Sea Levels Will Rise Faster Than Ever


 

sea-level-rise

Scientific research indicates sea levels worldwide have been rising at a rate of 0.14 inches (3.5 millimeters) per year since the early 1990s. The trend, linked to global warming, puts thousands of coastal cities, like Venice, Italy, (seen here during a historic flood in 2008), and even whole islands at risk of being claimed by the ocean. Photograph by Andrea Pattero/AFP/Getty Images (National Geographic)

By Scott Waldman, ClimateWire on November 8, 2016

Source: Scientific American The Atlantic coast will be one of the hardest hit regions

Sea levels across the globe will rise faster than at any time throughout human history if the Earth’s warming continues beyond 2 degrees Celsius.

The Atlantic coast of North America will be one of the worst-hit areas as melting glaciers cause the sea level to rise over the next century, a new study published yesterday in the Proceedings of the National Academy of Sciences finds.

However, that rise is not expected to be uniform, as gravity and the movement of the ocean will play a role in how the water is distributed, and some areas will be hit worse than others. New York and other cities along the East Coast could see seas rise by more than 3 feet by the end of the century if the Earth warms by 4 or 5 degrees beyond pre-industrial levels.

If the rate of carbon emissions continues unabated, the authors said, the globe would warm by 2 degrees and cause significant sea-level rise by 2040. It would be worse along the East Coast of North America and Norway, which are expected to experience a sea-level rise of about a foot. The relative speed of the sea’s rise means many areas won’t have time to adapt, researchers found. And from there, warming would accelerate even faster.

“The coastal communities of rapidly expanding cities in the developing world and vulnerable tropical coastal ecosystems will have a very limited time to adapt to sea-level rises after the ‘2 degrees Celsius’ threshold is likely to be reached,” said Svetlana Jevrejeva, a researcher at the National Oceanography Centre in Liverpool, England, and lead author of the study.

The sea-level rise comes as the Earth’s record-breaking warmth is expected to become the “new normal,” according to another study published this week in the Bulletin of the American Meteorological Society. While 2015 was the hottest year on record, it could be the average within the next decade if carbon emissions continue to rise at their current rate, it found. And even if countries take action to limit carbon dioxide, humanity may have already locked in the increased warmth by 2040.

But limiting emissions now will mean some of the regions of the globe are not locked in for the new levels of warmth, and that they can still have significant variability.

“It gives us hope to know that if we act quickly to reduce greenhouse gases, seasonal extremes might never enter a new normal state in the 21st century at regional levels for the Southern Hemisphere summer and Northern Hemisphere winter,” said Sophie Lewis, a researcher at the Australian National University.

Millions of urban dwellers at risk

Nations that signed the Paris Agreement limiting warming to a maximum of 2 degrees are meeting this week in Morocco to put the accord into motion. Meanwhile, the United Nations has already cautioned that the emission targets countries voluntarily set may not be strict enough to meet the 2-degree goal.

Two degrees of warming is expected to cause an average global sea-level rise of 8 inches, but virtually all coastal areas will see more of a rise, Jevrejeva found. If warming exceeds 2 degrees by 2100, as some climate scientists worry it might, about 80 percent of the global coastline could experience a rise in sea levels of 6 feet. Such a rapid rise in sea levels is unprecedented since the dawn of the Bronze Age about 5,000 years ago, according to the study.

The research takes further the potential for sea-level rise posed by the Intergovernmental Panel on Climate Change, which argued that sea-level rise of 11 to 38 inches is possible by 2100. Many climate scientists have since claimed that estimate is too conservative.

Absent a concerted effort to limit warming, cities and island nations across the globe are at risk, researchers found.

“Coastal communities, notably rapidly expanding cities in the developing world; small island states; United Nations Educational, Scientific and Cultural Organization Cultural World Heritage sites; and vulnerable tropical coastal ecosystems will have a very limited time after mid-century to adapt to these rises,” they wrote.

The rise for New York is predicated on a warming of 5 degrees by 2100, which some researchers have contested may be too high. But at the upper scale of that level of warming, tens of millions of people around the world would be displaced. That includes “2.5 million living in low-lying areas of Miami; 2.1 million in Guangzhou [in China]; 1.8 million in Mumbai; and more than 1 million each in Osaka [in Japan], Tokyo, New Orleans, New York, and [Vietnam’s] Ho Chi Minh City,” researchers contended.

