Should Plants and Animals That Relocate Because of Climate Change Be Considered Invasive?
04 August
Animals
America Pikas are found from the Sierra Nevada to the Rocky Mountains, and have been migrating to higher elevations. Jon LeVasseur / Flickr / Public Domain
By Jenny Morber
Caribbean corals sprout off Texas. Pacific salmon tour the Canadian Arctic. Peruvian lowland birds nest at higher elevations.
<p>In the past 100 years, the planet has warmed in the range of <a title="" href="https://earthobservatory.nasa.gov/features/GlobalWarming/page3.php" target="_blank">10 times faster</a> than it did on average over the past 5,000. In response, thousands of species are traveling poleward, climbing to higher elevations, and diving deeper into the seas, seeking their preferred environmental conditions. This great migration is challenging traditional ideas about native species, the role of conservation biology and what kind of environment is desirable for the future.</p><p>In a <a title="" href="https://science.sciencemag.org/content/355/6332/eaai9214?rss=1" target="_blank">2017 review for <em>Science</em></a>, University of Tasmania marine ecology professor Gretta Pecl and colleagues wrote, "[C]limate change is impelling a universal redistribution of life on Earth. For marine, freshwater, and terrestrial species alike, the first response to changing climate is often a shift in location." In fact, Pecl says, data suggest that at least 25% and perhaps as much as 85% of Earth's estimated 8.7 million species are already shifting ranges in response to climate change.</p><p>But when they arrive, will they be welcome? Traditional definitions classify species according to place. "Native" species arrived without human help and usually before widespread human colonization, so are likely to have natural predators and are unlikely to go rogue. Non-natives are newcomers and suspect. Though 90% cause no lasting damage, 10% become invasive — meaning that they harm the environment, the economy or human health. Last year <a title="" href="https://www.un.org/sustainabledevelopment/blog/2019/05/nature-decline-unprecedented-report/" target="_blank">a multinational report</a> flagged invasive species as a key driver of Earth's biodiversity crisis.</p>
<img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMzA5My9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyMzM0MTI3NH0.oMhAPPXcPHecfraPvGcNqifWPj2zCRImoy-dGHjAIwA/img.jpg?width=980" id="89fd0" class="rm-shortcode" data-rm-shortcode-id="5acc10628b03ca297c3b53aefdcaacb2" data-rm-shortcode-name="rebelmouse-image" />
Known and anticipated changes in species distribution due to climate change around the world have implications for culture, society ecosystems, governance and climate change. Figure used with permission from Gretta T. Pecl, originally published on 31 Mar 2017 in Science 355(6332).
<p>How we define species is critical, because these definitions influence perceptions, policy and management. The U.S. National Invasive Species Council (NISC) defines a biological invasion as "the process by which non-native species breach biogeographical barriers and extend their range" and states that "preventing the introduction of potentially harmful organisms is … the first line of defense." But some say excluding newcomers is myopic.</p><p>"If you were trying to maintain the status quo, so every time a new species comes in, you chuck it out," says Camille Parmesan, director of the French National Centre for Scientific Research, you could gradually "lose so many that that ecosystem will lose its coherence." If climate change is driving native species extinct, she says, "you need to allow new ones coming in to take over those same functions."</p><p>As University of Florida conservation ecologist Brett Scheffers and Pecl warned in a <a href="https://www.nature.com/articles/s41558-019-0526-5" target="_blank">2019 paper in <em>Nature Climate Change</em></a>, "past management of redistributed species … has yielded mixed actions and results." They concluded that "we cannot leave the fate of biodiversity critical to human survival to be randomly persecuted, protected or ignored."</p>Existing Tools
<p>One approach to managing these climate-driven habitat shifts, suggested by University of California, Irvine marine ecologist Piper Wallingford and colleagues in <a href="https://www.nature.com/articles/s41558-020-0768-2" target="_blank">a recent issue of Nature Climate Change</a>, is for scientists to adapt existing tools like the <a href="https://www.iucn.org/theme/species/our-work/invasive-species/eicat" target="_blank">Environmental Impact Classification of Alien Taxa (EICAT)</a> to assess potential risks associated with moving species. Because range-shifting species pose impacts to communities similar to those of species introduced by humans, the authors argue, new management strategies are unnecessary, and each new arrival can be evaluated on a case-by-case basis.</p><p>Karen Lips, a professor of biology at University of Maryland who was not associated with the study, echoes the idea that each case is so varied and nuanced that trying to fit climate shifting species into a single category with broad management goals may be impractical. "Things may be fine today, but add a new mosquito vector or add a new tick or a new disease, and all of a sudden things spiral out of control," she says. "The nuance means that the answer to any particular problem might be pretty different."</p><img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMzEwOC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTU5Nzc3Mzg5OH0.mfmERsqdqXWZxoqSAKjoS_djEwYmc5sqJGvc3vaxQhM/img.jpg?width=980" id="5d0ac" class="rm-shortcode" data-rm-shortcode-id="0b6c13afe6f55afc739919773358c08f" data-rm-shortcode-name="rebelmouse-image" />
In recent years, northern flying squirrels in Canada have found themselves in the company of new neighbors — southern flying squirrels expanding their range as the climate warms. Public Domain / USFW
