
By Arthur Sullivan
When was the last time you traveled by plane? Various researchers say as little as between 5 and 10 percent of the global population fly in a given year.
But things are changing. According to International Civil Aviation Organization (ICAO) estimates, there were 3.7 billion global air passengers in 2016 — and every year since 2009 has been a new record-breaker.
By 2035, the International Air Transport Association (IATA) predicts a rise to 7.2 billion. Like the planes themselves, the numbers just keep going up. And given the damage flying does to the planet, that is food for thought.
Not Just the CO2
Many estimates put aviation's share of global CO2 emissions at just above 2 percent. That's the figure the industry itself generally accepts.
But according to Stefan Gössling, a professor at Sweden's Lund and Linnaeus universities and co-editor of the book Climate Change and Aviation: Issues, Challenges and Solutions, "That's only half the truth."
Other aviation emissions such as nitrogen oxides (NOx), water vapor, particulates, contrails and cirrus changes have additional warming effects.
"The sector makes a contribution to global warming that is at least twice the effect of CO2 alone," Gössling told DW, settling on an overall contribution of 5 percent "at minimum."
But IATA spokesperson Chris Goater told DW the science behind this so-called 'radiative forcing' is "unproven."
Even if we accept the 2 percent emissions figure as final, if only 3 percent of the world's population flew last year, that relatively small group still accounted for a disproportionate chunk of global emissions.
A few years ago, environmental group Germanwatch estimated that a single person taking one roundtrip flight from Germany to the Caribbean produces the same amount of damaging emissions as 80 average residents of Tanzania do in an entire year: around four metric tons of CO2.
"On an individual level, there is no other human activity that emits as much over such a short period of time as aviation, because it is so energy-intensive," Gössling explained.
The WWF carbon footprint calculator is instructive in this regard. Even a serious environmentalist who eats vegan, heats using solar power and rides a bike to work, but who still take the occasional flight, wouldn't look very green at all.
Just two hypothetical short-haul return flights and one long-haul round-trip in a given year would outweigh otherwise exemplary behavior.
New Tech Can't Solve Everything
As awareness of the need to reduce our individual and collective carbon footprints in order to prevent climate catastrophe grows, several industries have come under sustained pressure to find clean solutions.
The aviation sector made its own promises — in October 2016, 191 nations agreed a UN accord which aims to cut global aviation carbon emissions to 2020 levels by 2035. Another ambitious target of that agreement is for the aviation industry to achieve a 50 percent carbon emission reduction by 2050, compared to 2005 levels.
Goater says there are four ways in which the aviation industry intends to achieve these things: through carbon offsetting in the short-term, the continued development of more efficient planes, deeper investment in sustainable fuels — such as biofuels — and through better route efficiency.
"Basically air traffic control is very inefficient," he explained. "It creates unnecessary fuel burns and more efficient use would create a 10 percent reduction in emissions."
He also highlights the fact that a number — albeit very few — of commercial flights are now powered with sustainable fuels every day, despite the fact that the first such flight took off less than a decade ago.
"That was something that happened much faster than anyone was expecting," he says. The key now, in his view, is for the industry to prioritize investment in the area and for governments to commit in the same way they have to e-mobility in the automobile sector.
But Gössling and many of his peers remain unconvinced.
"I think that essentially we need price hikes," he said. "We did interviews with industry leaders a few months ago and many of them agreed, secretly — they were anonymous interviews — that if we don't have a major price hike for fossil fuels, then there is no way alternative fuels could ever make it."
Daniel Mittler, political director of environmental NGO Greenpeace, agrees that fossil fuels need to be more expensive. "The first step is to end all fossil fuel subsidies, including those going to aviation and to properly tax the aviation industry," he told DW.
For Goater, that is not realistic. "Fuel is already a significant proportion of an airline's costs," he said. "Believe me, if we could fly without oil we would."
The hard truth?
So what's to be done? Gössling, who has devoted more than 20 years of research to the subject, sees only one solution.
"Do we really need to fly as much as we do, or is the amount we fly induced by the industry?" he asked. In addition to artificially low airplane ticket prices, the industry also promotes a lifestyle, he argued.
"Airline campaigns project an image where you can become part of a group of people who are young, urban frequent flyers, visiting another city every few weeks for very low costs," he said.
Yet for Goater, the idea of dictating who can fly and when is as unrealistic as it is outdated.
"Reducing emissions needs to be balanced with allowing people the opportunity to fly — I believe that's a settled consensus amongst the mainstream for many years," he said. "It's not up to people in one part of the world to take it on themselves to deny people in other parts of the world those opportunities."
For Mittler, it comes down to individual choice as much as anything else and he believes that while efficiency gains are vital, the first step is to reduce the amount we fly.
"We need to move towards a more sharing and caring way of living on this planet," he said, adding that doing without the weekend shop in New York might be one of the least painful ways of contributing to that.
"We need a prosperity that is based on community and based on real wealth of collective vision, rather than one that is based on relentless consumption. Aviation is a symbol of the kind of consumption that we need to leave behind."
