No trees were harmed in the making of this video (they were all felled in a big windstorm).

A video showing the trail up to the main peak of Mount Jade—the tallest mountain in Taiwan—and back, with narration on its history, ecology and climate.

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By Paul Hockenos

Home and commercial solar arrays provide nearly a fifth of Australia’s electricity generation, with panels atop one in every three homes. To extend those panels’ usefulness, owners are increasingly buying home batteries not only to store their power for later use, but to sell electrons to the grid at times of high demand. The arrangement enables grid operators to more effectively manage the mismatch between midday solar generation and real-time consumer demand, a process known as balancing. It also lowers market energy prices because utilities that draw on batteries can avoid building expensive new power plants and power lines.

Australia laid the groundwork for this transformation last year by offering homeowners and small businesses a 30 percent discount on residential batteries, which resulted in 430,000 battery installations in less than a year, three times more than expected. A recent expansion of the Cheaper Home Batteries Program is expected to boost the number of installations to more than 2 million by 2030. If they agree to install a smart meter, battery owners can sell energy to the grid and put cash in their pockets: between $80 and $1,600 a year, depending on how the program is structured.

In a dozen other countries, mostly in Europe and North America, grid operators are writing checks to homeowners for the right to lease their batteries. “We’re moving toward a world where homes don’t just consume energy — they store it, optimize it, and contribute back to the grid,” says Joe Frodsham of the Texas-based energy storage manufacturer Renon Power. A critical mass of home batteries scattered across a region and networked together through so-called virtual power plants, or VPPs, he says, marks “the shift from energy storage as backup to energy storage as an active grid asset.”

Last year, the amount of U.S. home battery capacity enlisted in virtual power plants grew by 153 percent. Unlike a net metering system, which sends unused energy from rooftop solar panels directly into the grid in return for an energy credit, a VPP requires a storage system and software that tells the battery to send energy to the grid when it needs more power, like on a hot summer day. Compensation for tapping a homeowner’s battery is paid by either a local utility or a VPP program, of which there are now more than 500 in the U.S. and thousands in Europe.

This rapid expansion of home batteries and advanced software that aggregates thousands of decentralized energy sources is “transforming not only the way electricity is generated, but also how it is traded, delivered, and consumed,” concludes a 2022 International Energy Agency report. These assets, the report said, “can provide valuable services to the grid when incentivized with appropriate technologies, policies, and regulations.”

Currently, fewer than 10 percent of Australian homeowners who have solar arrays have signed contracts with energy providers. But experts believe the model has immense potential to expand, thanks to a global “battery revolution” that has, in a matter of years, seen battery prices plummet and their storage capacity shoot up even as their size has shrunk. Today, a 10 kilowatt-hour unit — which can simultaneously run a few household appliances and some lighting and electronics for 24 hours — can snugly fit under a staircase or into a garage corner. Between 2010 and 2020, battery density increased by more than 700 percent, and between 2010 and 2023, the price of lithium-ion batteries plunged from about $1,400 per kilowatt-hour to less than $140 per kilowatt-hour — one of the fastest cost declines of any energy technology in history.

Climate experts hope that grids can be cheaply and effectively balanced by hundreds of thousands of batteries distributed across cities, suburbs, and rural areas — some in electric vehicles, others on the walls of garages or cellars, and some in utility-scale storage parks, which still provide the lion’s share of solar-energy storage everywhere in the world. Ideally, aggregating the capacity of decentralized batteries — whether they are charged by solar panels or directly through the grid during off-peak hours — will replace dirty gas peaker plants.

Large battery projects, says a May report from the energy think tank Ember, “are increasingly cost-competitive and faster to build than new gas power plants.” And their carbon footprint is about 87 percent smaller than an average-size gas peaker. Home batteries offer similar advantages. When home battery systems are programmed to charge during times of high renewable output and discharge during peak grid demand, studies show they can reduce average household emissions by 2.2 to 6.4 percent.

