What Climate Crisis Will Do to 3 Major American Cities by 2100
By Allegra Kirkland, Jeremy Deaton, Molly Taft, Mina Lee and Josh Landis
Climate change is already here. It's not something that can simply be ignored by cable news or dismissed by sitting U.S. senators in a Twitter joke. Nor is it a fantastical scenario like The Day After Tomorrow or 2012 that starts with a single crack in the Arctic ice shelf or earthquake tearing through Los Angeles, and results, a few weeks or years later, in the end of life on Earth as we know it.
Instead, we are seeing its creeping effects now — with hurricanes like Maria and Harvey that caused hundreds of deaths and billions of dollars in economic damage; with the Mississippi River and its tributaries overflowing their banks this spring, leaving huge swaths of the Midwestern plains under water. Climate change is, at this very moment, taking a real toll on wildlife, ecosystems, economies, and human beings, particularly in the global south, which experts expect will be hit first and hardest. We know from the increasingly apocalyptic warnings being issued by the United Nations that it will only get worse.
But these early omens of our unstable, hot, wet future can be difficult to wrap our heads around. So Teen Vogue partnered with the team at the nonprofit news service Nexus Media, who developed a timeline predicting how climate change could affect three major U.S. cities over the course of the 21st century. Climate change will look different in different places across the world, but we chose three places with distinct geographic concerns and climate vulnerabilities — to ground all the ominous statistics and headlines in a real sense of place. These are cities you may have visited, or where you may have family, or where you may even live.
According to the research Nexus compiled, St. Louis will see flooding, extreme heat, severe rainfall, and drought in the surrounding farmland. In Houston, on the Gulf of Mexico, hurricanes will grow more destructive and temperatures will soar. San Francisco will witness rising sea levels, fierce wildfires, and extreme drought.
This timeline is based on interviews with a dozen climate experts and a review of several dozen scientific studies. The projections assume an average sea level rise of six feet by 2100 — a little more in some places, and less in others — and the business-as-usual emissions scenario, which assumes that we will continue to pollute and use fossil fuels at our current rate.
Rather than a scientific assessment, it is a rigorously researched prediction of what our future could bring unless we come together as a country and as a global community — fast— to address climate change as the crisis it is.
As Katharine Hayhoe, a climate scientist at Texas Tech University, put it: "The future is not set in stone. Some amount of change is inevitable. It's as if we've been smoking a pack of cigarettes a day for decades, but we don't have lung cancer yet."
"The amount of change that we're going to see — whether it's serious, whether it's dangerous, whether it's devastating, whether it's civilization-threatening — the amount of change we're going to see is up to us," she continued. "It depends on our choices today and in the next few years."
It's starting to get hot. It's now about one degree Fahrenheit warmer in Houston than it was in the second half of the 20th century. Houstonians can expect especially balmy falls this decade, as autumns are warming faster than other seasons in Texas.
Houston knows how much it stands to lose from climate change. In 2017, Hurricane Harvey devastated the city, which was supercharged by warm waters in the Gulf. But Houston is also helping to drive the rise in temperature. Several major oil companies and a vast network of oil refineries and petrochemical plants call the city home.
This decade, St. Louis is expected to be more than two degrees Fahrenheit warmer than it was, on average, during the latter half of the 20th century. While locals have endured more sweltering summer days, they have felt the change the most during the cold months. Missouri winters are warming faster than summers, springs, and falls.
Warmer air holds more water, which can lead to more severe rainfall. In recent years, rainstorms have pummeled the Midwest and led to widespread flooding across the region. In 2019 in St. Louis, rivers reached near-historic levels, and floodwaters inundated the area around the city's iconic Gateway Arch.
For San Franciscans, the beginning of the decade will feel only a little different from past years. In 2020, it's expected to be less than one degree Fahrenheit warmer in San Francisco than it was, on average, between 1950 and 2000. The change is small, but locals can sometimes feel it in the spring, which is warming faster than the other seasons, or on especially hot days.
But there are new worries for the city. Rising temperatures have fueled ongoing drought in recent years, which has, in turn, led to more wildfires. Fires now burn more regularly across the Sierra Nevada as well as coastal mountain ranges. The flames may ruin plans for weekend getaways to Yosemite or deliver noxious smoke to the Bay Area. And locals may start to reach for air masks as dangerously smoky days become more common.
"We get a lot of the smoke that comes from the wildfires that happen in inland California, and that makes it really hard to breathe the air," said Kristy Dahl, a climate scientist at the Union of Concerned Scientists, who is based in San Francisco. "Last year when there was a massive wildfire hundreds of miles away, San Francisco for a day [ranked among] the worst air quality in the entire world."
