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Got Drinking Water? Watch Climate Change Turn It Toxic.

Posted by Richard Conniff on August 7, 2017

The algae bloom that ate Lake St. Clair. (Photo: NASA/NOAA)

by Richard Conniff/Yale Environment 360

It is a painful lesson of our time that the things we depend on to make our lives more comfortable can also kill us. Our addiction to fossils fuels is the obvious example, as we come to terms with the slow motion catastrophe of climate change. But we are addicted to nitrogen, too, in the fertilizers that feed us, and it now appears that the combination of climate change and nitrogen pollution is multiplying the possibilities for wrecking the world around us.

A new study in Science projects that climate change will increase the amount of nitrogen ending up in U.S. rivers and other waterways by 19 percent on average over the remainder of the century — and much more in hard-hit areas, notably the Mississippi-Atchafalaya River Basin (up 24 percent) and the Northeast (up 28 percent). That’s not counting likely increases in nitrogen inputs from more intensive agriculture, or from increased human population.

RunoffTennessee_USDA-NRCS-Tim-McCabe

Water flows off a farm in Tennessee following a storm. (Photo: Tim McCabe/USDA)

Instead, Stanford University researcher Eva Sinha and her co-authors simply took historical records of nitrogen runoff as a result of rainstorms over the past few decades, recorded by the U.S. Geological Survey. Then, assuming for the sake of argument that there will be no change in the amount of nitrogen being added to the environment, they calculated how much additional nitrogen would be leached out of farm fields and washed down rivers solely because of extreme weather events and increased total rainfall predicted in most climate change scenarios. The bottom line: “Anticipated changes in future precipitation patterns alone will lead to large and robust increases in watershed-scale nitrogen fluxes by the end of the century for the business-as-usual scenario.”

But the business-as-usual scenario is of course already in trouble, even without climate change. Headlines have tended to fixate on the Gulf of Mexico “dead zone” produced by nitrogen flushed down the Mississippi River from the cornfields of the upper Midwest. (This year’s “dead zone” is the largest ever, the National Oceanic and Atmospheric Administration announced last week.) But the problem is already much broader than that, says senior author Anna M. Michalak, also of Stanford, citing a series of recent incidents caused by nitrogen pollution. Last summer, for instance, a 33-square-mile algae bloom caused Florida to declare a four-county state of emergency. Another closed the Dungeness crab fishery along half of the Washington State coast last year and affected other fisheries as far south as Mexico.

The combined effect of climate change and nitrogen pollution is also evident on inland waterways, according to Hans Paerl, an aquatic ecologist at the University of North Carolina’s Institute of Marine Sciences. In the past, cleanup efforts on lakes and other freshwater bodies could achieve major improvements just by targeting phosphorous pollution, also from fertilizer. But now they routinely face toxic blue-green algae (or cyanobacteria) blooms, fueled by nitrogen pollution. That problem is being exacerbated, Paerl and his co-authors argued in a study last year, by warmer temperatures and increased rainfall associated with climate change. Efforts by water quality managers to protect the water supply may not work in the future, they wrote, because climate change introduces so many new uncertainties about hydrology, stratification, and nutrient dynamics.

These toxic algae blooms have become alarmingly widespread in recent decades, according to Paerl. One such bloom in the western end of Lake Erie forced Toledo, Ohio, to cut off the water supply temporarily to 500,000 residents in 2014. The same thing happened in China’s Lake Taihu in 2007, leaving 2.3 million people without water. The threat to human health was not hypothetical. Blue-green algae toxins in the drinking water at a dialysis center in Brazil caused 76 deaths from acute liver failure in a 1996 incident. Those toxins have also caused liver damage in children drinking from China’s Three Gorges Reservoir. In the United States, a 2015 study found evidence of blue-green algae blooms in 62 percent of the 3,100 U.S. counties surveyed and concluded that these blooms were “significantly related to the risk of non-alcoholic liver disease death.”

