Despite the fact that clouds envelop two-thirds of the planet at any given time, transport water on the wind, and shield the Earth from the sun, surprisingly little is known about how climate change affects them. Atmospheric scientists are not yet certain, for instance, whether rising temperatures will lead to more or fewer clouds, or make them better or worse at reflecting the heat of the sun.
To help unravel those mysteries and others, the European Space Agency and the Japanese Aerospace Exploration Agency lofted a satellite into orbit last week aboard a SpaceX rocket. The Earth Cloud Aerosol and Radiation Explorer, known as EarthCARE, will uncover the inner workings of clouds as well as how they, and tiny airborne particles called aerosols, shape — and are shaped by — climate change.
“Clouds are the number one cooling blanket we have on the planet,” saidPavlos Kollias, an atmospheric scientist from Stony Brook University who has been supporting the EarthCARE mission since 2008.
A cloud’s effect on temperature greatly depends on the height where it happens to float. Low-level formations, such as the blanket-like stratocumulus, do a particularly good job of keeping the planet cool by reflecting most of the sunlight that strikes them. Since they fly so close to the ground, their ambient temperatures are similar to those of the landscape below, and they transfer most of the Earth’s heat to space rather than holding it in the atmosphere.
The cooling effect this provides is so pronounced, Kollias said, that without it the planet would be 15 degrees Celsius warmer — or nearly 30 degrees Fahrenheit. That’s the difference between a mild spring and a blistering summer.
Though the impact clouds have on the planet in the present is well known, scientists are uncertain about how that may evolve as temperatures rise. “If you perturb the system by adding temperature,” Kollias said, “we don’t know how the clouds will respond.” They could become more common and more dense, thereby mitigating climate change in a minor way, or they could become less common and less dense, speeding climate change along.
High-altitude clouds, like the wispy cirrus, for instance, are typically made of tiny ice crystals and often trap the Earth’s heat more effectively than they block the sun’s light, both of which seems to make them more sensitive to warming. Aerosols, small particles like sulfates and sea salts, introduce further complications by impacting climate both directly, by reflecting sunlight, and indirectly, by acting as the nuclei around which clouds condense. Efforts to clean up industrial emissions are reducing airborne aerosols, with pronounced effects on climate.
EarthCARE’s cloud profiling radar allows scientists to observe the internal structure of clouds, providing detailed insights into their vertical structure and velocity, particle size distribution and water content.
ESA/ATG medialab
Kollias is eager to work with the data that will begin beaming down from the new satellite later this year. The mission carries an instrument never before used in space: a cloud profile radar. The device will emit successive bursts of radio waves, measuring the signal reflected by the vapor below. This information will help researchers better understand the size and circulation of the countless droplets that comprise a cloud. EarthCARE will also map the surface profile of clouds and aerosols with a method known as lidar that reflects a low-power laser off these atmospheric formations. Those measurements coupled with images captured by the spacecraft will provide a three-dimensional view of the ubiquitous pillows and blankets of condensation drifting through the sky.
The European Space Agency named EarthCARE its sixth Earth Explorer mission back in 2001. Though delays plague seemingly every satellite, EarthCARE faced notable and protracted setbacks due to the complexity and sophistication of the radar and lidar systems. It reached a point where, Kollias said, some outside the mission began to doubt whether the nearly $900 million satellite would ever reach the launchpad. Yet “nobody gave up,” Kollias said. “Everybody kept working.”
All that made last week’s successful launch a particularly emotional affair.
“Personally, I was very nervous in the moment,” Kollias said of the launch. But he added that the prolonged process has inadvertently given the scientific community more time to prepare to work with EarthCARE’s data. Numerical models have improved dramatically in the 23 years between selection and launch, researchers have more computing power available to them than ever before, and machine learning now allows big data to be digested with comparative ease.
The intervening years have also given the world a taste of the climate disasters yet to come. As a result, an added urgency drives the desire to resolve the uncertainties clouds introduce into climate models, so scientists can look out with finer eyes to tell us what the decades ahead hold.
More than 2,000 people are gathering in Hawaiʻi this week and next for the 13th Festival of Pacific Island Arts and Culture. It’s the largest gathering of Indigenous Pacific peoples in the world. And it comes at a critical time for the island region known as Oceania as sea levels, storms, and other climate effects threaten traditional ways of life and connections to land and sea.
Normally the festival takes place every four years and rotates between the three regions of the Pacific: Polynesia, Micronesia, and Melanesia. But because of the pandemic, the event hasn’t happened for eight years. It was last held on Guam, and this is the first time since it was established in 1972 that it’s occurring in Hawaiʻi. From now through June 16, Indigenous peoples from more than two dozen Pacific nations and territories will be sharing their weaving, tattoo creations, films, visual art, wood carvings, dances, songs, literature, music, food, and other expressions of Indigenous culture.
Tarcisius Kabutaulaka, a University of Hawaiʻi professor from the Solomon Islands and former director of the university’s Center of Pacific Island Studies, said even though the focus of the festival is on performing arts, Pacific cultures are deeply interwoven with the environment.
“We produce and perform our culture vis-à-vis the environment,” said Kabutaulaka. “The baskets that we weave, the dances that we dance, are often about the environment. We use materials around us to create material culture.”
That interdependency makes climate change an existential threat. In Kiribati, Kabutaulaka said, taro is a key source of food and cultural celebrations, but sea level rise and resulting saltwater intrusion into islands’ freshwater lens, is making it harder to grow the starch. Forced relocation is another ongoing problem. Just two weeks ago, Papua New Guinea was the site of a deadly landslide that buried a village. Climate change will make such extreme weather events more common, forcing villages to relocate and severing Indigenous Pacific peoples’ connection to their ancestral lands.
The festival is also happening as island nations continue to deal with the ongoing effects of colonialism. New Caledonia’s delegation pulled out at the last minute after France’s efforts to push through a referendum that would dilute Indigenous voting power prompted protests and violence.
On Friday, the festival will feature a roundtable discussion on climate change featuring political leaders from Palau and the Federated State of Micronesia. On Sunday, local activists are speaking on militarization and environmental justice, and the connections between Hawaiʻi and Palestine.
Kabutaulaka is also helping to organize an academic event called Protecting Oceania that will include discussions of climate change, deep sea mining, mental health, and other issues. “It grapples with the idea of protection, what we are trying to protect, and how we are protecting it,” he said.
But the heart of the festival is still the arts. Vilsoni Hereniko was a student in Fiji in 1972 when the first Festival of Pacific Island Arts and Culture was held. He’s now a weaver, playwright, scholar, and a professor of cinematic arts at the University of Hawaiʻi.