By 2030, temperatures are expected to have warmed almost two degrees Fahrenheit in Houston. Seas are expected to have risen a little more than a foot, enough to occasionally flood some low-lying areas outside the city. Warmer waters in the Gulf of Mexico will raise the speed limit for winds during hurricanes and ramp up rainfall during storms.
"Hurricanes are not getting more frequent, but they are getting stronger and bigger and slower," said Katharine Hayhoe, a climate scientist at Texas Tech University. "They're intensifying faster and they have a lot more rain associated with them today than they would have had a hundred years ago."
By 2030, temperatures are expected to have warmed around three degrees Fahrenheit in St. Louis. The kind of rainstorm that currently strikes the Midwest around once every five years will hit around once every three years this decade.
"We've seen these record-breaking, devastating floods in the Midwest," said Katharine Hayhoe, a climate scientist at Texas Tech University. "It's not like they've never had floods before, but the floods are just getting a lot worse and a lot more frequent."
This could mean trouble for local infrastructure. Rivers swell after heavy rains, and the rush of water can weaken bridges by carrying away sediment from around their foundations. This could be a big problem in Missouri, which is home to hundreds of aging bridges, many of which have been deemed deficient. Climate change could mean even more heavy repair costs for taxpayers.
This decade, the rise in temperature is expected to pass two degrees Fahrenheit in San Francisco. That may not feel like a lot in the city. But warmer weather is taking a serious toll.
California's drought will get progressively worse this decade, the product of warmer temperatures drying out soil and meager rainfall failing to replace the water lost. Rising temperatures will also yield less snowfall. The snow that does come down will melt in the spring and early summer, depriving the state of a critical source of water in the late summer, when, historically, melting snow has fed streams and rivers.
The snow drought will strain farmers in the Central Valley, while putting pressure on cities to use less water. The water restrictions the state put in place in 2018 will have grown much more severe in the past 12 years. Officials could urge Californians across the state to take shorter showers and stop watering their lawns to cope with the worsening drought.
This decade, sea level rise around Houston is projected to reach two feet, enough to inundate much of nearby Freeport and Jamaica Beach. That extra water will mean that hurricanes, when they strike, will deliver more powerful floods to coastal areas.
"A small and steady rise of the water level elevates a platform for flooding that we've had throughout history," said Maya Buchanan, a sea level rise scientist at Climate Central. "That means larger storm surges."
That's bad news for people who live near the shore. Around half of deaths caused by hurricanes are the result of coastal flooding, and waters tend to inundate poor neighborhoods and neighborhoods of color, which are more likely to lie in flood-prone areas.
In 2040, St. Louis is expected to be four degrees Fahrenheit warmer than it was at the end of the last century. While that may sound like a small number, it means big problems for the city. A small uptick in the average temperature could lead to milder winters, stifling summers and changing rainfall.
St. Louis will tend to see wetter springs and drier summers. That means the region will withstand heavier downpours, but it will also endure long stretches without a drop of rain. Despite the growing peril of major flooding, extended dry spells and rising temperatures will dry out the land. Drought will set in in Missouri, endangering farms.
And just remember — it will never be this cool again.
By 2040, sea levels are predicted to rise around one foot, enough to encroach the beaches on the west side of the city and Candlestick Point on the east, popular recreation areas. Parts of San Francisco Airport and Oakland Airport will flood regularly, making air travel in and out of the city more difficult.
Drought will have grown increasingly severe. Forests will dry out, and become vulnerable to bark beetles, which burrow into trees to lay their eggs. Healthy trees can ward off the bugs by covering them in resin — but already struggling trees have no way to protect themselves.
Large parts of forests will die, and the dead trees will become tinder for wildfire. In 2040, fires are expected to burn around twice as much big sections of the Sierra Nevada as they do today. Areas south of San Francisco will also grow more vulnerable to erupting in flames.
By midcentury, temperatures are expected to have warmed more than three degrees Fahrenheit in Houston. Waters in the Gulf of Mexico will have also warmed, fueling more dangerous storms.
In the decades to come, the Gulf will see more category-four and -five hurricanes, like Hurricane Harvey and Hurricane Katrina, according to Suzana Camargo, a climate scientist at Columbia University. Warm water is like ammunition for cyclones, arming them with more powerful winds and heavier rains. People might want to think twice before they purchase a home in Houston.
"I think people have to think very carefully how they are going to plan when they want to buy a house," Camargo said, explaining that in the future, cyclones will deliver more flooding to seaside cities and towns.
St. Louis is expected to have heated up by more than five degrees Fahrenheit on average by the middle of the century. Hot weather will dry out soil. Past 2050, the Central Plains, including much of Missouri, can look forward to decades-long drought.
This drought will be especially disastrous for Missouri farmers. Growers will have to take more water out of underground aquifers to feed their crops, drawing down a limited supply of groundwater, often at great cost. This, in turn, could drive up the price of food.
