Can Nature Help Curb Climate Change?
By Amanda Paulson
Just off Highway 880 at the edge of Hayward, the cityscape changes abruptly. Businesses and parking lots give way to large swaths of pickle grass and pools of water stretching out to the eastern edge of the San Francisco Bay.
On a recent sunny, windy March day – just before COVID-19 sent the Bay Area into lockdown – Dave Halsing stood on the trails at Eden Landing Ecological Reserve and pointed out what used to be old industrial salt ponds. He noted how they're gradually being restored into a rich mosaic of tidal wetlands and other ecosystems in the South Bay Salt Pond Restoration Project.
Little by little, he explains, over 15,000 acres of salt ponds – largely ecological dead zones that had been transferred from industrial companies to the state – are being brought back to functional ecosystems. They provide important habitat for species like the Western snowy plover and California least tern, add recreational trails for Bay Area residents, and provide flood protection for the San Francisco Bay – a needed adaptation in an era of rising seas. "It's inspiring but challenging," says Mr. Halsing, the executive project manager.
The work to restore the Bay Area's tidal marshes is just one example of a strategy that has been gaining attention in the past few years from climate change experts. Often described as "nature-based climate solutions," this strategy encompasses a wide range of conservation and restoration approaches involving trees, mangroves, soil, and marshlands.
Many current projects – like the South Bay Salt Pond Restoration Project – have locally targeted goals: improved habitat for species or resilience to climate change-related events like hurricanes, floods, or fire. But investing in such approaches at a large scale has another potential benefit, too, say experts: harnessing the natural ability of trees, plants, and soil to store carbon.
"Nature figured out how to solve the toxic carbon dioxide problem 3 billion years ago when it invented photosynthesis, and we're trying to invent similar processes now to solve carbon dioxide in the atmosphere. So why not use nature," explains Peter Ellis, a forest carbon scientist with The Nature Conservancy, who co-authored a landmark study in 2017 showing that natural climate solutions could accomplish about one-third of the mitigation work required in the next decade to keep warming below 2 degrees Celsius.
Could Planting One Trillion Trees Actually Work?
Those promoting natural climate solutions emphasize that it's just one piece of a puzzle that also requires a major shift away from fossil fuels and carbon-based energy. But many experts are seeing these natural solutions as low-hanging fruit that have yet to be tapped at a large scale.
In January, the World Economic Forum launched the ambitious One Trillion Trees initiative, with the goal of planting and conserving 1 trillion trees around the globe in the coming decade. Even President Donald Trump signed on.
The initiative has received some criticism, even among climate activists, who worry it's overly simplistic, takes emphasis off of the energy shift that needs to happen, and will encourage poorly conceived projects that might perpetuate other environmental issues.
And some climate experts have argued that the claims made by natural-solutions proponents in general are lofty and overly optimistic – that they couldn't come close to reducing carbon dioxide at the magnitude some studies have found.
But those debates, ultimately, are unproductive, says James Mulligan, a senior associate in the World Resources Institute's food, forests, and water program. Climate solutions, he notes, aren't a zero-sum game. Nature-based solutions won't ever be enough on their own, says Mr. Mulligan, but they have some big upsides, particularly that most are relatively low cost, some have more bipartisan appeal, and many are "win-win," with none of the "losers" that can be a byproduct of other strategies.
"The question for me is: would this help? And the answer is yes," says Mr. Mulligan. "Do I think we can restore a trillion trees to the planet? Probably not. ... In the U.S., our analysis shows we could restore 60 billion trees to the American landscape." That, he says, would be a "tall order," but would remove about a half a gigaton of CO2 per year.
"That's a meaningful wedge," he says. "And that's just one nature-based solution."
Protection Before Planting?
All trees – and all nature-based solutions – aren't created equal. And many advocates stress that it makes sense to focus on the ecosystems with the most to offer, or the methods that yield the biggest dividends.
"We need to protect first, to hold the line," says Mr. Ellis of The Nature Conservancy, explaining that he views good management of existing ecosystems as being even more important than restoration.
Certain ecosystems, like mangroves and peatlands, are of vital importance to conserve, says Will Turner, senior vice president of global strategies for Conservation International. In those ecosystems, the soil stores so much carbon that losing much more of it in coming years would be devastating, he says.
But to Dr. Turner, conservation and restoration are two sides of a coin, both necessary. Protecting critical ecosystems like tropical forests and mangroves that are being destroyed at a steady rate is crucial in terms of reducing current emissions, he says. But removing carbon dioxide already in the atmosphere is also necessary, if there is any hope of keeping warming below 2 degrees Celsius.
