Global warming policies we set today will determine the next 10,000 years
By Andrew Freedman18 hours ago.
The decisions made in the next couple of decades about reducing greenhouse gas emissions will determine the severity of global warming — including potentially catastrophic sea level rise — for the next 10,000 years, according to a provocative statement by prominent climate scientists.
The research, published Monday in the journal Nature Climate Change, examines the "deep time" implications of emissions of global warming pollutants such as carbon dioxide.
The study vividly demonstrates how the lag effects that are inherent in the climate system affect policy decisions that today's leaders must make through the middle of this century.
These lag effects — namely the ability of carbon dioxide to remain in the air for thousands of years, and the high sensitivity and long memory of global ice sheets to this temperature increase — will ensure that today's policy choices will play out on a stage longer than the history of human civilization.
"If carbon dioxide emissions continue unchecked, the carbon dioxide released during this century will commit Earth and its residents to an entirely new climate regime," the study states.
The study reviews evidence from ice cores, tree rings and other sources showing the past 20,000 years of the Earth's climate history, including how sea levels fell during the last ice age and rose as the climate entered a new, more stable and mild period known as the Holocene.
The study also notably details projections for the next 10,000 years based on different scenarios of rising greenhouse gas emissions from burning fossil fuels such as coal and oil.
It does not base its results on the highest emissions scenario, also known as a worst-case scenario, but the results are sobering nonetheless.
For example, the study shows that future rates of sea level rise due to melting ice caps and warming, expanding seas, could be on the order of up to 4 meters, or 13.1 feet, per century, which would be unprecedented in more than 8,000 years.
Screenshot of a sea level rise projection showing the complete inundation of Shanghai, China if sea level rises by 30 meters, or 98 feet.
Image: Climate Central
To compare this with more commonly cited projections through 2100, most assessments project up to around 1 meter, or 3.3 feet, of sea level rise during that period.
In total, the study projects a global mean sea level rise of between 25 to 52 meters, or 82 to 171 feet within the next 10,000 years, noting that at least 1.2 to 2.2 meters of that is already virtually guaranteed, due to emissions-to-date.
"Even if emissions were capped or reduced to some lower rate, we would still be committed to global mean sea level rise that is substantially larger than that experienced over much of recorded human civilization," the study states.
The only way to avoid such a scenario would be to drive emissions down to zero, or even into negative territory, in which the environment is taking out more carbon than is being added to it.
"This research is a deeply urgent wake-up call to become much more ambitious," wrote study co-author Benjamin Strauss of the research and journalism organization Climate Central.
Sea level rise commitment
Based on the sea level rise projections, the study calculated the parts of the world that would be most directly impacted. The world population on land below the level of projected sea level rise is 1.3 billion, or 19% of the 2010 global population, the study found.
A 30-meter, or 98-foot, rise in sea level along the U.S. East Coast would inundate nearly all of New York City, Boston, Miami (along with the rest of South Florida), and coastal Louisiana, among other areas.
Sea level rise projection for New York City based on 30 meters, or 98 feet, of sea level rise. Dark blue areas are submerged.
Image: Climate central
A total of 122 countries would see at least 10% of their current population in areas that would be directly submerged, the study found, with 25 coastal megacities seeing half their population submerged, based on current population levels.
Anders Levermann, a study co-author and researcher at the Potsdam Institute for Climate Impacts Research in Germany, told Mashable in an email that the study shows how current emissions are creating a new era in geological time, which many scholars have now termed the "Anthropocene" for the human influence on the Earth.
"I think a very interesting perspective (but not the only one) is to say that this paper really says that humans are creating a new geological epoch. What we are doing now in a very brief moment in history is changing the Earth for millennia to come," Levermann wrote.
"The Anthropocene will be at least as long as the Holocene," he added, referring to the geological epoch during which time human civilization became established and flourished.
Discounting the future
Policy makers and economists often discount the future cost of choices made today, which can result in a lack of consideration for future generations when setting climate policies. The authors of the study designed this research to show how problematic this is.
"No generation has ever had such an opportunity to help or harm so many hundreds of generations coming after it," Strauss said. "We have the chance to build a legacy as the most hated or the greatest generation for 10,000 years."