“There will always be academic conferences,” said Hereniko, who is Indigenous to Rotuma, a Polynesian island in Fiji. “But you won’t always have a hundred people from Fiji to come to Hawaii to dance the old dances and sing and chant in the ways of ancestors.”
He plans to show two of his films on the coconut tree in Hawaiʻi, where the tree, beset by invasive beetles, has often been reduced to an ornament for tourists, instead of a critical source of food and nourishment. “In a way, the coconut tree without its coconut symbolizes colonization and what it’s done to the Native people,” Hereniko said.
The festival officially kicked off with an opening ceremony Thursday evening. But the day before it began with a private event on the windward side of Oʻahu, where thousands gathered to welcome crew members of voyaging canoes. Among them was the canoe Marumaru Atua, which arrived in Honolulu last weekend after sailing for 23 days from Rarotonga in the Cook Islands. The 16-person crew navigated to Hawaiʻi using traditional knowledge of the stars and sea.
Teina Ranga is a Māori Cook Islander who is part of the Cook Islands voyaging society but flew separately to Honolulu at the last minute to join the delegation. He runs a nongovernmental organization helping young islanders reconnect with their culture through fishing and farming, and hopes the festival will continue to focus more on environmental issues moving forward.
“When do we ever have an opportunity to bring Pasifika together?” he said. “We need to push the idea of valuing who we are. The world cannot just continue [on this path]. I don’t want the Cook Islands to look like this conquering city.”
The Midwest’s largest potential reservoir to store carbon is buried deep under the farmland of Illinois, and the state’s lawmakers just hit the brakes on any plans for a carbon capture and storage boom there.
A controversial technology where carbon dioxide is captured and then stored deep underground, carbon capture and storage, or CCS, is a big part of the Biden administration’s push for a greener planet. And a federal roll out of massive incentives for the nascent industry has spurred a carbon capture gold rush nationwide. In Illinois alone, three pipelines and 22 carbon sequestration wells have already been proposed. But local farmers, landowners, and environmental advocates are skeptical of the suddenly booming business and called on the state for stricter safety regulations.
That’s what happened at the end of May.
The state’s lawmakers passed the Safety CCS Act through both chambers at the tail end of the legislative session over the Memorial Day weekend. Illinois governor J.B. Pritzker, a Democrat, has yet to sign the legislation, but has signaled his intention to do so.
The package includes sweeping regulations for the state’s burgeoning carbon capture industry, including a moratorium of up to two years on pipelines transporting CO2 or until federal authorities pass new pipeline safety guidelines. It’s the first ban of its kind in the Midwest.
“It does offer some really good protections for Illinois that are needed at a time when we are not just anticipating projects — but those projects are moving forward rapidly,” said Pam Richart, the co-founder of the Coalition to Stop CO2 Pipelines, an environmental advocacy group that has been organizing across southern and central Illinois.
The sweeping package of new rules breaks down into three categories: requirements for how carbon emissions must be captured, regulations around pipeline construction, and rules for what happens once the carbon is stored underground.
The legislation establishes a “do no harm standard,” which would prevent polluting facilities from pumping more emissions to take advantage of the beefed up federal tax credits, according to Jenny Cassel, a senior attorney with Earthjustice, a public interest environmental law organization.
The new rules do so by requiring that capture facilities store more carbon pollution than they produce. At the same time, power plants and other carbon-intensive industries must keep greenhouse gas emissions below what their permits allow.
“We should not be creating more of a problem than we’re addressing with this,” said Cassel. “And that’s what this mandate will require.”
Richart’s organization has been calling for a CO2 pipeline moratorium since it was founded in 2022. The moratorium will last two years or until the federal Pipelines and Hazardous Materials Safety Administration finalizes its long-awaited safety rules. The law also empowers Illinois’ public utility commission to complement PHMSA’s incoming rules with expanded safety regulations.
Lastly, the law fills a giant liability-shaped hole left wide open by existing federal regulations. Companies looking to get into carbon storage need federal permits for Class-VI wells, which are used for the long term storage of carbon dioxide. But Cassel said those permits are lacking: They provide no guidance for who is on the hook if something goes wrong, nor do they settle the question of exactly who owns pore space, which is the geological formation used to store CO2.
The law settles both questions: It requires companies to monitor injection sites for at least 30 years and produce publicly available safety modeling. It also requires companies to pay into a statewide emergency fund. Under the new rules, pore space belongs to its surface owner, and companies interested in utilizing it must pay surface owners a fee.
Proponents of the controversial technology maintain if it pans out as intended, it won’t just be good for the climate — it could be a major economic windfall for Illinois.
“We can create about 14,000 jobs and about a $3 billion economic impact,” according to Mark Denzler, the president and CEO of the Illinois Manufacturers’ Association, citing a report by the University of Illinois’ Prairie Research Institute.
Denzler said the new regulations aren’t perfect. “We didn’t get everything we wanted. The environmental advocates didn’t get everything they wanted. But it’s a compromise,” he said. Denzler adds that at least now there’s regulatory certainty, and private interest knows what to expect and how to proceed.
Richart said the rules are a huge step forward for protecting major swaths of Illinois, but she has no plans to stop her advocacy. She points to crucial protections that were left out of the landmark legislation.
“We did not get the protections in place for the Mahomet aquifer,” Richart said of the sole source aquifer that serves over 500,000 people in central Illinois and advocates worry is dangerously close to where companies want to stash CO2.
Richart says her coalition has brought together unlikely allies, and that’s because as carbon capture begins to settle into the Midwest one thing is obvious: “We all recognize there’s a need to protect our land, our public health, and our water,” she said. “All of those things we can agree on.”
United Nations Secretary-General António Guterres has called for immediate action to avoid the world being in “climate hell” after this May was the warmest ever recorded, according to a recent report from the European Commission’s Copernicus Climate Change Service (C3S).
“It’s climate crunch time,” Guterres said at New York’s American Museum of Natural History on Wednesday, as UN News reported. “We stand at a moment of truth.”
Guterres emphasized that, though the need for measures to combat the climate crisis globally is at an all-time high, so are the occasions for sustainable development and economic prosperity.
“In the case of climate, we are not the dinosaurs. We are the meteor. We are not only in danger, we are the danger. But, we are also the solution,” Guterres said.
The UN chief cited C3S in saying emissions worldwide must be reduced by nine percent annually to maintain the 1.5 degrees Celsius temperature limit established in the 2015 Paris Agreement. Global emissions increased by one percent last year.