<p>Laura Meyerson, a professor in the Department of Natural Resources Science at the University of Rhode Island says scientists should use existing tools to identify and address invasive species to deal with climate-shifting species. "I would like to operate under the precautionary principle and then reevaluate as things shift. You're sort of shifting one piece in this machinery; as you insert a new species into a system, everything is going to respond," she says. "Will some of the species that are expanding their ranges because of climate change become problematic? Perhaps they might."</p><p>The reality is that some climate-shifting species may be harmful to some conservation or economic goals while being helpful to others. While sport fisherman are excited about red snapper moving down the East Coast of Australia, for example, if they eat juvenile lobsters in Tasmania they could harm this environmentally and economically important crustacean. "At the end of the day … you're going to have to look at whether that range expansion has some sort of impact and presumably be more concerned about the negative impacts," says NISC executive director Stas Burgiel. "Many of the [risk assessment] tools we have are set up to look at negative impact." As a result, positive effects may be deemphasized or overlooked. "So that notion of cost versus benefit … I don't think it has played out in this particular context."</p>Location, Location, Location
<p>In a <a href="https://www-nature-com.ezp3.lib.umn.edu/articles/s41558-020-0770-8" target="_blank">companion paper</a> to Wallingford's, University of Connecticut ecology and evolutionary biology associate professor Mark Urban stressed key differences between invasive species, which are both non-native and harmful, and what he calls "climate tracking species." Whereas invasive species originate from places very unlike the communities they overtake, he says, climate tracking species expand from largely similar environments, seeking to follow preferred conditions as these environments move. For example, an American pika may relocate to a higher mountain elevation, or a marbled salamander might expand its New England range northward to seek cooler temperatures, but these new locations are not drastically different than the places they had called home before.</p><p>Climate tracking species may move faster than their competitors at first, Urban says, but competing species will likely catch up. "Applying perspectives from invasion biology to climate-tracking species … arbitrarily chooses local winners over colonizing losers," he writes.</p><img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMzExOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNDcyNzA3Mn0.n_ebiiONrITEyBQmEWJFAbXDUd4ZWzPOBE8CKnyHm1Q/img.jpg?width=980" id="ec01c" class="rm-shortcode" data-rm-shortcode-id="84cbbac4ee5597e41544f6cedfcce139" data-rm-shortcode-name="rebelmouse-image" />
The marbled salamander, a native of the eastern U.S., is among species whose range could expand northward to accommodate rising temperatures. Seánín Óg / Flickr / CC BY-NC-ND 2.0
<p>Urban stresses that if people prevent range shifts, some climate-tracking species may have nowhere to go. He suggests that humans should even <a href="https://ensia.com/features/time-for-trees-to-pack-their-trunks/" target="_blank">facilitate movement</a> as the planet warms. "The goal in this crazy warming world is to keep everything alive. But it may not be in the same place," Urban says.</p><p>Parmesan echoes Urban, emphasizing it's the distance that makes the difference. "[Invasives] come from a different continent or a different ocean. You're having these enormous trans-global movements and that's what ends up causing the species that's exotic to be invasive," she says. "Things moving around with climate change is a few hundred miles. Invasive species are moving a few thousand miles."</p><p>In 2019 University of Vienna conservation biology associate professor Franz Essl published a similar argument for species classification beyond the native/non-native dichotomy. Essl uses "neonatives" to refer to species that have expanded outside their native areas and established populations because of climate change but not direct human agency. He argues that these species should be considered as native in their new range.</p>They Never Come Alone
<p>Meyerson calls for caution. "I don't think we should be introducing species" into ecosystems, she says. "I mean, they never come alone. They bring all their friends, their microflora, and maybe parasites and things clinging to their roots or their leaves. … It's like bringing some mattress off the street into your house."</p><p>Burgiel warns that labeling can have unintended consequences. We in the invasive species field … focus on non-native species that cause harm," he says. "Some people think that anything that's not native is invasive, which isn't necessarily the case." Because resources are limited and land management and conservation are publicly funded, Burgiel says, it is critical that the public understands how the decisions are being made.</p><p>Piero Genovesi, chair of the International Union for the Conservation of Nature's Invasive Species Specialist Group, sees the debate about classification — and therefore about management — as a potential distraction from more pressing conservation issues.</p><p>"The real bulk of conservation is that we want to focus on the narrow proportion of alien species that are really harmful," he says. In Hawaii "we don't discuss species that are there [but aren't] causing any problem because we don't even have the energy for dealing with them all. And I can tell you, no one wants to remove [non-native] cypresses from Tuscany. So, I think that some of the discussions are probably not so real in the work that we do in conservation."</p><p>Indigenous frameworks offer another way to look at species searching for a new home in the face of climate change. According to <a href="https://link.springer.com/article/10.1007%2Fs11625-018-0571-4" target="_blank">a study</a> published in Sustainability Science in 2018 by Dartmouth Native American studies and environmental studies associate professor Nicholas Reo, a citizen of the Sault Ste. Marie Tribe of Chippewa Indians, and Dartmouth anthropology associate professor Laura Ogden, some Anishnaabe people view plants as persons and the arrival of new plants as a natural form of migration, which is not inherently good or bad. They may seek to discover the purpose of new species, at times with animals as their teachers. In their paper Reo and Ogden quote Anishnaabe tribal chairman Aaron Payment as saying, "We are an extension of our natural environment; we're not separate from it."</p>The Need for Collaboration