The study is part of a growing body of research that looks for possible scenarios that involve the potential for catastrophic sea-level rise, but more attention should be paid to the loss of land ice, as well, said Tad Pfeffer, a glaciologist at the University of Colorado, Boulder. While researchers typically focus on the loss of glaciers in Antarctica and Greenland, the loss of land ice in other spots across the globe is now contributing to sea-level rise at almost the same rate as the Arctic’s melting ice, he said. It’s the full scope of the current glacial loss that concerns political leaders and policymakers because it has already presented a pressing need to be addressed, he said.

“This near-term time scale is the time of greatest concern to decision makers,” he said. “Research that reaches out to 2100 and beyond is scientifically exciting, but really of secondary importance to the people who are trying to make sense of the science for decision-making.”

Reprinted from ClimateWire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.

The Scientist Who First Warned of Climate Change Says It’s Much Worse Than We Thought


 

Oceans are warming. (photo: Shutterstock)

Oceans are warming. (photo: Shutterstock)

By Amelia Urey, Grist – 23 March 16

The rewards of being right about climate change are bittersweet. James Hansen should know this better than most — he warned of this whole thing before Congress in 1988, when he was director of NASA’s Institute for Space Studies. At the time, the world was experiencing its warmest five-month run since we started recording temperatures 130 years earlier. Hansen said, “It is time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here.”

Fast forward 28 years and, while we’re hardly out of the Waffle House yet, we know much more about climate change science. Hansen is still worried that the rest of us aren’t worried enough.

Last summer, prior to countries’ United Nations negotiations in Paris, Hansen and 16 collaborators authored a draft paper that suggested we could see at least 10 feet of sea-level rise in as few as 50 years. If that sounds alarming to you, it is — 10 feet of sea-level rise is more than enough to effectively kick us out of even the most well-endowed coastal cities. Stitching together archaeological evidence of past climate change, current observations, and future-telling climate models, the authors suggested that even a small amount of global warming can rack up enormous consequences — and quickly.

However the paper, publicized before it had been through peer review, elicited a mix of shock and skepticism, with some journalists calling the news a bombshell but a number of scientists urging deeper consideration.

Now, the final version of the paper has been published in the journal Atmospheric Chemistry and Physics. It’s been reviewed and lightly edited, but its conclusions are still shocking — and still contentious.

So what’s the deal? The authors highlight several of threats they believe we’ll face this century, including many feet of sea-level rise, a halting of major ocean circulatory currents, and an outbreak of super storms. These are the big threats we’ve been afraid of — and Hansen et al. say they could be here before we know it — well before the Intergovernmental Panel on Climate Change’s sanctioned climate models predict.

Here we help you understand their new paper:

Sea-level rise

The scientists estimate that existing climate models aren’t accounting well enough for current ice loss off of the Antarctic and Greenland ice sheets. Right now, Antarctica and Greenland ice sheets both contribute under or near 1 millimeter to sea-level rise every year; they each contain enough stored ice to drive up ocean levels by 20 and 200 feet, respectively.

This study suggests that, since the rate of ice loss is increasing, we should think of it not as a straight line but as an exponential curve, doubling every few years. But how much time it takes to double makes a big difference. Right now, measurements of ice loss aren’t clear enough to even make a strong estimate about how long that period might be. Is it 10 years or is it 40? It’s hard to say based on the limited data we have now, which would make a big difference either way.

But then again, we don’t even know that ice loss is exponential. Ian Joughin — a University of Washington researcher unaffiliated with the paper and who has studied the tipping points of Antarctic glaciers — put it this way: Think about the stock market in the ’80s. If you observed a couple years of accelerating growth, and decided that rate would double every 4 years — you’d have something like 56,000 points in the Dow Jones Industrial by now.

Or if stocks aren’t your thing, think about that other exponentially expanding force of nature: bacteria. Certain colonies of bacteria can double their population in a matter of hours. Can they do this forever? No, or else we’d be nothing but bacteria right now (and while we’re certainly a high percentage of bacteria, there’s still room for a couple other things).

Nature tends to put limits on exponential growth, Joughin points out — and the same probably goes for ice loss: “There’s only so fast you can move ice out of an ice sheet,” Joughin explained. While some ice masses may be collapsing at an accelerating rate, others won’t be as volatile.

