Kendra Pierre-Louis

Invasive grasses, or grasses that have encroached from other regions, can make wildfires more frequent, not just in California but nationwide, according to a study published Monday in the journal PNAS. The study looked at grasses like cane grass, which is native to Myanmar but is damaging ecosystems in Florida, and buffelgrass, which is helping to ignite fires in the Southwest and has origins outside of North America.

“These grasses can act as kindling,” said Emily J. Fusco, a postdoctoral researcher at the University of Massachusetts, Amherst, and lead author of the study.

The species add to fire risk because they are growing in regions that once had far fewer grasses and because of their physical structure. Absent rainfall, the long, thin blades dry out quickly. This creates potential problems in places like California, where most rainfall happens in the fall and winter, leaving the grasses to dry out in summer.

“It’s like having thin strips of papers standing all through the dry season in whatever habitat it happens to be in,” said Carla D’Antonio, a professor in the department of ecology, evolution and marine biology at the University of California, Santa Barbara.

The grasses are more prone to burning than the native shrub land typically found in much of the West, including parts of California’s Ventura County, where the Maria fire broke out late last week. After a fire, these grasses are able to grow back faster, leading to concern that they may replace less flammable shrubs.

“If we turn this place into a grassland, we’re going to be seeing fire every other year in individual locations,” D’Antonio said.

For the study, the researchers took data on the locations of 12 invasive grass species that were known to promote at least some fires locally and combined it with data on wildfire occurrences. They found that in the case of at least eight species, there was a relationship between how often wildfires broke out and the presence of invasive grasses.

“It’s an impressive project,” said D’Antonio, who was not involved in the study. “It’s impressive in its scope, geographically speaking. It’s impressive in the number of different variables and number of species they are able to address.”

Humans introduce the invasive species onto the landscape in a variety of ways. Arundo donax, or giant cane, was deliberately brought to the United States as roofing material and to make reeds for instruments like the clarinet. But more commonly, the introduction is accidental.

“Roads are certainly a corridor for invasive species,” said Fusco, the study author. Seeds and plant fragments can grab an easy ride into new ecosystems on car tires or on people’s boots and clothing.

One concern regarding the Trump administration’s plan to put an end to road-building restrictions in Alaska’s Tongass National Forest, one of the world’s largest intact temperate rainforests, is that it would allow for the spread of invasive grasses that would heighten wildfire risk in a part of the country where climate change will likely increase the size and intensity of wildfires, according to the National Climate Assessment. In 2018 the forest experienced warm, dry weather that fueled a busier than normal wildfire season.

The concerns over encroaching grasslands aren’t limited to the West.

Earlier this year, D’Antonio walked through a park in Washington, D.C., while the city was in drought and spotted one of the invasive grasses on the study’s list.

“There was a 30-centimeter deep layer of dead grass,” she said. “This is an environment you would never imagine a fire occurring. And I walked through there thinking, ‘Wow, somebody could throw out a cigarette and this understory would start to burn immediately.’ ”

Invasive-plant managers are working to reduce the risk, “but it’s pretty time- and labor-intensive,” Fusco said.

“If we can be vigilant about keeping these grasses out of systems before they start to take over, you’re going to be way more effective at controlling them,” Fusco said. “And in the places where they already are, it’s prioritizing what kinds of systems we want to try to protect and restore.”

This article originally appeared in

Invasive Grasses May Worsen Wildfires, Study Suggests

The fires that have ignited in California, leading to mass evacuations and seemingly otherworldly scenes, may have gotten their start from a surprising source.

“The ocean is very important to us,” said Ka’imi Kaupiko, who lives in Milolii, a community often called the last Hawaiian fishing village, on the Big Island. The way of life there depends on the fish provided by the reefs, reefs which are now becoming sick in the warming waters.

“It affects a lot of how we are going to survive,” Kaupiko said.

Researchers said the heat wave was reminiscent of 2014, when a hot spot that became known as the blob began forming in the Pacific. It expanded and lingered over much of the Pacific Coast from Mexico to Alaska for years.

At First, Healthy Coral

Both marine heat waves are “super unusual,” according to Andrew Leising, a research oceanographer with the National Oceanic and Atmospheric Administration. Nearly every other marine heat wave NOAA has recorded in 40 years of satellite monitoring shrinks in comparison.

“The event in ’14-15 was maybe eight to 10 times the size of Alaska. And the current event we’re having is nearly that big,” Leising said. “And then, everything else is sort of an even further distant third or fourth.”