On Wednesday, the United Nations World Meteorological Organization said the temperature threshold has an 80 percent likelihood of being surpassed within the next five years.
“We are playing Russian roulette with our planet,” Guterres said, as reported by UN News. “We need an exit ramp off the highway to climate hell, and the truth is we have control of the wheel.”
C3S data revealed that every month since July of 2023 had been a minimum of 1.5 degrees Celsius above pre-industrial levels, with an average global temperature in the past 12 months 1.63 degrees warmer than in industrial times, CNN reported.
“This is a harbinger of progressively more dangerous climate impacts close on the horizon,” said climate professor Richard Allan from the United Kingdom’s University of Reading, as reported by CNN.
Guterres went on to say it was “still just about possible” to avoid the worst effects of climate change, but that we must try harder, UN News reported. He added that this decade of choices made by political leaders — particularly the coming 18 months — are crucial.
Guterres explained that half a degree of planetary warming could lead to some coastal communities or island nations disappearing.
If the 1.5 degrees Celsius target is breached, entire coral reef systems could vanish. The West Antarctic and Greenland ice sheets could also collapse, leading to disastrous sea level rise, scientists have said.
The extreme weather in East Asia, the U.S. and other parts of the world has been made much worse by the climate crisis, “destroying lives, pummelling economies and hammering health,” Guterres added.
The secretary-general slammed “the Godfathers of climate chaos – the fossil fuel conglomerates” that, despite billions of people all over the planet suffering from the damages and increased cost of climate change, “rake in record profits and feast off trillions in taxpayer-funded subsidies.”
Guterres made a plea for all countries to stop supporting fossil fuel companies and institute a ban on their advertising.
“I call on these companies to stop acting as enablers to planetary destruction. Stop taking on new fossil fuel clients, from today, and set out plans to drop your existing ones,” Guterres said, as reported by UN News.
The UN chief highlighted the importance of protecting forests and oceans, which absorb carbon dioxide produced by humans. He pointed out that renewables — which now provide 30 percent of the planet’s energy — are here to stay.
“Economic logic makes the end of the fossil fuel age inevitable,” Guterres said.
The world’s biggest emitters of toxic emissions, as well as the most prosperous nations, must assume the largest burden for action, the UN chief said.
“Advanced G20 economies should go furthest, fastest” while giving financial and technical support to developing nations, he said.
“We cannot accept a future where the rich are protected in air-conditioned bubbles while the rest of humanity is lashed by lethal weather in unliveable lands.”
Guterres added that solving the climate crisis must be a collaborative effort and expressed thanks to climate activists who have been pushing for action.
“Make your voices heard and your choices count. This is an all-in moment,” Guterres said in New York. “Now is the time to mobilise, now is the time to act, now is the time to deliver. This is our moment of truth.”
According to the new World Energy Investment 2024 report from the International Energy Agency (IEA), despite financing pressures, global clean energy investment will be nearly twice that of fossil fuels this year.
In 2024, the world’s total energy investment is projected to surpass $3 trillion for the first time. Approximately $2 trillion will be put toward green technologies like renewable power sources, grids and storage; electric vehicles (EVs); low-emissions fuels; nuclear power; and heat pumps and efficiency improvements, the report said. The remaining just over $1 trillion will fund oil, gas and coal.
“Clean energy investment is setting new records even in challenging economic conditions, highlighting the momentum behind the new global energy economy. For every dollar going to fossil fuels today, almost two dollars are invested in clean energy,” said Fatih Birol, IEA’s executive director, in the press release.
The report warns of big imbalances and shortages in energy investment that still exist all over the globe. It points to the low amount of green energy spending in developing and emerging economies outside China. However, with Brazil and India leading the way, for the first time these investments are predicted to be more than $300 billion. But that is just roughly 15 percent of renewable energy investment worldwide — far less than is needed to meet the increasing energy demand in many nations.
“The rise in clean energy spending is underpinned by strong economics, by continued cost reductions and by considerations of energy security. But there is a strong element of industrial policy, too, as major economies compete for advantage in new clean energy supply chains,” Birol said. “More must be done to ensure that investment reaches the places where it is needed most, in particular the developing economies where access to affordable, sustainable and secure energy is severely lacking today.”
In 2015, when the Paris Agreement was signed, the total green and nuclear investment for power generation was two times that being put toward fossil fuel energy. This year, it is set to increase to 10 times, according to the report, led by solar photovoltaic (PV) technologies.
“More money is now going into solar PV than all other electricity generation technologies combined. In 2024, investment in solar PV is set to grow to $500 billion as falling module prices spur new investments,” the press release said.
The biggest renewable energy investment share in 2024 will come from China at roughly $675 billion, primarily from solar, EVs and lithium batteries. The second largest will be provided by Europe and the United States with $370 and $315 billion, respectively.
The transition to clean energy has been hampered by power grids and electricity storage. However, grid spending is projected to reach $400 billion this year after being stuck at about $300 billion per year from 2015 to 2021.
The jump is mostly due to new policies and funding in the U.S., Europe and China, as well as some Latin American countries. As battery storage costs continue to fall, investments are set to be $54 billion.
“Yet again, this spending is highly concentrated. For every dollar invested in battery storage in advanced economies and China, only one cent was invested in other emerging and developing economies,” the press release said.
For the first time, researchers have found the presence of additives found in vehicle tires in leafy crops grown for human consumption.
While residues from other substances, such as pharmaceuticals and personal care products, have been detected previously, there has been no investigation into how pollution from car tires may affect food, the authors noted.
While vehicle tires are made in part by a natural material, rubber, they also utilize a blend materials, including synthetic rubber made from fossil fuels and chemicals to improve their durability, performance and safety. Tires are typically comprised of around 5% to 15% of chemical additives for performance enhancements.
But as the researchers noted, these chemicals can create pollution that leaches into environments and could impact our food.
“The toxicity of tire and road wear particles is related to their organic additives and associated transformation products,” Anya Sherman, first author of the study and a Ph.D. student at the University of Vienna’s Centre for Microbiology and Environmental Systems Science, said in a statement.
The researchers tested 28 commercial leafy vegetable samples they collected in four countries. They analyzed the samples for 16 different types of tire-derived chemicals using high-resolution mass spectrometry.