<p>The successful conservation of Earth's species in a way that keeps biodiversity functional and healthy will likely depend on collaboration. Without global agreements, one can envision scenarios in which countries try to impede high-value species from moving beyond their borders, or newly arriving species are quickly overharvested.</p><p>In Nature Climate Change, Sheffers and Pecl call for a Climate Change Redistribution Treaty that would recognize species redistribution beyond political boundaries and establish governance to deal with it. Treaties already in place, such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which regulates trade in wild plants and animals; the Migratory Bird Treaty Act; and the Agreed Measures for the Conservation of Antarctic Fauna and Flora, can help guide these new agreements.</p><p>"We are living through the greatest redistribution of life on Earth for … potentially hundreds of thousands of years, so we definitely need to think about how we want to manage that," Pecl says.</p><p>Genovesi agrees that conservationists need a vision for the future. "What we do is more to be reactive [to known threats]. … It's so simple to say that destroying the Amazon is probably not a good idea that you don't need to think of a step ahead of that." But, he adds, "I don't think we have a real answer in terms of okay, this is a threshold of species, or this is the temporal line where we should aim to." Defining a vision for what success would look like, Genovesi says, "is a question that hasn't been addressed enough by science and by decision makers."</p><p>At the heart of these questions are values. "All of these perceptions around what's good and what's bad, all [are based on] some kind of value system," Pecl says. "As a whole society, we haven't talked about what we value and who gets to say what's of value and what isn't."</p><p>This is especially important when it comes to marginalized voices, and Pecl says she is concerned because she doesn't "think we have enough consideration or representation of Indigenous worldviews." Reo and colleagues <a href="https://cpb-us-e1.wpmucdn.com/sites.dartmouth.edu/dist/9/52/files/2012/10/Reo_etal_AIQ_invasive_species_2017.pdf" target="_blank">wrote in American Indian Quarterly in 2017</a> that climate change literature and media coverage tend to portray native people as vulnerable and without agency. Yet, says Pecl, "The regions of the world where [biodiversity and ecosystems] are either not declining or are declining at a much slower rate are Indigenous controlled" — suggesting that Indigenous people have potentially managed species more effectively in the past, and may be able to manage changing species distributions in a way that could be informative to others working on these issues.</p><p>Meanwhile, researchers such as Lips see species classification as native or other as stemming from a perspective that there is a better environmental time and place to return to. "There is no pristine, there's no way to go back," says Lips. "The entire world is always very dynamic and changing. And I think it's a better idea to consider just simply what is it that we do want, and let's work on that."</p>
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To save insects we must give them the space they need to survive. asadykov / iStock / Getty Images Plus
By Andrew Urevig
Butterflies and bees, ants and beetles, cockroaches and flies — whether loved or feared, insects help humans. Just sample the ways these animals enable life as we know it: they pollinate crops, give us new medicines, break down waste and support entire ecosystems.
Yet many insects around the world are in decline.
<p>Writing in the journal Biological Conservation, more than two dozen scientists from countries around the world are <a href="https://www.sciencedirect.com/science/article/pii/S0006320719317823" target="_blank">warning</a> of a wave of insect extinctions — and urging swift steps to curb the crisis. In a <a href="https://www.sciencedirect.com/science/article/pii/S0006320719317793#ec0030" target="_blank">paper sketching solutions</a>, the scientists say that to save insects we must give them the space they need to survive in the face of <a href="https://www.ecowatch.com/tag/climate-change" target="_self">climate change</a>: livable, interconnected habitats flush with a rich <a href="http://www.ecowatch.com/tag/biodiversity">diversity</a> of plant and animal life.</p><p>Ensuring that insects have room to thrive means setting aside local habitat, including parks, gardens, roadsides and the edges of farm fields. It also entails protecting continent-scale migratory passages like the <a href="https://e360.yale.edu/features/can-the-monarch-highway-help-save-a-butterfly-under-siege" target="_blank">corridor that monarch butterflies traverse</a> from Minnesota to Mexico.</p>
<p>Not just any areas will do, the researchers caution. Insects need quality space, too. The closer an area is to the condition it was in before humans altered it for the worse, the better. "We need to move the needle of novel landscapes towards one of greater ecological integrity and more complex interaction networks," Michael Samways, one of the paper's authors and an insect conservationist at South Africa's Stellenbosch University, wrote in an email to Ensia.</p><p>Space that's free from pollution and invasive species, with diverse plant life and a varied landscape, will best help insects — and that includes enough room for the six-legged critters to find food, seek mates and just rest.</p>
<p>"Part of being able to move around is to be able to 'dodge' natural enemies, from bats and birds, to other insects like predatory ladybugs and parasitic wasps," Samways explained.</p><p>Our changing climate pushes many insects to evolve, move or die — a dynamic that often puts them up against the extensive transformation humans have wrought on Earth's surface. Habitat fragmentation exacerbates the threat by limiting insects' ability to traverse the landscapes separating them from more suitable surroundings.</p><p>But with quality space that's connected by <a href="https://www.ecowatch.com/tag/conservation" target="_self">conservation</a> corridors and other adequate habitat, the researchers write, insects can leave enough healthy offspring to sustain their species.</p>