By 2050, temperatures in San Francisco are expected to have risen more than three degrees Fahrenheit. In the second half of this century, changing weather patterns will yield lasting dry spells, leaving much of California to endure long stretches without rain. Around the time someone graduating high school today turns 50, they can expect California to enter a decades-long drought — with disastrous consequences.
Farmers in California will have to draw more and more water from underground. Eventually, they may not be able to grow fruits and vegetables in parts of the state. This will drive up the cost of many foods, such as strawberries, almonds, and lemons.
Snow will also start to disappear from the Sierra Nevada. By 2050, projections say, there will be a third less snow than we see today. San Francisco depends on that snow for its water, and a dry Sierra Nevada could mean a looming water crisis for the city.
The drought will also leave California's forests all the more vulnerable to wildfire — fires that could cover San Francisco in smoke, making it dangerous to go outside.
Where San Francisco residents are expected to move when they're displaced by rising seas..
Local sea level rise, meanwhile, is expected reach three feet during this decade. This will raise the level of Buffalo Bayou, the waterway that stretches through the middle of Houston. The Scholes International Airport in nearby Galveston will sink into the sea, and at high tide, water will flood much of the San Jacinto Battleground, site of the 1836 clash where Sam Houston, the city's namesake, overcame the Mexican Army.
St. Louis is expected hit a six-degrees-Fahrenheit increase in its average temperature this decade. While this might be bad news for humans, it's good for many insects, who love warm weather. Rising temperatures will bring disease-carrying mosquitoes to St. Louis's doorstep. Missourians will have to be more vigilant about their health as the bugs could spread tropical viruses like Zika, dengue, and yellow fever around the warming Midwest.
Climate change will also bring more deer ticks to St. Louis. Because warmer air can hold more water, as temperatures rise, so does humidity — and deer ticks thrive in humid weather. While ticks are little seen in Missouri today, later this century they will fan out across the state, potentially spreading Lyme disease. Those afflicted will endure fever, headache, and fatigue. They may see their joints swell or feel their face droop.
By 2060, temperatures in San Francisco are expected to have risen by more than four degrees Fahrenheit.
Wildfires will burn roughly three times as much of broad swaths of the Sierra Nevada as they do today, laying waste to large stretches of California's pristine forests.
This decade, sea level rise is projected hit two feet. Water will begin to spill over the edges of the Mission Creek Channel, while threatening routine floods around San Francisco's iconic Fisherman's Wharf. Waters will have flooded much of nearby San Rafael, north of San Francisco. To the south, Foster City will be underwater, displacing thousands of residents — many of whom currently work in the tech industry.
By 2070, Houston is projected to be more than five degrees Fahrenheit hotter than at the end of the 20th century. This warming is part of a larger trend that is heating up the planet and melting ice in Greenland and Antarctica, raising the sea level near the city.
"As flooding events get more severe, that can impact property values, and that could impact where people decide to live," Buchanan said, explaining that rising seas will drive down the value of homes in low-lying areas.
By this time, waters will have already subsumed much of the coastline from Freeport, south of Houston, all the way to New Orleans. Rising seas will make much of the Gulf coast unrecognizable as the ocean swallows up most of southern Louisiana. Later this decade, sea levels are expected to have risen by four feet.
In 2070, St. Louis is projected to be more than seven degrees Fahrenheit hotter than it was at the end of the last century. Before the decade is through, the city is expected to see eight degrees Fahrenheit of warming. Rising temperatures will have utterly transformed the weather in Missouri, making it virtually unrecognizable to current residents. The city will see around 20 fewer days of frost each year than it does today, as well as around 20 extra days with temperatures over 95 degrees Fahrenheit. The heat will be felt most acutely in neighborhoods short on trees and parks.
Outside the city, severe heat will cripple the growth of corn and soybeans at nearby farms. So will drought, which experts say will be worse than at any time in living memory. The state will endure more consecutive days without rain. When it does rain, however, it will pour. Warmer temperatures will produce more extreme rainfall.
By 2070, San Francisco's average temperature is expected to have warmed by more than five degrees Fahrenheit. Drought will be more severe than at any time in living memory. Rising temperatures and diminished rainfall will take a toll on trees around the San Francisco Bay. More and more evergreen forests will die off and grasslands will spring up in their place, fundamentally changing the landscape around the city.
This is what Houston, St. Louis, and San Francisco will feel like in 2080.
By 2080, temperatures are projected to have warmed around six degrees Fahrenheit on average, a dizzying change in the weather that means Houston won't feel like Houston anymore.
The city will grow warmer and wetter. Around 2080, Houston will feel something like Ciudad Mante in Mexico does today, with its warmer, drier winter.
As the climate changes, Houston's native wildlife could start to head north. At the same time, plants and animals that currently make their home south of Houston may start to work their way toward the city.