Researchers say they think that climate change strongly influenced the original blob’s creation.

The blob also led to the first known mass bleaching event in Hawaii, in which coral reefs stressed by the extreme temperatures shed the symbiotic plant that both gives them their flamboyant coloration and provides them with oxygen.

“Parts of Hawaii saw about 50% coral loss for the 2015 event,” Jamison Gove, a research oceanographer with NOAA, said by email. “It was particularly devastating in areas off Hawaii Island and Maui.” Reef watchers said they were worried about a repeat.

After Bleaching, a Dire Outlook

Last time, researchers were unprepared for the marine heat wave, said Greg Asner, director of the Center for Global Discovery and Conservation Science at Arizona State University, who is based in Hawaii part of the year.

This time, in addition to satellite observation and a network of sensors they deployed in July, researchers are using a community science project in which members of the public use a web platform to document any bleached coral that they see. It helps guide researchers’ decisions about where to survey, given how sprawling the Hawaiian Islands are.

Green on the platform’s maps means no bleaching, yellow and orange mean some bleaching, and red means a lot of bleaching. “And if you asked me if you looked at that a month ago, it was just a few yellow dots,” Asner said. “And then the orange dots started popping up. And now we have red dots.”

Then, the Algae

Entire fisheries collapsed along the Pacific during the previous heat wave as high water temperatures upended the aquatic food web. According to some estimates, 100 million cod disappeared off the coast of southern Alaska.

Warming waters can trigger the release of a neurotoxin called domoic acid from algae. Shellfish eat the algae, and when animals eat the shellfish they get sick and can die. Tens of thousands of dead seabirds washed up on beaches during the blob, as did sick and dying sea lions, most likely a result of domoic acid poisoning. In 2016, domoic acid also prompted officials to close the California Dungeness crab fishery.

The Return of the 'Blob': Hawaii's Reefs Threatened by Marine Heat Wave

The ocean off the Pacific Coast is simmering, threatening coral reefs and livelihoods around Hawaii and causing many to worry of worse to come.

An “oppressive and dangerous heat,” warned the National Weather Service. “Excessive heat, a ‘silent killer’,” echoed a news release by the National Oceanic and Atmospheric Administration. “Extreme heat is hazardous,” tweeted the NYC Emergency Management Department.

But people with health issues, older people and young children are especially susceptible to the effects of extreme heat. It’s a threat that grows as climate change continues.

Climate change makes heat waves more frequent

To understand how climate change increases the frequency of heat waves, it helps to think of the Earth’s temperature as a bell curve, said Michael Mann, the director of the Penn State Earth System Science Center.

Climate change is shifting that bell curve toward the hotter part of the temperature scale. Even a tiny shift in the center means that more of the curve touches the extreme part of the temperature scale.

“So you know, a warming of 1 degree Celsius, which is what we’ve seen thus far, can lead to a 10-fold increase in the frequency of 100 degree days in New York City for example,” said Mann. According to the U.S. Global Change Research Program, since the 1960s the average number of heat waves — defined as two or more consecutive days where daily lows exceeded historical July and August temperatures — in 50 major American cities has tripled.

The program used historic lows because the most serious effects of extreme heat tend to come when nighttime temperatures don’t cool off. By the 2010s, the average number of heat waves had risen from an average of two per year in the 1960s to the current average of nearly six per year.

Climate change is also making heat waves longer

There’s another way that climate change worsens heat waves: by changing the jet stream. Those air currents in the atmosphere help move weather systems around and are driven by temperature differences, which are shrinking. So when heat waves arrive, they stay in place longer.

“We’re warming up the Arctic faster than the rest of the northern hemisphere,” said Mann. “So that’s decreasing that temperature contrast from the subtropics to the pole, and it’s that temperature contrast that drives the jet stream in the first place.”

At the same time, under certain circumstances the jet stream can get “stuck” between an atmospheric wall in the subtropics, and at the Arctic, trapping weather systems in place.

“That’s when you get these record breaking weather events," said Mann, “either the unprecedented heat wave and drought, to wildfires and floods.”

This accounts for last summer’s European heat wave, as well as the recent European heat wave, he says, and is behind the current North American heat wave.

Nationwide, the time period in which heat waves might be expected to occur is 45 days longer than it was in the 1960s, according to the U.S. Global Change Research Program.

Heat deaths may soon surpass deaths from cold weather

According to the Centers for Disease Control and Prevention, which uses methods most in accordance with global standards, currently, cold weather kills more people than hot weather does.