Reposted with permission from Deutsche Welle.
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By Suresh Dhaniyala and Byron Erath
A fast-spreading variant of the coronavirus that causes COVID-19 has been found in at least 10 states, and people are wondering: How do I protect myself now?
Airborne Particles Are Still the Biggest Problem
<p>The <a href="https://theconversation.com/why-it-matters-that-the-coronavirus-is-changing-and-what-this-means-for-vaccine-effectiveness-152383" target="_blank" rel="noopener noreferrer">SARS-CoV-2 variants</a> are believed to spread primarily through the air rather than on surfaces.</p><p>When someone with the coronavirus in their respiratory tract coughs, talks, sings or even just breathes, infectious respiratory droplets can be expelled into the air. These droplets are tiny, predominantly in the range of <a href="https://www.sciencedirect.com/science/article/pii/S0021850211001200?casa_token=KtyrsEfbeqcAAAAA:vv10sSxm33tzg0EQvNMIFtV7GCu5gE9QAzuyzHKr2_4Cl0OFkUJoGwzn4d0ZnEWS19NsOTuH" target="_blank" rel="noopener noreferrer">1-100 micrometers</a>. For comparison, a human hair is about 70 micrometers in diameter.</p><p>The larger droplets fall to the ground quickly, rarely traveling farther than 6 feet from the source. The bigger problem for disease transmission is the tiniest droplets – those less than 10 micrometers in diameter – which can remain suspended in the air as aerosols for <a href="https://academic.oup.com/cid/article/50/5/693/325466" target="_blank">hours at a time</a>.</p><span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="bb67b83dcafe589f350daf3df60fa29d"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/UNCNM7AZPFg?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
Daily case reports and 7-day rolling average as of Jan. 16, 2021.Chart: The Conversation, CC-BY-ND Source: COVID Tracking Project Get the data
What Can You Do to Stay Safe?
<p>1) Pay attention to the type of face mask you use, and how it fits.</p><p>Most off-the-shelf face coverings are not 100% effective at preventing droplet emission. With the new variant spreading more easily and likely infectious at lower concentrations, it's important to select coverings with materials that are most effective at stopping droplet spread.</p><p>When available, N95 and surgical masks consistently perform the best. Otherwise, face coverings that use <a href="https://www.sciencedirect.com/science/article/pii/S2352431620301802?casa_token=-Dj6nGBAm24AAAAA:qq9BpbzCKaPDFcV73ohA2fCnhE_Zlkss6Bei3kUwq9QYndhHj0Vafbbd-ef_855lx6knDfUt" target="_blank">multiple layers of material</a> are preferable. Ideally, the material should be a tight weave. High thread count cotton sheets are an example. Proper fit is also crucial, as gaps around the nose and mouth can <a href="https://pubs.acs.org/doi/10.1021/acsnano.0c03252" target="_blank" rel="noopener noreferrer">decrease the effectiveness by 50%</a>.</p><p>2) Follow social distancing guidelines.</p><p>While the current social distancing guidelines are not perfect – <a href="https://theconversation.com/what-a-smoky-bar-can-teach-us-about-the-6-foot-rule-during-the-covid-19-pandemic-145517" target="_blank" rel="noopener noreferrer">6 feet isn't always enough</a> – they do offer a useful starting point. Because aerosol concentrations levels and infectivity are highest in the space immediately surrounding anyone with the virus, increasing physical distancing can help reduce risk. Remember that people are infectious <a href="https://medical.mit.edu/faqs/COVID-19#faq-10" target="_blank" rel="noopener noreferrer">before they start showing symptoms</a>, and they many never show symptoms, so don't count on seeing signs of illness.</p><p>3) Think carefully about the environment when entering an enclosed area, both the ventilation and how people interact.</p><p>Limiting the size of gatherings helps reduce the potential for exposure. Controlling indoor environments in other ways can also be a highly effective strategy for reducing risk. This includes <a href="https://theconversation.com/what-a-smoky-bar-can-teach-us-about-the-6-foot-rule-during-the-covid-19-pandemic-145517" target="_blank" rel="noopener noreferrer">increasing ventilation rates</a> to bring in <a href="https://theconversation.com/keeping-indoor-air-clean-can-reduce-the-chance-of-spreading-coronavirus-149512" target="_blank" rel="noopener noreferrer">fresh air and filtering existing air</a> to dilute aerosol concentrations.</p><p>On a personal level, it is helpful to pay attention to the types of interactions that are taking place. For example, many individuals shouting can create a higher risk than one individual speaking. In all cases, it's important to minimize the amount of time spent indoors with others.</p><p>The CDC has warned that B.1.1.7 could <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7003e2.htm?s_cid=mm7003e2_w" target="_blank" rel="noopener noreferrer">become the dominant SARS-CoV-2 variant</a> in the U.S. by March. Other fast-spreading variants have also been found in <a href="https://virological.org/t/genomic-characterisation-of-an-emergent-sars-cov-2-lineage-in-manaus-preliminary-findings/586" target="_blank" rel="noopener noreferrer">Brazil</a> and <a href="https://www.who.int/csr/don/31-december-2020-sars-cov2-variants/en/" target="_blank" rel="noopener noreferrer">South Africa</a>. Increased vigilance and complying with health guidelines should continue to be of highest priority.</p>- FDA Approves First In-Home Test for Coronavirus - EcoWatch ›
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EcoWatch Daily Newsletter
By Tara Lohan
A key part of the United States' clean energy transition has started to take shape, but you may need to squint to see it. About 2,000 wind turbines could be built far offshore, in federal waters off the Atlantic Coast, in the next 10 years. And more are expected.