Last year, the amount of U.S. home battery capacity enlisted in virtual power plants grew by 153 percent.

Programs in Puerto Rico and California that paid homeowners for their stored energy were a “key driver of the growth,” according to policy and research analyst Madeline Turner of San Diego-based Ohm Analytics. California’s VPP program, according to Canary Media, “has shown that its fleet of home batteries can be relied on much like a traditional power plant.” During a two-hour test last July, roughly 100,000 home batteries delivered about 539 megawatts of energy — more than the output of a large gas peaker plant.

In the U.S., an installed 10 kilowatt-hour system costs roughly $8,000 to $13,000. A 30-percent federal clean energy credit ended in 2025, although customers can still benefit until 2027 from tax incentives by leasing a battery system from a commercial solar or battery company. California offers an additional baseline rebate of around $150 per kilowatt-hour.

In Puerto Rico, which has a particularly rickety power grid, 70,000 home batteries are helping to reduce the risk of blackouts.

Residential storage markets function differently from country to country, and in the U.S. from state to state, as do their payment schemes. In Germany this spring, Octopus Energy’s PowerDrive bundle began providing customers with a smart meter and an EV charger that enables electricity to flow in two directions, allowing it to manage its customers’ EV charging in exchange for up to 10,000 free miles of driving, plus an annual bonus of up to $409 if the EV is plugged in, at home, for 300 or more hours. Octopus makes money selling the power stored in customers’ EVs when demand peaks and prices spike. The nation’s EV ownership rate is just under 3 percent, though, so the total impact of vehicle-to-grid technology is quite small.

Since 2022, the U.K. has had a system that pays homeowners for reducing demand when the grid is stressed — whether by high demand or a lack of wind, which provides about 30 percent of the U.K.’s total electricity generation. Battery owners have the advantage of being able to rely on their batteries during these periods. In Puerto Rico, which has a particularly rickety power grid, some 70,000 home batteries are helping to reduce the risk of blackouts, according to the grid operator.

Germany’s largest VPP is Statkraft, whose software links a multitude of decentralized energy resources including a few large fossil-fueled power plants, biogas and hydroelectric plants, thousands of solar and wind farms, and thousands more residential and commercial batteries. It markets its tidy bundles of energy on short-term European power exchanges.

With the growing demand for power, and long waits for grid connections, utilities are prepared to pay storage owners for the right to lease their batteries. But because the demand for and price of energy on a macro scale is different than the needs of a single household, most VPPs won’t optimize price fluctuations to benefit a household budget. Rather, they will optimize those fluctuations to benefit their own business model. A homeowner may prefer to charge their battery overnight, when the price of power drops, and discharge it in the late afternoon, when prices surge. But a VPP will charge and discharge the battery as needed to balance the grid — even if prices are unfavorable to the homeowner.

The primary drawbacks of joining a VPP, says Toby Couture of E3 Analytics, a Berlin-based energy think tank, are the household’s loss of control over when and how much power a third party can call upon (though most plans allow battery owners to set a reserve level), uncertain financial returns, and some additional wear and tear on the battery from extra cycling. A 2025 study found that EVs enrolled in a VPP program degraded 9 to 14 percent faster over a 10-year period. Another drawback is the high purchase price of home batteries, although some countries and several U.S. states offer subsidies.

Australia’s policies, which have reduced regulatory hurdles and challenges to integrating residential power, have made it the frontrunner in bidirectional storage, and similar policies in other countries could propel the clean energy transition forward. Where two-way battery storage makes financial sense to grid operators and battery owners, whether large or small, virtual power plants will likely expand in places where regulatory conditions allow, experts say. This is the logic of a battery revolution that is just beginning to transform our electricity markets.

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By Susan Cosier

Five small islands roughly the size of backyard swimming pools float next to the concrete riverbank of Bubbly Creek, a stretch of the Chicago River named for the gas that once rose to the surface after stockyards dumped animal waste and byproducts into the waterway. Clumps of short, native grasses and plants, including sedges, swamp milkweed, and queen of the prairie, rise from a gravel-like material spread across each artificial island’s surface. A few rectangles cut from their middles hold bottomless baskets, structures that will, project designers hope, provide an attachment surface for freshwater mussels that once flourished in the river.

