected to decline.” The good news is that municipalities are increasing porous pavement, rainwater harvesting, roadside plantings to limit sewer backups, and investing in systems that avoid sewer overflows into surface water.
My favorite aspect of the Third National Climate Assessment is that more than ever before, there is the ability to look at what is behind the figures, graphs, and key findings for those who are taking steps to prepare and protect communities. Take a look at the region where you live and see what the climate assessment has to say and tell us what you think.