Studies including this new research have shown that unless greenhouse gas emissions are reduced significantly through the middle of this century, we will be locked into a rate and magnitude of global warming that human civilization has never experienced before, with profound consequences particularly for low-lying and poor nations around the world.
This was acknowledged by diplomats at the Paris Climate Summit in December, but the deal struck there only covers emissions through the year 2030, with a fuzzy long-term emissions target of peaking global emissions by an unspecified date.
While the agreement struck in Paris was historic, it would still allow for global emissions to increase through the year 2030. Based on the emissions pledges submitted to the U.N., which are also known as Intended Nationally-Determined Contributions, or INDCs, the world is in for around 3 degrees Celsius, or 5.4 degrees Fahrenheit, of warming through 2100.
That's is enough warming to set in motion a cascade of impacts for centuries to come, according to the new study,
"The eventual magnitude as well as the rate of change is still in our hands," Levermann said. "The more we emit, the more and the faster we change."
Climate 'carbon budget' soon maxed out: study
February 23, 2016
"Start reducing our emissions immediately," urges report author Joeri Rohelj (pictured: Sofia, Bulgaria)
The window of opportunity for humanity to cap global warming by slashing greenhouse gases is closing faster than previously thought, according to a study released Tuesday.
Earlier estimates of our "carbon budget" -- the amount of heat-trapping carbon dioxide we can still put into the atmosphere without warming Earth by more than two degrees Celsius (3.6 degrees Fahrenheit) -- have ranged from 590 billion to 2.4 trillion tonnes.
The new research says the upper limit is actually half that, some 1.24 trillion tonnes of CO2.
"We have figured out that this budget is at the low end of what studies indicated before," said lead author Joeri Rogelj, a climate scientist at the International Institute for Applied Systems Analysis in Austria.
"If we don't start reducing our emissions immediately, we will blow it in a few decades."
The goal of holding the rise in surface temperature to 2C -- widely seen at the time as the threshold for dangerous warming -- was first agreed by the world's nations in 2010.
But thousands of subsequent scientific studies have showed that even a smaller jump on the thermometer would have severe consequences, especially for poor nations.
With an increase so far of less than 1C (1.8F) over pre-Industrial Revolution levels, the world has already seen climate-boosted droughts, floods and megastorms.
- Radical increase in ambition -
As a result, the Paris Agreement adopted by the UN climate forum in December last year embraced a more ambitious target of "well below 2C," while pledging to strive for a 1.5C cap if possible.
CO2 emissions were about 40 billion tonnes in 2015, and are projected to continue climbing over the next decade, even taking into account the carbon-cutting pledges submitted by nearly 190 nations as part of the Paris Agreement.
If current emission rates are held steady, the 2C carbon budget would be spent in about 15 to 30 years, according to the new calculations.
For a 1.5C target, the carbon budget "would be exhausted in about one decade," Rogelj told AFP.
"It is beyond doubt that ambition thus needs to be increased radically from anything we have experienced to stabilise warming at either 1.5C or 2C -- or even higher temperature levels," he said by email.
Rogelj and half-a-dozen colleagues sought to understand why previous estimates of the carbon budget vary so widely.
Part of the gap stems from different methods and scenarios that project trends into the future.
Another factor is that many studies looked only at the dominant greenhouse gas CO2, using it as a proxy for all others, including methane and nitrous oxide.
Carbon dioxide accounts for more than 80 percent of global warming.
"Neglecting the warming from other greenhouse gases leads to larger carbon budgets," Rogelj explained.
Focusing only on CO2 helps scientists understand how the Earth system works, but is not very useful for real-world policy, he added.
"In our proposed carbon budget range, we take into account warming by all human emissions, and thus shave of the top-end of studies that looked at CO2 only."
Ocean Levels Are Rising Faster Than Ever — And We're to Blame
By Ruth Reader
Climate change may eventually force people out of coastal cities. A new study reports that global sea levels could rise more than 4 feet by 2100, thanks to human-induced climate change.
Global warming, a term given to the advent of rising temperatures around the world, is caused by man-made pollutants.
"Carbon dioxide and other global warming pollutants are collecting in the atmosphere like a thickening blanket, trapping the sun's heat and causing the planet to warm up," said the National Resources Defense Council. Researchers have found that climate change has a variety of consequences, including drought, forest fires and rising sea levels.