"We have a long way to go before we have any technology that is capable of removing CO2 from the atmosphere at scale except trees," says Dr. Turner. "We'd be foolish not to invest incredibly heavily in regrowing forests."
Despite all the potential of natural climate solutions, most of the examples being tried so far are at a relatively small scale.
WRI's plan for 60 billion trees planted in the U.S. over the next 20 years, Mr. Mulligan notes, would require about $4 billion a year in federal subsidies. But many of these efforts are "happening at the pace and scale of the conservation sector," he says. And that figure, while relatively modest in terms of government spending, is far beyond what the nonprofit community can handle.
Dr. Turner, of Conservation International, agrees. What the conservation community has done well, he says, is shown how these projects can work, how technology can be used to monitor and verify emissions reductions, and how financial mechanisms can allow governments or corporations to invest in these strategies.
Discovering an Ecosystem in Every Backyard
Meanwhile, part of the beauty of nature-based solutions, Dr. Turner says, is that – while some may certainly have more payoff than others in terms of climate mitigation – "there is something that can happen anywhere. Every community has an option to protect a forest or grow a forest or protect a grassland, or to better manage grazing lands so you can get greater carbon stored in the soil."
And many of those solutions – like the marsh restoration taking place in the San Francisco Bay – offer significant local benefits that go far beyond potential emissions reduction: habitat for endangered species, cleaner air and water, recreation opportunities for residents, flood risk mitigation at a time of rising seas.
In the Bay Area, emissions mitigation isn't a real driver of the restoration work, and the carbon market for wetlands isn't as robust as that for forests. But that doesn't mean those benefits don't exist, says Letitia Grenier, co-director of the Resilient Landscapes Program for the San Francisco Estuary Institute.
In her role at the institute, Dr. Grenier looks for creative ways to harness the natural benefits of ecosystems in ways that work for both people and nature – and they are plentiful, she says.
"One of the things climate change has shown us is that we live in ecosystems," says Dr. Grenier. "Not only do we impact ecosystems, but our ecosystem impacts us." In many instances, she says, when she looks at, say, a large watershed, the system is essentially broken. Too many discordant elements have been introduced.
"Suddenly, our system is not working for us," says Dr. Grenier. "Climate change is creating the realization of that, and the opportunity to fix it."
This story originally appeared in The Christian Science Monitor and is republished here as part of Covering Climate Now, a global journalism collaboration strengthening coverage of the climate story.
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EcoWatch Daily Newsletter
Farmers are the stewards of our planet's precious soil, one of the least understood and untapped defenses against climate change. Because of its massive potential to store carbon and foundational role in growing our food supply, soil makes farming a solution for both climate change and food security.
Soil can act as a natural "carbon sink." Climate Central, 2019
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By Shelly Miller
The vast majority of SARS-CoV-2 transmission occurs indoors, most of it from the inhalation of airborne particles that contain the coronavirus. The best way to prevent the virus from spreading in a home or business would be to simply keep infected people away. But this is hard to do when an estimated 40% of cases are asymptomatic and asymptomatic people can still spread the coronavirus to others.
It’s All About Fresh, Outside Air<p>The safest indoor space is one that constantly has lots of <a href="https://www.epa.gov/indoor-air-quality-iaq/how-does-outdoor-air-enter-building" target="_blank">outside air</a> replacing the stale air inside.</p><p>In commercial buildings, <a href="https://www.ncbi.nlm.nih.gov/books/NBK143277/" target="_blank">outside air is usually pumped in</a> through heating, ventilating and air-conditioning (HVAC) systems. In <a href="https://www.epa.gov/indoor-air-quality-iaq/how-does-outdoor-air-enter-building" target="_blank">homes, outside air gets in</a> through open windows and doors, in addition to seeping in through various nooks and crannies.</p><p>Simply put, the more fresh, outside air inside a building, the better. Bringing in this air dilutes any contaminant in a building, whether a virus or a something else, and <a href="https://doi.org/10.1111/j.1600-0668.2010.00703.x" target="_blank">reduces the exposure of anyone inside</a>. Environmental engineers like me quantify how much outside air is getting into a building using a measure called the <a href="https://doi.org/10.1038/jes.2013.30" target="_blank">air exchange rate</a>. This number quantifies the number of times the air inside a building gets replaced with air from outside in an hour.