St. Louis is expected to be nearly nine degrees Fahrenheit warmer by 2080. The temperature will have changed so drastically that St. Louis no longer feels like the same city.
Around 2080, St. Louis will start to feel like Prosper, Texas, does today. This new St. Louis will be hotter and drier. Summer weather will go from balmy to sweltering, and the city will see much less rain during the warm months.
It's not just that St. Louis will feel more like Prosper. It might start to look like it too. Animals that currently live around Prosper could head northward as the climate changes, searching for a new home that feels like their old one. At the same time, the shrubs and grasslands that stretch across north Texas could start to edge their way toward Missouri.
By 2080, the average temperature is expected to have risen by more than six degrees Fahrenheit in San Francisco. The city will start to feel a lot like present-day Los Angeles. The weather will be warmer and drier, much like the current climate in Palos Verdes Estates, a coastal city in the L.A. area.
With less rainfall, many of the trees that make their home in San Francisco will die. At the same time, the smaller, scrubbier plants that make their home in L.A. could migrate toward the city. It's not just that San Francisco will start to feel like L.A., scientists say. It might start to look like it too.
By now, temperatures are projected to have warmed close to seven degrees Fahrenheit, while sea levels will have risen five feet, subsuming the coastline. Much of nearby Galveston is underwater.
It's not just hot days that threaten Houston. Rising temperatures will allow the air to hold more water, increasing humidity — which could be a big problem for public health.
"As humidity rises, it becomes harder and harder for the sweat to evaporate off our skin — and it's that evaporation of sweat that cools our bodies," said Kristy Dahl, a climate scientist at the Union of Concerned Scientists. "So it might only be a temperature reading of 90 degrees, but if you have 60% humidity, it's going to feel hotter than 90 degrees."
Dahl said that Houston will heat up so much that it will be hard to quantify how hot it will feel.
"By the end of the century, Houston would see about three weeks of what we call off-the-charts heat conditions, which are when the combination of temperature and humidity falls above the national weather services heat index scale," she said. "What that means is that we can't even calculate a heat index to reliably warn people about how dangerous it is."
St. Louis is expected to have warmed by almost 10 degrees Fahrenheit, a transformational change in the climate of the city. Rising temperatures could provoke a spike in violent crime — when people are hot, research shows, they tend to feel more aggressive.
By the end of the century, St. Louis will endure around 80 days per year where the heat index is above 100 degrees — compared to just 11 days at the end of the 20th century, according to Kristy Dahl, a climate scientist at the Union of Concerned Scientists.
"It's really striking because historically those off-the-charts conditions have only occurred in the Sonoran desert region of the U.S., the California-Arizona border," Dahl said.
In addition to extreme heat, the city will also endure severe drought, punctuated by the occasional supercharged rainstorm. The kind of downpour that currently strikes the Midwest around once every five years will hit around once every year or two. The most severe storms — the kind that currently show up once every 20 years — now arrive once every six or seven years.
Heavy rainfall will lead to flooding, and floodwaters will mix with raw sewage, helping to spread bacteria. Rains will also swamp homes and businesses, offering a place for mold to grow.
By now, San Francisco is projected to have heated up more than seven degrees Fahrenheit on average. The extra heat will mean many people will be spending more time outdoors, potentially leading to a spike in violent crime.
The state will be mired in lasting drought. Wildfires could consume around four times as much of huge sections of the Sierra Nevada as they do today, as well as forests closer to San Francisco, endangering locals.
The Bay Area is expected to have seen more than three feet of sea level rise. The San Francisco and Oakland Airports will be completely underwater. Across the bay, coastal flooding will inundate parts of Alameda. Low-lying areas on the south end of the San Francisco Bay will also be flooded, including some of San Jose.
By the end of this century, temperatures are expected to have warmed close to eight degrees Fahrenheit in Houston. In the summer, Houston will feel something like Jeddah, Saudi Arabia, does today. High temperatures will average over 100 degrees Fahrenheit during the warmest months.
By making life harder for workers, severe hotter weather will shrink the economy of the greater Houston area by 6%. Extreme heat will also kill hundreds more people each year. Poorer neighborhoods tend to be warmer, in part because they tend to have fewer trees. People who live in those neighborhoods are also less likely to have air conditioners, which will put them at greater risk.
On top of the heat, Houston is expected to have seen close to six feet of sea level rise by 2100. Waters encroach on the east side of town near the water, where oil refineries and chemical plants could continue to service our catastrophic addiction to oil and gas. Routine flooding of these facilities may cause dangerous explosions and potentially release toxic chemicals into the air.
Much of the city, however, will stay safe from the encroaching sea. That means the Houston could absorb hundreds of thousands of new residents by 2100 — people who were driven from Miami and New Orleans by ever-worsening coastal floods.