Three thousand square feet in total, these artificial wetlands are part of an effort to clean up a portion of a river that has long served the interests of industry. This floating wetland project is one of many proliferating around the world as cities increasingly look to green infrastructure to address toxic legacies. In the United States, researchers are conducting experiments in Boston and Baltimore as well as in Chicago, each team sharing best practices with the other to maximize the ecological benefits of their systems. The Canadian government and local municipalities are allotting more funding for innovative projects. Floating wetlands are also multiplying in the United Kingdom, and studies to quantify additional benefits continue in Australia and Brazil.

Floating wetlands filter contaminants and take up excess agricultural nutrients that can lead to algal blooms and dead zones.

Like natural wetlands, floating versions provide a range of ecosystem services. They filter sediment and contaminants from stormwater, and laboratory experiments show that some plants have the ability to lock up some chemicals and metals found in acid mine drainage. These systems take up excess agricultural nutrients that can lead to algal blooms and dead zones, and recent research suggests they could be used to reduce manmade contaminants that persist in the environment. Though it’s difficult to quantify the exact benefits these systems offer, and they have limitations as a tool in remediating polluted waterways, they could provide another option, researchers say.

Nick Wesley, executive director of Urban Rivers, a nonprofit working with the Shedd Aquarium on the Chicago project, believes floating systems are a natural fit for the urban environment. Many urbanized river systems, he says, have the same “steel sheet pile wall, some rough-wrap riprap on the edges. We’re trying to [restore] what the naturalized river would be.” In many cities, he continues, floating wetlands could provide a low-cost alternative to conventional infrastructure projects because they’re modular and easy to install and to monitor.

Wesley’s group began, in 2018, with a floating wetlands project on the Chicago River’s North Branch. Called the Wild Mile, the installation aims to improve water quality and has already begun attracting invertebrates, including mollusks and crustaceans. Last month, the group expanded to the shores of Bubbly Creek. Urban Rivers, Shedd employees, and a team of volunteers bolted together polyethylene and metal frames, draped them with matting, dropped them in the water, added plants, and anchored the islands to the river bottom so they stay in place as the roots grow into the water. The plants will grow for years to come, part of a “riverponic” system, as Wesley calls it, that requires no soil or other substrate for support.

Floating wetlands “are having a bit of a moment,” says Richard Grosshans, a research scientist with the International Institute for Sustainable Development who works on the floating structures. “They function very similarly to a natural wetland: they have the same processes, plants and microorganisms, bacteria and algae, [which] naturally break down toxins. They take up nutrients and provide habitat. It’s kind of common sense to those of us who work with these types of systems.”

Floating wetlands were first tested in retention ponds, the kind often located near developments to hold stormwater, to see if they filtered pollution. “The front end of it was, ‘Will they work? How well do they work? And what plants should we recommend?’” says Sarah White, an environmental toxicologist and horticulturalist at Clemson University who has worked on floating wetlands since 2006. Partnering with researchers at Virginia Tech, White found that the wetland plants she tested not only did well in ponds with lots of nutrient pollution, but the adaptable, resilient plants actually thrived. She did not always choose native plants, opting instead for those that would make the islands more attractive, so that more urban planners would use them.

In the early 2010s, Chris Walker, a researcher at the University of South Australia, began testing floating wetlands in wastewater, quantifying the pollutants that four species of plants took up in their tissues and improvements to water quality. Two species, twig rush Baumea articulata and the common reed Phragmites australis, showed the highest uptake of nitrogen and phosphorus of any floating wetland research to date. “That creates a real opportunity for [the] permanent removal of sequestered nutrients,” says Walker, who is also the principal scientist for a floating wetland company called Clarity Aquatic.