</p><p>While the exact rate depends on the number of people and size of the room, most experts consider roughly <a href="https://doi.org/10.1034/j.1600-0668.2002.01145.x" target="_blank">six air changes an hour</a> to be good for a 10-foot-by-10-foot room with three to four people in it. In a pandemic this should be higher, with one study from 2016 suggesting that an exchange rate of nine times per hour <a href="https://doi.org/10.1177%2F1420326X16631596" target="_blank">reduced the spread of SARS, MERS and H1N1</a> in a Hong Kong hospital.</p><p>Many buildings in the U.S., <a href="https://doi.org/10.1111/ina.12403" target="_blank">especially schools</a>, do not meet recommended ventilation rates. Thankfully, it can be pretty easy to get more outside air into a building. Keeping <a href="https://doi.org/10.1016/S0960-1481(99)00012-9" target="_blank">windows and doors open</a> is a good start. Putting a box fan in a window blowing out can greatly increase air exchange too. In buildings that don't have operable windows, you can change the mechanical ventilation system to increase how much air it is pumping. But in any room, the more people inside, the faster the air should be replaced.</p>
Using CO2 to Measure Air Circulation<p>So how do you know if the room you're in has enough air exchange? It's actually a pretty hard number to calculate. But there's an easy-to-measure proxy that can help. Every time you exhale, you <a href="https://doi.org/10.1111/ina.12383" target="_blank">release CO2</a> into the air. Since the coronavirus is most often spread by breathing, coughing or talking, you can use <a href="https://pdfs.semanticscholar.org/dd7e/b2870c38f70e5285e5118ed6f158c091f7cf.pdf" target="_blank">CO2 levels</a> to see if the room is filling up with potentially infectious exhalations. The CO2 level lets you estimate if enough fresh outside air is getting in.</p><p>Outdoors, CO2 levels are just above 400 parts per million (ppm). A well ventilated room will have around <a href="https://doi.org/10.1111/j.1600-0668.1999.00003.x" target="_blank">800 ppm of CO2</a>. Any higher than that and it is a sign the room might need more ventilation.</p><p>Last year, researchers in Taiwan reported on the <a href="https://doi.org/10.1111/ina.12639" target="_blank">effect of ventilation on a tuberculosis outbreak</a> at Taipei University. Many of the rooms in the school were underventilated and had CO2 levels above 3,000 ppm. When engineers improved air circulation and got CO2 levels under 600 ppm, <a href="https://doi.org/10.1111/ina.12639" target="_blank">the outbreak completely stopped</a>. According to the research, the increase in ventilation was responsible for 97% of the decrease in transmission.</p><p>Since the coronavirus is spread through the air, higher CO2 levels in a room likely mean there is a <a href="https://doi.org/10.1111/ina.12639" target="_blank">higher chance of transmission</a> if an infected person is inside. Based on the study above, I recommend trying to keep the CO2 levels below 600 ppm. You can buy <a href="https://doi.org/10.5194/amt-7-3325-2014" target="_blank">good CO2 meters</a> for around $100 online; just make sure that they are accurate to within 50 ppm.</p>
Air Cleaners<p>If you are in a room that can't get enough outside air for dilution, consider an air cleaner, also commonly called air purifiers. These machines remove particles from the air, usually using <a href="https://doi.org/10.1016/j.cap.2005.07.013" target="_blank">a filter</a> made of tightly woven fibers. They can <a href="https://shellym80304.files.wordpress.com/2020/06/miller-leiden-et-al-1996.pdf" target="_blank">capture particles containing bacteria and viruses</a> and can help reduce disease transmission.</p><p>The U.S. Environmental Protection Agency says that <a href="https://www.epa.gov/coronavirus/air-cleaners-hvac-filters-and-coronavirus-covid-19" target="_blank">air cleaners can do this for the coronavirus</a>, but not all air cleaners are equal. Before you go out and buy one, there are few things to keep in mind.</p><p>The first thing to consider is <a href="https://shellym80304.files.wordpress.com/2020/06/air-cleaner-report.pdf" target="_blank">how effective an air cleaner's filter is</a>. Your best option is a cleaner that uses a high-efficiency particulate air (<a href="https://doi.org/10.1016/S0021-8502(05)80214-9" target="_blank">HEPA</a>) filter, as these remove more than <a href="https://doi.org/10.1063/1.2771421" target="_blank">99.97% of all particle sizes</a>.</p><p>The second thing to consider is how powerful the cleaner is. The bigger the room – or the more people in it – the more air needs to be cleaned. I worked with some colleagues at Harvard to put together a tool to help teachers and schools determine <a href="https://docs.google.com/spreadsheets/d/1NEhk1IEdbEi_b3wa6gI_zNs8uBJjlSS-86d4b7bW098/edit#gid=1275403500" target="_blank">how powerful of an air cleaner you need for different classroom sizes</a>.</p><p>The last thing to consider is the validity of the claims made by the company producing the air cleaner.</p><p>The Association of Home Appliance Manufacturers certifies air cleaners, so the AHAM Verifide seal is a good place to start. Additionally, the California Air Resources Board has a <a href="https://ww2.arb.ca.gov/our-work/programs/air-cleaners-ozone-products/california-certified-air-cleaning-devices" target="_blank">list of air cleaners</a> that are certified as safe and effective, though not all of them use HEPA filters.</p>
