The United States released its fourth National Climate Assessment Report last week – and it’s not looking good for water security in the North American republic.
The Congressionally mandated Assessment summarizes the impacts of climate change on the United States, now and in the future. More than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the US National Academy of Sciences.
The authors report that the quality and quantity of water available for use by people and ecosystems across the country are being affected by climate change, increasing risks and costs to agriculture, energy production, industry, recreation, and the environment.
The administration of Donald Trump has come under fire for attempting to “bury” the report by releasing it November 23, during the US Thanksgiving holiday period. The famously climate-change-denying President subsequently told reporters that he doesn’t believe his own government’s climate change findings. “I’ve seen it, I’ve read some of it, and it’s fine,” he said outside the White House November 26. “I don’t believe it".
The Assessment’s chapter on water describes changes in water quantity and quality in the US; risks associated with deteriorating water infrastructure; and calls for changes in water management to adapt to changing climate.
ON CHANGES IN WATER QUANTITY AND QUALITY:
"Significant changes in water quantity and quality are evident across the country. These changes, which are expected to persist, present an ongoing risk to coupled human and natural systems and related ecosystem services. Variable precipitation and rising temperature are intensifying droughts, increasing heavy downpours, and reducing snowpack. Reduced snow-to-rain ratios are leading to significant differences between the timing of water supply and demand. Groundwater depletion is exacerbating drought risk. Surface water quality is declining as water temperature increases and more frequent high-intensity rainfall events mobilize pollutants such as sediments and nutrients".
ON DETERIORATING WATER INFRASTRUCTURE AT RISK:
"Deteriorating water infrastructure compounds the climate risk faced by society. Extreme precipitation events are projected to increase in a warming climate and may lead to more severe floods and greater risk of infrastructure failure in some regions. Infrastructure design, operation, financing principles, and regulatory standards typically do not account for a changing climate. Current risk management does not typically consider the impact of compound extremes (co-occurrence of multiple events) and the risk of cascading infrastructure failure".
ON WATER MANAGEMENT IN A CHANGING FUTURE:
"Water management strategies designed in view of an evolving future we can only partially anticipate will help prepare the Nation for water- and climate-related risks of the future. Current water management and planning principles typically do not address risk that changes over time, leaving society exposed to more risk than anticipated. While there are examples of promising approaches to manage climate risk, the gap between research and implementation, especially in view of regulatory and institutional constraints, remains a challenge".