The problem with nitrogen is evident, finally, even on land. Atmospheric nitrogen – from intensive farming and livestock operations, power plants, road traffic, and other sources – now gets deposited everywhere, making soils more fertile. That has the paradoxical effect of reducing plant diversity by displacing native species adapted to nutrient-poor soils. A study last year in Proceedings of the National Academy of Sciences (PNAS) examined more than 15,000 forest, woodland, grassland, and shrubland sites across the United States and found that a quarter of them have already exceeded the nitrogen levels associated with species loss. Researchers don’t know yet how nitrogen and climate change together will affect plant diversity. But in an experiment in an arid southern California habitat, added nitrogen together with changing rainfall patterns caused a community of native shrubs to shift to non-native grasses.

 

Farmers are acutely aware of their leading role in this unfolding disaster. In Europe, they have managed to reduce nitrogen use substantially without any decrease in productivity over the past quarter century because of mandatory European Union limits. The United States has so far relied on a voluntary approach, with mixed results. But when the city of Des Moines, Iowa sued upstream farm counties two years ago for the cost of equipment to remove nitrogen runoff from its drinking water supply, many farmers heard alarm bells. (A federal court ultimately dismissed the lawsuit early this year.)

“I haven’t seen a willingness to engage in a conservation program like this in my lifetime,” says Nick Goeser, a soil scientist and director of the Soil Health Partnership. The issue resonates with farmers in part because applying nitrogen fertilizer accounts for up to half the cost of running a farm, and they would naturally prefer the expenditure to pay off in increased yield rather than have it wash away down the river. They recognize that nitrogen runoff is contaminating their own drinking water, says Goeser, and they have also noticed the effects of climate change on their crops.

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The Soil Health Partnership, which combines agribusiness funding with technical advice from the Environmental Defense Fund and the Nature Conservancy, works to scale up three solutions to the nitrogen problem—use of off-season cover crops to reduce the runoff that inevitably occurs when fields remain bare through the winter, low- or no-till farming, and “advanced nutrient management,” or what Goeser describes as “spoon-feeding” nitrogen in the precise amount and time that the plant needs it.

None of that is as simple as it may sound. For instance, use of cover crops “makes an incredible difference, with a 60-80 percent improvement in runoff,” says Goeser. It’s expensive, however, and could actually decrease corn or soybean yield the following year if the farmer does it wrong. It only starts to improve resilience to extreme weather events like flooding or drought, and thus yield, after three to five years. But in the Midwest, says Goeser, 60 percent of the acreage is operated on a one-year rental basis, meaning farmers have no incentive to invest in the long-term health of the land. Fewer than 5 percent of them plant cover crops.

Advanced nutrient management means switching from applying fertilizer in the fall to the spring, and not all at once in the spring, but in small doses throughout the season, with sensors indicating exactly how much nitrogen a specific section of field actually needs. But the 10-foot-high equipment to work with a growing crop is expensive.

The combined threat of climate change and nitrogen pollution could soon mandate far more dramatic changes in agriculture. Among the long-term solutions put forward by University of Victoria researchers in a companion piece to the new study in Science: Genetically-engineered cereals to fix nitrogen from the atmosphere, and laboratory cultured meat, to reduce the global herd from 1.5 billion head of cattle to a population of just 30,000 that will be used as stem-cell donors. Climate change means that it will be necessary, the co-authors note, to cut agricultural nitrogen use in the Mississippi River Valley not by 32 percent, as the U.S. Environmental Protection Agency now proposes, but by almost double that amount.

The challenge will be far greater in the developing world, particularly Asia. The Stanford-led research team identified three risk factors that make an area more vulnerable to the compounding effects of nitrogen pollution and climate change: heavy nitrogen inputs (mostly for agriculture), a high current rate of precipitation, and a large projected increase in precipitation because of climate change.

East, South, and Southeast Asia face the greatest peril, with India especially vulnerable “because it exhibits all three risk factors across more than two-thirds of its area … and has one of the fastest-growing populations.” People throughout the region “are heavily dependent on surface water supplies,” the researchers note. But as climate change multiplies the rate of nitrogen runoff, they may increasingly find their water undrinkable.