One acre of floating wetland can absorb the nutrient pollution from seven to 15 acres of urban development, one researcher found.

His team also started testing the ability of floating wetlands to filter out emerging contaminants like per- and polyfluoroalkyl substances (PFAS), which are not always filtered by treatment plants and are linked to elevated cholesterol levels, problems with reproductive health, and kidney and testicular cancers. The reed Phragmites australis placed in a floating wetland began absorbing the pollutant into its tissues in less than a month.

Islands anchored in cities are giving scientists an opportunity to study environments that have long been ignored. In Chicago, Austin Happel, a research biologist at the Shedd Aquarium, is beginning a study on fish near the floating wetlands in Bubbly Creek. Starting in the spring, he’ll use acoustic telemetry to tag fish captured near the wetland and monitor where they go. By the following year, he should be able to see if they use the floating wetlands as a buffet or as a place to hide from predators.

In Boston, Max Rome, a PhD student at Northeastern University, is attempting to quantify the benefits of wetlands that have been floating since 2020 in the Charles River, another historically degraded waterway. He found that one acre of wetland can absorb the nutrient pollution — usually dumped into the river via stormwater — from seven to 15 acres of dense urban development.

Rome is also looking into whether floating wetlands can create small pockets of improved water quality or habitat that allow certain native species, like freshwater sponges, to regain a toehold in the river. To do that, he monitored water quality near the wetlands and compared it to other places in the river.

“The last generation did a really good job of dealing with point source pollution — and it was a huge task,” he says, referring to the success of the Clean Water Act in reducing effluent from discharge pipes. His generation has a new job, he adds: grappling with “ecological restoration of these degraded water bodies at the same time that we do pollution reduction,” something the wetlands could help address.

Despite the benefits of floating wetlands, obstacles to widespread adoption remain. They require time and energy to install and monitor, and they could potentially cause flooding if they become unmoored and interfere with water flow. A city would also need hundreds of floating wetlands to clean up the most polluted stretches of waterways and manage the contaminants that continue to flow into them.

Another potential drawback is the threat of invasive plants colonizing a floating wetland, which would then require maintenance. One species that effectively sucked up PFAS in the Australian study, for example, is an aggressive invader already colonizing wetlands across the U.S. In addition, if the goal of a floating wetland is to permanently remove phosphorous and nitrogen from an ecosystem, managers may need to remove and compost plants so they don’t release the nutrients back into the environment when they go dormant, though ongoing research suggests that biofilms that form on plant roots and on the bottom of wetlands could continue to remove nutrients even after plants start to senesce. Plants that remove PFAS would likely need to be incinerated.

The National Aquarium in Baltimore is planning to expand its 400-square-foot floating wetland to 10,000 square feet by 2024.

Still, say researchers, floating wetlands do benefit the environment. “I think we’re just looking for one more tool in our toolbox to help manage water quality,” says Clemson’s White. “This gives us another place in the landscape where we can actually have a technology that will do it.”

The types of places that could be improved by these projects are growing more varied. The National Aquarium in Baltimore was the first place in the U.S. to test floating wetlands in a tidal system, and today 400 square feet planted in saltmeadow hay and smooth cordgrass float in the city’s Inner Harbor. The project has been so successful at lowering levels of nutrients and bacteria and at creating a refuge for wildlife — including American eels, gizzard shad, and ghost anemones — that the aquarium now plans to expand the islands to 10,000 square feet in 2024, says Charmaine Dahlenburg, the aquarium’s director of field conservation.

The Harbor islands are the National Aquarium’s fourth attempt at creating a thriving wetland system, demonstrating how difficult it can be to tailor a floating wetland to a specific location. When the aquarium first installed wetlands in 2010, geese invaded them and ate the plants. A similar problem occurred with a second version two years later. The third attempt fared better, thanks to fencing that excluded geese, but the fourth iteration — which incorporates a channel that prevents algal blooms from killing plants — fared the best.