But as global temperatures increase, the number of deaths associated with extreme cold are predicted to decrease. At the same time, the number of deaths associated with extreme heat will increase. And those deaths, according to the National Climate Assessment, will exceed the decline in deaths from extreme cold, meaning an overall increase in mortality.

It’s important to note that not everyone suffers equally when temperatures soar. In addition to the vulnerable groups, like elderly people, it also matters where you live. Researchers at the University of California, Berkeley, analyzed data from the 2000 census and found that people of color were up to 52% more likely to live in the hottest parts of cities.

Similarly, Eric Klinenberg, the director of the Institute for Public Knowledge at New York University, found that during the 1995 Chicago heat wave that killed more than 700 people, the death tolls were highest in places that were not just poor and segregated, but what he calls “institutionally depleted.”

“In a heat wave and many climate events, it’s social isolation that proves to be truly dangerous,” he said. “If you’re home and alone in a heat wave when you’re old and frail you’re more likely to die if you don’t have air conditioning.”

The solution is reigning in greenhouse gas emissions, said Mann.

If we don’t, he said, “think about the most extreme summer heat you’ve ever experienced in your lifetime. That will become a typical summer day by the middle of this century, if we continue on the path that we’re on.”

This article originally appeared in <a href="https://www.nytimes.com/2019/07/18/climate/heatwave-climate-change.html" id="d74599fb-4456-3373-a316-6b7e9fb56dd6">The New York Times</a>.

Heat Waves in the Age of Climate Change: Longer, More Frequent and More Dangerous

Two thirds of the United States is expected to bake under what could be record high temperatures heading into the weekend. As a result, government agencies have issued warnings that can feel ominous.

But people with health issues, older people and young children are especially susceptible to the affects of extreme heat. It’s a threat that grows as climate change continues.

For advice, a few of them are turning to Jesse Keenan, a lecturer at the Harvard University Graduate School of Design. At least once a day, Keenan, who studies urban development and climate adaptation, gets an email from someone asking where to move to be safe from climate change. The messages come from people who are thinking about moving not because they have already been hit by catastrophe, but because they see the writing on the wall.

So, what does Keenan suggest to these advance planners? Maybe climate-proof Duluth.

That’s a slogan that he created as part of an economic development and marketing package commissioned by the University of Minnesota Duluth. Some community leaders think they can spur growth by bringing in more people, and they sense an opportunity in climate change. And Duluth isn’t the only urban area that has climate migration on their radar. In a February speech, the mayor of Buffalo, New York, Byron W. Brown, declared his city a “climate refuge.”

Keenan emphasized one day in mid-March as we stood on the ice of Lake Superior that the Duluth slogan was meant to be tongue-in-cheek. The science behind it, though, is no joke.

Nowhere in the world is immune from climate change, including Duluth. “We’re getting more precipitation in bigger amounts than we ever really observed,” said Kenneth Blumenfeld, a senior climatologist at the Minnesota Department of Natural Resources.

“But when you stand back and look around, it’s almost like, ‘But we’ve got it good.’”

Climate projections suggest that, because of geographic factors, the region around Duluth, the Great Lakes area, will be one of the few places in America where the effects of climate change may be more easily managed.

First, it’s cool to begin with. That means, as temperatures increase, it will remain mild in relative terms. By 2080, even under relatively high concentrations of carbon dioxide emissions, Duluth’s climate is expected to shift to something like that of Toledo, Ohio, with summer highs maxing out in the mid-80s Fahrenheit.

“We’re not seeing worse heat waves or longer heat waves or more of those long nights that don’t fall below 75 degrees,” Blumenfeld said. “Instead, what we’re seeing is warmer winters, fewer days during winter where we get to negative 30 Fahrenheit.”

Because the region will remain relatively cool, it will have a lower wildfire risk than the West or the Southeast. Wildfires thrive in hotter temperatures, which dry out plants and make them easier to ignite.

And, because Duluth is inland, it’s mostly protected from the effects of sea level rise.

Duluth, which sits at the western end of Lake Superior, the greatest of the Great Lakes by volume, also has fresh water. A lot of it. Superior is so voluminous that, if poured out, it would submerge North and South America under a foot of water.

“At the end of the day, it’s really about fresh water,” Keenan said. “It’s that simple. You’ve got to have fresh water.”

You’ve got to have quite a bit, in fact. To meet our minimum needs, from drinking to cooking and cleaning, the World Health Organization says we need 13 to 26 gallons of water a day, or about 50 to 100 liters. The average American uses 80 to 100 gallons.