By the end of this century, St. Louis is expected to have warmed by roughly 11 degrees Fahrenheit. Winter will scarcely look like winter. Summers will have gone from hot to unbearable.
During the hottest months, it will be so scorching that it will be dangerous to go outside for much of the day. People will depend more on air conditioners to stay cool, leading to bigger electric bills. Elderly people, particularly those who can't afford to run an air conditioner, will face the risk of heat stroke and death.
The intense heat will take an immense toll on the local economy. Farms in Missouri and southern Illinois could see yields cut in half, ruining livelihoods.
In St. Louis itself, experts project that heat will stifle productivity by making it too hot to work. This could help cut the city's economic output by around 8%.
By 2100, San Francisco is expected to have heated up by more than eight degrees Fahrenheit on average. It will be hot and dry. Snow will be hard to find in the Sierra Nevada. By 2100, the mountain range will see two thirds less snow than we see today, depriving San Francisco of a much-needed water source.
Seas will have risen four feet, projections say. Large parts of Alameda will be underwater. Hunters Point will have flooded, as well as much of Mission Bay. And flooding won't be limited to San Francisco.
Sea level rise could flood the homes of 13 million Americans by the end of the century, leading to a massive exodus from many coastal areas. By one estimate, rising seas in places like Oakland, Alameda, and San Mateo could spur close to 300,000 residents to move to inland cities in Arizona, Texas, and New Jersey. It is the poorest neighborhoods that will be the most vulnerable to floods.
Note: This story is based on RCP 8.5, the so-called "business-as-usual" emissions scenario that assumes that Earth will continue to heavily rely on fossil fuels as the global economy grows. Per Nexus Media, "As we are currently doing virtually nothing to stop climate change, RCP 8.5 is a pretty good predictor of what's going to happen over the next couple of decades. Part of that is because it will take a while for the climate to reach a new equilibrium, so even if we stopped polluting now, the planet would continue to warm for decades." It looks at a sea level rise of six feet, on average, globally, based on the findings of this widely-cited 2014 study.
This story originally appeared in Teen Vogue in partnership with Nexus Media. It is republished here as part of EcoWatch's partnership with Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.
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While the nation overall struggles with rising COVID cases, New York State is seeing the opposite. After peaking in March and April and implementing strict shutdowns of businesses, the state has seen its number of positive cases steadily decline as it slowly reopens. From coast-to-coast, Governor Andrew Cuomo's response to the crisis has been hailed as an exemplar of how to handle a public health crisis.
By Gavin Naylor
Sharks elicit outsized fear, even though the risk of a shark bite is infinitesimally small. As a marine biologist and director of the Florida Program for Shark Research, I oversee the International Shark Attack File – a global record of reported shark bites that has been maintained continuously since 1958.
A Big, Diverse Family<p>Not all sharks are the same. Only a dozen or so of the roughly 520 shark species pose any risk to people. Even the three species that account for almost all shark bite fatalities – the <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/carcharodon-carcharias/" target="_blank">white shark</a> (<em>Carcharodon carcharias</em>), <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/galeocerdo-cuvier/" target="_blank">tiger shark</a> (<em>Galeocerdo cuvier</em>) and <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/carcharhinus-leucas/" target="_blank">bull shark</a> (<em>Carcharhinus leucas</em>) – are behaviorally and evolutionarily very different from one another.</p><p>The tiger shark and bull shark are genetically as different from each other as a dog is from a rabbit. And both of these species are about as different from a white shark as a dog is from a kangaroo. The evolutionary lineages leading to the two groups split 170 million years ago, during the age of dinosaurs and before the origin of birds, and <a href="https://www.ck12.org/book/CK-12-Human-Biology/section/7.2/" target="_blank">110 million years before the origin of primates</a>.</p>
White, tiger and bull sharks are distinct species that diverged genetically tens of millions of years ago. Gavin Naylor / CC BY-ND<p>Yet many people assume all sharks are alike and equally likely to bite humans. Consider the term "shark attack," which is scientifically equivalent to "mammal attack." Nobody would equate dog bites with hamster bites, but this is exactly what we do when it comes to sharks.</p><p>So, when a reporter calls me about a fatality caused by a white shark off Cape Cod and asks my advice for beachgoers in North Carolina, it's essentially like asking, "A man was killed by a dog on Cape Cod. What precautions should people take when dealing with kangaroos in North Carolina?"</p>