National Aquarium researchers investigating how the floating wetlands help mitigate such blooms found that microscopic organisms on plant roots and on the bottom of the wetlands help move nitrogen from the water and through the food chain — from barnacle to crab to fish. There are ecosystem benefits above the waterline, too: Night herons and otters visit the islands, finding refuge in the grasses. Research on fish, birds, and mammals attracted to floating wetlands is not well developed, but these structures clearly provide habitat in places where buildings, bulkheads, and riprap have replaced natural wetlands.

The amount of contamination that plants can remove from aquatic environments depends on the amount and type of pollution, the plant species used, and the size of the floating wetlands. But some scientists, including Dahlenburg and Rome, are hoping that as research accumulates, government agencies will consider using such projects to mitigate contamination and wetland development.

In three Boston-area watersheds, a new regulation under the Clean Water Act will require certain commercial, industrial, and institutional properties with one or more acres of impervious surface to reduce nutrient and bacterial pollution in stormwater running off their properties, something never mandated before. Britain recently announced a requirement for homes and water companies to reduce water pollution. Floating wetlands that do that are already growing in London, and plans for other locations are in the works.

Regulations like these could compel cities to take a more aggressive approach to green stormwater infrastructure. “As that begins to happen,” says Rome, “the role that can be played by floating treatment wetlands is going to come into focus.”

The growing use of the buoyant, lush gardens — in cities that range from Australia to Europe to North America — show how even small wetland islands can make a difference. “Our little postage stamp of a wetland isn’t going to solve everything,” says Dahlenburg, of the Baltimore project. “What we’re trying to create is this model urban waterfront. We want other cities to know that there are ways to incorporate natural habitat, to bring back the ecosystem services that were lost because of industrial development.”

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cross-posted from: https://slrpnk.net/post/39477452

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FULL ARTICLE: While fuel shortages due to the Iran war made some countries double down on electrification, they also highlighted one industry that could be quite literally grounded without fossil fuels: aviation. Flying relies on fossil-based jet fuels and is extremely hard to decarbonize.

Researchers in China now report a process that could help bring down flying’s carbon emissions while also tackling the plastic waste crisis. The two-step process converts plastic waste into high-quality jet fuel more efficiently and at much less cost than other methods researchers have reported in the past to convert plastic waste to fuels.

The team’s preliminary analysis, reported in published in Nature Energy, shows that the plastic-based fuel would cut carbon dioxide emissions by 73% compared with petroleum-based jet fuel.

The plastic that the researchers break down is polystyrene. This lightweight polymer, often commonly called Styrofoam, is used to make packaging and insulation. It is notoriously expensive and challenging to recycle. Besides usually being contaminated, it is composed mostly of air, which makes sorting and transportation difficult. Nearly all waste polystyrene goes to landfill today.

The team from Nanjing Forestry University and Tsinghua University designed a new catalyst that breaks down polystyrene at high temperatures in the presence of hydrogen. Their process runs continuously in a tandem reactor.

The first reactor heats the polystyrene to 460°C in a hydrogen atmosphere step. This breaks the long polymer chains in polystyrene to shorter strands. In the second reactor, the fragments are passed over the ruthenium catalyst at 160°C. The resulting chemical reactions convert the fragments into molecules called alkanes. These are energy-dense hydrocarbon molecules that work for jet fuel.

Past work on making fuels from plastic waste include a one-step, low-temperature process as well as a method that is powered by sunlight and also utilizes carbon dioxide. This new method needs higher temperatures, but it is faster, has a much higher yield and requires lower pressures. But still, whether or not it can be cost-effectively scaled up remains to be seen.

In their study, the researchers show that the method converts 94.8% of waste polystyrene to liquid fuels. And their preliminary analysis shows that the fuel would sell for a minimum of $1–1.80 per kilogram, competitive with conventional fossil-based jet fuel.

Source: Jia Wang et al. Ambient-pressure conversion of plastic waste to jet fuel cycloalkanes by tandem hydropyrolysis and vapour-phase hydrogenation. Nature Energy, 2026.