Threats to Birds
<p>One of the gravest threats facing birds is climate change, according to Audubon, which found that rising temperatures threaten <a href="https://www.audubon.org/2019climateissue" target="_blank" rel="noopener noreferrer">nearly two-thirds of North America's bird species</a>. That's why the impending development of offshore wind is a good thing, says Shilo Felton, a field manager in the organization's Clean Energy Initiative, but it also comes with dangers to birds that need to be better studied and mitigated.</p><p>The most obvious risk comes from birds colliding with spinning turbine blades. But offshore wind developments can also displace birds from foraging or roost sites, as well as migratory pathways.</p><p>Along the Atlantic Coast four imperiled species are of top concern to conservationists: the endangered piping plover, red knot, roseate tern and black-capped petrel, which is being considered for listing under the Endangered Species Act.</p><p>"Those four species are of utmost importance to make sure that we understand the impacts," says Felton. "But beyond that there are many species that are protected under the Migratory Bird Treaty Act and the Fish and Wildlife Conservation Act that could potentially see more impacts from offshore wind."</p><p>Northern gannets, for example, are at risk not just for collision but <a href="https://www.researchgate.net/publication/308703197_Possible_impacts_of_offshore_wind_farms_on_seabirds_a_pilot_study_in_Northern_Gannets_in_the_southern_North_Sea" target="_blank">habitat displacement</a>.</p>A northern gannet flying along Cape May, N.J. Ann Marie Morrison / CC BY-NC-ND 2.0
<p>"There's <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320716303196" target="_blank">some evidence</a> that they just won't use areas where turbines are, but that also excludes them from key foraging areas," says Felton. Researchers are still studying what this may mean for the birds. But a <a href="https://www.sciencedirect.com/science/article/pii/S0141113620305304" target="_blank">study</a> published in December 2020 conducted at Bass Rock, Scotland — home to the world's largest northern gannet colony — found that wind developments could reduce their growth rate, though not enough to cause a population decline.</p><p>Other birds, such as great cormorants and European shags, are <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320716303196" target="_blank">attracted to wind developments</a> and use the infrastructure to rest while opening up new foraging areas farther from shore.</p><p>"There's plenty of potential for a bird to use a wind farm and still to avoid the turbines themselves," says Felton.</p><p>Birds like pelicans, however, are less versatile in their movements and are at particular risk of collision because of their flight pattern, she says.</p><p>But how disruptive or dangerous offshore turbines will be along the East Coast isn't yet known.</p><p>Federal and state agencies, along with nongovernmental organizations, says Felton, have done good research to try to better understand those potential impacts. "But these are all theoretical, because we don't have a lot of offshore wind yet in the United States."</p>Threats to Ocean Life
<p>Birds aren't the only wildlife of concern. More development in ocean waters could affect a litany of marine species, some of which are already facing other pressures from overfishing, pollution, habitat destruction and climate change.</p><p>Scientists have found that marine mammals like whales and dolphins could be disturbed by the jarring sounds of construction, especially if pile driving is used to hammer the steel turbine platform into the seafloor.</p><p>The noises, though short-lived, could impede communication between animals, divert them from migration routes or cause them to seek less suitable areas for feeding or breeding. Research from Europe found that harbor porpoises, seals and dolphins may avoid development areas during construction. In most, but <a href="https://iopscience.iop.org/article/10.1088/1748-9326/7/4/045101" target="_blank">not all cases</a>, the animals were believed to have returned to the area following construction.</p><p>The biggest concern for conservation groups in the United States is the critically endangered North American right whale. There are fewer than 400 remaining, and the species' habitat overlaps with a number of planned wind development areas along the East Coast.</p><p>"Offshore wind is in no way the cause of the challenges the whales face, but it's going to be another pressure point," says John Rogers, senior energy analyst for the Union of Concerned Scientists.</p><p>Researchers aren't sure how right whales will respond to the noise from pile driving.</p><p>"But we are concerned, based on what we know about how whales react to other noise sources, that they may avoid [wind development] areas," says Kershaw.</p><p>And if that displacement causes them to miss out on important food resources, it could be dangerous for a species already on the brink.</p><p>There are a few other potential threats, too.</p><p>Ships associated with the development — more plentiful during construction — also pose a danger. In the past few years cargo ships, fishing boats and other vessels have caused half of all deaths of North Atlantic right whales.</p>A juvenile right whale breaches against the backdrop of a ship near the St. Johns River entrance. Florida Fish and Wildlife Conservation Commission / NOAA Research Permit #775-1600-10