GettyImages-74916827_2000

Workers navigate through an algae bloom in Lake Taihu, China’s third largest freshwater lake. (Photo: LIU JIN/AFP/Getty Images)

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3 Responses to “Got Drinking Water? Watch Climate Change Turn It Toxic.”

  1. the major issue is how products are used, Nitrogen when used in natural organic form in small use with proper microbes in soils can benefit the environment & food production, we have found. The major issue is lake of soil microbes & education of it’s use, even earthworms can help change sandy ground into beneficially producing soils with addition of organic material as in rotted organic type wood by products. Several insects we have found can also help in production of plants

  2. Traveled from AMSTERDAM to BUDAPEST drove though Germany Austria & discovered how little people cared about the health of the planet. They all felt everything is fine, looking up at the sky, I would point out the toxic amount of CHEMTRAIL’s SCARING THE SKY, Asked people in Munich look at the sky? They would just look up respond by saying yes air planes! I would explain the toxic spraying of chemicals & people would look at me as if I was making it up. Then ask why are these planes criss x crossing the sky doing a grid pattern, yet people are blinded by not wanting to know, not wanting to rock the boat as they say.This is when I realize how little people care about the world, they are all slaves like robots just fill a void, nothing more nothing less. I still care and with no children maybe I shouldn’t care what happens but I care about Earth, she has made me, I am made up of her every cell in this body. At least before I go to next life maybe I can help now!
    SOILS have intrigued me as 1st I’m a grower 2nd I care about what I eat & soils is the first line of what type of plant it will benefit the best to that type of ground earth/soil! The problem is most extension agents promote Monsanto’s products, such as using Roundup in growing plants in fields to combat competing weeds. Advocating using Fertilizer in high amounts to produce good yields, while not taking into account pH or microbe present in soils. Even local landscapes around residential homes are mistreated not handled properly at all, the entire system is flawed heavily. What angers me the most, is people just don’t look farther than themselves, they don’t look at soils as living organic substance which needs nourishment, just like we do. Why is this so hard to understand? It’s important to create an environment which benefits all conditions of good growing mediums require. Keep forgetting about beneficial microbes & microbe producing insects such as earthworms. In southwest Florida sand soils we’ve been able to revitalize soils, grow rich black soils, by taking rotting organic matter like grounded down wood, local wood chippings, allowing methane gaseous to release, then allowed to rot. This process is excelled when we turn the wood ply over ever few weeks then after 3-4 months apply earthworm eggs, allow them to hatch. After a while apply this mulch to surface of sandy areas, 2 to 3 inches thick. After a while the top layer changes, microbes develop, earthworms help turn wood into food for plants & help microbes develop rapidly faster & faster.over time. Repeated layers every 6 months to 1 yr builds soil into rich health ground able to support any plant. We found the pH changes, once the sandy ground with pH of 8-9 becomes 6.5 to 7 after 1 yr. at 4 inches. Taking this material top rich ground & deeper sandy ground blending the two together when planting anything bigger than 1 gallon plants, then using this mixture as back fill, benefits the plant for a long time & with addition of this organic mulch applied every 1year allows nutrients to develop & little if no fertilizers are needed. Recycling our own organic matter is the key to developing positive soils, I don’t see any other way of handling waste s other than reusing all organic waste, but putting through a break-down process proir to applying it to any conditions.

  3. New study discusses the growing blue-green algae threat to drinking and recreational water bodies. Here’s the press release:

    Harmful algal blooms known to pose risks to human and environmental health in large freshwater reservoirs and lakes are projected to increase because of climate change, according to a team of researchers led by a Tufts University scientist.

    The team developed a modeling framework that predicts that the largest increase in cyanobacterial harmful algal blooms (CyanoHABs) would occur in the Northeast region of the United States, but the biggest economic harm would be felt by recreation areas in the Southeast.

