News Article | February 23, 2017
The warming trend that has accompanied anthropogenic climate change to date has reduced Colorado River flows by 0.5 million acre-feet (at the very least) over just a 14-year time period (2000–2014). This is according to new research from the University of Arizona and Colorado State University. To explain that better: Between the years of 2000–2014, Colorado River flows declined to around 81% of the 20th-century average. During this 14-year time period, a reduction of around 2.9 million acre-feet of water flow per year occurred. So, out of the total 2.9-million-acre-feet-a-year reduction, a limited but notable portion was the result of rising temperatures — owing to lower drainage into the river and also higher evaporative rates. This work is notable because many projections of future Colorado River flow don’t take the direct effects of rising temperatures into account. “This paper is the first to show the large role that warming temperatures are playing in reducing the flows of the Colorado River,” commented Jonathan Overpeck, UA Regents’ Professor of Geosciences and of Hydrology and Atmospheric Sciences and director of the UA Institute of the Environment. The new study found that the higher temperatures in the region since 2000 (1.6° Fahrenheit higher than the average since record-keeping there began) are responsible for between one-sixth to one-half of the river flow reductions seen since 2000. That means that, as temperatures in the region continue rising, the 40 million people who currently rely on the Colorado River for their survival may be out of luck and forced to move. These people are spread throughout 7 US states and the Mexican states of Sonora and Baja California. “We’re the first to make the case that warming alone could cause Colorado River flow declines of 30% by midcentury and over 50% by the end of the century if greenhouse gas emissions continue unabated,” Overpeck continued. Co-author Bradley Udall, a senior water and climate scientist/scholar at CSU’s Colorado Water Institute, commented as well: “The future of (the) Colorado River is far less rosy than other recent assessments have portrayed. A clear message to water managers is that they need to plan for significantly lower river flows.” The press release provides more: “The team began its investigation because Udall learned that recent Colorado flows were lower than managers expected given the amount of precipitation. The two researchers wanted to provide water managers with insight into how future projections of temperature and precipitation for the Colorado River Basin would affect the river’s flows. “Udall and Overpeck began by looking at the drought years of 2000-2014. About 85% of the river’s flow originates as precipitation in the Upper Basin — the part of the river that drains portions of Wyoming, Utah, Colorado and New Mexico. The team found during 2000-2014, temperatures in the river’s Upper Basin were 1.6° Fahrenheit (0.9° Celsius) higher than the average for the previous 105 years. “To see how increased temperatures might contribute to the reductions in the river’s flow that have been observed since 2000, Udall and Overpeck reviewed and synthesized 25 years of research about how climate and climate change have and will affect the region and how temperature and precipitation affect the river’s flows. “Water loss increases as temperatures rise because plants use more water, and higher temperatures increase evaporative loss from the soil and from the water surface and lengthen the growing season.” Something that’s important to note here is that current climate models apparently can’t simulate the 20- to 60-year megadroughts that are known to have occurred in the region at various points in the relatively recent past. Also notable is that most of these current climate models didn’t predict/reproduce the current drought — so clearly there are limitations to them in that regard. However, some earlier research has made it clear that, as temperatures in the region continue rising, such “megadroughts” will become more and more likely — and that this rising level of risk is much higher than current climate models predict. “A megadrought in this century will throw all our operating rules out the window,” Udall noted. There’s no doubt about that. Such an event would cause significant problems for the US, and would very likely spur a large-scale migration like that seen during the Dust Bowl. Many other regions of the world will be facing a similar situation as the southwestern US (and northern Mexico) over the coming century with regard to water scarcity — and the geopolitical outcomes aren’t likely to be too dissimilar. Mass migration, increasing levels of conflict, and everything that goes along with those two. … The emergence of defacto state-less zones in areas of extreme water scarcity seems likely over the coming decades. The new research is detailed in a paper published in the American Geophysical Union journal Water Resources Research. Buy a cool T-shirt or mug in the CleanTechnica store! Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech daily newsletter or weekly newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter. James Ayre 's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.