<p>And after construction, the noise from the spinning turbines will be present in the water at low decibels. "We don't quite know how the great whales will react to those sounds," says Jeremy Firestone, the director of the Center for Research in Wind at the University of Delaware.</p><p>Other marine mammals may also perceive the noise, but at low decibels it's unlikely to be an impediment, <a href="http://www.int-res.com/abstracts/meps/v309/p279-295/" target="_blank">research has found</a>.</p><p>And it's possible that wind development could help some ocean life. Turbine foundations can attract fish and invertebrates for whom hard substrates create habitat complexity — known as the "reef effect," according to researchers from the University of Rhode Island's <a href="https://dosits.org/animals/effects-of-sound/anthropogenic-sources/wind-turbine/" target="_blank" rel="noopener noreferrer">Discovery of Sound in the Sea</a> program. Exclusion of commercial fishing nearby may also help shelter fish and protect marine mammals from entanglements in fishing gear.</p>Ensuring Safe Development
<p>Despite the potential dangers, researchers have gathered a few best practices to help diminish and possibly eliminate some risks.</p><p>When it comes to ship strikes, the easiest thing is to slow boats down, mandating a speed of <a href="https://biologicaldiversity.org/w/news/press-releases/vessel-speed-limits-sought-protect-endangered-north-atlantic-right-whales-2020-08-06/" target="_blank">10 knots</a> in wind development areas, and using visual and acoustic monitoring for whales.</p><p>Adjusting operations to reduce boat trips between the shore and the wind development will also help. A new series of service operating vessels can allow maintenance staff to spent multiple days onsite, says Kershaw, cutting down on boat traffic.</p><p>For construction noise concerns, developers can avoid pile driving during times of the year when whales are present. And, depending on the marine environment, developers could use "quiet foundations" that don't require pile driving. These include gravity-based or suction caisson platforms.</p><p>Floating turbines are also used in deep water, where they're effectively anchored in place — although that poses its own potential danger. "We have concerns that marine debris could potentially become entangled around the mooring cables of the floating arrays and pose a secondarily entanglement risk to some species," says Felton, who thinks more research should be conducted before those become operational in U.S. waters — a process that's already underway in Maine, where a <a href="https://composites.umaine.edu/2020/08/05/diamond-offshore-wind-rwe-renewables-join-the-university-of-maine-to-lead-development-of-maine-floating-offshore-wind-demonstration-project/" target="_blank" rel="noopener noreferrer">demonstration project is being built</a>.</p><p>If loud noises are unavoidable during construction, noise-reducing technologies such as bubble curtains can help dampen the sound. And scheduling adjacent projects to conduct similar work at the same time could limit the duration of disturbances.</p>The foundation installation of the off shore wind farm Sandbank using a bubble curtain. Vattenfall / Ulrich Wirrwa / CC BY-NC-ND 2.0
<p>Once turbines become operational, reducing the amount of light on wind platforms or using flashing lights could help deter some seabirds, NRDC <a href="https://www.nrdc.org/sites/default/files/harnessing-wind-advance-wind-power-offshore-ib.pdf" target="_blank" rel="noopener noreferrer">researchers reported</a>. And scientists are exploring using ultrasonic noises and ultraviolet lighting to keep bats away. "Feathering," or shutting down the turbine blades during key migration times, could also help prevent fatalities.</p><p>"We need to make sure that offshore wind is the best steward it can be of the marine ecosystem, because we want and expect it to be a significant part of the clean energy picture in some parts of the country," says Rogers. "We also have to recognize that we're going to learn by doing, and that some of these things we're going to figure out best once we have more turbines in the water."</p><p>That's why environmental groups say it's important to establish baseline information on species before projects begin, and then require developers to conduct monitoring during construction and for years after projects are operational.</p><p>Employing an "adaptive management framework" will ensure that developers can adjust their management practices as they go when new information becomes available, and that those best practices are incorporated into the requirements for future projects.</p>Putting Research Into Action
<p>Advancing these conversations at the federal level during the Trump administration, though, has been slow going.</p><p>"We didn't really have any productive discussions with the administration in the last four years," says Kershaw.</p><p>And when it comes to birds, Felton says the Bureau of Ocean Energy Management's recently completed "draft cumulative environmental impact statement" covering offshore wind developments had a lot of good environmental research, but little focus on birds.</p><p>"Part of that comes from the current administration's interpretation of the Migratory Bird Treaty Act," she says.</p><p>President Trump has been hostile to both wind energy <em>and</em> birds, <a href="https://www.nytimes.com/2021/01/05/climate/trump-migratory-bird-protections.html" target="_blank">and finished gutting the Migratory Bird Treaty Act</a> in his administration's the final days, removing penalties for companies whose operations kill migratory birds.</p><p>There's hope that the Biden administration will take a different approach. But where the federal government has been lacking lately, Kershaw says, they've seen states step up.</p><p>New York, for example, has established an <a href="https://www.nyetwg.com/" target="_blank" rel="noopener noreferrer">Environmental Technical Working Group</a> composed of stakeholders to advise on environmentally responsible development of offshore wind.</p><p>The group is led by the New York State Energy Research and Development Authority, but it isn't limited to the Empire State. It's regional in focus and includes representatives from wind developers with leases between Massachusetts and North Carolina; state agencies from Massachusetts to Virginia; federal agencies; and science-based environmental NGOs.