The city hasn’t formally adopted Keenan’s climate refuge plan so far, but it has the attention of the mayor, Emily Larson. “This idea that we have this national researcher who has identified Duluth as a place that has kind of a secret sauce when it comes to being a place for refuge and sustainability and resiliency, that is something you want to be a part of,” she said.

For the plan to work, people would need to actually move to Duluth. The city’s infrastructure can accommodate 150,000 people, but the current population is just 86,000. From 2010 to 2016, though, the city added only 56 people.

Presented to the public at the end of a two-day conference focused on understanding Duluth’s future in a warming world, Keenan’s research, which partly aims to predict which states are likely to see more people leaving because of climate change, suggested that present-day Texans and Floridians might make excellent future Duluthians.

“What do people from Florida really want?” said Keenan, himself a former Floridian who still keeps a residence in the state. “They want the infinite horizon of the ocean.”

This may be why one of Keenan’s sample advertisements, “Duluth, it’s not as cold as you think,” featured an image of a surfer in a wet suit.

That appeared to be tongue-in-cheek, too. When he showed the photo during his presentation, the audience laughed. Duluth does have a surf season. But the proposed ad glides past the fact that it’s in winter. Surfers head out into the lake in temperatures as low as minus 15 Fahrenheit, or minus 26 Celsius.

“We had one week in particular that it was negative 60 almost every day with wind chill,” said Kyle Skarp, an electrician, as he watched friends play board games in the backroom of Blacklist Artisan Ales, a brew pub in Duluth. “You didn’t want to go outside. And not because it was uncomfortable, but because it’s unsafe.”

Skarp said he liked the idea of more people coming to Duluth. He said it would mean more jobs.

But not everyone agrees with Keenan’s plan. Because it favors those who are financially able to move, it selects for the affluent and, he acknowledged, raises questions of gentrification.

After the presentation, Karen Diver, a faculty fellow at the College of Saint Scholastica who served as special assistant to the president for Native American affairs during the Obama administration, cautioned that the city had an uneven track record when it comes to embracing diversity.

“From my perspective we haven’t even figured out how to interact in a positive way with our indigenous people,” said Diver, a member of the Fond du Lac Band of Lake Superior Chippewa who lives near Duluth on her tribe’s reservation.

Larson seemed to acknowledge that. “I think we have a tremendous amount of work to do as a community to truly be a place where migration and immigration are seen as being strength and vitality and growth,” she said.

Ultimately, if Duluth decides to invest in attracting climate migrants, whether voluntary or displaced, the city may face competition.

At least one other Great Lakes city, Buffalo, 700 miles away on the eastern tip of Lake Erie, also has winter cold, and the same geographic blessings as Duluth. Buffalo is predicted to have fresh water even as the climate warms, and its summers will remain relatively cool.

“We’ve never had a 100 degree day,” said Stephen J. Vermette, a professor of geography at Buffalo State.

But Buffalo has already received what could be described as a wave of climate migrants, after Hurricane Maria devastated Puerto Rico in the autumn of 2017.

They came partly because Buffalo has an established Puerto Rican population, which meant that many prospective migrants had friends and relatives in the city.

At the same time, Buffalo had advertised itself on Puerto Rican television in search of Spanish language teachers. They came because they had connections and knew that there was a chance they could make a life there.

“About 10,000 people came here after the hurricane in Puerto Rico,” said George Besch, chairman of the board of directors at Designing to Live Sustainably, a nonprofit group working to help the Buffalo-Niagara region adapt to climate change.

According to Matthew Hauer, an assistant professor of sociology at Florida State University, people who migrate, whether by choice or not, still like to stick close to home, moving just far enough to get out of harm’s way but often remaining within the same state or region.

When people do go far away, he said, they either move for higher paying jobs, or they “tend to follow kin networks and friend networks.”

This article originally appeared in <a href="https://www.nytimes.com/2019/04/15/climate/climate-migration-duluth.html" id="2af0396d-4f76-3642-a7f1-71fa4d5f9b30">The New York Times</a>.

Want to Escape Global Warming? These Cities Promise Cool Relief

DULUTH, Minn. — As the West burns, the South swelters and the East floods, some Americans are starting to reconsider where they choose to live.

At least one other Great Lakes city, Buffalo, 700 miles away on the eastern tip of Lake Erie, has the same kind of winter cold, and all the geographic blessings, that Duluth has. It’s predicted to have fresh water even as the climate warms, and its summers will remain relatively cool.