News Article | February 21, 2017
Warming in the 21st century reduced Colorado River flows by at least 0.5 million acre-feet, about the amount of water used by 2 million people for one year, according to new research from the University of Arizona and Colorado State University. The research is the first to quantify the different effects of temperature and precipitation on recent Colorado River flow, said authors Bradley Udall of CSU and Jonathan Overpeck of the UA. "This paper is the first to show the large role that warming temperatures are playing in reducing the flows of the Colorado River," said Overpeck, UA Regents' Professor of Geosciences and of Hydrology and Atmospheric Sciences and director of the UA Institute of the Environment. From 2000-2014, the river's flows declined to only 81 percent of the 20th-century average, a reduction of about 2.9 million acre-feet of water per year. One acre-foot of water will serve a family of four for one year, according to the U.S. Bureau of Reclamation. From one-sixth to one-half of the 21st-century reduction in flow can be attributed to the higher temperatures since 2000, report Udall and Overpeck. Their analysis shows as temperature continues to increase with climate change, Colorado River flows will continue to decline. Current climate change models indicate temperatures will increase as long as humans continue to emit greenhouse gases into the atmosphere, but the projections of future precipitation are far less certain. Forty million people rely on the Colorado River for water, according to the U.S. Bureau of Reclamation. The river supplies water to seven U.S. Western states plus the Mexican states of Sonora and Baja California. Udall, a senior water and climate scientist/scholar at CSU's Colorado Water Institute, said, "The future of Colorado River is far less rosy than other recent assessments have portrayed. A clear message to water managers is that they need to plan for significantly lower river flows." The study's findings, he said, "provide a sobering look at future Colorado River flows." The Colorado River Basin has been in a drought since 2000. Previous research has shown the region's risk of a megadrought--one lasting more than 20 years--rises as temperatures increase. Overpeck said, "We're the first to make the case that warming alone could cause Colorado River flow declines of 30 percent by midcentury and over 50 percent by the end of the century if greenhouse gas emissions continue unabated." The paper by Udall and Overpeck, "The 21st Century Colorado River Hot Drought and Implications for the Future," went online Feb. 17 in the American Geophysical Union journal Water Resources Research. The Colorado Water Institute, National Science Foundation, the National Oceanic and Atmospheric Administration and the U.S. Geological Survey funded the research. The team began its investigation because Udall learned that recent Colorado flows were lower than managers expected given the amount of precipitation. The two researchers wanted to provide water managers with insight into how future projections of temperature and precipitation for the Colorado River Basin would affect the river's flows. Udall and Overpeck began by looking at the drought years of 2000-2014. About 85 percent of the river's flow originates as precipitation in the Upper Basin--the part of the river that drains portions of Wyoming, Utah, Colorado and New Mexico. The team found during 2000-2014, temperatures in the river's Upper Basin were 1.6 degrees F (0.9 C) higher than the average for the previous 105 years. To see how increased temperatures might contribute to the reductions in the river's flow that have been observed since 2000, Udall and Overpeck reviewed and synthesized 25 years of research about how climate and climate change have and will affect the region and how temperature and precipitation affect the river's flows. Water loss increases as temperatures rise because plants use more water, and higher temperatures increase evaporative loss from the soil and from the water surface and lengthen the growing season. In previous research, Overpeck and other colleagues showed current climate models simulated 20th-century conditions well, but the models cannot simulate the 20- to 60-year megadroughts known to have occurred in the past. Moreover, many of those models did not reproduce the current drought. Those researchers and others suggest the risk of a multidecadal drought in the Southwest in the 21st century is much higher than climate models indicate and that as temperatures increase, the risk of such a drought increases. Udall said, "A megadrought in this century will throw all our operating rules out the window." Udall and Overpeck found all current climate models agree that temperatures in the Colorado River Basin will continue rising if the emission of greenhouse gases is not curbed. However, the models' predictions of future precipitation in the Basin have much more uncertainty. Overpeck said, "Even if the precipitation does increase, our work indicates that there are likely to be drought periods as long as several decades when precipitation will still fall below normal." The new study suggests Colorado River flows will continue to decline. Udall said, "I was surprised at the extent to which the uncertain precipitation aspects of the current projections hid the temperature-induced flow declines." The U.S. Bureau of Reclamation lumps temperature and precipitation together in its projections of Colorado River flow, he said. "Current planning understates the challenge that climate change poses to the water supplies in the American Southwest," Udall said. "My goal is to help water managers incorporate this information into their long-term planning efforts."