Know Your Species<p>Understanding local species' behavior and life habits is one of the best ways to stay safe. For example, almost all shark bites that occur off Cape Cod are by white sharks, which are a large, primarily cold-water species that spend most of their time in isolation feeding on fishes. But they also aggregate near seal colonies that provide a reliable food source at certain times of the year.</p><p>Shark bites in the Carolinas are by warm-water species like bull sharks, tiger sharks and <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/carcharhinus-limbatus/" target="_blank">blacktips</a> (<em>Carcharhinus limbatus</em>). Each species is associated with particular habitats and dietary preferences.</p><p>Blacktips, which we suspect are responsible for most relatively minor bites on humans in the southeastern United States, feed on schooling bait fishes like menhaden. In contrast, bull sharks are equally at home in fresh water and salt water, and are often found near estuaries. Their bites are more severe than those of blacktips, as they are larger, more powerful, bolder and more tenacious. Several fatalities have been ascribed to bull sharks.</p><p>Tiger sharks are also large, and are responsible for a significant fraction of fatalities, particularly off the coast of volcanic islands like Hawaii and Reunion. They are tropical animals that often venture into shallow water frequented by swimmers and surfers.</p>
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Humans Are Not Targets<p>Sharks do not "hunt" humans. Data from the International Shark Attack File compiled over the past 60 years show a tight association between shark bites and the number of people in the water. In other words, shark bites are a simple function of the probability of encountering a shark.</p><p>This underscores the fact that shark bites are almost always cases of mistaken identity. If sharks actively hunted people, there would be many more bites, since humans make very easy targets when they swim in sharks' natural habitats.</p><p>Local conditions can also affect the risk of an attack. Encounters are more likely when sharks venture closer to shore, into areas where people are swimming. They may do this because they are following bait fishes or seals upon which they prey.</p><p>This means we can use environmental variables such as temperature, tide or weather conditions to better predict movement of bait fish toward the shoreline, which in turn will predict the presence of sharks. Over the next few years, the Florida Program for Shark Research will work with colleagues at other universities to monitor onshore and offshore movements of tagged sharks and their association with environmental variables so that we can improve our understanding of what conditions bring sharks close to shore.</p>
More to Know<p>There still is much to learn about sharks, especially the 500 or so species that have never been implicated in a bite on humans. One example is the tiny <a href="https://www.newsweek.com/one-worlds-rarest-sharks-also-one-most-adorable-325280" target="_blank">deep sea pocket shark</a>, which has a strange pouch behind its pectoral fins.</p><p>Only two specimens of this type of shark have ever been caught – one off the coast of Chile 30 years ago, and another more recently in the Gulf of Mexico. We're not sure about the function of the pouch, but suspect it stores luminous fluid that is released to distract would-be predators – much as its close relative, the <a href="https://sharkdevocean.wordpress.com/2015/04/23/second-ever-pocket-shark-discovered-in-gulf-of-mexico/" target="_blank">tail light shark</a>, releases luminous fluid from a gland on its underside near its vent.</p>
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="5783b39d0838d6e410344a852ed0dcc3"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/UTO5debfmsg?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Sharks range in form from the bizarre <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/mitsukurina-owstoni/" target="_blank">goblin shark</a> (<em>Mitsukurina owstoni</em>), most commonly encountered in Japan, to the gentle filter-feeding <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/rhincodon-typus/" target="_blank">whale shark</a> (<em>Rhincodon typus</em>). Although whale sharks are the largest fishes in the world, we have yet to locate their nursery grounds, which are likely teeming with thousands of <a href="https://www.earthtouchnews.com/oceans/sharks/baby-whale-shark-rescued-from-gillnet-in-india-video/" target="_blank">foot-long pups</a>. Some deepwater sharks are primarily known from submersibles, such as the giant <a href="https://twitter.com/gavinnaylor/status/1146144452681113601" target="_blank">sixgill shark</a>, which feeds mainly on carrion but probably also preys on other animals in the deep sea.</p><p>Sharks seem familiar to almost all of us, but we know precious little about them. Our current understanding of their biology barely scratches the surface. The little we do know suggests they are profoundly different from other vertebrate animals. They've had 400 million years of independent evolution to adapt to their environments, and it's reasonable to expect they may be hiding more than a few tricks up their gills.</p>
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Current efforts to curb an infectious disease show the potential we have for collective action. That action and more will be needed if we want to stem the coming wave of heat-related deaths that will surpass the number of people who die from all infectious diseases, according to a new study, as The Guardian reported.
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By Jenny Morber
Caribbean corals sprout off Texas. Pacific salmon tour the Canadian Arctic. Peruvian lowland birds nest at higher elevations.