</p><p>New York's latest solicitation for clean energy projects includes up to 2,500 megawatts of offshore wind and <a href="https://www.nyetwg.com/announcements" target="_blank" rel="noopener noreferrer">requires developers</a> to contribute at least $10,000 per megawatt for regional monitoring of fisheries and other wildlife.</p><p>Environmental groups have also worked directly with developers, including an agreement with Vineyard Wind — an 800-megawatt project off the Massachusetts coast that could be the first utility-scale wind development in federal waters — to help protect North Atlantic right whales.</p><p>The agreement includes no pile driving from Jan. 1 to April 30, ceasing activities at other times when whales are visually or acoustically identified in the area, speed restrictions on vessels, and the use of noise reduction technology, such as a bubble curtain during pile driving.</p><p>"The developers signed the agreement with us, and then they incorporated, most, if not all of those measures into the federal permitting documents," says Kershaw. "The developers really did a lot of bottom up work to make sure that they were being very protective of right whales."</p><p>Environmental groups are in talks with other developers on agreements too, but Felton wants to see best practices being mandated at the federal level.</p><p>"It's the sort of a role that should be being played by the federal government, and without that it makes the permitting and regulation process less stable and less transparent," she says." And that in turn slows down the build out of projects, which is also bad for birds because it doesn't help us address and mitigate for climate change."</p><p>Kershaw agrees there's a lot more work to be done, especially at the federal level, but thinks we're moving in the right direction.</p><p>"I think the work that's been done so far in the United States has really laid the groundwork for advancing this in the right way and in a way that's protective of species and the environment," she says. "At the same time, it's important that offshore wind does advance quickly. We really need it to help us combat the worst effects of climate change."</p><p><em><a href="https://therevelator.org/author/taralohan/" target="_blank" rel="noopener noreferrer">Tara Lohan</a> is deputy editor of The Revelator and has worked for more than a decade as a digital editor and environmental journalist focused on the intersections of energy, water and climate. Her work has been published by The Nation, American Prospect, High Country News, Grist, Pacific Standard and others. She is the editor of two books on the global water crisis.</em></p><p><em style="">Reposted with permission from <a href="https://therevelator.org/offshore-wind-wildlife" target="_blank" style="">The Revelator</a>. </em></p>- U.S. Offshore Wind Power Blown on Course - EcoWatch ›
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Trending
Cities Can Help Migrating Birds on Their Way By Planting More Trees and Turning Lights Off at Night
By Frank La Sorte and Kyle Horton
Millions of birds travel between their breeding and wintering grounds during spring and autumn migration, creating one of the greatest spectacles of the natural world. These journeys often span incredible distances. For example, the Blackpoll warbler, which weighs less than half an ounce, may travel up to 1,500 miles between its nesting grounds in Canada and its wintering grounds in the Caribbean and South America.
Blackpoll warbler abundance in breeding, non-breeding and migration seasons. Cornell Lab of Ornithology / CC BY-ND
<p>For many species, these journeys take place at night, when skies typically are calmer and predators are less active. Scientists do not have a good understanding yet of how birds navigate effectively at night over long distances.</p><p><span></span>We study bird migration and how it is being affected by factors ranging from <a href="https://scholar.google.com/citations?user=S04C3UMAAAAJ&hl=en" target="_blank">climate change</a> to <a href="https://scholar.google.com/citations?user=pPk38-8AAAAJ&hl=en" target="_blank">artificial light at night</a>. In a recent study, we used millions of bird observations by citizen scientists to document the <a href="https://doi.org/10.1016/j.envpol.2020.116085" target="_blank">occurrence of migratory bird species in 333 U.S. cities</a> during the winter, spring, summer and autumn.</p>Blackpoll warbler. PJTurgeon / Wikipedia
<p>We used this information to determine how the number of migratory bird species varies based on each city's level of <a href="https://www.britannica.com/science/light-pollution" target="_blank" rel="noopener noreferrer">light pollution</a> – brightening of the night sky caused by artificial light sources, such as buildings and streetlights. We also explored how species numbers vary based on the quantity of tree canopy cover and impervious surface, such as concrete and asphalt, within each city. Our findings show that cities can help migrating birds by planting more trees and reducing light pollution, especially during spring and autumn migration.</p>Declining Bird Populations
<p>Urban areas contain numerous dangers for migratory birds. The biggest threat is the risk of <a href="https://doi.org/10.1650/CONDOR-13-090.1" target="_blank">colliding with buildings or communication towers</a>. Many migratory bird populations have <a href="http://dx.doi.org/10.1126/science.aaw1313" target="_blank">declined over the past 50 years</a>, and it is possible that light pollution from cities is contributing to these losses.</p><p>Scientists widely agree that light pollution can <a href="https://doi.org/10.1073/pnas.1708574114" target="_blank">severely disorient migratory birds</a> and make it hard for them to navigate. Studies have shown that birds will cluster around brightly lit structures, much like insects flying around a porch light at night. Cities are the <a href="https://doi.org/10.1002/fee.2029" target="_blank" rel="noopener noreferrer">primary source of light pollution for migratory birds</a>, and these species tend to be more abundant within cities <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13792" target="_blank" rel="noopener noreferrer">during migration</a>, especially in <a href="https://doi.org/10.1016/j.landurbplan.2020.103892" target="_blank" rel="noopener noreferrer">city parks</a>.</p>Composite image of the continental U.S. at night from satellite photos. NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center