The corals were found about 150 miles southeast of Boston in the Northeast Canyons and Seamounts Marine National Monument, a vast area of undersea mountains and valleys that was designated a monument by President Barack Obama in 2016.

“There’s a lot of predictions right now that suggests this area of the Atlantic, the northwest Atlantic, is going to heat up three times faster than any other part of the Atlantic,” said Timothy Shank, a deep-sea biologist at the Woods Hole Oceanographic Institute who led the expedition.

Warming waters can kill coral, the same way extreme heat can kill humans. They can also reduce the level of nutrients in the water that corals need to survive.

Concern about rising temperatures is partly why Obama made the area a marine monument, the first in the Atlantic. His declaration immediately banned mineral and oil extraction inside the monument area and called for phasing out fishing over a seven-year period in an effort to ease pressure on the ecosystem.

But in 2017, a coalition of New England fishing groups filed a lawsuit against the designation.

“Our lawsuit argues that the monument designation is unlawful,” said Jonathan Wood, the attorney representing the fishing groups. It says that the Antiquities Act, which gives presidents the authority to create national monuments, does not apply at sea.

A judge in U.S. District Court for the District of Columbia rejected that argument. The ruling is under appeal.

There have been signs, however, that the Trump administration is considering withdrawing the monument status, a move that would make the court battle irrelevant. In 2018, the Interior Department accidentally made public emails that included drafts of presidential proclamations overturning the Obama-era designation.

Cold-water corals are notoriously slow to grow. Shank once sampled one that stood 4 feet tall. “We dated it, and it was over 4,000 years old,” he said.

The canyons are much deeper than a human can dive, so Shank’s team, which included researchers from the University of Connecticut and NASA’s Jet Propulsion Laboratory, used underwater drones and a submersible vehicle provided by exploration group OceanX.

Peter J. Auster, a research professor emeritus of marine sciences at the University of Connecticut who toured the seamounts on an unrelated expedition, said the experience was “like a stroll through Dr. Seuss’ garden.”

“Between the corals their size and their shapes and the fish that live there, it’s a pretty otherworldly experience,” he said.

This article originally appeared in <a href="https://www.nytimes.com/2019/04/09/climate/coral-atlantic-warming.html" id="713be5ff-5100-3311-aab1-55d96c4a85d5">The New York Times</a>.

'Dr. Seuss' Garden' Yields a Deep-Sea Discovery, but It Already Faces Threats

Researchers announced Tuesday that they had found two new species of cold-water coral in undersea canyons off New England, a discovery that highlighted concerns about the effects global warming on the word’s oceans.

Supporters of the Green New Deal, according to a Republican talking point, are anti-patty. “They want to take away your hamburgers,” Sebastian Gorka, a former adviser to President Donald Trump, said last week at the Conservative Political Action Conference.

Other Republicans, including Trump, have made similar claims. But the Green New Deal, a broad climate policy proposal, makes no mention of hamburgers, cows or beef.

Instead, the resolution, introduced by Rep. Alexandria Ocasio-Cortez, D-N.Y., and Sen. Edward J. Markey, D-Mass., underscores the role of agricultural emissions in climate change.

Among its many goals, it calls for “working collaboratively with farmers and ranchers in the United States to remove pollution and greenhouse gas emissions from the agricultural sector as much as is technologically feasible.”

Cows have been a focus of some agriculture policy discussions because they release methane, a powerful planet-warming gas. A fact sheet about the Green New Deal that Ocasio-Cortez’s office published last month, then withdrew, said it would be hard to “get rid of farting cows.” But some critics of the plan saw that as a suggestion that getting rid of cows entirely would be a good thing.

“It’s not to say you get rid of agriculture,” Ocasio-Cortez later clarified on Showtime show “Desus and Mero.” “It’s not to say you are going to force everybody to go vegan or anything crazy like that. But it’s to say, listen, we’ve got to address factory farming, maybe we shouldn’t be eating a hamburger for breakfast, lunch and dinner.”

The back-and-forth has raised some tricky questions for burger lovers.

What do hamburgers have to do with climate change?

Agriculture was responsible for 9 percent of greenhouse-gas emissions in the United States in 2016, according to the Environmental Protection Agency. While the sectors with the most emissions were transportation and electricity generation, at 28 percent each, U.S. agricultural emissions were still greater than Britain’s total emissions in 2014, according to data from the World Bank.

Cows and other ruminants are responsible for two-thirds of those agricultural emissions. Their guts produce methane, a powerful greenhouse gas that’s more potent at trapping heat in the atmosphere than carbon dioxide, though it also dissipates faster. Cows release some of that methane through their flatulence, but much more by burping.