This means, while some parts of ice sheet collapse may very well proceed exponentially, we can’t expect such simple mathematics to model anything in the real world except the terror spike of the Kingda Ka.

Ocean turnover

Mmm mm, ocean turnover: Is it another word for a sushi roll or a fundamental process that keeps the climate relatively stable and moderate?

That’s right — we’re talking the Atlantic Meridonal Overturning Circulation, or AMOC, and other currents like it.

As cold meltwater flows off of glaciers and ice sheets at enormous rates, it pools at the ocean’s surface, trapping the denser but warmer saltwater beneath it. This can seriously mess with the moving parts of the ocean, the so-called “conveyor belts” that cycle deep nutrient-rich water to the surface. These slow currents are driven by large-scale climate processes, like wind, and drive others, like the carbon cycle. But they also rely on gradients in temperature and density to run; if too much cold water from the glaciers pools at the surface, the whole conveyor belt could stutter to a stop.

In the North Atlantic, this would mean waters get colder, while the tropics, denied their influx of colder water, would heat up precipitously. Hansen says we’re already seeing the beginnings of AMOC’s slowdown: There’s a spot of unusually cool water hanging out off of Greenland, while the U.S. East Coast continues to see warmer and warmer temperatures. Hansen said it plainly in a call with reporters: “I think this is the beginning of substantial slowdown of the AMOC.”

Superstorms

Pointing to giant hunks of rock that litter the shore of the Bahamas, among other evidence of ancient climates, the study’s authors suggest that past versions of Earth may have featured superstorms capable of casually tossing boulders like bored Olympians.

And as the temperature gradient between the tropic and the polar oceans gets steeper, thanks to that slowing of ocean-mixing currents, we could see stronger storms, too.

This is surprisingly intuitive: Picture a temperature gradient like a hill, with the high temperatures up at the top and the low temperatures down at the bottom. As the highs get higher and the lows get lower, that hill gets a lot steeper — and the storms are the bowling balls you chuck down the hill. A bowling ball will pick up a lot more speed on a steep hill, and hurt a lot more when it finally runs into something. Likewise, by the time these supercharged storms are slamming into coasts in the middle latitudes, they will be carrying a whole lot of deadly force with them.

So what does it all mean?

Whether other scientists quibble over these results or not — and they probably will — the overall message is hardly new. It’s bad, you guys. It might be really, truly, deeply bad, or it might be slightly less bad. Either way, says Hansen, what we know for sure is that it’s time to do something about it. “Among the top experts, there’s a pretty strong agreement that we’ve reached a point where this is truly urgent,” he said.

So Hansen is frustrated once more with the failure of humanity to respond adequately. The result he’d hoped for when he released an early version of the paper online last summer was to get world leaders to come together in Paris to agree on a global price on carbon. As he told Grist’s Ben Adler at the time, “It’s going to happen.” (It didn’t happen, but some other stuff did.)

Still, true urgency would require more of us than just slowing the growth of emissions — it requires stopping them altogether. In a paper published in 2013, Hansen found that we have to cut 6 percent of our use of carbon-based fuels every year, if we want to avoid dangerous climate change.

Carbon prices and emissions cuts are more the purview of politicians and diplomats, but if anything, Hansen has shown he is unafraid to stray beyond the established protocol of academic science.

“I think scientists, who are trained to be objective, have something to offer by analyzing the problem all the way to the changes that are needed in order to address it,” he said on a press call. “That 6 percent reduction — that’s not advocacy, that’s science. And then I would advocate that we do that!”

And to pre-empt the haters, Hansen wants you to remember one thing. “Skepticism is the life blood of science. You can be sure that some scientists will find some aspects in our long paper that they will think of differently,” he said. “And that’s normal.”

So while scientists continue their debate over whether the ice sheets are poised to collapse in the next 50 years or the next 500, the prognosis is the same: The future is wetter, stranger, stormier unless we make serious moves to alternative energy sources now. Will we? Maybe. We’ve started but we still have a long, long way to go. If it’s a race between us and the ice sheets, neither I nor James Hansen nor anyone else can tell you for sure who will win.

Hey, no one said telling the future was easy.