Keep Air Fresh or Get Outside<p>Both the <a href="https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions" target="_blank">World Health Organization</a> and <a href="https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/deciding-to-go-out.html" target="_blank">U.S. Centers for Disease Control and Prevention</a> say that poor ventilation increases the risk of transmitting the coronavirus.</p><p>If you are in control of your indoor environment, make sure you are getting enough fresh air from outside circulating into the building. A CO2 monitor can help give you a clue if there is enough ventilation, and if CO2 levels start going up, open some windows and <a href="https://www.advisory.com/daily-briefing/2020/07/17/outdoor-gathering" target="_blank">take a break outside</a>. If you can't get enough fresh air into a room, an air cleaner might be a good idea. If you do get an air cleaner, be aware that they don't remove CO2, so even though the air might be safer, CO2 levels could still be high in the room.</p><p>If you walk into a building and it feels hot, stuffy and crowded, chances are that there is not enough ventilation. Turn around and leave.</p><p>By paying attention to air circulation and filtration, improving them where you can and staying away from places where you can't, you can add another powerful tool to your anti-coronavirus toolkit.</p>
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The tiny island nation of Mauritius, known for its turquoise waters, vibrant corals and diverse ecosystem, is in the midst of an environmental catastrophe after a Japanese cargo ship struck a reef off the country's coast two weeks ago. That ship, which is still intact, has since leaked more than 1,000 metric tons of oil into the Indian Ocean. Now, a greater threat looms, as a growing crack in the ship's hull might cause the ship to split in two and release the rest of the ship's oil into the water, NPR reported.
On Friday, Prime Minister Pravind Jugnauth declared a state of environmental emergency.
France has sent a military aircraft carrying pollution control equipment from the nearby island of Reunion to help mitigate the disaster. Additionally, Japan has sent a six-member team to assist as well, the BBC reported.
The teams are working to pump out the remaining oil from the ship, which was believed to be carrying 4,000 metric tons of fuel.
"We are expecting the worst," Mauritian Wildlife Foundation manager Jean Hugues Gardenne said on Monday, The Weather Channel reported. "The ship is showing really big, big cracks. We believe it will break into two at any time, at the maximum within two days. So much oil remains in the ship, so the disaster could become much worse. It's important to remove as much oil as possible. Helicopters are taking out the fuel little by little, ton by ton."
Sunil Dowarkasing, a former strategist for Greenpeace International and former member of parliament in Mauritius, told CNN that the ship contains three oil tanks. The one that ruptured has stopped leaking oil, giving disaster crews time to use a tanker and salvage teams to remove oil from the other two tanks before the ship splits.
By the end of Tuesday, the crew had removed over 1,000 metric tons of oil from the ship, NPR reported, leaving about 1,800 metric tons of oil and diesel, according to the company that owns the ship. So far the frantic efforts are paying off. Earlier today, a local police chief told BBC that there were still 700 metric tons aboard the ship.
The oil spill has already killed marine animals and turned the turquoise water black. It's also threatening the long-term viability of the country's coral reefs, lagoons and shoreline, NBC News reported.
"We are starting to see dead fish. We are starting to see animals like crabs covered in oil, we are starting to see seabirds covered in oil, including some which could not be rescued," said Vikash Tatayah, conservation director at Mauritius Wildlife Foundation, according to The Weather Channel.
While the Mauritian authorities have asked residents to leave the clean-up to officials, locals have organized to help.
"People have realized that they need to take things into their hands. We are here to protect our fauna and flora," environmental activist Ashok Subron said in an AFP story.
Reuters reported that sugar cane leaves, plastic bottles and human hair donated by locals are being sewn into makeshift booms.
Human hair absorbs oil, but not water, so scientists have long suggested it as a material to contain oil spills, Gizmodo reported. Mauritians are currently collecting as much human hair as possible to contribute to the booms, which consist of tubes and nets that float on the water to trap the oil.