The “Setup Lab” shows the first step of the sample processing. The samples were purchased in grocery stores in Switzerland, then shipped frozen to the scientists. They were first freeze-dried (to remove water), and then extracted in the laboratory, before measuring them with liquid chromatography-mass spectrometry. Anya Sherman / Center for Microbiology and Environmental Systems Science
The results, which were published in the journal Frontiers in Environmental Science, revealed that six compounds found in vehicle tires were taken up by crops. These compounds included benzothiazole, 2-hydroxybenzothiazole, 1,3-diphenylguanidine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N-Isopropyl-N-phenyl-4-phenylenediamine and N-phenyl-N-cyclohexyl-p-phenylenediamine.
The findings revealed relatively low concentrations of these additives, but the authors are still concerned about how they could affect humans that consume produce containing tire-derived chemicals.
“While the concentrations and daily intake are fortunately relatively low, additives from car tires are still found in food,” Thilo Hofmann a co-author of the study and professor at University of Vienna, shared in a statement. “That’s not where they belong.”
The study authors wrote that more research is needed to determine all the ways these chemicals are moving from roads to crops, how they may affect different crops and ultimately how consumption could affect human health.
The study adds to growing research on the way vehicle tires can potentially pollute environments. An analysis published in 2022 found that car tires can generate 2,000 times more pollution than a vehicle tailpipe. Tires can also shed microplastics, and researchers have been researching different materials to use in tires, including rubber made from dandelions.
In the first flush of an Arctic spring,the boreal forest begins to stir, emerging from a silvered quiet. Icicles shatter like glass. Meltwater babbles, braiding in puddles and then in deltas. Snow drops in clumps from the branches of black spruce. Saplings remain crooked from a long wait, as if Dr. Seuss had drawn springtime.
The trees’ twisted crowns are evidence of the forest’s scrappiness: A black spruce seed riding the wind in 1728 — the year the first Danish explorer crossed the Bering Sea between Asia and North America — might have found purchase in the rocky till revealed by retreating glaciers. When ice turned Captain Cook back from the Arctic Ocean a few decades later, the sapling would have just been bearing its first cones. A century later, when the United States purchased Alaska from Russia for $7.2 million in gold, the slow-growing tree might only have reached 30 feet. By the time the 1980 Alaska National Interest Lands Conservation Act created the sprawling system that now manages many of these forests, the aging spruce might still have been a spindly perch for some of the billions of birds that wing north as the days lengthen.
These flocks have thinned in recent years. One in three of the birds that used to make the arrowing trip have disappeared. The boreal forest, meanwhile, is now teetering. As temperatures rise, the permafrost that supported its roots is thawing, drowning whole stands. Many of its trees have been logged, and development has plowed through its muskeg, destroying the habitat that more than half of North America’s birds rely on. The majority of Alaska’s bird species are now at least moderately vulnerable to extinction.
Statistics like these paint a world in an orderly decline, where change can be methodically tabled and tracked. But the boreal doesn’t neatly begin and end. Its very name betrays the folly of artificial separations. The forest’s moniker is drawn from Boreas, the Greek god of the north wind, a word that in turn stems from the earlier Balto-Slavic for “forest” and “mountain.” All of its ancient meanings hold the idea of great distance, of the connections between air and land and trees. Spruce are a keystone of one of the world’s largest biomes, and together, the forest and the birds that fill its skies are pieces of a rich biological puzzle. While the boreal encompasses about a third of the world’s forests, it also holds more fresh water than any other ecosystem, with vast wetlands and shorelines providing sanctuary for millions of birds that stop to rest before continuing on to the tundra or, at last, the sea.
George Matz, an avid birder, has watched these migrations for decades. On a recent chilly morning, he stood on the mudflats of Homer, Alaska, lifting the binoculars around his neck as a pair of sandhill cranes kited and swooped toward shore. The Kenai Peninsula marks the edge of Alaska’s boreal forest. While its western coast is stubbled with spruce, its eastern fjords hold the rainforests of the Pacific maritime, a lusher ecosystem that continues down the coast of Canada. On this brink between the two, Matz has been counting birds for the last 16 years. Faithfully watching the rocky beaches as the snow begins to recede, he and a small group of volunteer birders have developed a database that documents the peninsula’s changes. From these records, Matz says, “We can get an idea of overall populations, and how climate change affects trends.”
Much like the birds Matz watches, the boreal forest is also migrating, warming more rapidly than nearly any other place on Earth. In a series of satellite images from 1985 to 2019, scientists at Northern Arizona University found that the warmest margins of the forest are now browning, with so many trees perishing you could watch them die from space. Meanwhile, its northern edge has been racing toward the pole, new trunks sprouting on formerly treeless plains.
A bald eagle perches within the boreal forest near Seward, Alaska.
Ilan Shacham / Getty Images
On the Kenai, the boreal’s rapid retreat is jarring. The southern peninsula is in a rain shadow, sheltered from moisture by the peaks of a nearby ice field. “It’s not wet enough for the Pacific maritime to advance,” says Dawn Robin Magness, a landscape ecologist at the Kenai National Wildlife Refuge. “We’re at the trailing edge of a biome shift, with no leading edge.” Whatever habitat eventually emerges here, in other words, will be new.
In the meantime, rising temperatures are reshaping what were once safe harbors such as Homer, an important resting stop on the great continental flyway that stretches from Alaska to Chile. The common murres that regularly splash into its warming waters have recently been part of massive bird die-offs, their bodies littering beaches around Alaska. In this wavering future, shifts that normally happen in geological timescales are accelerating toward collapse.
Magness and her colleagues at the Kenai National Wildlife Refuge have had to acknowledge that their longstanding goal — to maintain or restore historical conditions — is now impossible. Instead, they’ve begun to use a basic question to guide their choices: Is climate change to be resisted, accepted, or directed? The deceptively simple question is a radical departure from previous policies. “Our mandates are all about biodiversity and maintaining species,” Magness says. “But what happens when you can’t?”
This is not the boreal’s first transformation. For the last 12,500 years, the forest has ebbed with the rise and fall of ice at its margins. During the last ice age, black spruce took root as far south as the tablelands of Colorado and New Mexico. As the glaciers receded, their immense weight scraped away the underlying soil, leaving behind winding eskers and stony moraines. In these essentially lifeless landscapes, endless cycles of freeze and thaw cracked the exposed rock, where the first colonies of feather moss found purchase. Dying, their decay formed new soil. Grasses took root, splintering the bedrock. Shrubs and saplings rose. In time, deep forest once again emerged from bare rock.