    The research, which is published in print today in the journal Environmental Science & Technology, is part of larger, ongoing efforts among scientists to quantify and monetize the degree to which climate change will impact and damage various U.S. sectors.

    “Some of the biggest CyanoHAB impacts will occur in more rural regions, such as those in the Southeast and Midwest — areas that don’t often come up in conversation about unavoidable effects of climate change,” said Steven C. Chapra, Ph.D., lead author and Louis Berger Chair of Civil and Environmental Engineering in the School of Engineering at Tufts. “The impact of climate change goes way beyond warmer air temperatures, rising sea levels and melting glaciers.”

    “Our study shows that higher water temperature, changes in rainfall, and increased nutrient inputs will combine to cause more frequent occurrence of harmful algal blooms in the future,” he added.

    Cyanobacteria are the earth’s oldest oxygenic photosynthetic organisms. Throughout their 3.5 billion-year-old evolutionary history, these organisms have proven resilient and adaptable to a wide range of climates. Consequently, many cyanobacteria exhibit optimal growth and bloom potentials at high water temperatures relative to other aquatic plants. Therefore, global warming plays a key role in their expansion and persistence, said Chapra.

    In order to capture the range of possible futures, the analysis used climate change projections from five general circulation models, two greenhouse gas emission scenarios, and two cyanobacterial growth scenarios. It is among the few studies to combine climate projections with a hydrologic/water quality network model of U.S. lakes and reservoirs. The modeling approach is unique in its practice of coupling climate, hydrologic, and water quality models into a unified computational framework that is applied on a national scale.

    The model chain starts with projections of alternative future climates from General Circulation Models (GCMs). The GCM projections of temperature and precipitation are then entered into two other models:

    a rainfall-runoff model to simulate monthly runoff in each of the 2,119 watersheds of the continental U.S.; and
    a water demand model, which projects water requirements of each watershed’s municipal, industrial, and agriculture sectors. Given these runoff and demand projections, a water resources systems model produces a time series of reservoir storage, release, and demand allocations (e.g., agriculture, environmental flows, and hydropower).

    Finally, these water flows and reservoir states are entered into a water quality model to simulate a number of water quality characteristics, including cyanobacteria concentrations, in each of the nation’s waterbodies. The end result is a framework that can predict the combined impact of climate, population growth, and other factors on future water quality for different U.S. regions.

    It has been estimated that lakes and reservoirs serving as drinking water sources for 30 million to 48 million Americans may be contaminated periodically by algal toxins. Researchers cited an example in 2014, when nearly 500,000 residents of Toledo, Ohio, lost access to drinking water after water drawn from Lake Erie revealed the presence of cyanotoxins.

    Beyond the human health effects, CyanoHABs have a variety of negative consequences for aquatic ecosystems, including the creation of unsightly surface scums and a reduction in recreational use and access to shorelines. Also, because most cyanobacteria are inedible by zooplankton and planktivorous fish, they represent a “dead end” in the aquatic food chain — a scenario that ultimately hurts both commercial and recreational fishing industries.

    Chapra noted that the research indicates that as water temperatures increase, more stringent and costly nutrient controls would be necessary in order to maintain current water quality.

    “The study provides a framework that offers insights on cause and effect linkages to help support planning, policy, and identify data gaps for future research,” said Chapra.

    Story Source:

    Materials provided by Tufts University. Note: Content may be edited for style and length.

    Journal Reference:

    Steven C. Chapra, Brent Boehlert, Charles Fant, Victor J. Bierman, Jim Henderson, David Mills, Diane M. L. Mas, Lisa Rennels, Lesley Jantarasami, Jeremy Martinich, Kenneth M. Strzepek, Hans W. Paerl. Climate Change Impacts on Harmful Algal Blooms in U.S. Freshwaters: A Screening-Level Assessment. Environmental Science & Technology, 2017; 51 (16): 8933 DOI: 10.1021/acs.est.7b01498

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