Leonardo DiCaprio Devotes Oscars Speech to Climate Change


Leonardo DiCaprio at the Oscars in 2016. (photo: EcoWatch)

Leonardo DiCaprio at the Oscars in 2016. (photo: EcoWatch)

By Lorraine Chow, EcoWatch, 29 February 16
Source: Readers Supported News

After six nominations, Leonardo DiCaprio won his first Oscar for Best Actor for his role in The Revenant at last night’s Academy Awards. The noted environmental activist devoted half of his acceptance speech to call for urgent collective action to fight climate change, calling it “the most urgent threat facing our species.”

The 41-year-old actor, who was favored to win the Oscar and had swept the Best Actor category in every major award show leading up to the Academy Awards, first thanked the cast and crew in his speech and then shined a spotlight on a his passion project.

Making The Revenant was about man’s relationship to the natural world. A world that we collectively felt in 2015 as the hottest year in recorded history,” he said, describing how the entire production needed to move to the southern tip of this planet in Argentina just to be able to find snow.

“Climate change is real, it is happening right now,” DiCaprio continued. “It is the most urgent threat facing our entire species, and we need to work collectively together and stop procrastinating.”

He also spoke about the need to support leaders who fight the biggest polluters, as well as the need to stand up for the rights of indigenous people and for the “billions and billions of underprivileged people” affected by a warming planet.

“For our children’s children, and for those people out there whose voices have been drowned out by the politics of greed. I thank you all for this amazing award tonight. Let us not take this planet for granted. I do not take tonight for granted. Thank you so very much,” he concluded.

DiCaprio’s speech was given a standing ovation by the star-studded audience at the Dolby Theatre in Los Angeles.

The Revenant, which was nominated for 12 Oscars—more than any other film this year—took home two other awards at Sunday’s ceremony, including one for cinematographer Emmanuel Lubezki and director Alejandro G. Iñárritu. The entire cast and crew braved the elements and faced extreme weather conditions in locations such as Mexico, Argentina, British Columbia and Alberta.

DiCaprio, who played fur trapper and legendary frontiersman Hugh Glass in the film, made similar comments at previous awards ceremonies about the The Revenant‘s grisly filming conditions.

“We shot at high altitudes in Calgary, and weather conditions were unprecedented,” DiCaprio said backstage after taking home a Screen Actors Guild Award last month.

DiCaprio, who is working on a documentary about climate change, told reporters at the SAG awards, “We are in the process of changing our climate for tens of thousands if not millions of years at this very moment, so this is a very significant turning point for me to witness it first-hand while doing this movie and simultaneously doing the documentary, and it’s absolutely, absolutely terrifying.”

As EcoWatch reported, DiCaprio saw the impacts of climate change first hand while traveling to film the documentary. He was “astonished to see that ancient glaciers” in Greenland and the Arctic are “rapidly disappearing well ahead of scientific models.” In India, he saw farmers’ fields devastated by unprecedented flooding. He said we need to keep fossil fuels in the ground, urged business leaders to divest from fossil fuels and pushed for a rapid transition to renewables.

DiCaprio is so passionate about environmental issues, that he recently told The Sunday Times (via the Mirror) that he once considered saying bye-bye to Hollywood to focus on environmental issues full-time instead.

“I had a friend say, ‘Well, if you’re really this passionate about environmentalism, quit acting,’” he said. “But you soon realize that one hand shakes the other, and being an artist gives you a platform. Not that necessarily people will take anything that I say seriously, but it gives you a voice.”

The longtime environmental advocate formed his Leonardo DiCaprio Foundation in 1998 to protect biodiversity and threatened ecosystems. DiCaprio—who urges a “transition to a clean energy economy that does not rely on fossil fuels”—is a United Nations Messenger of Peace and played an active role at the Paris climate talks, urging mayors and governors to “commit to no less than 100 percent renewable energy as soon as possible.”

Last month, DiCaprio and Pope Francis met at Vatican City to have a conversation focused on how they can work together to address the immediate need for major action to stop the devastating impacts of climate change.

Watch and read DiCaprio’s full Oscars speech below.

“Thank you all so very much. Thank you to the Academy, thank you to all of you in this room. I have to congratulate the other incredible nominees this year. The Revenant was the product of the tireless efforts of an unbelievable cast and crew. First off, to my brother in this endeavor, Mr. Tom Hardy. Tom, your talent on screen can only be surpassed by your friendship off screen… thank you for creating a transcendent cinematic experience. Thank you to everybody at Fox and New Regency … my entire team. I have to thank everyone from the very onset of my career … To my parents, none of this would be possible without you. And to my friends, I love you dearly, you know who you are.