<p>Scientists know what insects need, but scaling proven strategies up to the massive level needed to make a dent in extinctions is a different challenge entirely.</p><p>"Especially when you're thinking about insects, you have to get public buy-in," said DeAnna Beasley, an ecologist at the University of Tennessee at Chattanooga who was not involved in the paper. Highlighting this key hurdle, the report authors bemoaned "the current lack of sufficient collective political will and concerted effort" to save insects.</p>
<p>To build that will, the scientists call for greater efforts to communicate the value of insects to society. For example, Beasley has used cicadas — a kind of insect that needs "a large, contiguous space" to sustain big populations — in <a href="https://bioone.org/journals/Florida-Entomologist/volume-95/issue-2/024.095.0236/The-use-of-Citizen-Scientists-to-Record-and-Map-13/10.1653/024.095.0236.full" target="_blank">citizen science research</a>, getting more data for <a href="http://www.ecowatch.com/science/" target="_self">science</a> while building more appreciation for insects among the public. In one project the paper spotlights, students at schools in Austria successfully <a href="https://link.springer.com/article/10.1007/s10841-017-0010-3" target="_blank">assessed the quality of space for butterflies</a>, laying the groundwork for follow-up by trained scientists.</p><p>With many insects unnoticed or misunderstood, the researchers also recommend the continued use of "insect icons" and "flagship species" to promote support for conservation.</p>
<p>"Highlighting the animals that people know best is vital for our effort to get people engaged in invertebrate or insect conservation," says Scott Hoffman Black, executive director of the Xerces Society for Invertebrate Conservation, who was not involved in the new paper. Black also underscores that charismatic insects are just a starting point.</p><p>"We need people to understand the consequences of not taking action and give them solutions that they can enact in their own lives," Black says. "As well as getting them to push their governments to take action."</p>
<p><em>Reposted with permission from <a href="https://ensia.com/notable/insects-extinction-habitat/" target="_blank">Ensia</a>.</em></p>From Your Site Articles
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By Mary Hoff
Klaus Lackner has a picture of the future in his mind, and it looks something like this: 100 million semi-trailer-size boxes, each filled with a beige fabric configured into what looks like shag carpet to maximize surface area. Each box draws in air as though it were breathing. As it does, the fabric absorbs carbon dioxide, which it later releases in concentrated form to be made into concrete or plastic or piped far underground, effectively cancelling its ability to contribute to climate change.
Though the technology is not yet operational, it's "at the verge of moving out of the laboratory, so we can show how it works on a small scale," said Lackner, director of the Center for Negative Carbon Emissions at Arizona State University. Once he has all the kinks worked out, he figured that, combined, the network of boxes could capture perhaps 100 million metric tons (110 million tons) of CO2 per day at a cost of $30 per ton—making a discernible dent in the climate-disrupting overabundance of CO2 that has built up in the air since humans began burning fossil fuels in earnest 150 years ago.
<p>Lackner is one of hundreds, if not thousands, of scientists around the world who are working on ways to remove CO2 from the atmosphere, capturing carbon from the atmosphere using plants, rocks or engineered chemical reactions and storing it in <a href="http://www.ecowatch.com/tag/soil">soil</a>, products such as concrete and plastic, rocks, underground reservoirs or the deep blue sea.</p><p>Some of the strategies—known collectively as carbon dioxide removal or negative emissions technologies—are just twinkles in their envisioners' eyes. Others—low-tech schemes like planting more forests or leaving crop residues in the field, or more high-tech "negative emissions" setups like the <a href="https://www.washingtonpost.com/news/energy-environment/wp/2017/04/10/the-quest-to-capture-and-store-carbon-and-slow-climate-change-just-reached-a-new-milestone/?utm_term=.53fe8781148b" target="_blank">CO2-capturing biomass fuel plant that went online last spring</a> in Decatur, Illinois—are already underway. Their common aim: To help us out of the climate change fix we've gotten ourselves into.</p><p>"We can't just decarbonize our economy, or we won't meet our carbon goal," said Noah Deich, co-founder and executive director with the <a href="http://www.centerforcarbonremoval.org/" target="_blank">Center for Carbon Removal</a> in Oakland, California. "We have to go beyond to clean up carbon from the atmosphere ... [And] we need to start urgently if we are to have real markets and real solutions available to us that are safe and cost effective by 2030."</p><p><strong>Many Approaches</strong></p><p>Virtually all climate change experts agree that to avoid catastrophe we must first and foremost put everything we can into reducing CO2 emissions. But an increasing number are saying that's not enough. If we are to limit atmospheric warming to a level below which irreversible changes become inevitable, they argue, we'll need to actively remove CO2 from the air in fairly hefty quantities as well.</p><p>"It's almost impossible that we would hit 2°C, and even less so 1.5°C, without some sort of negative emissions technology," said Pete Smith, chair in plant and soil science at the University of Aberdeen and one of the world's <a href="https://ensia.com/voices/the-hidden-risk-of-negative-emissions-technologies/" target="_blank">leaders in climate change mitigation</a>.</p><p>In fact, scientists from around the world who recently drew up a <a href="http://science.sciencemag.org/content/355/6331/1269.full" target="_blank">"road map" to a future</a> that gives us good odds of keeping warming below the 2 ºC threshold lean heavily on reducing carbon emissions by completely phasing out fossil fuels—but also require that we actively remove CO2 from the atmosphere. Their scheme calls for sequestering 0.61 metric gigatons (a gigaton, abbreviated Gt, is a billion metric tons or 0.67 billion tons) of CO2 per year by 2030, 5.51 by 2050, and 17.72 by 2100. Human-generated CO2 emissions were around 40 Gt in 2015, <a href="https://www.climate.gov/news-features/climate-qa/which-emits-more-carbon-dioxide-volcanoes-or-human-activities" target="_blank">according to the National Oceanic and Atmospheric Administration</a>.