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Environmentalists and ornithologists found a friend in a federal court on Tuesday when a judge struck down a Trump administration attempt to allow polluters to kill birds without repercussions through rewriting the Migratory Treaty Bird Act (MBTA).
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By Elizabeth Claire Alberts
There are trillions of microplastics in the ocean — they bob on the surface, float through the water column, and accumulate in clusters on the seafloor. With plastic being so ubiquitous, it's inevitable that marine organisms, such as sharks, will ingest them.
Polyproylene fibers found in one of the sampled sharks. Kristian Parton
Spiny dogfish. NOAA / Wikimedia Commons<p>"There appear to be two routes for these particles to end up in the sharks," Parton said. "The first through their food source [such as] crustaceans. Their prey may already contain these fibers, and consequently it's passed to the shark through bioaccumulation up the food chain. The second pathway is direct ingestion from the sediment. As these sharks feed, they'll often suck up sediment into their mouths, some of this is expelled straight away, although some is swallowed, therefore fibers and particles that may have sunk down into the seabed may be directly ingested from the surrounding sediment as these sharks feed."</p><p>Some sharks only contained a few plastic particles, but others contained dozens. The larger the shark, the more plastic was in it, the findings suggested. The highest number of microplastics was found in an individual bull huss, which had 154 polypropylene fibers inside its stomach and intestines.</p><p>"It's perhaps likely this individual shark had swallowed a larger piece of fishing rope/netting and this has broken down during digestive processes within the shark, and also broken down into smaller pieces during our analysis," Parton said.</p>
Lesser-spotted dogfish caught as bycatch. Kristian Parton<p>While this study only examined the stomach and digestive tracts of demersal sharks, Parton says it's possible that plastic would be present in other parts of the sharks' bodies, such as the liver and muscle tissue. However, more research would be needed to prove this.</p><p>At the moment, there is also limited understanding of how microplastic ingestion would impact a shark's health, although microplastics are known to negatively influence feeding behavior, development, reproduction and life span of zooplankton and crustaceans.</p><p>"If we can show that these fibers contain inorganic pollutants attached to them, then that could have real consequences for these shark species at a cellular level, impacting various internal body systems," Parton said.</p>
Parton in the lab. Kristian Parton<p>This new study demonstrates how pervasive and destructive plastic pollution can be in the marine environment, according to Will McCallum, head of oceans for Greenpeace U.K.</p><p>"Our addiction to plastics combined with the lack of mechanisms to protect our oceans is suffocating marine life," McCallum said in a statement. "Sharks sit on top of the marine food web and play a vital role in ocean ecosystems. Yet, they are completely exposed to pollutants and other human impactful activities. We need to stop producing so much plastic and create a network of ocean sanctuaries to give wildlife space to recover. The ocean is not our dump, marine life deserves better than plastic."</p>
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By Loveday Wright and Stuart Braun
After a Japanese-owned oil tanker struck a reef off Mauritius on July 25, a prolonged period of inaction is threatening to become an ecological disaster.
<div id="bb0a7" class="rm-shortcode" data-rm-shortcode-id="e5aefc0fff61ab1aea2f4b03c5399864"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1291765757013983238" data-partner="rebelmouse"><div style="margin:1em 0">The #oilspill is devastating but I want to honour the community mobilisation at the Mahebourg waterfront today (to… https://t.co/UWFkZFdjdi</div> — Fabiola Monty (@Fabiola Monty)<a href="https://twitter.com/LFabiolaMonty/statuses/1291765757013983238">1596815930.0</a></blockquote></div><p>"Booms are made of nylon mesh filled with #sugarcane straws all hand-stitched by Mauritian volunteers, empty plastic bottles used as buoys," described Mauritian journalist Zeenat Hansrod in a tweet. </p>
How to Tackle Oil Spills<p>The method for tackling oil spills depends on several factors, including the type and amount of oil in question, location and weather conditions.</p><p>"Once the oil comes to shore, the more intensive the cleaning technique. You can risk causing further damage," said Nicky Cariglia, an independent consultant at Marittima, who specializes in marine pollution. </p><p>"If you wanted to remove all traces of oil, the techniques available become increasingly aggressive the less oil that remains. In mangroves, you would have the added risk of causing damage by trampling," Cariglia told DW. Highly sensitive mangrove ecosystems line the Mauritius east coast that is threatened by the current spill.</p><p>Because oil normally has a lower density than water, it floats on the surface of the ocean. This means that for clean-up action to be most effective, it should happen very quickly after a spill, before the oil disperses. </p>
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