News Article | October 5, 2016
The U.S. Southwest is almost guaranteed to suffer scorching, decades-long "megadroughts" if the world continues producing greenhouse gas emissions at its current pace, a new study warns. Southwestern states could see the risks of megadroughts rise up to 99 percent by the end of this century as global warming drives up regional temperatures, a team of U.S. researchers said. SEE ALSO: The Earth just permanently passed a symbolic carbon dioxide threshold On the flip side, lowering global emissions and limiting future global warming would reduce the Southwest's risk of prolonged droughts, the researchers found in a paper published Wednesday in the journal Science Advances. "Megadroughts are virtually certain in a business-as-usual greenhouse gas emissions scenario," Toby Ault, the study's lead author and an assistant professor at Cornell University in New York, told Mashable. "There really still are benefits to adopting an aggressive [emissions] mitigation strategy to reduce the risk of megadroughts," he added. The paper builds on the team's earlier findings that rising carbon emissions could drastically increase the risk of decades-long droughts, which would further strain the region's already limited water supplies and spark substantially more forest fires, dust storms and tree diseases. The 2015 NASA-backed study found that, by the second half of this century, the Southwest and Central Plains could see droughts that are drier and longer than those experienced in the region in the last 1,000 years. Wednesday's paper is the first to put a precise number on that risk. It also helps to clarify which factors will likely spur the future megadroughts. Ault said the team found that regional temperature increases alone will push megadrought risks to 70 percent, 90 percent or 99 percent by 2100. Future precipitation patterns, by contrast, will have virtually no effect. The researchers found, to their surprise, that regional rainfall could increase, decrease or stay the same, and it wouldn't change their estimates for megadrought risks. That's because the rising air temperatures would drive higher evaporation rates on the ground; the warmer the soil, the less likely it is to lock in moisture. Rainfall would have to rise at least 50 percent in the Southwest in the coming decades — which nobody is projecting will happen — to compensate for the rise in regional temperatures. Their finding that precipitation won't stem megadrought risk is significant given the broader uncertainty about how rainfall patterns will change due to global warming, said Samantha Stevenson, a project scientist at the National Center for Atmospheric Research in Boulder, Colorado, who wasn't involved in the study. "This model shows that uncertainty in precipitation doesn't really matter, as much as the fact that megadrought risk is going to increase," she told Mashable. "Everything is just warming up, so it's going to get harder to store moisture in the soil, even if it rains more," she said. When megadroughts struck the Southwest in the distant past, the impacts on water supplies and agriculture were enough to destroy or break apart prehistoric civilizations. Around the 13th century, a megadrought forced the Ancient Puebloans (also called Anasazi) to abandon their dwellings in the Four Corners region of Arizona, Colorado, New Mexico and Utah. Modern Americans might not face such a catastrophic conclusion to megadroughts. Southwestern residents could still haul in water from over hundreds of miles away or move to less arid communities without spurring the decline of U.S. society, Ault said. But the region would still likely suffer substantial consequences from megadroughts, including a more severe version of the drought conditions they're experiencing today, said Jonathan Overpeck, co-director of the University of Arizona's Institute of the Environment in Tuscon. He noted that the Southwest is enduring a 16-year-long drought, an event that's putting enormous strain on the Colorado River, which provides water supplies for major cities including Phoenix, Las Vegas, Salt Lake City, Denver, Los Angeles and San Diego. Dry conditions have also killed off broad swaths of trees, or made them more vulnerable to deadly beetle infestations. The dead timber and parched soil have also enabled a wave of dangerous, sweeping forest fires in recent years. "In the Southwest, climate change is here, and it's already threatening our water supplies, our ecosystems and our health," he said. "This current drought is just a glimpse of what the megadrought would be like," he added.