Deer, camels and sheep also produce methane. But in the United States, it’s cows that primarily account for the 26.9 percent of methane emissions, more than any other source. Natural gas accounts for 25 percent.

If it’s so bad, why don’t we just get rid of all the cows?

It’s not that easy, said Robin White, an assistant professor of animal sciences at Virginia Tech.

She was a co-author of a 2017 study that looked at an extreme case — what would happen if all animals were removed from farming. It found that total U.S. greenhouse gas emissions would be reduced by only a modest amount, while nutritional deficiencies would increase.

Other studies of possible agricultural changes “often don’t consider what we currently produce in terms of food in the United States,” White said. When those studies remove meat, eggs and dairy from the equation, she said, they tend to assume that other foods will be available.

But today’s agricultural system relies on a suite of crops that researchers have spent decades fine-tuning for specific niches. It isn’t clear that the country could easily grow a new set of crops that would make up for the lost nutrition from meat for the entire population. (Many individuals, of course, already opt against eating meat for ethical, religious or other reasons.)

“We don’t make that assumption,” White said. “We kind of ask the inverse question: Given the food that’s available, how do we feed people?”

Christian Peters, an associate professor at the Friedman School of Nutrition Science and Policy at Tufts University, said much of the country’s current agricultural output was used to feed animals. “There is a large amount of what we call co-products that come out of the food production system,” he said. “We have these things that we would otherwise turn into a waste, and we use them to raise animals.”

In addition, grazing cows are able to wrest calories from grasslands that are not suitable for growing food for humans.

Cows are also a source of fertilizer, White said. Her analysis looked at livestock manure that is used as fertilizer and assumed that it would have to be replaced with synthetic fertilizers, which are often made from natural gas. The main component of natural gas is methane, the same gas that makes cows so problematic in the first place.

So, how many burgers is too many?

From a greenhouse gas emissions perspective, it depends.

In addition to greenhouse-gas emissions, the food system has environmental challenges, like overtaxed agricultural lands; the dead zones that form each year in the Gulf of Mexico, fueled by nutrient runoff from Midwestern fields growing animal feed; and the pollution associated with concentrated animal feeding operations, or so-called factory farms.

Consuming lots of meat is also making people in the United States and other affluent nations unwell, according to a recent report on sustainable diets in the medical journal The Lancet. People in the United States would be better off eating much less red meat, the report said, while those in undernourished parts of the world, like South Asia, would benefit from eating more.

The World Cancer Research Fund has said that limiting red meat to 3.5 ounces — a little less than a quarter-pound burger — no more than three times a week reduces cancer risk. Going lower than that, sticking to one 3.5-ounce serving of red meat a week reduced related greenhouse-gas emissions by nearly half, the Lancet report said.

Peters published a study in 2016 that suggested that a lacto-ovo diet, which contains dairy and eggs, might be the most sustainable while also providing proper nutrition.

But at a high level, even a lacto-ovo diet necessitates the creation of at least some meat. A laying hen can live six years or longer but stops laying eggs efficiently after a year. A cow can live up to 20 years, but milk production for most cows drops somewhere between the ages of 5 and 8. Not slaughtering them for meat would mean a commitment to keeping them alive — and committing the resources to do so — for quite some time. It may be more efficient to simply eat them.

If all of this sounds messy, it is. Researchers generally agree that agriculture is one of the hardest parts of the economy to decarbonize; it’s not just about lowering greenhouse-gas emissions, but also about keeping the world fed.

The question, Peters said, boils down to finding sustainable ways of producing food that meet both the food security needs of the United States and the many other nations that depend on it for exports.

“It would be very safe to say that eating less meat is going to make it easier to accommodate a larger number of people on the planet, and every study I’ve seen is pointed to that,” Peters said. “The question is by how much, and how quickly does that need to change?”

This article originally appeared in <a href="https://www.nytimes.com/2019/03/08/climate/hamburgers-cows-green-new-deal.html" id="5619a183-3a5f-33f8-a8b8-4300a0995945">The New York Times</a>.

The hamburger is suddenly embroiled in a political dispute.

Source of the Problem, Also Part of the Solution

The study found that the amount of seafood that humans could sustainably harvest from a wide range of species shrank by 4.1 percent from 1930 to 2010, a casualty of human-caused climate change.

“That 4 percent decline sounds small, but it’s 1.4 million metric tons of fish from 1930 to 2010,” said Chris Free, lead author of the study, which appears in the journal Science.