The Power of Citizen Science
<p>It's not easy to observe and document bird migration, especially for species that migrate at night. The main challenge is that many of these species are very small, which limits scientists' ability to use electronic tracking devices.</p><p>With the growth of the internet and other information technologies, new data resources are becoming available that are making it possible to overcome some of these challenges. <a href="https://doi.org/10.1038/d41586-018-07106-5" target="_blank">Citizen science initiatives</a> in which volunteers use online portals to enter their observations of the natural world have become an important resource for researchers.</p><p>One such initiative, <a href="https://ebird.org/home" target="_blank" rel="noopener noreferrer">eBird</a>, allows bird-watchers around the globe to share their observations from any location and time. This has produced one of the <a href="https://doi.org/10.1111/ecog.04632" target="_blank" rel="noopener noreferrer">largest ecological citizen-science databases in the world</a>. To date, eBird contains over 922 million bird observations compiled by over 617,000 participants.</p>Light Pollution Both Attracts and Repels Migratory Birds
<p>Migratory bird species have evolved to use certain migration routes and types of habitat, such as forests, grasslands or marshes. While humans may enjoy seeing migratory birds appear in urban areas, it's generally not good for bird populations. In addition to the many hazards that exist in urban areas, cities typically lack the food resources and cover that birds need during migration or when raising their young. As scientists, we're concerned when we see evidence that migratory birds are being drawn away from their traditional migration routes and natural habitats.</p><p>Through our analysis of eBird data, we found that cities contained the greatest numbers of migratory bird species during spring and autumn migration. Higher levels of light pollution were associated with more species during migration – evidence that light pollution attracts migratory birds to cities across the U.S. This is cause for concern, as it shows that the influence of light pollution on migratory behavior is strong enough to increase the number of species that would normally be found in urban areas.</p><p>In contrast, we found that higher levels of light pollution were associated with fewer migratory bird species during the summer and winter. This is likely due to the scarcity of suitable habitat in cities, such as large forest patches, in combination with the adverse affects of light pollution on bird behavior and health. In addition, during these seasons, migratory birds are active only during the day and their populations are largely stationary, creating few opportunities for light pollution to attract them to urban areas.</p>Trees and Pavement
<p>We found that tree canopy cover was associated with more migratory bird species during spring migration and the summer. Trees provide important habitat for migratory birds during migration and the breeding season, so the presence of trees can have a strong effect on the number of migratory bird species that occur in cities.</p><p>Finally, we found that higher levels of impervious surface were associated with more migratory bird species during the winter. This result is somewhat surprising. It could be a product of the <a href="https://www.epa.gov/heatislands" target="_blank">urban heat island effect</a> – the fact that structures and paved surfaces in cities absorb and reemit more of the sun's heat than natural surfaces. Replacing vegetation with buildings, roads and parking lots can therefore make cities significantly warmer than surrounding lands. This effect could reduce cold stress on birds and increase food resources, such as insect populations, during the winter.</p><p>Our research adds to our understanding of how conditions in cities can both help and hurt migratory bird populations. We hope that our findings will inform urban planning initiatives and strategies to reduce the harmful effects of cities on migratory birds through such measures as <a href="https://www.arborday.org/programs/treecityusa/index.cfm" target="_blank" rel="noopener noreferrer">planting more trees</a> and initiating <a href="https://aeroecolab.com/uslights" target="_blank" rel="noopener noreferrer">lights-out programs</a>. Efforts to make it easier for migratory birds to complete their incredible journeys will help maintain their populations into the future.</p><p><em><span style="background-color: initial;"><a href="https://theconversation.com/profiles/frank-la-sorte-1191494" target="_blank">Frank La Sorte</a> is a r</span>esearch associate at the </em><em>Cornell Lab of Ornithology, Cornell University. <a href="https://theconversation.com/profiles/kyle-horton-1191498" target="_blank">Kyle Horton</a> is an assistant professor of Fish, Wildlife, and Conservation Biology at the Colorado State University.</em></p><p><em></em><em>Disclosure statement: Frank La Sorte receives funding from The Wolf Creek Charitable Foundation and the National Science Foundation (DBI-1939187). K</em><em>yle Horton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</em></p><p><em>Reposted with permission from <a href="https://theconversation.com/cities-can-help-migrating-birds-on-their-way-by-planting-more-trees-and-turning-lights-off-at-night-152573" target="_blank">The Conversation</a>. </em></p>By Lynne Peeples
Editor's note: This story is part of a nine-month investigation of drinking water contamination across the U.S. The series is supported by funding from the Park Foundation and Water Foundation. Read the launch story, "Thirsting for Solutions," here.
