A new analysis released July 12 in the journal Science implies that the seas could rise dramatically higher over the next few centuries than scientists previously thought—somewhere between 18-to-29 feet above current levels, rather than the 13-to-20 feet they were talking about just a few years ago.
The increase in sea level would largely come from the partial melting of giant ice caps in Greenland and Antarctica, which have remained largely intact since the end of the last ice age, nearly 20,000 years ago. But rising global temperatures, thanks to human greenhouse-gas emissions, have already begun to melt that ancient ice, sending the sea level up 8 inches since 1880 alone, with as much as 6 feet or so of additional increase projected by 2100.
That’s not enough to inundate major population centers by itself, but coupled with storm surges, it could threaten millions of Americans long before the century ends. Around the world, sea level rise will put trillions of dollars in property at risk within the next few decades.
Twenty-nine feet of sea level rise, by contrast, or even 18, would put hundreds of coastal cities around the globe entirely under water, displacing hundreds of millions of people and destroying untold trillions in property. It would, in short, be a disaster of unimaginable proportions.
The only good news, said the study’s lead author, Andrea Dutton, a geochemist at the University of Florida, in an interview: “This isn’t going to happen overnight.” It takes a long time to melt such huge volumes of ice. But since global temperatures are likely to remain high for centuries once they’ve been ratcheted up, it might be inevitable.
This scary new scenario for Earth’s future comes from deep in the planet’s past. Geologists have long known that about 120,000 years ago, the world emerged from an ice age into a relatively warm interglacial period. Before plunging back into the deep freeze, global temperatures rose to about the level where they are now, or maybe a little warmer, and hovered there for perhaps 20,000 years.
Naturally enough, Earth’s glaciers and ice caps melted back significantly, and the ocean rose—and since this so-called Last InterGlacial (LIG) is the best example we have of what happens in a warmer world, scientists look to that time for an idea of where the planet is heading.
Getting a handle on exactly how high the ocean rose back then is complicated, however. Dutton and her co-author Kurt Lambeck, of the Australian National University, went about it by looking for fossilized corals, especially those of species that thrive right at the surface of the sea. Their very existence, therefore, shows just how high the ocean was when the corals were alive.
It’s also straightforward enough to calculate when a particular coral sample was alive, thanks to the same general sort of radioactive dating that gives the ages of ancient humans, for example.
There’s one big complication, though: local changes in sea level can vary a lot from the global average for all sorts of reasons. In the past, scientists have generally left out many of these confounding factors to simplify their calculations. Dutton and Lambeck, by contrast, took them into account.
By itself, the new study would be important enough. But combined with a 2009 paper in Nature, it verges on being downright definitive. The reason: both analyses come to pretty much the same conclusion, using different evidence and different statistical tools. “The fact that both techniques come up with such similar answers,” said Ben Strauss, director of Climate Central’s Program on Sea Level Rise, “is a strong indication that they’re both on the right track.”
What all of this means for future sea level rise isn’t entirely certain. The world was a different place during the LIG, most notably because the Earth’s orbit around the sun was more elongated at the time.
“The Northern Hemisphere,” said Rutgers scientist Robert Kopp, who co-authored the earlier study, “got more intense sun in the summer, while the Southern Hemisphere had a longer melt season.” Overall, however, global temperatures were less than 4°F higher than they are today. If we keep adding heat-trapping greenhouse gases to the atmosphere at the current rate, said Kopp, “we could overshoot that within the next few decades.”
The key question then becomes how long temperatures will remain high, and how the world’s ice sheets will respond—especially the ice in West Antarctica, which could add 20 feet to the world’s oceans all by itself if it melted. Several recent studies suggest that could already be starting to happen.
Even without these new and ominous results, it was already clear that even a moderate amount of sea level rise poses a big danger to people living near the world’s coastlines (Americans can calculate their own risk for the near future by using Climate Central’s “Surging Seas” interactive map).
If the latest research continues to hold up, however, the future may be even riskier than we thought.
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EcoWatch Daily Newsletter
By Mark Hertsgaard
What follows are not candidate endorsements. Rather, this nonpartisan guide aims to inform voters' choices, help journalists decide what races to follow, and explore what the 2020 elections could portend for climate action in the United States in 2021 and beyond.