FULL ARTICLE: There’s some good news growing along the coasts of countries around the world.

Mangrove forests, the imperiled ecosystems championed for their ability to store carbon and protect land from storm-driven flooding, are bouncing back.

These woodlands that thrive at the soggy boundary between land and sea suffered alarming declines through much of the 20th century, chopped down chiefly to make way for fish ponds, rice paddies and other kinds of agriculture. But in the last decade, mangroves have been gaining ground, erasing nearly all of the losses since 1980, according to research recently published in Science.

“After decades of loss, we’re finally seeing a global turning point for mangroves,” said Zhen Zhang, a postdoctoral researcher at Tulane University and lead author of the study.

Zhang and colleagues used computer programs to comb through 40 years of satellite images from around the world. The distinctive way mangrove forests reflect light enabled them to train the computers to pick out this vegetation and track its ebb and flow over time.

The analysis revealed that in much of the world, years of loss began changing course in recent decades. Between the 1980s and 2010, global mangrove forests shrank from around 155,000 square kilometers to 152,000 square kilometers, a loss equal to half of Rhode Island. While that might not sound like a lot, mangroves often grow in relatively narrow coastal strips, so their coast-protecting benefits are outsized compared to their overall dimensions.

Since 2010, forests have rebounded to nearly 154,000 square kilometers, almost enough to recover from the losses dating back to the 80s.

“While some mangroves are still being lost, this could make them a rare conservation success story and an important source of optimism for climate action,” said Daniel Friess, a co-author who heads The Mangrove Lab at Tulane.

The greatest gains have come in southeast Asia, home to roughly a third of the world’s mangrove forests. The region gained more than 1,000 square kilometers of mangroves since 2010, the researchers found. Forests have begun bouncing back in other parts of Asia, South America and the Middle East as well.

While the reasons for the rebound vary from place to place, the researchers say many of the gains appear to be from forests colonizing terrain created by abandoned aquaculture ponds and from mudflats emerging along shorelines as sediment builds up. That is coupled with efforts to plant new mangrove forests, as governments and conservation groups have come to better appreciate their benefits.

In Indonesia, once a center for mangrove declines, the recent gains appear to be linked to increased awareness and restoration on the heels of the devastating 2004 Indian Ocean tsunami, coupled with increased legal protections and management, the authors reported.

It’s not all good news, however. Some regions continue to lose ground, notably in Africa. There, mangroves have declined in recent years in Nigeria’s Niger Delta, the continent’s largest mangrove system, due at least in part to damage from oil pollution.

And some places that are making gains still haven’t recovered from previous losses. Myanmar has witnessed a 10% increase in mangrove forests since 2010. But that still leaves it with a net 29% decline since the 1980s.

The tree’s remarkable ability to quickly colonize land suggests that rather than pursuing tree-planting projects, conservation work might be better spent protecting existing forests and the earth-building dynamics that create mudflats, the authors noted. The trees can then spread on their own. Sometimes the most important thing humans can do for restoring nature is get out of the way.

Zhang, et. al. “Unexpected expansion and regrowth in Earth’s mangrove forests over the past four decades.” Science. June 4, 2026.

FULL ARTICLE: In the coastal waters off British Columbia, tribal volunteers from the Haida Nation dive for purple sea urchins amid a dense forest of rippling golden-brown kelp fronds. Sunlight filters through the canopy, creating a mesmerizing dance of light and shadow, as rays and sea lions wend through the kelp maze, sharks glide past, and bright orange garibaldis dash between the swaying fronds.

Kelp forests are biodiversity hotspots teeming with a colorful variety of seaweeds, sponges, crustaceans, and other small ocean animals, many of them found nowhere else. At one time, vast kelp beds grew in nutrient-rich shallow waters along roughly a third of the world’s coastlines, where they helped to reduce the strength of waves, minimized coastal erosion, and provided shelter to fish, invertebrates, and marine mammals.