Known and anticipated changes in species distribution due to climate change around the world have implications for culture, society ecosystems, governance and climate change. Figure used with permission from Gretta T. Pecl, originally published on 31 Mar 2017 in Science 355(6332).<p>How we define species is critical, because these definitions influence perceptions, policy and management. The U.S. National Invasive Species Council (NISC) defines a biological invasion as "the process by which non-native species breach biogeographical barriers and extend their range" and states that "preventing the introduction of potentially harmful organisms is … the first line of defense." But some say excluding newcomers is myopic.</p><p>"If you were trying to maintain the status quo, so every time a new species comes in, you chuck it out," says Camille Parmesan, director of the French National Centre for Scientific Research, you could gradually "lose so many that that ecosystem will lose its coherence." If climate change is driving native species extinct, she says, "you need to allow new ones coming in to take over those same functions."</p><p>As University of Florida conservation ecologist Brett Scheffers and Pecl warned in a <a href="https://www.nature.com/articles/s41558-019-0526-5" target="_blank">2019 paper in <em>Nature Climate Change</em></a>, "past management of redistributed species … has yielded mixed actions and results." They concluded that "we cannot leave the fate of biodiversity critical to human survival to be randomly persecuted, protected or ignored."</p>
Existing Tools<p>One approach to managing these climate-driven habitat shifts, suggested by University of California, Irvine marine ecologist Piper Wallingford and colleagues in <a href="https://www.nature.com/articles/s41558-020-0768-2" target="_blank">a recent issue of Nature Climate Change</a>, is for scientists to adapt existing tools like the <a href="https://www.iucn.org/theme/species/our-work/invasive-species/eicat" target="_blank">Environmental Impact Classification of Alien Taxa (EICAT)</a> to assess potential risks associated with moving species. Because range-shifting species pose impacts to communities similar to those of species introduced by humans, the authors argue, new management strategies are unnecessary, and each new arrival can be evaluated on a case-by-case basis.</p><p>Karen Lips, a professor of biology at University of Maryland who was not associated with the study, echoes the idea that each case is so varied and nuanced that trying to fit climate shifting species into a single category with broad management goals may be impractical. "Things may be fine today, but add a new mosquito vector or add a new tick or a new disease, and all of a sudden things spiral out of control," she says. "The nuance means that the answer to any particular problem might be pretty different."</p>
In recent years, northern flying squirrels in Canada have found themselves in the company of new neighbors — southern flying squirrels expanding their range as the climate warms. Public Domain / USFW<p>Laura Meyerson, a professor in the Department of Natural Resources Science at the University of Rhode Island says scientists should use existing tools to identify and address invasive species to deal with climate-shifting species. "I would like to operate under the precautionary principle and then reevaluate as things shift. You're sort of shifting one piece in this machinery; as you insert a new species into a system, everything is going to respond," she says. "Will some of the species that are expanding their ranges because of climate change become problematic? Perhaps they might."</p><p>The reality is that some climate-shifting species may be harmful to some conservation or economic goals while being helpful to others. While sport fisherman are excited about red snapper moving down the East Coast of Australia, for example, if they eat juvenile lobsters in Tasmania they could harm this environmentally and economically important crustacean. "At the end of the day … you're going to have to look at whether that range expansion has some sort of impact and presumably be more concerned about the negative impacts," says NISC executive director Stas Burgiel. "Many of the [risk assessment] tools we have are set up to look at negative impact." As a result, positive effects may be deemphasized or overlooked. "So that notion of cost versus benefit … I don't think it has played out in this particular context."</p>
Location, Location, Location<p>In a <a href="https://www-nature-com.ezp3.lib.umn.edu/articles/s41558-020-0770-8" target="_blank">companion paper</a> to Wallingford's, University of Connecticut ecology and evolutionary biology associate professor Mark Urban stressed key differences between invasive species, which are both non-native and harmful, and what he calls "climate tracking species." Whereas invasive species originate from places very unlike the communities they overtake, he says, climate tracking species expand from largely similar environments, seeking to follow preferred conditions as these environments move. For example, an American pika may relocate to a higher mountain elevation, or a marbled salamander might expand its New England range northward to seek cooler temperatures, but these new locations are not drastically different than the places they had called home before.</p><p>Climate tracking species may move faster than their competitors at first, Urban says, but competing species will likely catch up. "Applying perspectives from invasion biology to climate-tracking species … arbitrarily chooses local winners over colonizing losers," he writes.</p>