The latter is the subject of a new study tying rising tides to carbon emissions. Global sea levels have been rising at an increased rate since the 19th century. In the 20th century, sea levels rose 5.5 inches — faster than they did any of the 27 centuries before it.
The reason? Global warming, according to the study. Researchers say that if the world's climate wasn't changing, it's likely sea levels would have risen only half as much.
The study further notes that even with some mitigation of emissions, sea levels are likely to rise at least 9.5 to 24 inches before the beginning of the next century. A worst-case scenario puts projections for sea-level rise at 20 to 31 inches if measures aren't taken to reduce climate change.
Some nations are already implementing measures to lower carbon emissions in their own region. Germany and Brazil have been particularly active, with the former promising that 40% of its energy will come from renewable sources in 2025, and the latter hoping to end deforestation by 2030. Meanwhile, in the U.S., President Barack Obama has vowed to reduce carbon emissions by a third over the next 14 years.
Earth saw 'explosive' annual growth in carbon dioxide in 2015
By Andrew Freedman
Earth saw its largest annual spike in atmospheric carbon dioxide concentrations on record in 2015, according to new data released by the National Oceanic and Atmospheric Administration (NOAA).
The increase is significant because it demonstrates the continued march toward higher levels of global warming pollutants in the atmosphere. Those increasingly higher levels are helping to destabilize parts of Antarctica and Greenland, raise sea levels around the world, and cause more frequent and intense heat waves in many regions.
It is a sobering milestone too, since countries are working more diligently than ever to cut emissions of planet-warming greenhouse gases, but the atmosphere is not yet seeing the results.
According to NOAA, carbon dioxide measurements taken at the Mauna Loa Observatory in Hawaii show that carbon dioxide concentrations jumped by 3.05 parts per million (ppm) during 2015, the largest year-to-year increase in 56 years of research.
Data stretching back at least 800,000 years shows that carbon dioxide levels are now higher than at any other time in human history.
Annual growth rate of carbon dioxide based on Mauna Loa record.
In another first, NOAA found that 2015 was the fourth straight year in which carbon dioxide concentrations grew by more than 2 ppm, according to Pieter Tans, who leads NOAA's Global Greenhouse Gas Reference Network.
“Carbon dioxide levels are increasing faster than they have in hundreds of thousands of years,” Tans said in a press release. “It’s explosive compared to natural processes.”
In February 2016, the average global atmospheric carbon dioxide level stood at 402.59 ppm. This is a dramatic increase from preindustrial times, when atmospheric carbon dioxide levels averaged about 280 ppm.
The world is currently on course to see carbon dioxide levels push past 450 to 500 parts per million by the end of the current century, unless emissions of greenhouse gases from burning fossil fuels are cut dramatically during the next two decades.
A single molecule of carbon dioxide can remain in the atmosphere for as long as 1,000 years, ensuring that global warming will continue for generations to come.
According to Tans, the current rate of increase in carbon dioxide levels is 200 times faster than the last time the planet saw such a sustained increase, which was between 17,000 and 11,000 years ago, when there was an 80 ppm increase during that timespan.
The iconic "Keeling Curve" record of CO2 concentrations observed at Mauna Loa observatory in Hawaii.
The jump in carbon dioxide levels this year beat the old record, set in 1997-98. Both years featured strong El Niño events in the tropical Pacific, which tend to speed up the release of carbon dioxide as trees and other carbon-absorbing systems adjust to wild swings in weather patterns.
However, the long-term increase in carbon dioxide emissions is mainly due to the burning of fossil fuels such as coal, oil and natural gas.
The carbon dioxide concentration record contrasts with the recent trend in global annual emissions of greenhouse gases, which may have stalled or fallen slightly in 2015 compared to previous years. However, it would take a much more significant drop in emissions — all the way to zero or so-called "negative emissions," in which the Earth absorbs more carbon dioxide than people emit, in order to stabilize and then drag down atmospheric levels over time.
UN science report warns of fewer bees, other pollinators
By SETH BORENSTEIN8 hours ago
WASHINGTON (AP) — Many species of wild bees, butterflies and other critters that pollinate plants are shrinking toward extinction, and the world needs to do something about it before our food supply suffers, a new United Nations scientific mega-report warns.