In late September 2020, officials in Wrangell, Alaska, warned residents who were elderly, pregnant or had health problems to avoid drinking the city's tap water — unless they could filter it on their own.
Unintended Consequences
<p>Chemists first discovered disinfection by-products in treated drinking water in the 1970s. The trihalomethanes they found, they determined, had resulted from the reaction of chlorine with natural organic matter. Since then, scientists have identified more than 700 additional disinfection by-products. "And those only represent a portion. We still don't know half of them," says Richardson, whose lab has identified hundreds of disinfection by-products. </p>What’s Regulated and What’s Not?
<p>The U.S. Environmental Protection Agency (EPA) currently regulates 11 disinfection by-products — including a handful of trihalomethanes (THM) and haloacetic acids (HAA). While these represent only a small fraction of all disinfection by-products, EPA aims to use their presence to indicate the presence of other disinfection by-products. "The general idea is if you control THMs and HAAs, you implicitly or by default control everything else as well," says Korshin.</p><p>EPA also requires drinking water facilities to use techniques to reduce the concentration of organic materials before applying disinfectants, and regulates the quantity of disinfectants that systems use. These rules ultimately can help control levels of disinfection by-products in drinking water.</p>Click the image for an interactive version of this chart on the Environmental Working Group website.
<p>Still, some scientists and advocates argue that current regulations do not go far enough to protect the public. Many question whether the government is regulating the right disinfection by-products, and if water systems are doing enough to reduce disinfection by-products. EPA is now seeking public input as it considers potential revisions to regulations, including the possibility of regulating additional by-products. The agency held a <a href="https://www.epa.gov/dwsixyearreview/potential-revisions-microbial-and-disinfection-byproducts-rules" target="_blank">two-day public meeting</a> in October 2020 and plans to hold additional public meetings throughout 2021.</p><p>When EPA set regulations on disinfection by-products between the 1970s and early 2000s, the agency, as well as the scientific community, was primarily focused on by-products of reactions between organics and chlorine — historically the most common drinking water disinfectant. But the science has become increasingly clear that these chlorinated chemicals represent a fraction of the by-product problem.</p><p>For example, bromide or iodide can get caught up in the reaction, too. This is common where seawater penetrates a drinking water source. By itself, bromide is innocuous, says Korshin. "But it is extremely [reactive] with organics," he says. "As bromide levels increase with normal treatment, then concentrations of brominated disinfection by-products will increase quite rapidly."</p><p><a href="https://pubmed.ncbi.nlm.nih.gov/15487777/" target="_blank">Emerging</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b05440" target="_blank" rel="noopener noreferrer">data</a> indicate that brominated and iodinated by-products are potentially more harmful than the regulated by-products.</p><p>Almost half of the U.S. population lives within 50 miles of either the Atlantic or Pacific coasts, where saltwater intrusion can be a problem for drinking water supplies. "In the U.S., the rule of thumb is the closer to the sea, the more bromide you have," says Korshin, noting there are also places where bromide naturally leaches out from the soil. Still, some coastal areas tend to be spared. For example, the city of Seattle's water comes from the mountains, never making contact with seawater and tending to pick up minimal organic matter.</p><p>Hazardous disinfection by-products can also be an issue with desalination for drinking water. "As <a href="https://ensia.com/features/can-saltwater-quench-our-growing-thirst/" target="_blank" rel="noopener noreferrer">desalination</a> practices become more economical, then the issue of controlling bromide becomes quite important," adds Korshin.</p>Other Hot Spots
<p>Coastal areas represent just one type of hot spot for disinfection by-products. Agricultural regions tend to send organic matter — such as fertilizer and animal waste — into waterways. Areas with warmer climates generally have higher levels of natural organic matter. And nearly any urban area can be prone to stormwater runoff or combined sewer overflows, which can contain rainwater as well as untreated human waste, industrial wastewater, hazardous materials and organic debris. These events are especially common along the East Coast, notes Sydney Evans, a science analyst with the nonprofit Environmental Working Group (EWG, a collaborator on <a href="https://ensia.com/ensia-collections/troubled-waters/" target="_blank">this reporting project</a>).</p><p>The only drinking water sources that might be altogether free of disinfection by-products, suggests Richardson, are private wells that are not treated with disinfectants. She used to drink water from her own well. "It was always cold, coming from great depth through clay and granite," she says. "It was fabulous."</p><p>Today, Richardson gets her water from a city system that uses chloramine.</p>Toxic Treadmill