</p><p>Reports periodically appear pointing out that one approach or another is not going to cut it: Trees can store carbon, but they compete with agriculture for land, soil can't store enough, machines like the ones Lackner envisions take too much energy, we don't have the engineering figured out for underground storage.</p><p>It's likely true that no one solution is the fix, all have pros and cons, and many have bugs to work out before they're ready for prime time. But in the right combination, and with some serious research and development, they could make a big difference. And, as <a href="https://www.earth-syst-dynam.net/8/577/2017/esd-8-577-2017.pdf" target="_blank">an international team of climate scientists recently pointed out</a>, the sooner the better, because the task of reducing greenhouse gases will only become larger and more daunting the longer we delay.</p><p>Smith suggests dividing the many approaches into two categories—relatively low-tech "no regrets" strategies that are ready to go, such as reforestation and improving agricultural practice, and advanced options that need substantial research and development to become viable. Then, he suggests, deploy the former and <a href="http://nas-sites.org/dels/studies/cdr/" target="_blank">get working on the latter</a>. He also advocates for minimizing the downsides and maximizing the benefits by carefully matching the right approach with the right location.</p><p>"There are probably good ways and bad ways of doing everything," Smith said. "I think we need to find the good ways of doing these things."</p><p>Deich, too, supports the simultaneous pursuit of multiple options. "We don't want a technology, we want <em>lots </em>of complementary solutions in a broader portfolio that updates often as new information about the solutions emerges."</p><p>With that in mind, here is a quick look at some of the main approaches being considered, including a ballpark projection based on current knowledge of CO2 storage potential distilled from a variety of sources—including <a href="https://deepblue.lib.umich.edu/handle/2027.42/136610" target="_blank">preliminary results from a University of Michigan study</a> expected to be released later this year—as well as summaries of advantages, disadvantages, maturity, uncertainties and thoughts about the circumstances under which each might best be applied.</p><p><strong>Afforestation and Reforestation</strong></p><p>Pay your entrance fee, drive up a winding road through Sequoia National Park in California, hike half a mile through the woods, and you'll find yourself at the feet of General Sherman, the world's largest tree. With some 52,500 cubic feet (1,487 cubic meters) of wood in its trunk, the behemoth has <a href="http://www.dewharvest.com/carbon-dioxide-stored-by-general-sherman-giant-sequoia.html" target="_blank">more than 1,400 metric tons</a> (1,500 tons) of CO2 trapped in its trunk alone.</p><p>Though its size is clearly exceptional, the General gives an idea of trees' potential to suck CO2 from the air and store it in wood, bark, leaf and root. In fact, the Intergovernmental Panel on Climate Change estimated that a single hectare (2.5 acres) of forest can take up somewhere between 1.5 and 30 metric tons (1.6 and 33 tons) of CO2 per year, depending on the kinds of trees, how old they are, the climate and so on.</p><p>Worldwide forests currently sequester on the order of 2 Gt CO2 per year. Concerted efforts to plant trees in new places (afforest) and replant deforested acreage (reforest) could increase this by a gigaton or more, depending on species, growth patterns, economics, politics and other variables. Forest management practices emphasizing carbon storage and genetic modification of trees and other forest plants to improve their ability to take up and store carbon could push these numbers higher.</p><p>Another way to help enhance trees' ability to store carbon is to make long-lasting products from them—wood-frame buildings, books and so on. Using carbon-rich wood for construction, for example, could extend trees' storage capacity beyond forests' borders, with wood storage and afforestation combining for a potential 1.3–14 Gt CO2 per year possible, <a href="http://www.climateinstitute.org.au/verve/_resources/BelowZero_March2014.pdf" target="_blank">according to The Climate Institute</a>, an Australia-based research organization.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzU5Ny9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYyODkyODczNn0.nbKpg4hIKZDMR5XbedjkA9SeMekuuHuX8r678BZXypY/img.png?width=980" id="872ef" class="rm-shortcode" data-rm-shortcode-id="8cda5d0ec88717659c143a28193fa547" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit">iStockphoto.com/holgs</small></p><p><strong>Carbon Farming</strong></p><strong></strong>Most farming is intended to produce something that's harvested from the land. <a href="https://www.ecowatch.com/carbon-farming-2457937143.html">Carbon farming</a> is the opposite. It uses plants to trap CO2, then strategically uses practices such as <a href="https://ensia.com/features/the-farm-that-grows-climate-solutions/" target="_blank">reducing tilling, planting longer-rooted crops and incorporating organic materials into the soil</a> to encourage the trapped carbon to move into—and stay in—the soil.<p>"Currently, many agricultural, horticultural, forestry and garden soils are a net carbon source. That is, these soils are losing more carbon than they are sequestering," noted Christine Jones, founder of the Australia-based nonprofit <a href="http://www.amazingcarbon.com/" target="_blank">Amazing Carbon</a>. "The potential for reversing the net movement of CO2 to the atmosphere through improved plant and soil management is immense. Indeed, managing vegetative cover in ways that enhance the capacity of soil to sequester and store large volumes of atmospheric carbon in a stable form offers a practical and almost immediate solution to some of the most challenging issues currently facing humankind."</p><p>Soil's carbon-storing capacity could go even higher if research initiatives by the <a href="https://arpa-e.energy.gov/?q=arpa-e-programs/roots" target="_blank">Advanced Research Projects Agency–Energy</a>, a U.S. government agency that provides research support for innovative energy technologies, and others aimed at improving crops' capacity to transfer carbon to the soil are successful. And, points out Eric Toensmeier, author of <a href="https://ensia.com/features/the-farm-that-grows-climate-solutions/" target="_blank">The Carbon Farming Solution</a>, the capacity of farmland to store carbon can be dramatically increased by including trees in the equation as well.