The 20,000 or so species of pollinators are key to hundreds of billions of dollars' worth of crops each year — from fruits and vegetables to coffee and chocolate. Yet 2 out of 5 species of invertebrate pollinators, such as bees and butterflies, are on the path toward extinction, said the first-of-its-kind report. Pollinators with backbones, such as hummingbirds and bats, are only slightly better off, with 1 in 6 species facing extinction.
"We are in a period of decline and there are going to be increasing consequences," said report lead author Simon Potts, director of the Centre for Agri-Environmental Research at the University of Reading in England.
And it's not just honeybees. In some aspects they're doing better than many of their wild counterparts, like the bumblebee, despite dramatic long-term declines in the United States and a mysterious disorder that has waned.
The trouble is the report can't point to a single villain. Among the culprits: the way farming has changed so there's not enough diversity and wild flowers for pollinators to use as food; pesticide use, including a controversial one, neonicotinoid, that attacks the nervous system; habitat loss to cities; disease, parasites and pathogens; and global warming.
The report is the result of more than two years of work by scientists across the globe who got together under several different U.N. agencies to come up with an assessment of Earth's biodiversity, starting with the pollinators. It's an effort similar to what the United Nations has done with global warming, putting together an encyclopedic report to tell world leaders what's happening and give them options for what can be done.
The report, which draws from many scientific studies but no new research, was approved by a congress of 124 nations meeting in Kuala Lumpur on Friday.
"The variety and multiplicity of threats to pollinators and pollination generate risks to people and livelihoods," the report stated. "These risks are largely driven by changes in land cover and agricultural management systems, including pesticide use."
FILE - In this July 21, 2015 file photo, a bumblebee sits on a sunflower on a field in Munich, Germa …
But these are problems that can be fixed, and unlike global warming, the solutions don't require countries to agree on global action — they can act locally, said Robert Watson, a top British ecological scientist and vice chairman of the scientific panel. The solutions offered mostly involve changing the way land and farming is managed.
"There are relatively simple, relatively inexpensive mechanisms for turning the trend around for native pollinators," said David Inouye of the University of Maryland, a co-author of a couple chapters in the report.
One of the biggest problems, especially in the United States, is that giant swaths of farmland are devoted to just one crop, and wildflowers are disappearing, Potts and others said. Wild pollinators especially do well on grasslands, which are usually more than just grass, and 97 percent of Europe's grasslands have disappeared since World War II, Potts said.
England now pays farmers to plant wildflowers for bees in hedge rows, Watson said.
There are both general and specific problems with some pesticide use, according to the report.
"Pesticides, particularly insecticides, have been demonstrated to have a broad range of lethal and sub-lethal effects on pollinators in controlled experimental conditions," the report said. But it noted more study is needed on the effects on pollinators in the wild. Herbicides kill off weeds, which are useful for wild pollinators, the report added.
The report highlighted recent research that said the widely used insecticide neonicotinoid reduces wild bees' chances for survival and reproduction, but the evidence of effects on honeybees is conflicting.
In a statement, Christian Maus, global pollinator safety manager for Bayer, which makes neonicotinoids, said: "The report confirms the overwhelming majority of the scientific opinion regarding pollinator health — that this is a complex issue affected by many factors. Protecting pollinators and providing a growing population with safe, abundant food will require collaboration."
Potts said global warming is "very clearly a real future risk" because pollinators and their plants may not be at the same place at the same time. England has seen one-quarter of its bumblebee species threatened, and those are the type of bees most sensitive to climate change, he said.
England has lost two species of wild bumblebees to extinction and the U.S. has lost one, Inouye said.
The story of honeybees is a bit mixed. Globally over the last 50 years, the number of managed honeybee hives — ones where humans keep them either as a hobbyists or as professional pollinators — has increased, but it has dropped in North America and Europe, where there is the most data, the report said.
Potts said the number of managed hives in the United States dropped from 5.5 million in 1961 and dropped to a low of 2.5 million in 2012, when colony collapse disorder was causing increased worries. The number of hives is now back up slightly, to 2.7 million.
Dennis vanEngelsdorp, a University of Maryland bee expert who wasn't part of the report, praised it for looking at the big picture beyond honeybees.
Doing something is crucial, he said.
"Everything falls apart if you take pollinators out of the game," vanEngelsdorp said. "If we want to say we can feed the world in 2050, pollinators are going to be part of that."