As the boreal returned to the north — the black spruce sending its spires up from bogs and its cousin, white spruce, bristling the drier slopes across the Arctic — the forest began to remake its world. The trees’ roots drew water up from the soil and into their needles, billowing out as vapor when their pores opened in the sun. This process, called transpiration, helps forests make their own rain. Transpiration contributes roughly half of annual rainfall in European forests, and helps drive the Amazon’s seasonal monsoons. Spruce are particularly good at it, releasing compounds that condense water molecules — essentially seeding raindrops. Collectively, these exhalations also make the boreal the greatest planetary source of oxygen.
Fishing boats hug the forested shores of the Kenai Peninsula, Alaska. Prisma Bildagentur / Universal Images Group / Getty Images
Some, in fact, suggest the boreal may serve as a giant bellows, pumping the planet’s air circulation. Anastassia Makarieva, a Russian physicist, theorizes that as trees grow clouds, they change atmospheric pressures, encouraging air circulation and propelling wind patterns. In many places, forests can create “flying rivers” that carry coastal moisture inland for thousands of miles. In fact, the boreal regions of Scandinavia and Russia provide China with more than 80 percent of its water.
Yet as the forest falters, these prodigal cycles are dwindling. When trees die, the loss of their transpiration can spark hotter and drier conditions; recent models predict that deforestation will reduce rainfall in some regions by almost a third. Hot, dry summers are killing spruce that shrug off polar winters but can’t cope with drought. Higher temperatures have also catalyzed once-rare lightning strikes across Alaska, kindling unprecedented wildfires. Every year since 2000, 50 percent more of the Arctic has burned than in any decade of the previous century. In satellite images, you can now see flecks of smoldering fires that seethe through the frigid winters — “zombie” fires biding through the cold before flaring up again.
The outsize grandeur of the boreal can still appear so wild, so endless, it’s hard for newcomers to recognize the loss. Each generation’s perception of normal is molded by the environment they encounter, masking the gradual fade, a diminishing world stripped of its former richness. Driving north to Alaska, my own first glimpse of the boreal forest was of blackened spruce skeletons from a highway that wound through the oil fields of Alberta. At a small roadside lake, pumpjacks worked through the night. Someone had taken a knife to a lone birch trunk: if i fell, would you hear me? The next morning, I ran over a yellow warbler — no time to step off the gas. It fluttered on the macadam in the rearview mirror as I pressed forward, the skinny spruce closing in along the road.
“It’s changed so much,” says Jill Johnstone, a former professor of biology at the University of Saskatchewan, where she started the Northern Plant Ecology Lab. She explains that, in many ways, spruce is made to burn. Black spruce cones hold their seeds close until fire releases their long, thin wings. Flames will dance through the crowded stands, jumping between resinous canopies. Occasionally, the tops of whole trees will pop off like sparkling fireworks. The seared cones are left open to release seeds on the newly bare soil.
But as more of the Arctic burns, and then burns again, wildfire is outpacing the trees’ ability to regrow. In the early 2000s, after what was then a record-breaking fire year, Johnstone established a network of research sites across the boreal. She found that fires were returning too quickly, while trees were too young to have produced cones. They were also burning hotter, scorching deep into the soil, depleting critical nutrients and searing into something like concrete. “Tree colonization is the key to maintaining the boreal forest,” she says, “and it’s really sensitive to disturbances, especially fire.” As a result, in many places, black spruce is failing, being replaced by aspen and birch. Meanwhile, these deciduous trees are themselves being attacked, plagued by a novel canker disease and an invasive insect called the leaf miner.
Over the next decades, parts of the boreal may transform away from forest altogether. In some places on the Kenai Peninsula, the woods are already morphing into grassland. In the 1990s, a devastating spruce beetle outbreak and wildfire felled almost a million acres of spruce. A grass called bluejoint colonized the burn, choking out the baby trees that managed to take root. This new savannah now provides springtime fuel for earlier fires, killing vulnerable saplings, and pushing the area even farther from forest.
“I’ve been trying to understand which parts of the landscape can act as refugia in the face of these changes,” Johnstone says, as her feelings about her research have shifted from fascination to “a certain amount of genuine fear.” Widespread disruptions are now inevitable — meaning the people whose jobs are to maintain these ecosystems are facing the difficult choice of how much to intervene.
After decades planting experimental plots, Johnstone has found that southern trees like lodgepole pine can thrive when planted in Interior Alaska, even though their range hasn’t yet naturally expanded that far north. “We have what we might call empty niches, or species that could be growing in northern environments that aren’t there now,” she says. “Most species do not fully occupy their climate envelope, particularly in the north.” In southeast Alaska, for example, warmer winters are killing yellow cedar trees, whose shallow roots require snowpack to insulate them; one study found more than 70 percent have already died. But snowfall on the Kenai, just north of the cedar’s natural range, is still more reliable. Should we plant the cedar in places it has never grown, to help it avoid extinction?
The glaciers of Kenai Peninsula, such as this one near Seward, Alaska, have experienced rapid melting in recent decades.
A&J Fotos / Getty Images
Scientists are now experimenting with just this kind of assisted migration around the country, from selecting key genotypes most likely to handle changing conditions, to helping entire species move great distances. From California to the Yukon, field trials have planted interlopers to see how they’ll fare; within the lifespan of these saplings, the climate around them could warm by 4 degrees Celsius (7.2 degrees Fahrenheit).
This level of tinkering can conjure a long history of the unintended consequences that can follow human meddling. Take rats, which were accidentally introduced to Hawai‘i in the 1700s, where their voracious appetite for palm seeds destroyed vast swathes of lowland forest, and their population boom carried the deadly bubonic plague. Importing mongoose to try to control the rodents only led to the extinction of many native species, like ground-nesting birds.
But today, even government agencies are increasingly calling for direct interventions. A provision of the Endangered Species Act allows for reintroductions, and under its auspices, the U.S. Fish and Wildlife Service has attempted to revive 47 different species in locations where their populations had previously disappeared. But it’s not always clear exactly where an animal may have once ranged. Seasonal shifts, development of once-undisturbed habitat, and changing conditions all influence the ebb and flow of ecosystems.
Advocates of assisted migration say deciding to intentionally direct some of these changes is merely to acknowledge the profound impact we’ve had on the landscapes around us. “We’ve tended to separate humans from nature,” says Magness, but she notes that home gardeners regularly introduce new species. In a 2021 report, the National Park Service suggested federal agencies start using the Resist-Accept-Direct framework to make more realistic conservation goals — accepting, for instance, that spruce may not return after fire in the boreal. Directing change might mean introducing bison to the Kenai Refuge — where they haven’t roamed for 20,000 years — to help control the bluejoint, making the new grassland healthier. And in August 2023, the Fish and Wildlife Service passed a revision to the Endangered Species Act that officially green-lit introducing vulnerable species to new habitats nationwide.