“And lastly I just want to say this: Making The Revenant was about man’s relationship to the natural world. A world that we collectively felt in 2015 as the hottest year in recorded history. Our production needed to move to the southern tip of this planet just to be able to find snow. Climate change is real, it is happening right now. It is the most urgent threat facing our entire species, and we need to work collectively together and stop procrastinating. We need to support leaders around the world who do not speak for the big polluters, but who speak for all of humanity, for the indigenous people of the world, for the billions and billions of underprivileged people out there who would be most affected by this. For our children’s children, and for those people out there whose voices have been drowned out by the politics of greed. I thank you all for this amazing award tonight. Let us not take this planet for granted. I do not take tonight for granted. Thank you so very much.”

The Last Time the Arctic Was Ice-Free During the Summer…


antarctic-sea-record-breaking-ice

…Modern Humans Didn’t Exist

By Eric Holthaus, Slate Magazine

04 December 14

Ice has been a relatively constant feature of the Arctic for most of the past 36 million years, but there have been some gaps. Scientists aren’t exactly sure what happened during the most recent major ice-free period, but it’s often considered an analog to our future, warmer Earth. The only difference is, the gap in Arctic sea ice that scientists believe will happen by midcentury is being caused by us.*

Scientists are now piecing together the puzzle in an increasingly urgent attempt to understand what might happen once Arctic ice goes away again, effectively for good. One new study, published last week in the journal Nature Communications, attempts determine what happened during that last major gap in Arctic ice.

The study provides new evidence that the last major gap ended about 2.6 million years ago, after which ice sheets spread southward and humanity’s ancestors began to respond to colder temperatures in Africa, forcing adaptation like the use of stone tools. Humans themselves wouldn’t evolve for more than a million more years.

The study cites geological changes in the Arctic region, like mountainous uplifts and the connection of North and South America in present-day Panama, as mostly responsible for the burst of ancient ice. Those changes altered ocean dynamics and sharply increased the availability of freshwater in the Arctic, which freezes more easily than salty water.

To come to this conclusion, the researchers used a proxy for the presence of sea ice—a “mono-unsaturated highly branched isoprenoid lipid” that’s produced by single-celled sea plants and deposited in ancient sediment at the bottom of the ocean. The sediment core sample they obtained spans more than 4 million years—a complete chronicle of the entire ancient ice-free period. The samples were taken from the Fram Strait, off the east coast of Greenland.

Here’s the rough timeline they came up with (with some additional dates for perspective):

5.3 million years ago, there were dense spruce and pine forests in the far northern Arctic. Greenland had 30 percent less ice than today, and global seas were about 60 feet higher.

4 million years ago, there was about as much ice in the winter as currently exists in the summer, and summers were probably ice-free. This is an analog for what we may experience in the near future; estimates suggest global temperatures could rise four degrees Celsius higher than today in the next 85 years, about as hot as temperatures were back then.

2.6 million years ago, geologic uplift forced the closure of Arctic Ocean gateways, like the Bering Strait, and thermally isolated the region. That restricted the Arctic’s circulation, causing a build-up of fresh water and conditions favorable for major ice sheets to form. From that point, there was runaway cooling as ice sheets grew as far south as present-day St. Louis and New York City. The most current cycle of ice ages began, and human ancestors were forced to adapt. This started the transition that would result in homo sapiens.

200,000 years ago, modern humans emerged.

12,000 years ago, the most recent ice age ended, setting the stage for the beginning of human civilization.

250 years ago, coal was first used to power steam engines in England.

1 year ago, atmospheric carbon dioxide reaches 400 parts per million for the first time in at least 800,000 years, probably longer.

It took 100,000 generations for human ancestors to transition to something resembling us. For each of those 100,000 generations, the planet was crowned with ice. Now, that ice will probably go away. That incredibly rapid rate of change—10 times faster than any change recorded over the past 65 million years—is extinction-worthy. The research will help improve models of a melting Arctic, so we can better understand the implications for those of us that’ll have to deal with them. Our ancestors didn’t see their version of climate change coming. Our descendants will.

Correction, Dec. 2, 2014: This post originally misstated that the Arctic is facing a gap in sea ice. This gap is expected by scientists to occur by midcentury, but is not occurring now.

Source: Reader Supported News

Also see: Antarctic Ice Loss Tripled in Last 10 Years

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