Will the White House Turn Green?<p>Whether the White House changes hands is the most important climate question of the 2020 elections. President Donald Trump rejects climate science, is withdrawing the United States from the Paris Agreement, and has accelerated fossil fuel development. His climate policy seems to be, as he tweeted in January when rejecting a U.S. Army Corps of Engineers proposal to protect New York City from storm surges, "Get your mops and buckets ready."</p><p>Joe Biden, who started the 2020 campaign with a climate position so weak that activists gave it an "F," called Trump a "climate arsonist" during California's recent wildfires. Biden backs a $2 trillion plan to create millions of jobs while slashing emissions—a Green New Deal in all but name. Equally striking, his running mate, California Senator Kamala Harris, has endorsed phasing out fossil fuel production—a politically explosive scientific imperative.</p><p>The race will be decided in a handful of battleground states, five of which already face grave climate dangers: Florida (hurricanes and sea-level rise), North Carolina (ditto), Texas (storms and drought), Michigan (floods), and Arizona (heat waves and drought). <a href="https://climatecommunication.yale.edu/visualizations-data/ycom-us/" target="_blank">Public concern is rising</a> in these states, but will that concern translate into votes?</p>
Will Democrats Flip the Senate, and by Enough to Pass a Green New Deal?<p>With Democrats all but certain to maintain their majority in the U.S. House of Representatives, the Senate will determine whether a potential Biden administration can actually deliver climate progress. Democrats need to pick up three seats to flip the Senate if Biden wins, four if he doesn't. But since aggressive climate policy is shunned by some Democrats, notably Joe Manchin of coal-dependent West Virginia, Democrats probably need to gain five or six Senate seats to pass a Green New Deal.</p><p>Environmentalists, including the League of Conservation Voters, are targeting six Republicans who polls suggest are vulnerable.</p><ul><li>Steve Daines of Montana, who denies climate science</li><li>Martha McSally of Arizona</li><li>Thom Tillis of North Carolina</li><li>Susan Collins of Maine</li><li>Joni Ernst of Iowa (bankrolled by Charles Koch)</li><li>John James of Michigan (also a Koch beneficiary)</li></ul><p>Republican Senators are even at risk in conservative Kansas and Alaska. In both states, the Democratic candidates are physicians—not a bad credential amid a pandemic—who support climate action. In Kansas, Barbara Bollier faces an incumbent funded by Charles Koch. In Alaska, Al Gross urges a transition away from oil, though his openness to limited drilling in the Arctic National Wildlife Preserve dims his appeal to green groups. He faces incumbent Republican Dan Sullivan, who receives an 8 percent lifetime voting record from the League of Conservation Voters.</p>
Will Local and State Races Advance Climate Progress?<h4>THE CLIMATE HAWKS</h4><p>Under Democratic and Republican leadership alike, Washington has long been a graveyard for strong climate action. But governors can boost or block renewable energy; the Vermont and New Hampshire races are worth watching. Attorneys general can sue fossil fuel companies for lying about climate change; climate hawks are running for the top law enforcement seats in Montana and North Carolina. State legislatures can accelerate or delay climate progress, as the new Democratic majorities in Virginia have shown. Here, races to watch include Pennsylvania, North Carolina, and Colorado.</p><h4>THE CLIMATE POLICY MAKERS</h4><p>Perhaps the most powerful, and most overlooked, climate policy makers are public utility commissions. They control whether pipelines and other energy infrastructure gets built; they regulate whether electric utilities expand solar and energy efficiency or stick with the carbon-heavy status quo. Regulatory capture and outright corruption are not uncommon.</p><p>A prime example is Arizona, where a former two-term commissioner known as the godfather of solar in the state is seeking a comeback. Bill Mundell argues that since Arizona law permits utilities to contribute to commissioners' electoral campaigns, the companies can buy their own regulators. Which may explain why super-sunny Arizona has so little installed solar capacity.</p><p>In South Dakota, Remi Bald Eagle, a Native American U.S. Army veteran, seeks a seat on the South Dakota Public Utilities Commission, which rules on the Standing Rock oil pipeline. And in what <em>HuffPost</em> called "the most important environmental race in the country," Democrat Chrysta Castaneda, who favors phasing out oil production, is running for the Texas Railroad Commission, which despite its name decides what oil, gas, and electric companies in America's leading petro-state can build.</p>
Will the Influencers Usher in a Green New Era?<h4>THE UNCOUNTED</h4><p>The story that goes largely under-reported in every U.S. election is how few Americans vote. In 2016, some 90 million, <a href="https://www.pewresearch.org/politics/2018/08/09/an-examination-of-the-2016-electorate-based-on-validated-voters/" target="_blank" rel="noopener noreferrer">roughly four out of every 10 eligible voters</a>, did not cast a ballot. Attorney Nathaniel Stinnett claims that 10 million of these nonvoters nevertheless identify as environmentalists: They support green policies, even donate to activist groups; they just don't vote. Stinnett's <a href="https://www.environmentalvoter.org/" target="_blank" rel="noopener noreferrer">Environmental Voter Project</a> works to awaken this sleeping giant.</p><h4>THE SUNRISE MOVEMENT</h4><p>Meanwhile, the young climate activists of the <a href="http://www.sunrisemovement.org/" target="_blank" rel="noopener noreferrer">Sunrise Movement</a> are already winning elections with an unabashedly Green New Deal message. More than any other group, Sunrise pushed the Green New Deal into the national political conversation, helping Representative Alexandria Ocasio-Cortez and Senator Ed Markey draft the eponymous congressional resolution. In 2020, Sunrise has helped Green New Deal champions defeat centrists in Democratic primaries, with Markey dealing Representative Joe Kennedy Jr. the first defeat a Kennedy has ever suffered in a Massachusetts election. But can Sunrise also be successful against Republicans in the general elections this fall?</p><h4>THE STARPOWER</h4><p>And an intriguing wild card: celebrity firepower, grassroots activism, and big-bucks marketing have converged behind a campaign to get Latina mothers to vote climate in 2020. Latinos have long been the U.S. demographic most concerned about climate change. Now, <a href="https://votelikeamadre.com/" target="_blank" rel="noopener noreferrer">Vote Like A Madre</a> aims to get 5 million Latina mothers in Florida, Texas, and Arizona to the polls. Jennifer Lopez, Salma Hayak, and Lin-Manuel Miranda are urging mothers to make a "pinky promise" to vote for their kids' climate future in November. Turning out even a quarter of those 5 million voters, though no easy task, could swing the results in three states Trump must win to remain president, which brings us back to the first category, "Will the White House Turn Green?"</p>
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By Tony Carnie
South Africa is home to around 1,300 of the world's roughly 7,100 remaining cheetahs. It's also the only country in the world with significant cheetah population growth, thanks largely to a nongovernmental conservation project that depends on careful and intensive human management of small, fenced-in cheetah populations. Because most of the reserves are privately funded and properly fenced, the animals benefit from higher levels of security than in the increasingly thinly funded state reserves.