Putting a thumb on the evolutionary scale is not without risks. “Humans have real potential to modify the diversity of these systems,” Johnstone says. “We need to make good choices about how much we want to do that.”
When some of the people responsible for the decisions about Alaska’s shifting habitats logged on to a video call on a gloomy late-winter morning, the internet connection was slow, stalled by the relentlessly falling snow. There was talk of climate volatility and range contractions, of conservation connectivity and gene flows — all code for the swelling birch buds and the rivers that would soon rise and fall, bearing the promise that, at least this year, clouds of spruce pollen will still billow across the midnight sun.
But the boreal’s changes will soon cascade, affecting everything that lives in it. Tree line has already shifted upward in Denali National Park, altering where birds can live. As animal behavior and abundance morphs, so do plants’ natural ability to move across the landscape, says Evan Fricke, an ecologist at the Massachusetts Institute of Technology. An adult grizzly bear can eat 200,000 berries a day, spreading seeds across its several-hundred-mile range. But Fricke and his collaborators found that wildlife declines have already reduced the ability of plants to adapt to climate change by an average of 60 percent globally, with especially strong declines in northern temperate regions. “For long-lived trees,” Fricke says, “often there’s simply an assumption there’s enough seeds to grow wherever they need to grow.” But with increased fires and the loss of large animals that disperse seeds over distances, “that’s a pretty tall order.”
The disturbing reality, Fricke says, is that “many of our ecosystems have already lost a lot of their seed dispersers.” Some, like the thunders of bison on the Great Plains, have been gone for centuries — as have the lost crops that they used to help seed, which may have once fed as many Indigenous people as maize. Without companion animals to carry them, plants will have a harder time moving toward more suitable conditions as temperatures rise.
Conservation, Fricke says, needs to consider not just the individual species that make an ecosystem, but also their relationships. Yet climate change is swiftly decoupling these intricate connections. On average, spring now arrives in the boreal two weeks before it used to.
One consequence is that robins, which often migrate shorter distances, are arriving 12 days earlier than they did in 1994, changing their behavior so their nestlings can grow when food is most abundant. But long-distance migrants, such as arctic terns, likely rely on fixed cues like day length in order to time their epic flights around the world, and they are falling behind the new arrival of spring. In essence, the climate has become a wayward conductor, driving the cadence of seasons and pulse of natural cycles out of syncopation. A 2024 study found that as spring shifts, three-quarters of the Western Hemisphere’s species are now failing to migrate in time.
Arctic terns, like this one in southern Alaska, migrate 12,000 miles annually to breed in the Arctic. DrFerry / Getty Images
In the race to catch up, some birds are adapting by shortening their rests in stopovers like Matz’s Homer, risking arriving at their nesting grounds too exhausted to breed. Hudsonian godwits, for example, wing from Patagonia to Hudson’s Bay, where, recently, chick survival has been as low as 6 percent. Other shorebirds have shown similar declines. If the insects or blooms no longer swell at reliable times, even the birds that manage to breed do so out of step with food sources, meaning their chicks may starve. A diminishing number of birds in turn spurs radical changes around the globe, since the birds of the boreal play a vital role in dispersing seeds, pollinating, and controlling pests.
Dwindling bird populations can seem like an abstract concern, just another of the faraway disasters that have become so familiar these days, scrolling past a hypnotic blur of online tragedy. And yet, as recently as last summer, people who’d never even heard of the boreal could feel it burning. In 2023, an unusually dry and warm spring melted the boreal’s snow quickly — more than doubling the likelihood of extreme fire weather. As flames licked through Canada’s forests, millions of trees transformed into their composite organic and mineral parts, the weathered trunks transmuting to tiny particles that wafted through the atmosphere. For days, an orange sun crept behind the glass walls of eastern skylines; skies were so dark streetlights flipped on automatically.
The summer of 2023 became Canada’s worst-ever wildfire season, engulfing 34 million acres, about the area of Florida. As people fled their homes and toxic air choked cities across North America, migrating birds arrived from their long journeys to towering columns of smoke. Warblers and sparrows would have pulled the particles into their tiny bodies with every breath. Avian lungs take in air even during their exhalations, which makes birds more susceptible to air pollution, the origin of the idiom “canary in the coal mine.”
The wildfires’ billowing plumes also released greenhouse gases — and a lot of them. The boreal surrendered an estimated 2 billion tons of carbon that summer, about three times as much as all the rest of Canada’s cars and power plants and planes and farms put together. The boreal has long been considered a carbon sink. In fact, burning all of the world’s oil reserves would still release less carbon than is currently stored beneath its roots. Yet in the span of my lifetime, some scientists believe the forest has become a massive global carbon source.
Smoke is seen from the Swan Lake Fire #3 in the Kenai Peninsula’s boreal forest in 2021. Gemma Winston / Getty Images
Before the skies cleared, it became the world’s warmest June on record. Then it got hotter. “It’s unlikely there’s been a hotter July since humans have been humans,” says Allegra LeGrande, a physical-research scientist at Columbia University. By the time her children are in their 40s, this summer will look vanishingly cool. On the Kenai, wild blueberry flowers rotted on their stems, bearing no fruit.
Understanding what drives animals’ flexibility is now essential, says Benjamin Van Doren, a professor at the University of Illinois Urbana-Champaign. Change can breed fragility, but incredible resilience too. He points to a recent study that looked back at former glacial periods, when ice covered much of what is now boreal forest, to see how migratory birds tracked past climatic shifts. It found that the red-backed shrike likely was able to adapt its migration over the last 10,000 years, breeding within Africa when the Earth was colder, and expanding northward as the Ice Age ended. While he cautioned that it was still just a theory, Van Doren says, “It’s heartening to know that birds are flexible enough to make these kinds of dramatic changes.”
That can teach us a lot about how birds may respond to future crises. A songbird called the Eurasian blackcap, for instance, has surprised scientists by beginning to winter over in the United Kingdom, some even migrating north from the European continent. Van Doren says that this is due, in part, to milder winters, but also because of the proliferation of backyard bird feeders. “In much less than a human lifetime, you’ve seen a dramatic change in the behavior of this migratory bird,” he says. Examples like this give him hope that conserving critical habitat may help birds navigate the climate crisis. “Nature, when we give it a chance, will rise to the challenge,” he adds. “We have to work to give it that chance.”