Today, however, many kelp forests are on life support, victims of water pollution from terrestrial agriculture and coastal development, bottom trawling for fish, and an explosion of kelp-devouring urchins, like those the Haida volunteers are collecting as part of an eradication program. But perhaps the most important driver of kelp decline is the rapid warming of the ocean.

Healthy kelp forests need cool, nutrient-rich seawater to survive. As ocean waters warm, kelp can no longer inhabit parts of their former range. The crisis is escalating quickly. Kelp forests are vanishing twice as fast as coral reefs and four times faster than tropical rainforests. An estimated 40 percent to 60 percent of kelp forests worldwide have been lost or significantly degraded in the last 50 years. These precipitous declines typically received far less scientific scrutiny than higher-profile ecological crises. But kelp has gradually been getting more attention as scientists and the environmental community come to recognize the value of the carbon that coastal ecosystems, including kelp forests, can capture.

A 2023 literature review of more than 180 papers that examined the potential for kelp to store carbon suggested that the climate benefits of these underwater forests may have been “grossly underestimated,” says Albert Pessarrodana, a research fellow at the University of Western Australia and the review’s lead author. “Kelps are one of the fastest growing plants on the planet,” he said in an email interview, “uptaking as much carbon as tropical rainforests per unit of area.”

Much of the carbon that kelp sequesters ends up being released back into the marine environment in the form of leaf litter (kelp, which is a macroalgae, has leaflike structures called blades that are its organs of photosynthesis.) This detritus is typically ingested by fish and other marine organisms and excreted in a matter of days. Still, a small percentage of it ends up in the deep ocean where it remains for centuries, or even millennia. Roughly 62 million tons of carbon is carried into the deep ocean by coastal currents each year, according to two studies published in 2024.

“Unfortunately,” Pessarrodana says, “excessive warming can either kill kelps or severely curtail their growth, reducing their ability to uptake carbon.”

To counter the decline, scientists around the world are breeding new kelp varieties that they transplant as saplings into kelp habitat. The Scripps Institution of Oceanography and the San Diego Zoo have begun using artificial intelligence to digitally replicate kelp ecosystems and assess their vulnerability to climate change. Their findings will help focus resources on areas that are most likely to be saved. The organizations have also established a biobank to preserve kelp varieties for potential use in kelp farming and restoration projects. Researchers at the Woods Hole Oceanographic Institution on Cape Cod are using selective breeding to develop kelp strains with a higher tolerance to warming waters. Similar efforts are underway in China and Australia.

The Nature Conservancy’s Scott Breschkin has been working for the past year to eliminate urchins and replant beds of golden kelp on Australia’s Great Southern Reef, an interconnected system of rocky kelp reefs spanning about 5,000 miles of coastline across southern Australia and the island of Tasmania. Though less famed than the Great Barrier Reef, it is equally biodiverse, boasting thousands of species, some of which are still unknown to science.

As Australia’s coastal waters warm, long-spined urchins are expanding their ranges, leaving virtually lifeless urchin barrens in their wake. “Once the reef transitions to an urchin desert, it is very hard to flip it back to a productive kelp habitat,” Breschkin explained, adding that urchins can persist for decades in a zombie-like state, awakening only occasionally to mow down any kelp sprouts that may appear, which makes it virtually impossible for kelp forests to recover. Eradicating sea urchins, he says, is a critical first step for kelp restoration.

Jono Wilson, the director of ocean science for The Nature Conservancy’s California chapter, works with KelpWatch.org, a partnership of academic institutions and government agencies that is using satellite imagery and drones to monitor the distribution of canopy-forming kelps along California’s Pacific coast and assess where kelp restoration efforts have been successful. These undersea forests are often characterized by boom-and-bust cycles, flourishing and retreating as ecological conditions change, Wilson says. But recent climate-driven losses have been unprecedented. A 2013 to 2015 ocean warming event known as “the Blob” reduced kelp populations in Northern California by 95 percent.