Vincent van der Merwe at a cheetah translocation. Endangered Wildlife Trust
Under Pressure<p>Cheetah populations elsewhere in Southern Africa have not prospered over the past 50 years. In Zimbabwe, cheetah numbers have crashed from 1,500 in 1975, to just 170 today. Botswana's cheetah population has held steady at around 1,500 over the same period, but illegal capture for captive breeding and conflicts with farmers and the growing human population are increasing. In Namibia, there were an estimated 3,000 cheetah in in 1975; roughly 1,400 remain today.</p><p>In contrast, South Africa's cheetah numbers have grown from about 500 in 1975 to nearly 1,300 today. Van der Merwe, who is also a Ph.D. student at the University of Cape Town's Institute for Communities and Wildlife in Africa (iCWild), says he's confident that South Africa will soon overtake Namibia and Botswana, largely because the majority of South African cheetahs are protected and managed behind fences, whereas most of the animals in the neighboring countries remain more vulnerable on mainly unfenced lands.</p><p>Wildlife researchers Florian Weise and colleagues have reported that private stock owners in Namibia still trap cheetahs mainly for translocation, but there are few public or private reserves large enough to contain them. Weise says that conservation efforts need to focus on improving tolerance toward cheetahs in commercial livestock and game farming areas to reduce indiscriminate trapping.</p><p>Van der Merwe says fences can be both a blessing and a curse. While these barriers prevent cheetahs and other wild animals from migrating naturally to breed and feed, they also protect cheetahs from the growing tide of threats from humanity and agriculture.</p><p>To simulate natural dispersion patterns that guard against inbreeding, the trust helps landowners swap their animals with other cheetah reserves elsewhere in the country. The South African metapopulation project has been so successful in boosting numbers that the trust is having to look beyond national boundaries to secure new translocation areas in Malawi, Zambia and Mozambique.</p><p>Cheetah translocations have been going on in South Africa since the mid-1960s, when the first unsuccessful attempts were made to move scores of these animals from Namibia. These relocations were mostly unsuccessful.</p>
Charli de Vos uses a VHF antenna to locate cheetahs in Phinda Game Reserve. Tony Carnie for Mongabay
Swinging for the Fences<p>But other wildlife conservation leaders have a different perspective on cheetah conservation strategy.</p><p>Gus Mills, a senior carnivore researcher retired in 2006 from SANParks, the agency that manages South Africa's national parks, after a career of more than 30 years in Kalahari and Kruger national parks. He says the focus should be on quality of living spaces rather than the quantity of cheetahs.</p><p>Mills, who was the founder of the Endangered Wildlife Trust's Carnivore Conservation Group in 1995, and who also spent six years after retirement studying cheetahs in the Kalahari, says it's more important to properly protect and, where possible, expand the size of existing protected areas.</p><p>He also advocates a triage approach to cheetah conservation, in which scarce funds and resources are focused on protecting cheetahs in formally protected areas, rather than diluting scarce resources in an attempt to try and save every single remaining cheetah population.</p><p>"People have an obsession with numbers. But I believe that it is more important to protect large landscape and habitats properly," Mills said.</p><p>He suggests that cheetahs enclosed within small reserves live in artificial conditions: "It's almost like glorified farming."</p><p>"In the long run we have to focus on consolidating formally protected areas," he added. "Africa's human population will double by 2050, so cheetah populations in unfenced areas will become unsustainable if they are eating people's livestock."</p>
Scientists are on the brink of scaling up an enzyme that devours plastic. In the latest breakthrough, the enzyme degraded plastic bottles six times faster than previous research achieved, as The Guardian reported.
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