To do so, says Meda DeWitt, a senior specialist at the Wilderness Society, “we have to look at ourselves as a species that also has to adapt.” Indigenous people, she says, have thousands of years of experience with assisted migrations and land stewardship to draw on. The Déné people of Alaska tell an ancient story about how Raven’s wife, the Fog Woman, attempted to teach him to save salmon, a cautionary tale that led to the development of fish incubation systems. “When the tribes moved into a new space, they would seed streams with salmon eggs,” DeWitt says.
Learning to live in a sublimating world — as ice changes phase and forests fall — will take creativity, a certain merciless correction. In a statewide threat assessment released in 2019, the U.S. Army Corps of Engineers found that 86 percent of Alaska Native communities are under threat by erosion, flooding, and permafrost thaw. “If that’s the case, we have to think about what the world’s going to look like,” DeWitt says. “Our traditional stories tell us it’s going to be a water world.”
She grew up listening to elders tell these kinds of stories, one building on another, learning that humans are part of nature, bound to the land as love is to loss. As the Kenai turns to grassland, she suggests talking to the elders in the prairie regions to learn things like which plants are best for controlling erosion. “Indigenous people have deep ecological knowledge,” she says, “and can advise which plants are cornerstone species.” Successful restoration has already come from this kind of consultation: The Fog Woman’s knowledge is being used to help restore Moose Creek, outside of Anchorage, replenishing its Chinook salmon population.
Stories, DeWitt says, are not static. Passed down, they shift through time and circumstance, just as their tellers will spend their own lifetimes changing — a fragile, precious flash. Adaptation may simply be a way to see those changes reflected in the world, a landscape and its relationships seen anew.
An adult Lesser sandhill crane photographed near Homer, Alaska.
pchoui / Getty Images
Johnstone says she sees the boreal’s recent transformations “like a big ship changing its course: very gradual — almost imperceptible at first — but with inevitable consequences as time goes by.” There is very little that can truly devastate an ecosystem; there’s almost always some form of recovery. “But it may be slow or in a direction we don’t like,” she says. “So much of the fear or perception of loss relates to our own expectations.”
On the beach on a winter morning, a fog creeps over the gnarled spruce along Homer’s shores. The first flush of birch buds have finally begun to unfurl. A pair of sandhill cranes swirl overhead, announcing their arrival with a clangorous joy. In 1937, the iconic environmentalist Aldo Leopold doubted the prehistoric birds would survive, writing of the day when “the last crane will trumpet his farewell and spiral skyward.” He was wrong. Their recovery, and the protection of the long string of lands and waters the sharp-eyed birds depend on, have become one of the last century’s great conservation success stories.
Eventually, the unlikely pair alight on the sand. They stalk the shore, silhouettes of choices past. The reddening salmon have begun to run. The boreal will never again be the same.
“That the situation appears hopeless,” wrote Leopold, “should not prevent us from doing our best.” There is something beyond the world as we know it, already growing.
Predicting the future has always been a difficult, sometimes fruitless task, but scientists are surprisingly good at divining how hot the year ahead will be. For decades, their models have largely ended up matching global temperatures. Then 2023 came along.
At the beginning of the year, climate scientists at four organizations — Berkeley Earth, NASA, the U.K. Met Office, and Carbon Brief — forecast that 2023 would be marginally hotter than the year before, with the consensus falling around 1.2 degrees Celsius of warming (2.2 degrees Fahrenheit) above preindustrial temperatures. But it blew past those projections to become the hottest year on record, reaching an estimated 1.5 C (2.7 F). “We were really far off, and we don’t know why,” said Zeke Hausfather, one of the scientists at Berkeley Earth who worked on the predictions.
The first sign that something was amiss came in March 2023, when the world’s oceans spiked to the hottest temperatures seen in modern history. Then the heat came for the land, too. It led to the hottest June ever recorded, followed by the hottest July, and the hottest every month since. On Wednesday, the European Union’s Copernicus Climate Change Service confirmed that last month was the hottest May in history, making for one year straight of record-shattering global temperatures, averaging 1.63 degrees C over preindustrial times. The report was released in tandem with World Meteorological Organization’s updated prediction that one of the next five years is likely to beat 2023 as the warmest year on record.
The two reports came as a heat wave sizzled through the Western U.S., with 29 million Americans under heat alerts and warnings from Wednesday into the weekend. “If we choose to continue to add greenhouse gases to the atmosphere, then 2023/4 will soon look like a cool year,” said Samantha Burgess, director of the Copernicus Climate Change Service, in a statement.
Much of this warming over the past year is well within the range of what scientists have long predicted would be the result of burning fossil fuels with abandon. The heat dialed up even more when a recurring climate pattern known as El Niño took hold last summer. But scientists say these two factors alone can’t account for the surging temperatures the world has seen recently, particularly in the second half of 2023. Was that extra warming a blip they can brush off, explained away by natural variability or randomly coinciding events, or was it a sign that climate change has begun to veer off predictable tracks?
A man cools off during a heat wave in Rio de Janeiro, Brazil, on November 18, 2023. Tercio Teixeira/AFP via Getty
“It’s not just some obscure quirk that nobody really cares about,” said Gavin Schmidt, the director of the NASA Goddard Institute for Space Studies in New York. “I mean, it really matters, and it has implications for the future, how this gets resolved.” Schmidt and other scientists are examining different theories that could explain the elevated temperatures, from a reduction in global aerosol pollution to underwater volcanic explosions. “Everything is on the table,” he said.
Here’s what scientists know so far: Climate change has warmed the planet by 1.3 degrees C compared to preindustrial times. But the last 12 months have been about 1.6 degrees C hotter, according to the latest data. Some of that heat — around 0.1 or 0.2 degree C — can be attributed to El Niño warming up the Pacific Ocean. That still leaves as much as 0.2 C unexplained.
Scientists have a solid explanation for maybe 0.1 degree C of that extra heat: It could be a side effect of global efforts to reduce pollution. Starting in January 2020, the International Maritime Organization began enforcing a mandatory reduction of sulfur oxide emissions from shipping fuel. These airborne particles can be harmful to human lungs, contribute to acid rain, and inhibit plant growth. However, they also increase cloud cover and help reflect heat back into space. A paper published in Nature last week found that when some of these aerosol particles abruptly vanished, the Earth began to absorb more heat.
The search is still on for other puzzle pieces. A 2022 volcanic eruption might have added warmth by sending a huge amount of heat-trapping water vapor into the atmosphere. Shifting weather patterns might have limited the Saharan sands that usually travels over the Atlantic Ocean, allowing more sunlight to heat ocean waters. An upswing in solar activity might have begun sooner than expected, trapping radiation within the atmosphere. Or, perhaps China has been cleaning up its air pollution faster than expected, and there are even less aerosols bouncing heat off the planet.