</p><p>"Generally it is practices that incorporate trees that have the most carbon [storage]—often two to 10 times more carbon per hectare, which is a pretty big deal," Toensmeier said.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzU5OS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0NjI4NTgyMn0.sksdei1Nj1BrIcc4wL3HGGXCAdga3iu4J7VPOQi58PU/img.png?width=980" id="d1c36" class="rm-shortcode" data-rm-shortcode-id="fa93f71067b59edbe6b2350cd208b182" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit">Creative Commons</small></p><p><strong>Other Vegetation</strong> </p><p>Although forests and farmland have drawn the most attention, other kinds of vegetation—grasslands, coastal vegetation, peatlands—also take up and store CO2, and efforts to enhance their ability to do so could contribute to the carbon storage cause around the world.</p><p><a href="https://ensia.com/voices/one-of-the-smartest-investments-we-can-make/" target="_blank">Coastal plants,</a> such as mangroves, seagrasses and vegetation inhabiting tidal salt marshes, excel at sequestering CO2 in vegetation—significantly more per area than terrestrial forests, <a href="https://vimeo.com/album/4621340/video/220313465" target="_blank">according to Meredith Muth</a>, international program manager with the National Oceanic and Atmospheric Administration.</p><p>"These are incredibly carbon-rich ecosystems," said Emily Pidgeon, <a href="http://www.conservation.org/Pages/default.aspx" target="_blank">Conservation International</a> senior director of strategic marine initiatives. That's because the oxygen-poor soil in which they grow inhibits release of CO2 back to the atmosphere, so rather than cycling back into the atmosphere, carbon simply builds up layer by layer over the centuries. With <a href="http://www.cifor.org/publications/pdf_files/Books/BMurdiyarso1401.pdf" target="_blank">mangroves sequestering roughly 1,400 metric tons (1,500 tons) per hectare (2. 5 acres); salt marshes, 900 metric tons (1,000 tons); and seagrass, 400 metric tons (400 tons)</a>, restoring lost coastal vegetation and extending coastal habitats holds potential to sequester substantial carbon. And researchers are eyeing strategies such as reducing pollution and managing sediment disturbance to <a href="http://www.anthropocenemagazine.org/2017/05/blue-carbon-ecosystems/" target="_blank">make these ecosystems absorb even more CO2</a>.</p><p>And, Pidgeon added, such vegetation provides a double climate benefit because it also helps protect coastlines from erosion as warming causes <a href="http://www.ecowatch.com/tag/sea-level-rise">sea levels to rise</a>.</p><p>"It's the perfect climate change ecosystem, especially in some of the more vulnerable places," she said. "It provides storm protection, erosion control, maintains the local fishery. In terms of climate change, it's immensely valuable, whether talking mitigation or adaptation."</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzYwMi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYwNTk1ODMzOX0.nYRfvHdgyPNNwMhMWqQTPX9cOSlGkzYcN6vGBlx7qI4/img.png?width=980" id="0ead1" class="rm-shortcode" data-rm-shortcode-id="630acc9f835f9288d1d0c7c7633b5853" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit"> iStockphoto.com/MorganLeeAlain</small></p><p><strong>Bioenergy & Bury</strong></p><p>In addition to tapping vegetation's capacity to store CO2 in plant parts and soil, humans can enhance sequestration by socking away the carbon plants absorb in other ways. A <a href="https://www.carbonbrief.org/analysis-negative-emissions-tested-worlds-first-major-beccs-facility" target="_blank">$208 million power plant that started operation earlier this year</a> in the heart of Illinois farm country is a tangible example of this approach and what is currently widely seen as the most promising technology-based strategy for removing large amounts of carbon from the air: bioenergy carbon capture and storage, or BECCS.</p><p>BECCS generally starts with converting biomass into a usable energy source such as liquid fuel or electricity. But then it takes the concept one key step further. Rather than sending the CO2 released during the process into the air, as conventional facilities do, it captures and concentrates it, then traps it in material such as concrete or plastic or—as is the case for the Decatur plant—injects it into rock formations that trap the carbon far below Earth's surface.</p><p class="shortcode-media shortcode-media-vimeo"><iframe src="https://player.vimeo.com/video/129245747" width="100%" height="480" frameborder="0" scrolling="no" class="rm-shortcode" data-rm-shortcode-id="72719230fc19c360721e516f9558375d"></iframe></p><p>A related strategy proposes using ocean plants such as kelp instead of land plants. This would reduce the need to compete with food production and land habitat preservation for land. This option has not been explored as much as land-based BECCS, however, so the number of unknowns is even higher.</p><p>On the storage end of things, many of the technologies proposed are still in concept or early development stage. But if developed correctly, the approach has "potentially got quite a significant impact," said professor Pete Smith of the University of Aberdeen.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzYwNC9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzMTM0MDMyM30.3124wyKafZKzPvRye_jyKA9FA_lMQ3tERoHk_dPkQo8/img.png?width=980" id="2428f" class="rm-shortcode" data-rm-shortcode-id="aa1abf43c1e9bd5991105bc6e02df100" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit">Creative Commons</small></p><p><strong>Biochar</strong> </p><p>Another way to enhance plants' ability to store carbon is to partly burn materials such as logging slash or crop waste to make a carbon-rich, slow-to-decompose substance known as <a href="http://midwestenergynews.com/2015/01/27/how-crop-waste-could-become-carbon-negative-energy/" target="_blank">biochar</a>, which can then be buried or spread on farmland. Biochar has been used for centuries to enrich soil for farming, but of late has been drawing increased attention for its ability to sequester carbon—as evidenced by the fact that three of 10 finalists in a $25 million <a href="http://www.virginearth.com/" target="_blank">Earth Challenge</a> launched by Virgin in 2007 tap this approach.