Shahbazi A.,Shahid Beheshti University |
Gonzalez-Olmos R.,Helmholtz Center for Environmental Research |
Gonzalez-Olmos R.,Institute of the Environment |
Kopinke F.-D.,Helmholtz Center for Environmental Research |
And 2 more authors.
Separation and Purification Technology | Year: 2014
Iron-containing zeolites were studied as adsorbents and heterogeneous Fenton-like catalysts for the removal of the non-ionic surfactant Triton® X-100 (TX-100) from water. Adsorption tests included a variety of zeolites with different structure types (ZSM5, Beta and Y) and SiO2/Al 2O3 ratios. Zeolites with 12-membered-ring channels and high molar ratio of SiO2/Al2O3, indicating higher surface hydrophobicity, proved to be the most suitable adsorbents for TX-100. For preparation of iron-loaded zeolites, a Beta zeolite with a molar ratio of SiO2/Al2O3 of 200 was selected, based on its excellent adsorption properties, and compared with a natural zeolite of clinoptilolite type. Batch experiments indicated that both Fe-zeolites are active in the heterogeneous Fenton-like oxidation of TX-100 at neutral pH. However, the synthetic Fe-Beta zeolite was preferable compared to the Fe-loaded natural zeolite with respect to catalytic activity and H2O 2 utilization efficiency, which was interpreted in terms of differences in iron speciation and adsorption properties towards TX-100. Fe-Beta (200) was successfully applied in two cycles of adsorption/oxidation steps in a column experiment. This study shows that Fe-loaded Beta zeolites with high hydrophobicity can be suitable materials for a combined approach of adsorption/wet peroxide oxidation of chemicals with relatively high molecular weight and chain-like molecule structure, such as the non-ionic surfactant TX-100. © 2014 Elsevier B.V. All rights reserved.
Reiley D.K.,University of Wisconsin - Madison |
Breshears D.D.,Institute of the Environment |
Zedler P.H.,University of Wisconsin - Madison |
Ebinger M.H.,Los Alamos National Laboratory |
Meyer C.W.,Los Alamos National Laboratory
Journal of Arid Environments | Year: 2010
Soil carbon often varies significantly among vegetation patch types, but less known is how the size and species of plants in the tree canopy patches and the cover types of the intercanopy patches affect the carbon storage, and whether vegetation characteristics affect storage in adjacent patches. To assess this, we measured fine-fraction soil carbon in a semiarid woodland in New Mexico USA for canopy patches of two co-dominant woody species, Pinus edulis and Juniperus monosperma that were paired with intercanopy patch locations covered by herbaceous grass (Bouteloua gracilis) or bare ground. Soil carbon at shallow depths was greater in canopy than intercanopy patches by a factor of 2 or more, whereas within intercanopy patches soil carbon in grass locations exceeded that in bare locations only after accounting for coarse-fraction carbon. Hypothesized differences among canopy patches associated with species or size were not detected (although some size-depth interactions consistent with expectations were detected), nor, importantly, were effects of species or size of woody plant on intercanopy soil carbon. The results are notable because where applicable they justify estimates of soil carbon inventories based on readily observable heterogeneity in above-ground plant cover without considering the size and species of the woody plants. © 2009 Elsevier Ltd. All rights reserved.
