<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Nature Sustainability March 2020<div class=""><div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p class=""><span class="" style="font-weight: 600;">Water scarcity and fish imperilment driven by beef production</span></p><p class=""><span class="">Brian D. Richter <span class="" style="vertical-align: 4pt;">1,2</span><span class="" style="vertical-align: 3pt;"> ✉</span>, Dominique Bartak<span class="" style="vertical-align: 4pt;">3</span>, Peter Caldwell<span class="" style="vertical-align: 4pt;">4</span>, Kyle Frankel Davis <span class="" style="vertical-align: 4pt;">5,6,7</span>,<br class="">Peter Debaere<span class="" style="vertical-align: 4pt;">8</span>, Arjen Y. Hoekstra <span class="" style="vertical-align: 4pt;">9,10</span>, Tianshu Li <span class="" style="vertical-align: 4pt;">11</span>, Landon Marston <span class="" style="vertical-align: 4pt;">12</span>, Ryan McManamay <span class="" style="vertical-align: 4pt;">13</span>, Mesfin M. Mekonnen <span class="" style="vertical-align: 4pt;">14</span>, Benjamin L. Ruddell<span class="" style="vertical-align: 4pt;">15</span>, Richard R. Rushforth<span class="" style="vertical-align: 4pt;">15 </span>and Tara J. Troy <span class="" style="vertical-align: 4pt;">16,17</span></span></p><p class=""><b class="">Abstract </b></p><p class=""><span class="">Human consumption of freshwater is now approaching or surpassing the rate at which water sources are being naturally replen- ished in many regions, creating water shortage risks for people and ecosystems. Here we assess the impact of human water uses and their connection to water scarcity and ecological damage across the United States, identify primary causes of river dewatering and explore ways to ameliorate them. We find irrigation of cattle-feed crops to be the greatest consumer of river water in the western United States, implicating beef and dairy consumption as the leading driver of water shortages and fish imperilment in the region. We assess opportunities for alleviating water scarcity by reducing cattle-feed production, finding that temporary, rotational fallowing of irrigated feed crops can markedly reduce water shortage risks and improve ecological sustainability. Long-term water security and river ecosystem health will ultimately require Americans to consume less beef that depends on irrigated feed crops.</span></p></div></div><div class="layoutArea"><div class="column"><p class=""><span class="" style="caret-color: rgb(201, 71, 41);"><b class="">Opening paragraphs of text:</b><font color="#919191" class=""> W</font></span>ater shortages have afflicted human societies for thousands of years<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">1</span>. As population centres grow and farmlands expand, freshwater consumption typically increases until renewable water supplies are fully utilized (for example, in Fig. <span class="" style="color: rgb(58, 105, 158);">1</span>); at this point, water users and freshwater ecosystems become highly vulnerable to water shortages during drier periods<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">2</span>. Historically, water shortages had local causes and consequences, involving only the communities that were directly dependent on an overused river or aquifer. Today, however, with trade networks encircling the globe, demand for asparagus in the United Kingdom can contribute to the depletion of an aquifer in the Peruvian desert<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">3</span><span class="" style="vertical-align: 3pt;">,</span><span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">4 </span>and water shortages in the Central Valley of California can affect the availability and price of almonds and pistachios imported into the European Union<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">5</span>.</p><p class="">Climate change exacerbates water shortages by affecting both water supplies and water demands. Higher temperatures increase evapotranspiration, reducing aquifer recharge and watershed run- off<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">6</span>. For example, Udall and Overpeck attributed one-third of recent declines in Colorado River flows (19% below average during 2000– 2014) to temperature increases<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">7</span>. The Intergovernmental Panel on Climate Change expressed high confidence that irrigation—the largest water-using sector globally—will increase in coming decades due to increased evapotranspiration<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">6</span>.</p><p class="">Human-induced depletion of river flows has deleteriously affected freshwater species and ecosystems across the globe<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">8</span><span class="" style="vertical-align: 3pt;">,</span><span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">9 </span>and is a leading cause of fish imperilment in the US<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">10</span><span class="" style="vertical-align: 3pt;">–</span><span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">12</span>. Richter et al.