Since 2015, water temperatures in California’s kelp forests have not dropped below 57 degrees F, a rough threshold beyond which kelp cannot thrive. Higher temperatures disrupt the kelp reproductive cycle, affecting their ability to produce viable offspring. Like corals, kelp bleaches when stressed, losing the chlorophyll that allows it to photosynthesize.

Kelp diebacks transform their ecosystems. “Kelp provide habitat and food for thousands of species,” says Wilson. “They are nurseries for abalone and economically important fish species like cod and rockfish. They are meccas for kayakers and recreational scuba divers.” The Nature Conservancy estimates that kelp forests contribute $250 million in economic value to California annually.

While kelp forests in Southern California are faring reasonably well — the dominant species, called giant kelp, grows quickly and can reach up to 200 feet tall — purple sea urchins are wiping out kelp beds dominated by bull kelp along the coasts of Central and Northern California. Wilson and his team are exploring ways to control those urchins. They are developing new kinds of more efficient urchin traps — round mesh devices baited with fish — and working with fertilizer companies to create a viable market for urchin shells, which contain calcium, nitrogen, and other plant nutrients. The Norwegian seafood firm Ava Ocean is currently using crushed urchin shells to produce a mineral-rich alternative to traditional bone-meal fertilizers.

There have also been attempts to support the native sunflower sea star, a voracious consumer of sea urchins. Populations of this predatory starfish, which can grow as large as a car tire, have been reduced by 90 percent since the outbreak, in 2013, of sea star wasting disease.

Scientists recently isolated the bacterium responsible for the epidemic, giving them a better shot at helping sea stars recover. Aquariums in California and Oregon have successfully treated their affected sea stars with antibiotics, and scientists are hoping to learn how to breed disease-resistant sunflower starfish that can be released into the wild.

There have also been efforts since the late 1980s to breed and reintroduce sea otters, another urchin predator, to the coastal waters where they once flourished. Driven to the edge of extinction by the fur trade in the 19th and early 20th centuries, otters have now substantially recovered in parts of their former range. They now number well over 3,000 individuals in Northern California. Otters are also staging a comeback along the coast of Washington and British Columbia. Kelp forests where the otters have been released are faring noticeably better than kelp forests without otters.

So far, kelp restoration projects in the U.S. have been small scale, with most covering less than a hundred acres. Such projects are “very expensive and subject to zoning laws that make [them] hard to initiate,” says Kyle Cavanaugh, a coastal geographer at the UCLA Institute of the Environment and Sustainability. “These localized projects need to be scaled up if we hope to turn the tide on the loss of kelp habitat.”

Kelp restoration is happening on a far larger scale in East Asia. More than half of South Korea’s kelp forests have been lost or badly degraded over the past century. But thanks to the world’s largest kelp restoration projects, the nation now boasts 71,660 acres of kelp forest. Its goal is to eventually re-green 75 percent of its coastline. Farmers in South Korea harvest nearly a billion dollars worth of seaweed each year, cutting only the upper fronds and blades of the macroalgae. There are also more than 700 restoration projects in Japan where kelp, known as kombu, is a staple in Japanese cuisine, most commonly used in soups.

Kelp’s value as a food source, and to a lesser extent as an ingredient in cosmetics, skincare products, and biodegradable packaging, may be one key to its survival. But if we don’t find a way to slash emissions of greenhouse gases, experts say, the long-term prospects of kelp and other key ocean ecosystems may be bleak. “It’s likely that we’ll see more destructive marine heat waves and warmer waters overall,” says Cavanaugh. “Beds of far less-productive turf algae will replace giant kelp and prevent it from becoming reestablished.”

In Maine and in other coastal regions around the world, carpet-like turf algae is already replacing kelp, according to a paper published last month by the Bigelow Laboratory for Ocean Sciences in Maine. This is “a radical ecological transformation,” says the University of Maine’s Shane Farrell, the study’s lead author. “The good news is we now understand what’s driving this shift, and this will help us predict when and where it will happen next and create different conservation strategies to combat it.”