Cejudo-Figueiras C.,Institute of the Environment |
Lvarez-Blanco I.,Institute of the Environment |
Bcares E.,University of Len |
Blanco S.,University of Len
Marine and Freshwater Research | Year: 2010
For bioassessment of freshwaters, diatom indices have been mainly used in streams although their applicability in shallow lakes has been demonstrated in several studies. However, the influence of sampling substrata on periphytic diatom communities and on the ecological quality inferred from them has been paid little attention. In this paper, we test the 'neutral substrate hypothesis', which predicts no relevant influence of host plant type on their epiphytic community. Nineteen shallow permanent lakes from north-west Spain were studied and classified into three trophic levels. Epiphytic diatom communities growing on three different macrophytes for each trophic level were sampled and analysed. We assess: (1) which of the most common diatom indices provides a reliable water quality assessment, (2) how different plant substrata influence the diatom communities growing on them and (3) how these differences affect water quality assessment. Similarity tests showed significant differences in the composition of diatom assemblages among nutrient concentrations and host macrophytes. In contrast, ANOVA results for selected diatom-based metrics showed significant differences among trophic levels but not between different plant substrata. This supports the use of epiphytic diatoms as biological indicators for shallow lakes irrespective of the dominant macrophyte. © 2010 CSIRO.
Blanco S.,University of León |
Blanco S.,Institute of the Environment |
Wetzel C.E.,Luxembourg Institute of Science and Technology LIST
Phytotaxa | Year: 2016
A cross-check of botanical names databases revealed the presence of 19 cases of homonymy which are hereby resolved by proposing replacement names. Most cases concern diatom genera (Bacillariophyta) names which are preoccupied by spermatophytes. While Loranthella nom. nov. (Spermatophyta, Loranthaceae) and Ochradiscus nom. nov. (Spermatophyta, Resedaceae) are proposed as new names for spermatophytes, new diatom names are proposed for genera that are currently placed in the families Amphipleuraceae, Coscinodiscaceae, Hemiaulaceae, Hemidiscaceae, Melosiraceae, Metascolioneidaceae nom. nov., Naviculaceae, Pyxillaceae, Stictodiscaceae and Surirellaceae. With one exception (i.e. Eileencoxia nom. nov.) all remaining diatom genera that are discussed in the present paper are marine and/or fossil elements. The particularities of each case are briefly discussed. A total of one hundred and three new combinations are proposed. © 2016 Magnolia Press.
Cejudo-Figueiras C.,University of León |
Cejudo-Figueiras C.,Institute of the Environment |
Blanco S.,University of León |
Blanco S.,Institute of the Environment |
And 4 more authors.
Vie et Milieu | Year: 2010
The Water Framework Directive requires that the European Union countries determine the biological state of their waters with respect to sites of high quality. Although bioindicators have been widely applied in running waters and deep lakes throughout Europe, little is known about their applicability in shallow lakes and wetlands. The objective of this work is to check the effectiveness of epiphytic diatoms as indicators of the trophic state in two wetlands of Álava Province (N Spain). Diatom and water chemical samples were collected during summer and autumn 2007, following standard methodology. Stems of submerged macrophyte (Carex riparia, Iris pseudacorus, Veronica anagallis-aquatica) were sampled in each lake. Based on the number of statistically significant correlations between diatom indices and environmental factors, the SID index was show as the most suitable method to assess nutrients within these systems. SID was significantly correlated with TP, NTK and ammonium levels. Among three different plants, only the indices calculated from /. pseudacorus samples were significantly correlated with nutrients.
Hecht S.,Institute of the Environment
Land Use Policy | Year: 2010
Deforestation captures most of the headlines, but there are also processes of forest expansion that are widespread in Latin America. This paper explores why this process is so invisible. Globalization plays an increasingly important role in structuring rural economies. This paper analyses how global integration of many types, ranging from remittances, state transfers, skilling and markets produced forest recovery in peasant landscapes. © 2009 Elsevier Ltd. All rights reserved.
News Article | August 22, 2016
Brazil's Institute of the Environment and Natural Resources, Ibama, has decided not to award an environmental license for the Sao Luiz do Tapajos hydroelectric plant, effectively ending development of the controversial 8,000 MW project.