Scientists have warned that global warming will put pressure on the world’s food supplies in coming decades. But the new findings — which separate the effects of warming waters from other factors, like overfishing — suggest that climate change is already having a serious effect on seafood.

Fish make up 17 percent of the global population’s intake of protein, and as much as 70 percent for people living in some coastal and island countries, according to the Food and Agriculture Organization of the United Nations.

“Fish provide a vital source of protein for over half of the global population, and some 56 million people worldwide are supported in some way by marine fisheries,” Free said.

As the oceans have warmed, some regions have been particularly hard-hit. In the northeast Atlantic Ocean and the Sea of Japan, fish populations declined by as much as 35 percent over the period of the study.

“The ecosystems in East Asia have seen some of the largest decline in fisheries productivity,” Free said. “And that region is home to some of the largest-growing human populations and populations that are highly dependent on seafood.”

Now a postdoctoral researcher at the University of California, Santa Barbara, Free began the research while a Ph.D. student at Rutgers University.

Marine life has been subjected to some of the most drastic effects of climate change. The oceans have absorbed 93 percent of the heat that is trapped by the greenhouse gases that humans pump into the atmosphere.

A study published in January, also in Science, found that ocean temperatures were increasing far faster than previous estimates.

Amid these changing conditions, fish are shifting where they live, in search of their preferred temperatures. High ocean temperatures can kill off both the fish themselves and the sources of food they depend on.

“Fish are like Goldilocks: They don’t like their water too hot or too cold,” said Malin L. Pinsky, an associate professor in the School of Environmental and Biological Sciences at Rutgers University and a co-author of the new study.

In about a quarter of the regions studied, fish had expanded their range. Off the Atlantic coast of the United States, sustainable catches of black sea bass increased by 6 percent over the study period.

Another quarter of the regions saw no significant changes in fish populations, like the northwest Atlantic Ocean, where Atlantic herring are abundant.

But half the regions did not fare as well. The northeast Atlantic Ocean — home to the Atlantic cod, the mainstay of fish and chips — saw a 34 percent decline in sustainable catches.

Overall, more populations of fish declined than increased over the eight decades in the study.

The researchers focused on sustainable catches, using a measure developed by the U.N. that quantifies the amount of food that can be repeatedly harvested from a base population of fish. “Fisheries are like a bank account, and we’re trying to live off the interest,” Pinsky said.

Several previous studies have predicted that climate change would lead to fewer ocean fish in the future, but the new research looked at historical data to determine that the declines had already begun.

“This is going to be one of those groundbreaking studies that gets cited over and over again,” said Trevor Branch, an associate professor at the University of Washington’s School of Aquatic and Fishery Sciences, who was not involved in the study. “Most of what I’ve seen before in terms of climate-change impacts have been speculative, in terms of, ‘We think this is what’s going to happen in the future.’ This one’s different.”

The researchers used a data set of 235 fish populations located in 38 ecological regions around the globe. The detailed data told them not only where the fish were but also how they reacted to environmental effects like changing water temperatures.

The team compared that data to records that showed how ocean temperatures had changed over time, broken down by the various regions. These regional analyses were important, because some parts of the ocean have warmed faster than others.

“We then connected those to which populations responded positively, negatively and which didn’t respond at all,” Pinsky said.

The data revealed some other trends. Fish populations in the colder parts of their ranges tended to fare better than those located in warmer areas — for those fish, the extra heat was too much. This was especially troubling to the researchers, because the data they used was less detailed in the tropics. Fish losses in those regions may have been higher than in the regions the study focused on, Pinsky said.

Warm areas fared even worse when they were overfished. The researchers suggested that overfishing made fish even more vulnerable to temperature changes by hurting their ability to reproduce and damaging the ecosystem.

Guarding against overfishing and improving the overall management of fisheries can help, the researchers said. But ultimately, they said, the solution lies in slowing or halting climate change.

A separate study, published Wednesday in the journal Science Advances, found that limiting warming to 2.7 degrees Fahrenheit (1.5 degrees Celsius) above preindustrial levels — a goal of the Paris climate agreement — could result in billions of dollars in extra revenue for fisheries globally. Much of that would be in the developing world, where many people rely on fish for protein.

“We hope that this highlights the importance of accounting for the fact that climate change is driving shifts in productivity,” Free said of his research. “Fishery managers need to come up with new innovative ways of accounting for those shifts. That includes reducing catch limits in warm negative years, but it can also include increasing catch limits in cooler positive years. Having regulations that are adaptive to climate change is going to be really important for maximizing food potential.”