Beyond record hot, February was 'astronomical' and 'strange'
By SETH BORENSTEIN8 hours ago
WASHINGTON (AP) — Earth got so hot last month that federal scientists struggled to find words, describing temperatures as "astronomical," ''staggering" and "strange." They warned that the climate may have moved into a new and hotter neighborhood.
This was not just another of the drumbeat of 10 straight broken monthly global heat records, triggered by a super El Nino and man-made global warming. February 2016 obliterated old marks by such a margin that it was the most above-normal month since meteorologists started keeping track in 1880, according to the National Oceanic and Atmospheric Administration.
The old record was set just last December and the last three months have been the most above-normal months on record, said NOAA climate scientist Jessica Blunden. And it's not just NOAA. NASA, which uses different statistical techniques, as well as a University of Alabama Huntsville team and the private Remote Sensing System team, which measure using satellites, also said February 2016 had the biggest departure from normal on record.
NOAA said Earth averaged 56.08 degrees (13.38 degrees Celsius) in February, 2.18 degrees (1.21 degrees Celsius) above average, beating the old record for February set in 2015 by nearly six-tenths of a degree (one-third of a degree Celsius). These were figures that had federal scientists grasping for superlatives.
"The departures are what we would consider astronomical," Blunden said. "It's on land. It's in the oceans. It's in the upper atmosphere. It's in the lower atmosphere. The Arctic had record low sea ice."
"Everything everywhere is a record this month, except Antarctica," Blunden said. "It's insane."
In the Arctic, where sea ice reached a record low for February, land temperatures averaged 8 degrees above normal (4.5 degrees Celsius), Blunden said. That's after January, when Arctic land temperatures were 10.4 degrees above normal (5.8 degrees Celsius).
Worldwide, February 2016 was warmer than about 125 of the last 136 Marches.
FILE - In this Feb. 16, 2016 file photo, a girl takes pictures of her dog, back dropped by freshly s …
It was also the warmest winter — December through February — on record, beating the previous year's record by more than half a degree (0.29 degrees Celsius).
Georgia Tech climate scientist Kim Cobb said she normally doesn't concern herself much with the new high temperature records that are broken regularly.
"However," she added in a Thursday email," when I look at the new February 2016 temperatures, I feel like I'm looking at something out of a sci-fi movie. In a way we are: it's like someone plucked a value off a graph from 2030 and stuck it on a graph of present temperatures. It is a portent of things to come, and it is sobering that such temperature extremes are already on our doorstep."
Scientists at NOAA's National Centers for Environmental Information in Asheville, North Carolina, were astonished by the "staggering" numbers, said Deke Arndt, the centers' global monitoring chief.
"Usually these are monthly reminders that things are changing," Arndt said. "The last six months have been more than a reminder, it's been like a punch in the nose."
NASA's chief climate scientist Gavin Schmidt usually discounts the importance of individual record hot months, but said this month was different, calling it "obviously strange."
This was due to the long-term warming from heat-trapping gases and the powerful El Nino, so these types of records will continue for a few more months, but probably will not be a permanent situation, Schmidt said in an email.
But other were not so sure, including Arndt, who compared it to moving into a new hotter neighborhood.
"We are in a new era," Arndt said. "We have started a new piece of modern history for this climate."
Jason Furtado, a meteorology professor at the University of Oklahoma who wasn't part of any of the government teams, simply wrote in an email: "Welcome to the new normal."
RELEASE OF CO2 FASTEST IN 66 MILLION YEARS: STUDY
By Marlowe Hood: 3/21/2016
.Paris (AFP) - Humans are disgorging heat-trapping carbon into the atmosphere 10 times faster than during any period of natural global warming in the last 66 million years, according to a study released Monday.
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That rate far exceeds even a cataclysmic climate event 55.8 million years ago, and pushes humanity into unchartered and dangerous territory, researchers said.
During the so-called the Palaeocene-Eocene Thermal Maximum (PETM), Earth's surface temperatures climbed by more than five degrees Celsius (nine degrees Fahrenheit) within a few thousand years.
With only 1C (1.8F) of warming so far, current climate change over the last two centuries -- mostly the last 50 years -- has already begun to unleash super-charged hurricanes, storm surges boosted by rising seas and devastating drought.