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzYwNi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1NTkwNzI2MH0.sjswoR3vZTWgG6Bzrzli8mDAItNUi4ZGPlNxM3plKRU/img.png?width=980" id="a3f3d" class="rm-shortcode" data-rm-shortcode-id="36ad15c9f6737042c048ebb907b1fcec" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit">Oregon Department of Forestry</small></p><p><strong>Fertilizing the Ocean</strong> </p><p>Plants and plantlike organisms that live in the <a href="http://www.ecowatch.com/tag/oceans">ocean</a> absorb immeasurable amounts of CO2 each year, their ability to do so limited only by the availability of iron, nitrogen and other nutrients they need to grow and multiply. So researchers are looking at strategies for fertilizing the ocean or bringing nutrients up from the depths to hyperdrive plants' ability to trap and store carbon.</p><p>A decade or so ago, companies began forming to do just that, with the plan of reaping rewards from the soon-to-be-established global carbon market. Such plans have largely remained on the drawing board, stymied by substantial uncertainties over how to put a price tag on carbon, concerns over disrupting fisheries and ocean ecosystems more generally, and the high energy requirements and costs that would likely be involved. In addition, we don't have a clear picture of how much of the carbon trapped would actually stay in the ocean rather than reentering the atmosphere.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzYwOC9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYxMDkzNDk0Nn0.UZ9ls7oJ-lQksR-grJ60eCaBdcOZ4HVP8oTaPbgQ2M0/img.png?width=980" id="aa178" class="rm-shortcode" data-rm-shortcode-id="0c760208fe94de1c7b22e3f96a43a87e" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit">Creative Commons</small></p><p><strong>Rock Solutions</strong></p><p>CO2 is naturally removed from the atmosphere every day through reactions between rainwater and rocks. Some climate scientists propose enhancing this process—and so increasing CO2 removal from the atmosphere—through artificial measures such as crushing rocks and exposing them to CO2 in a reaction chamber or spreading them over large areas of land or ocean, increasing the surface area over which the reactions can occur.</p><p>As currently imagined, strategies to enhance carbon storage by reacting CO2 with rocks are expensive and energy-intensive due to the need to transport and process large quantities of heavy material. Some also require extensive land use and so have potential to compete with other needs such as food production and <a href="http://www.ecowatch.com/tag/biodiversity">biodiversity</a> protection. <a href="https://theconversation.com/worthless-mining-waste-could-suck-co-out-of-the-atmosphere-and-reverse-emissions-76436?utm_medium=email&utm_campaign=Latest%20from%20The%20Conversation%20for%20April%2021%202017%20-%2072345490&utm_content=Latest%20from%20The%20Conversation%20for%20April%2021%202017%20-%2072345490+CID_bd26e66f4cd1762d7110c87e8c3a76f5&utm_source=campaign_monitor_uk&utm_term=Worthless%20mining%20waste%20could%20suck%20CO%20out%20of%20the%20atmosphere%20and%20reverse%20emissions" target="_blank">Researchers are looking</a> at ways to use mine waste and otherwise refine the strategy to reduce costs and increase efficiency.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzYxMi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYwNjQ2MzA0Nn0.DoWhYMjw7pPdVpNpLh2U9mTmZlDQrKpUlcZZCgG2fMc/img.png?width=980" id="d705d" class="rm-shortcode" data-rm-shortcode-id="149c8ae2528ac3b9450de3023c1a5588" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit">iStockphoto.com/Dushlik</small></p><p><strong>Direct Air Capture and Storage</strong></p><p>The carbon-sequestering containers from Arizona State University's Lackner, along with other projects such as <a href="https://www.carbonbrief.org/swiss-company-hoping-capture-1-global-co2-emissions-2025" target="_blank">Climeworks' just-opened carbon-trapping facility in Switzerland</a>, represent one of the more widely discussed greenhouse gas capture and storage technologies being proposed today. Known as direct air capture and storage, this approach uses chemicals or solids to capture the gas from thin air, then, as in the case of BECCS, stores it for the long haul underground or in long-lasting materials.</p><p>Already used in submarines beneath the surface of the ocean and in space vehicles far above it, direct air capture theoretically can remove CO2 from the air a thousand times more efficiently than plants, according to Lackner.</p><p>The technology, however, is embryonic. And because it requires plucking CO2 molecules from everything else in the air, it is a huge energy hog. On the flip side, this approach has the big advantage of being deployable anywhere on the planet.</p><p class="shortcode-media shortcode-media-rebelmouse-image"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xMDA0NzYxMy9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0MDk1MzM4NX0.u0trC9xPd4xkSjAJkXfjU4VQcZpA-gCuKhnUJypYAGg/img.png?width=980" id="a6a8b" class="rm-shortcode" data-rm-shortcode-id="75612d5a9eb9cc298dcdad3e700957ba" data-rm-shortcode-name="rebelmouse-image"><small placeholder="add photo credit..." class="image-media media-photo-credit"><a href="https://www.pri.org/stories/2015-08-30/artificial-tree-part-solution-climate-change-these-guys-think-so" target="_blank">Ari Daniel for PRI's The World</a></small></p><p><strong>Where to From Here?</strong> </p><p>If anything is clear from this summary, it's these two things: First, there is a lot of potential to augment efforts to reduce CO2 emissions with strategies to increase the removal of CO2 from the atmosphere. Second, there's a lot of work to be done before we're able to do so at a meaningful scale and in a way that not only closes the carbon gap but also protects the environment and meets more immediate human needs.</p><p>"Based on current technology, there really is no combination of negative emissions technologies currently available that would be employable at sufficient scale to help meet the below-2 °C target without truly significant impacts," said Peter Frumhoff, director of science and policy and a chief scientist with the <a href="http://www.ucsusa.org/" target="_blank">Union of Concerned Scientists</a>. "We can in principle deploy negative emissions technologies, but we do not have the understanding or the policies to do so on a sufficient scale."