This article originally appeared in <a href="https://www.nytimes.com/2019/02/28/climate/fish-climate-change.html" id="1f2eb731-9e18-38e6-a90b-8939dc0c9e25">The New York Times</a>.

The World Is Losing Fish to Eat as Oceans Warm, Study Finds

Fish populations are declining as oceans warm, putting a key source of food and income at risk for millions of people around the world, according to new research published Thursday.

President Donald Trump is among them, and he weighs in frequently.

“Be careful and try staying in your house,” he tweeted last week. “Large parts of the Country are suffering from tremendous amounts of snow and near record setting cold. Amazing how big this system is. Wouldn’t be bad to have a little of that good old fashioned Global Warming right now!”

The answer lies in the difference between local weather and climate.

Climate refers to how the atmosphere acts over a long period of time, while weather describes what’s happening on a much shorter time scale. The climate can be thought of, in a way, as the sum of long periods of weather.

Or, to use an analogy Trump might appreciate, weather is how much money you have in your pocket today, whereas climate is your net worth. A billionaire who has forgotten his wallet one day is not poor, any more than a poor person who lands a windfall of several hundred dollars is suddenly rich. What matters is what happens over the long term.

Even on a day when it is colder than average where you live, the world as a whole is frequently warmer than average, which you can see for yourself on daily maps put out by the University of Maine.

One example from a period of unusually frigid weather in December 2017: parts of the United States were 15 to 30 degrees Fahrenheit colder than average, but the world as a whole was about 0.9 degrees Fahrenheit warmer than the 1979-2000 average.

While climate scientists expect that the world could warm, on average, roughly 2 to 7 degrees Fahrenheit by the end of the century — depending on how quickly greenhouse-gas emissions rise — they don’t expect that to mean the end of winter altogether. Record low temperatures will still occur; they’ll just become rarer over time.

One 2009 study found that the United States saw roughly as many record highs as record lows in the 1950s, but by the 2000s there were twice as many record highs as record lows. Severe cold snaps were still happening, but they were becoming less common.

Some recent cold spells have been caused by the dreaded polar vortex. There’s growing evidence to suggest that the polar vortex is appearing outside the Arctic more frequently, because of changes in the jet stream that are attributed to the warming atmosphere. These changes help frigid air escape from the Arctic and swoop southward.

Politicians have tried to use cold snaps to prove a point before. Sen. James Inhofe, R-Okla., brought a snowball to the Senate floor in February 2015 as evidence that the Earth was not warming.

Trump, who has repeatedly denied the science of climate change, has recognized the threats where some of his properties are involved. His golf resort in Ireland intends to build two sea walls and cited the risks of global warming in one of its applications for the construction.

Trump has made a habit of airing his climate skepticism on Twitter, posting comments on “climate change” or “global warming” more than 100 times since 2011. Before his presidency, he called climate change a hoax and claimed the idea was perpetuated by the Chinese.

In 2018, he backed off that claim, saying: “I don’t think there’s a hoax. I do think there’s probably a difference. But I don’t know that it’s man-made.”

The U.S. government and hundreds of scientific organizations agree that human activities are primarily responsible for global warming.

This article originally appeared in <a href="https://www.nytimes.com/2019/01/28/nyregion/islamberg-ny-attack-plot.html" id="cef1ae50-56bc-3bcf-ad19-a8ee9cce41f5">The New York Times</a>.

As climate change heats up the planet, winters are warming faster than summers. But on days when the temperature tumbles below freezing, it leaves many people wondering, “If the Earth is getting warmer, how can winter still be so cold?”

If the Earth Is Warming, Why Is It So Cold Outside?

Today, plants and soil around the world absorb roughly a quarter of the greenhouse gases that humans release into the atmosphere, helping the Earth avoid some of the worst effects of climate change. In an ideal situation, as levels of carbon dioxide increased, plants would soak up more of these emissions, helping to fuel their growth.

But in a study published Wednesday in the journal Nature, researchers found that under a warming climate, rather than absorbing more greenhouse gas emissions, plants and soil may start absorbing less, accelerating the rate of change.

The last time the atmosphere contained as much carbon dioxide as it does now, dinosaurs roamed what was then a verdant landscape. The earth’s lushness was at least partly caused by the abundance of CO2, which plants use for photosynthesis. That has led to the idea that more CO2 in the atmosphere could create a literally greener planet.

Kendra Pierre-Louis

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