<p>Most community water systems in the U.S. use chlorine for disinfection in their treatment plant. Because disinfectants are needed to prevent bacteria growth as the water travels to the homes at the ends of the distribution lines, sometimes a second round of disinfection is also added in the pipes.</p><p>Here, systems usually opt for either chlorine or chloramine. "Chloramination is more long-lasting and does not form as many disinfection by-products through the system," says Steve Via, director of federal relations at the American Water Works Association. "Some studies show that chloramination may be more protective against organisms that inhabit biofilms such as Legionella."</p>Alternative Approaches
<p>When he moved to the U.S. from Germany, Prasse says he immediately noticed the bad taste of the water. "You can taste the chlorine here. That's not the case in Germany," he says.</p><p>In his home country, water systems use chlorine — if at all — at lower concentrations and at the very end of treatment. In the Netherlands, <a href="https://dwes.copernicus.org/articles/2/1/2009/dwes-2-1-2009.pdf" target="_blank">chlorine isn't used at all</a> as the risks are considered to outweigh the benefits, says Prasse. He notes the challenge in making a convincing connection between exposure to low concentrations of disinfection by-products and health effects, such as cancer, that can occur decades later. In contrast, exposure to a pathogen can make someone sick very quickly.</p><p>But many countries in Europe have not waited for proof and have taken a precautionary approach to reduce potential risk. The emphasis there is on alternative approaches for primary disinfection such as ozone or <a href="https://www.pbs.org/wgbh/nova/article/eco-friendly-way-disinfect-water-using-light/" target="_blank" rel="noopener noreferrer">ultraviolet light</a>. Reverse osmosis is among the "high-end" options, used to remove organic and inorganics from the water. While expensive, says Prasse, the method of forcing water through a semipermeable membrane is growing in popularity for systems that want to reuse wastewater for drinking water purposes.</p><p>Remucal notes that some treatment technologies may be good at removing a particular type of contaminant while being ineffective at removing another. "We need to think about the whole soup when we think about treatment," she says. What's more, Remucal explains, the mixture of contaminants may impact the body differently than any one chemical on its own. </p><p>Richardson's preferred treatment method is filtering the water with granulated activated carbon, followed by a low dose of chlorine.</p><p>Granulated activated carbon is essentially the same stuff that's in a household filter. (EWG recommends that consumers use a <a href="https://www.ewg.org/tapwater/reviewed-disinfection-byproducts.php#:~:text=EWG%20recommends%20using%20a%20home,as%20trihalomethanes%20and%20haloacetic%20acids." target="_blank" rel="noopener noreferrer">countertop carbon filter</a> to reduce levels of disinfection by-products.) While such a filter "would remove disinfection by-products after they're formed, in the plant they remove precursors before they form by-products," explains Richardson. She coauthored a <a href="https://pubs.acs.org/doi/10.1021/acs.est.9b00023" target="_blank" rel="noopener noreferrer">2019 paper</a> that concluded the treatment method is effective in reducing a wide range of regulated and unregulated disinfection by-products.</p><br>Greater Cincinnati Water Works installed a granulated activated carbon system in 1992, and is still one of relatively few full-scale plants that uses the technology. Courtesy of Greater Cincinnati Water Works.
<p>Despite the technology and its benefits being known for decades, relatively few full-scale plants use granulated active carbon. They often cite its high cost, Richardson says. "They say that, but the city of Cincinnati [Ohio] has not gone bankrupt using it," she says. "So, I'm not buying that argument anymore."</p><p>Greater Cincinnati Water Works installed a granulated activated carbon system in 1992. On a video call in December, Jeff Swertfeger, the superintendent of Greater Cincinnati Water Works, poured grains of what looks like black sand out of a glass tube and into his hand. It was actually crushed coal that has been baked in a furnace. Under a microscope, each grain looks like a sponge, said Swertfeger. When water passes over the carbon grains, he explained, open tunnels and pores provide extensive surface area to absorb contaminants.</p><p>While the granulated activated carbon initially was installed to address chemical spills and other industrial contamination concerns in the Ohio River, Cincinnati's main drinking water source, Swertfeger notes that the substance has turned out to "remove a lot of other stuff, too," including <a href="https://ensia.com/features/drinking-water-contamination-pfas-health/" target="_blank" rel="noopener noreferrer">PFAS</a> and disinfection by-product precursors.</p><p>"We use about one-third the amount of chlorine as we did before. It smells and tastes a lot better," he says. "The use of granulated activated carbon has resulted in lower disinfection by-products across the board."</p><p>Richardson is optimistic about being able to reduce risks from disinfection by-products in the future. "If we're smart, we can still kill those pathogens and lower our chemical disinfection by-product exposure at the same time," she says.</p><p><em>Reposted with permission from </em><em><a href="https://ensia.com/features/drinking-water-disinfection-byproducts-pathogens/" target="_blank">Ensia</a>. </em><a href="https://www.ecowatch.com/r/entryeditor/2649953730#/" target="_self"></a></p>At a time of impending global food scarcity, cell-based meats and seafood have been heralded as the future of food.
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