On present trajectories, greenhouse gas emissions will heat up Earth three to four degrees Celsius by 2100.
The PETM has been much scrutinised as a possible analog, or stand-in, for the potential impacts of carbon pollution.
"Of all the changes we have seen in 66 million years, this event is the one that most looks like anthropogenic, or man-made, warming," said Andy Ridgwell, a paleo-climatologist at the University of Bristol in England and a co-autor of the study.
The parallels are striking: massive carbon emissions, followed by rapid global warming and major loss of species.
Fifty-six million years ago, those extinctions took place mainly in the ocean. Today the so-called "sixth great extinction" is underway both in the sea and on land.
But up to now scientists couldn't figure out how quickly carbon -- whether in the form of CO2 or, more likely, methane from the ocean floor -- had been released.
"The biggest problem has been coming up with a firm timing for the PETM onset event," Ridgwell told AFP.
With only 1C of warming so far, current climate change over the last two centuries -- mostly the las …
"How quickly the emissions occurred is absolutely critical."
Some studies had suggested the massive outpouring of carbon -- 2,000 to 4,500 billion tonnes -- took place in as little as a few hundred years.
This would be marginally reassuring in so far as humanity has added about 400 billion tonnes so far, and may be able to limit the total to two or three times that, depending on how quickly the world economy can kick its carbon habit.
In December, 195 nations set a target of capping warming "well below 2C," even if many scientists say we are likely to punch through this barrier.
But if the discharge of carbon 56 million years ago took place over a much longer period, that would suggest lower rates of emissions could still have dramatic consequences.
- In unchartered territory -
In a clever bit of chemical detective work, Ridgwell, James Zachos of the University of California at Santa Cruz, and lead author Richard Zeebe from the University of Hawaii figured out how to nail down the duration of the carbon release without having to determine when exactly when it happened.
Their findings were published in Nature Climate Change.
Knowing there is a lag between greenhouse gas emissions and temperature increase, they compared oxygen and carbon tracers, called isotopes, from ocean sediment off the coast of New Jersey.
Oxygen isotopes track temperature, while carbon isotopes provide a record of C02 or methane.
"If the carbon was released rapidly we would find in the sediment core a lag with warming," Zeebe told AFP.
"If carbon is released slowly, the climate adjusts more or less in sync."
There was no lag at all. A quick calculation showed that the carbon could not have been emitted in less then 4,000 years, or about one billion tonnes per year.
By comparison, human activity -- industry, energy production, deforestation, agriculture -- is pumping out about 10 billion tonnes of carbon annually, 10 times as much.
"Aside from the huge impact that killed the dinosaurs, what we are seeing now is the fastest rate of climate change in 66 million years," said Ridgwell.
This is bad news for species loss, he continued.
"Ecosystem impacts tend to show up more with the rate, rather than the size, of the change in temperature," he said.
"It's all about the rate."
What is happening on Earth today, he noted, is closer in speed to the end of the Cretaceous -- when a comet cataclysm wiped out the dinosaurs -- than it is to events such as the PETM.
"We are in uncharted territory in the rate carbon is being released into the atmosphere and oceans," commented Candace Major, program director of the Division of Ocean Sciences at the US National Science Foundation, which funded the research.
If We Don't Cut Carbon Emissions, We're Even More Screwed Than We Thought
By Max PlenkeMarch 22, 2016 12:15 PM
Here's what the planet looks like right now: We're pumping out 10 billion tons of carbon a year, we're looking at a massive climate shift before the end of the century and we're probably bringing about the sixth great extinction. Surprise!
New reports from the journal Nature Geoscience and the journal Atmospheric Chemistry and Physics showed how, even with our efforts to curb global warming and keep emissions low, we humans are still dooming the planet we stand on.
More specifically, we're talking super-strong storms and hunks of the polar ice sheets fracturing off, effectively raising the sea level enough to drown coastal cities. Bye-bye, NYC.
According to James E. Hansen, a retired NASA climate scientist who led the Atmospheric Chemistry and Physics research, "We're in danger of handing young people a situation that's out of their control."
.Source: Getty Images
This news comes less than a month after researchers published an article in the journal Nature Climate Change saying humans need to cut their future greenhouse gas emissions roughly in half. Even this week, climate scientists warned the planet is getting dangerously close to the tipping point of being unable to curb the effects of climate change.