The marbled salamander, a native of the eastern U.S., is among species whose range could expand northward to accommodate rising temperatures. Seánín Óg / Flickr / CC BY-NC-ND 2.0<p>Urban stresses that if people prevent range shifts, some climate-tracking species may have nowhere to go. He suggests that humans should even <a href="https://ensia.com/features/time-for-trees-to-pack-their-trunks/" target="_blank">facilitate movement</a> as the planet warms. "The goal in this crazy warming world is to keep everything alive. But it may not be in the same place," Urban says.</p><p>Parmesan echoes Urban, emphasizing it's the distance that makes the difference. "[Invasives] come from a different continent or a different ocean. You're having these enormous trans-global movements and that's what ends up causing the species that's exotic to be invasive," she says. "Things moving around with climate change is a few hundred miles. Invasive species are moving a few thousand miles."</p><p>In 2019 University of Vienna conservation biology associate professor Franz Essl published a similar argument for species classification beyond the native/non-native dichotomy. Essl uses "neonatives" to refer to species that have expanded outside their native areas and established populations because of climate change but not direct human agency. He argues that these species should be considered as native in their new range.</p>
They Never Come Alone<p>Meyerson calls for caution. "I don't think we should be introducing species" into ecosystems, she says. "I mean, they never come alone. They bring all their friends, their microflora, and maybe parasites and things clinging to their roots or their leaves. … It's like bringing some mattress off the street into your house."</p><p>Burgiel warns that labeling can have unintended consequences. We in the invasive species field … focus on non-native species that cause harm," he says. "Some people think that anything that's not native is invasive, which isn't necessarily the case." Because resources are limited and land management and conservation are publicly funded, Burgiel says, it is critical that the public understands how the decisions are being made.</p><p>Piero Genovesi, chair of the International Union for the Conservation of Nature's Invasive Species Specialist Group, sees the debate about classification — and therefore about management — as a potential distraction from more pressing conservation issues.</p><p>"The real bulk of conservation is that we want to focus on the narrow proportion of alien species that are really harmful," he says. In Hawaii "we don't discuss species that are there [but aren't] causing any problem because we don't even have the energy for dealing with them all. And I can tell you, no one wants to remove [non-native] cypresses from Tuscany. So, I think that some of the discussions are probably not so real in the work that we do in conservation."</p><p>Indigenous frameworks offer another way to look at species searching for a new home in the face of climate change. According to <a href="https://link.springer.com/article/10.1007%2Fs11625-018-0571-4" target="_blank">a study</a> published in Sustainability Science in 2018 by Dartmouth Native American studies and environmental studies associate professor Nicholas Reo, a citizen of the Sault Ste. Marie Tribe of Chippewa Indians, and Dartmouth anthropology associate professor Laura Ogden, some Anishnaabe people view plants as persons and the arrival of new plants as a natural form of migration, which is not inherently good or bad. They may seek to discover the purpose of new species, at times with animals as their teachers. In their paper Reo and Ogden quote Anishnaabe tribal chairman Aaron Payment as saying, "We are an extension of our natural environment; we're not separate from it."</p>
The Need for Collaboration<p>The successful conservation of Earth's species in a way that keeps biodiversity functional and healthy will likely depend on collaboration. Without global agreements, one can envision scenarios in which countries try to impede high-value species from moving beyond their borders, or newly arriving species are quickly overharvested.</p><p>In Nature Climate Change, Sheffers and Pecl call for a Climate Change Redistribution Treaty that would recognize species redistribution beyond political boundaries and establish governance to deal with it. Treaties already in place, such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which regulates trade in wild plants and animals; the Migratory Bird Treaty Act; and the Agreed Measures for the Conservation of Antarctic Fauna and Flora, can help guide these new agreements.</p><p>"We are living through the greatest redistribution of life on Earth for … potentially hundreds of thousands of years, so we definitely need to think about how we want to manage that," Pecl says.</p><p>Genovesi agrees that conservationists need a vision for the future. "What we do is more to be reactive [to known threats]. … It's so simple to say that destroying the Amazon is probably not a good idea that you don't need to think of a step ahead of that." But, he adds, "I don't think we have a real answer in terms of okay, this is a threshold of species, or this is the temporal line where we should aim to." Defining a vision for what success would look like, Genovesi says, "is a question that hasn't been addressed enough by science and by decision makers."</p><p>At the heart of these questions are values. "All of these perceptions around what's good and what's bad, all [are based on] some kind of value system," Pecl says. "As a whole society, we haven't talked about what we value and who gets to say what's of value and what isn't."</p><p>This is especially important when it comes to marginalized voices, and Pecl says she is concerned because she doesn't "think we have enough consideration or representation of Indigenous worldviews." Reo and colleagues <a href="https://cpb-us-e1.wpmucdn.com/sites.dartmouth.edu/dist/9/52/files/2012/10/Reo_etal_AIQ_invasive_species_2017.pdf" target="_blank">wrote in American Indian Quarterly in 2017</a> that climate change literature and media coverage tend to portray native people as vulnerable and without agency. Yet, says Pecl, "The regions of the world where [biodiversity and ecosystems] are either not declining or are declining at a much slower rate are Indigenous controlled" — suggesting that Indigenous people have potentially managed species more effectively in the past, and may be able to manage changing species distributions in a way that could be informative to others working on these issues.</p><p>Meanwhile, researchers such as Lips see species classification as native or other as stemming from a perspective that there is a better environmental time and place to return to. "There is no pristine, there's no way to go back," says Lips. "The entire world is always very dynamic and changing. And I think it's a better idea to consider just simply what is it that we do want, and let's work on that."</p>
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