</p><p>With the need to do something becoming ever more urgent, researchers are starting to <a href="https://deepblue.lib.umich.edu/handle/2027.42/136610" target="_blank">take a closer look at the pros, cons and potential of the various opportunities</a> and put together <a href="https://www.carbonbrief.org/uk-launches-world-first-research-programme-into-negative-emissions" target="_blank">research agendas</a> to advance the most promising in the right places at the right time. In May 2017, a National Academy of Sciences study panel began holding <a href="http://nas-sites.org/dels/studies/cdr/" target="_blank">a series of strategy sessions</a> to identify research priorities for moving forward.</p><p>"Our job on this committee is to recommend a research agenda to solve a lot of these problems, to bring the cost down, to bring the efficiency of the program up, to overcome the barriers for scale up and implementation and governance and especially verification and monitoring," panel chair Stephen Pacala, professor of ecology and evolutionary biology with Princeton University, said in a <a href="https://vimeo.com/222359789" target="_blank">video describing the initiative</a>.</p><p>That said, it's important to remember that technology may not be the limiting factor in the long run.</p><p>"I don't think it's a technical challenge," said Deich. "I think it's a willingness to pay and a willingness to get clear, consistent and fair regulations around these solutions." In other words, getting carbon storage up and running ultimately is about creating markets and/or policies that reward it while also taking into consideration social and environmental dimensions. "It's not necessarily, 'Can these things get to scale?' It's, 'Is there somebody who's willing to pay for them to get to scale?"</p><p>The most obvious way to do this would be to affix a <a href="http://www.ecowatch.com/tag/carbon-tax">price to carbon</a>, which would translate into financial benefit for socking it away.</p><p>In the end carbon storage is not cheap, Smith admits—but, he points out, neither is climate change.</p><p>The way Lackner puts it is this: We're traveling at high speed down a mountain in a car coming up to a hairpin turn, and it's not so much a question of whether we hit the guard rail as to whether we can slow down enough, so that when we do we bounce off rather than catapult over it into oblivion.</p><p>"I cannot guarantee it will work," he said of his CO2-trapping devices. "I'm an optimist, but I likely cannot guarantee it. The fact that it might not work, the possibility that it might not work, is not by itself an excuse not to try. If we don't make it work, I am very certain we will be in for very tough times."</p><p><em>Reposted with permission from our media associate <a href="https://ensia.com/features/sequestration/" target="_blank">Ensia</a>.</em></p>
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By Mary Hoff
What should we be thinking about when we think about the future of biodiversity, conservation and the environment? An international team of experts in horizon scanning, science communication and conservation recently asked that question as participants in the eighth annual Horizon Scan of Emerging Issues for Global Conservation and Biological Diversity. The answers they came up, just published in the scientific journal Trends in Ecology & Evolution and summarized below, portend both risks and opportunities for species and ecosystems around the world.
"Our aim has been to focus attention and stimulate debate about these subjects, potentially leading to new research foci, policy developments or business innovations," the authors wrote in introducing their list of top trends to watch in 2017. "These responses should help facilitate better-informed forward-planning."
1. Altering Coral Bacteria
Around the world, coral reefs are bleaching and dying as ocean temperatures warm beyond those tolerated by bacteria that live in partnership with the corals. Scientists are eyeing the option of replacing bacteria forced out by heat with other strains more tolerant of the new temperatures—either naturally occurring or genetically engineered. Although the practice holds promise for rescuing or resurrecting damaged reefs, there are concerns about unintended consequences such as introduction of disease or disruption of ecosystems.
2. Underwater Robots Meet Invasive Species
If you think getting rid of invasive species on land is a challenge, you haven't tried doing it in the depths of the ocean. Robots that can crawl across the seafloor dispatching invaders with poisons or electric shock are being investigated as a potential tool for combating such species. The technology is now being tested to control crown-of-thorns starfish, which have devastated Great Barrier Reef corals in recent years and invasive lionfish, which are competing with native species in the Caribbean Sea.
3. Electronic Noses
The technology behind electronic sensors that detect odors has advanced markedly in recent years, leading biologists to ponder applications to conservation. Possibilities include using the devices to sniff out illegally traded wildlife at checkpoints along transportation routes and to detect the presence of DNA from rare species in the environment.
4. Blight of the Bumblebees
We tend to think of pollinating insects as our ecological friends, but in the wrong place nonnative bees can spell trouble instead by competing with native insects, promoting reproduction in nonnative plants and potentially spreading disease. And they're doing just that, thanks to people who transport them internationally for plant-pollination purposes. Out-of-place bumblebees are already spreading through New Zealand, Japan and southern South America, and there is concern they could do the same in Australia, Brazil, Uruguay, China, South Africa and Namibia.
5. Microbes Meet Agriculture
Select bacteria and fungi are emerging as potential agricultural allies for their ability to help kick back pests or stimulate growth in crops. As research advances in this area, questions are being raised about potential implications for nontarget species, ecosystems, soils and more.