Super-strong storms. Hunks of the polar ice sheets fracturing off, effectively raising the sea level enough to drown coastal cities. Bye-bye, NYC.
According to researchers on the Nature Geoscience study, what's happening now to our world looks remarkably similar to what's called the Paleocene-Eocene thermal maximum — an ancient planetary-warming event from around the time of dinosaurs.
After a spike in massive carbon emissions from the planet, the PETM was marked by a steep rise in Earth's overall temperature and the loss of many species due to floods, droughts, storms and an acidification of the ocean — so this connection should be terrifying to us.
As a global community, we're getting to the point where, no matter what we do, we'll be screwed. But we still have some time. If climate scientists and politicians can make dramatic changes to how we live our lives — for instance, cutting those greenhouse emissions in half — then we might stand a chance at making it to the year 2100 without the East Coast turning into the set from Waterworld.
Antarctica alone may lift seas a meter by 2100: study
March 30, 2016
Melting ice from Antarctica could raise oceans by a metre before 2100 at current rates of greenhouse gas emissions, a new study finds (AFP Photo/Eitan Abramovich)
Paris (AFP) - Melting ice from Antarctica could raise oceans by a metre before 2100 at current rates of greenhouse gas emissions, doubling previous forecasts for sea level rise, according to a study released Wednesday.
Such an abrupt change would spell disaster for major cities and coastal areas across the globe, forcing hundreds of millions of people to seek higher ground.
Over a longer time scale, the study concluded, the picture is even grimmer: within 500 years, Earth's once-frozen continent will have lifted water lines by more than 15 meters (50 feet), reconfiguring the planet's coastlines.
"Frankly, I hope we're wrong about this," Robert DeConto, lead author of the study and a climate scientist at the University of Massachusetts, told AFP.
But independent experts contacted by AFP said the study was probably on target.
While sharing DeConto's sense of alarm, they praised the new research, published in the peer-reviewed journal Nature, as "really good science."
Up to now, estimates of how many centimetres or inches Antarctic melt-off would add to the world's oceans over the next 85 years have been conservative.
The latest report from the UN Intergovernmental Panel on Climate Change (IPCC), a federation of several thousand scientists that report to governments on global warming and its impacts, put that number at about a dozen centimetres (five inches), all of it from a relatively small section called the West Antarctic Ice Sheet.
The IPCC predicted that total sea level rise from all sources -- including the expansion of water as it warms, melting glaciers, and the Greenland ice sheet -- would probably not top a meter by century's end.
But the low figure for Antarctica had more to do with gaps in knowledge than differences of opinion.
Scientists have long struggled, for example, to understand the role Earth's southern extremity played during earlier periods of global warming -- 125,000 and three million years ago -- when temperatures barely warmer than our own raised oceans to levels six-to-10 metres higher than today.
"In both cases, the Antarctic ice sheet has been implicated as the primary contributor, hinting at its future vulnerability," the study said.
But how, exactly, the planet's ice continent -- far colder than the Arctic, and thus less subject to melting -- disintegrated remained a mystery.
- Wake up call -
Building on earlier work, DeConto and David Pollard, a climate scientist at Pennsylvania State University, created computer models integrating for the first time two mechanisms that appeared to solve the puzzle.
One is a process called hydrofracturing.
As any teenage can tell you, if you put a sealed bottle of water or beer in a freezer, the liquid will expand and crack the container.
"That's what happened here," said Anders Levermann, an expert on the dynamics of ice sheets at the Potsdam Institute in Germany and a lead author of the chapter on sea levels in the most recent IPCC report.
"You have melt water going deep into crevices in the ice sheet, and then it expands and cracks the ice open," pushing it toward the sea, he told AFP, commenting on the study.
Until now, scientists have focused mostly on the impact warming oceans have on the overhang from ice sheets, which sit on land.
But it turns out that air temperatures have risen enough to cause some melting on top as well.
The other natural mechanism is the breakup of buttressing ice shelves, and the failure of ice cliffs, that both act as dams for the ice sheets behind them.
"These are not 'new' processes' per se," DeConto said. "But they haven't been considered at the continental scale in Antarctica before."
When the researchers applied their models to the previous periods of warming, the pieces of the puzzle fell into place, he said.