More ominously, some scientists argue that the planet is more sensitive to climate change than previously thought. “The climate system is an angry beast, and we are poking it with sticks,” the geochemist Wallace Broecker, who died in 2019, often said. Daniel Swain, a climate scientist at the University of California, Los Angeles, thinks it might be time to update that metaphor. “We’re getting closer to the beast, and we’re aggravating it with ever greater frequency and magnitude,” he said. “So at some point, there may be surprises out there.”
According to Swain, solar activity and other suspects are unlikely explanations for the “wild card” that caused so much warming in 2023. He wonders whether it’s even possible to solve the puzzle. Schmidt, on the other hand, hopes scientists will have solved the X-factor by the end of this year.
Even as this year’s temperatures continue to shatter records, scientists have been less surprised than they were in 2023. The last several months of heat align more closely with what they expected from El Niño. And this summer, El Niño’s twin, a cooling pattern called La Niña, is expected to take over. If temperatures don’t fall as predicted two or three months from now, Hausfather said, “I think it’s an indication that you know something is happening that we don’t expect and don’t really have a good explanation for.”
Take a few steps into a leafy forest in New York’s Hudson Valley, close your eyes, and listen: That’s not the sound of rain, it’s millions of caterpillars chewing and pooping.
On a clear spring day, the pitter-patter of spongy moth caterpillars eating their way through oak, maple, crab apple, basswood, and aspen trees can be heard over the sound of birds singing. Bits of green leaves litter the ground like confetti — evidence of the insatiable chewing taking place in the canopy above. Hundreds of caterpillars bob on long, wispy silk threads, waiting for a breeze to carry them to a new tree.
The Northeast and Midwest are enduring what is, in some places, the worst outbreak of spongy moths on record. One of the factors driving the proliferation of very hungry caterpillars is climate change-spurred drought, which allows spongy moths to breed with abandon, producing up to a million caterpillars per acre. Trees are resilient, but this outbreak has been especially long and damaging. After two consecutive years of intensive spongy moth feeding, up to 80 percent of trees in a hardwood forest that has been defoliated, or stripped of its leaves, will die. The current spongy moth epidemic has lasted five years in some parts of the U.S.
“When trees are defoliated like this right at this time of year, they are using reserves that are in the trunk and in the roots to put out a second flush of growth,” said Brian Eshenaur, a plant pathologist at Cornell University’s Integrated Pest Management Program. “If the tree has to do that two years in a row, it’s really tapping all the reserves it has.”
The caterpillars aren’t the only forest pests benefiting from climate change. Many invasive species in the U.S. are expanding, generally thanks to milder winters brought on by warmer-than-average global temperatures. Insects like the hemlock woolly adelgid, the emerald ash borer, the Japanese beetle, and the spotted lanternfly are chewing their way through the country’s trees at record paces — leading to widespread tree mortality and stressed forests that are susceptible to drought and more disease. No one species is capable of taking down the nation’s forests, which collectively store some 60 billion metric tons of carbon, but the rising tide of invasive species is doing serious cumulative damage.
Spongy moths have been in the United States since 1869, when a French artist and amateur entomologist named Etienne Leopold Trouvelot imported some from Europe and began raising them in netting in his backyard near Boston. Trouvelot was hoping to breed a silkworm suited to American climes that could be used for commercial textile production. Spongy moths, known as gypsy moths at the time, float from leaf to leaf and tree to tree on long, durable lines of silky thread. But the moths soon escaped from captivity, perhaps because a heavy storm tore through Trouvelot’s netting, and some of the bugs decamped to the Massachusetts woods.
A member of the Massachusetts state forest health program looks at trees defoliated by spongy moths.
Suzanne Kreiter / The Boston Globe via Getty Images
Two decades later, in the midst of the first spongy moth infestation on record, one resident of the town in which Trouvelot lived described a world carpeted with black, hairy caterpillars. “I do not exaggerate when I say that there was not a place on the outside of the house where you could put your hand without touching caterpillars,” the resident told the Boston Post in 1889. (The caterpillars don’t bite humans, but coming into contact with their spiky hairs causes some people to develop an itchy and painful rash.)
For more than a century after that initial outbreak, spongy moths spread at a rate of about 13 miles per year through New England, the Mid-Atlantic, the Midwest, and parts of the South, feasting on 300 species of leafy trees and shrubs and leaving entire stretches of forest bare in their wake. The moths defoliated 81 million acres cumulatively between 1970 and 2013. Because of the toll they take on trees, keeping spongy moth populations in check has become one of the U.S. Forest Service’s highest priorities. The economic cost of managing spongy moths has averaged $30 million per year for the past 20 years.
And climate change is making things worse. Outbreaks typically occur every eight to 12 years, and each surge lasts one to three years. The current outbreak has lasted longer than usual, said Tom Coleman, a Forest Service entomologist who manages the agency’s Slow the Spread spongy moth program, in part because of drought in some of the areas that the moths inhabit.
Drought affects the spread of a fungal pathogen called Entomophaga maimaiga that curbs spongy moth populations. The fungal pathogen, originally found in Japan, was introduced by researchers to the U.S. as a spongy moth control measure in the early 1900s. The pathogen can be incredibly effective at killing the moths in their caterpillar stage, but it needs a cool, wet spring in order to proliferate. Cyclical outbreaks of spongy moths often follow years that are drier than average, when the pathogen is not as prevalent in the environment. “Without that fungal pathogen keeping the populations in control, we get these large outbreaks,” Coleman said.
It’s unclear whether rising temperatures will cause spongy moths to emerge more frequently, but it is safe to assume that a warmer, drier environment will cause cyclical outbreaks to become more intense over time. Luckily, the Forest Service has had some luck deploying more than 100,000 pheromone-laced traps to catch the bugs as they try to push west. The agency has also treated 10 million acres of forest with a biological insecticide that kills the caterpillars, preventing the bugs from establishing in new places.
Still, experts worry about the multipronged threats America’s trees face from pests and climate change, and the intersection of those two dangers. “Not only can climate change affect insects, it can also make trees that are native to a certain area less suited,” Eshenaur said. “A lot of our trees in the Northeast can’t tolerate high temperatures and sustained drought. That can make them more susceptible to these new pests that are coming in.”
Correction: A photo caption in this story originally misidentified a different type of moth as a spongy moth.