<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">12 </span>documented that 62% of sub-watersheds in the western US contain at least one species endangered by flow depletion, with a total of 367 plant and animal species affected, including two-thirds of all native fish species in the Colorado River basin. To protect species listed under the US Endangered Species Act, water regulators have been forced to curtail water use for irrigation in some watersheds, lead- ing to severe political controversy and economic hardship<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">13</span><span class="" style="vertical-align: 3pt;">,</span><span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">14</span>. The annual cost of recovering Endangered Species Act-listed fish species (more than US$800 million per year) now exceeds expenditures for all other animal and plant groups combined<span class="" style="color: rgb(58, 105, 158); vertical-align: 3pt;">15</span>. </p></div></div></div><div class=""><div class=""><span class="" style="font-size: 12px;">**********************************************************************************</span><br class=""><span class="" style="font-size: 12px;">“It’s time that<span class="" style="background-color: rgb(255, 251, 0);"> everyone</span>, from the humble homeowner to the highest levels of business and government, rethink their relationship with energy and take action. </span></div><div class=""><span class="" style="font-size: 12px;"><br class=""></span></div><div class=""><span class="" style="font-size: 12px;">"Relying on renewables alone won’t be enough.”<br class=""><br class=""><<<a href="https://www.forbes.com/sites/mikehughes1/2019/08/02/climate-change-18-months-to-save-the-world/#166763c749bd" class="">https://www.forbes.com/sites/mikehughes1/2019/08/02/climate-change-18-months-to-save-the-world/#166763c749bd</a>>></span></div><div class=""><br class=""></div><div class=""><span class="" style="font-size: 12px;">***********************************************************************<br class="">“Collective action works; we have proved that. But to change everything, we need<span class="" style="background-color: rgb(255, 251, 0);"> everyone. </span></span></div><div class=""><span class="" style="font-size: 12px;"><br class=""></span></div><div class=""><span class="" style="font-size: 12px;">"Each and <span class="" style="background-color: rgb(255, 251, 0);">every one </span>of us must participate in the climate resistance movement.”<br class=""><br class="">Greta Thunberg, youth climate strike leader in Sweden.<br class="">Luisa Neubauer, German climate activist.<br class="">Angela Valenzuela, Fridays for Future in Santiago, Chile.<br class=""><br class=""><<<a href="https://www.commondreams.org/views/2019/11/29/why-we-strike-again" class="">https://www.commondreams.org/views/2019/11/29/why-we-strike-again</a>>></span></div></div></div><div class="">
<div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Verdana; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div><span style="font-size: 12px;" class="">**********************************************************************************</span><br class=""><span style="font-size: 12px;" class="">“It’s time that<span style="background-color: rgb(255, 251, 0);" class=""> everyone</span>, from the humble homeowner to the highest levels of business and government, rethink their relationship with energy and take action. </span></div><div><span style="font-size: 12px;" class=""><br class=""></span></div><div><span style="font-size: 12px;" class="">"Relying on renewables alone won’t be enough.”<br class=""><br class=""><<<a href="https://www.forbes.com/sites/mikehughes1/2019/08/02/climate-change-18-months-to-save-the-world/#166763c749bd" class="">https://www.forbes.com/sites/mikehughes1/2019/08/02/climate-change-18-months-to-save-the-world/#166763c749bd</a>>></span></div><div><br class=""></div><div><span style="font-size: 12px;" class="">***********************************************************************<br class="">“Collective action works; we have proved that. But to change everything, we need<span style="background-color: rgb(255, 251, 0);" class=""> everyone. </span></span></div><div><span style="font-size: 12px;" class=""><br class=""></span></div><div><span style="font-size: 12px;" class="">"Each and <span style="background-color: rgb(255, 251, 0);" class="">every one </span>of us must participate in the climate resistance movement.”<br class=""><br class="">Greta Thunberg, youth climate strike leader in Sweden.<br class="">Luisa Neubauer, German climate activist.<br class="">Angela Valenzuela, Fridays for Future in Santiago, Chile.<br class=""><br class=""><<<a href="https://www.commondreams.org/views/2019/11/29/why-we-strike-again" class="">https://www.commondreams.org/views/2019/11/29/why-we-strike-again</a>>></span></div></div>
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