It also gave rise to alarming conclusions about the what lies ahead.
"The fact that a model -- tested and calibrated against past examples of sea level rise -- simulates such a strong future response to warming if very concerning," he said.
"This should be a wake up call."
The study adds to new evidence that ocean water marks may go up more and faster that previously thought, other scientists said.
"The recent modelling now favour the view that continuing rapid warming will cause sea level rise to be larger, and perhaps much larger, especially if we look beyond the end of this century," said Richard Alley, also a scientist at Pennsylvania State University.
DeConto did note, however, that if humanity succeeds in drastically reducing greenhouse gas emissions in the coming decades, there is relatively little contribution to sea level rise from Antarctica.
"That's the good news here," he added.
Greenland Ice Sheet's "Extreme Melt Event" Shatters Temperature Records, Stuns Scientists
April 15, 2016
The Greenland ice sheet covers most of the country: about 656,000 square miles in total. But it's quickly disappearing. In fact, the ice sheet is melting so quickly that, at first, the scientists who measure it assumed their recent data was wrong.
Seasonal melt is normal in Greenland: Parts of the ice sheet melt each spring and then freeze again when the weather gets cold. But lately the melt has been starting earlier and reaching higher levels than normal, Slate reported. This year, when climate scientists at the Danish Meteorological Institute (DMI) began to measure the seasonal melt, the data was unlike anything they had ever seen before.
"We had to check that our models were still working properly," climate scientist Peter Langen told Polar Portal. But they were.
"Almost 12% of the Greenland ice sheet had more than 1 mm of melt on Monday," Polar Portal reported, "smashing" the past records for ice melt. Slate reports that Greenland has seen a similar melt in the past — but that was in July.
Temperatures were also much higher than normal for April. "Thermometers on and around the ice showed temperatures as high as 64 degrees Fahrenheit on Monday — more than 35 degrees warmer than normal for this time of year," Slatereported.
So what does this mean for Greenland? There's a possibility that the weather will cool again in the coming weeks and some of the melt will refreeze, but climate scientists will be keeping a close eye on what Polar Portal calls an "unseasonable and rather extreme melt event."
A New Dark Age Looms
By WILLIAM B. GAILAPRIL 19, 2016
Boulder, Colo. — IMAGINE a future in which humanity’s accumulated wisdom about Earth — our vast experience with weather trends, fish spawning and migration patterns, plant pollination and much more — turns increasingly obsolete. As each decade passes, knowledge of Earth’s past becomes progressively less effective as a guide to the future. Civilization enters a dark age in its practical understanding of our planet.
To comprehend how this could occur, picture yourself in our grandchildren’s time, a century hence. Significant global warming has occurred, as scientists predicted. Nature’s longstanding, repeatable patterns — relied on for millenniums by humanity to plan everything from infrastructure to agriculture — are no longer so reliable. Cycles that have been largely unwavering during modern human history are disrupted by substantial changes in temperature and precipitation.
As Earth’s warming stabilizes, new patterns begin to appear. At first, they are confusing and hard to identify. Scientists note similarities to Earth’s emergence from the last ice age. These new patterns need many years — sometimes decades or more — to reveal themselves fully, even when monitored with our sophisticated observing systems. Until then, farmers will struggle to reliably predict new seasonal patterns and regularly plant the wrong crops. Early signs of major drought will go unrecognized, so costly irrigation will be built in the wrong places. Disruptive societal impacts will be widespread.
Such a dark age is a growing possibility. In a recent report, the National Academies of Sciences, Engineering and Medicine concluded that human-caused global warming was already altering patterns of some extreme weather events. But the report did not address the broader implication — that disrupting nature’s patterns could extend well beyond extreme weather, with far more pervasive impacts.
Our foundation of Earth knowledge, largely derived from historically observed patterns, has been central to society’s progress. Early cultures kept track of nature’s ebb and flow, passing improved knowledge about hunting and agriculture to each new generation. Science has accelerated this learning process through advanced observation methods and pattern discovery techniques. These allow us to anticipate the future with a consistency unimaginable to our ancestors.
But as Earth warms, our historical understanding will turn obsolete faster than we can replace it with new knowledge. Some patterns will change significantly; others will be largely unaffected, though it will be difficult to say what will change, by how much, and when.
The list of possible disruptions is long and alarming. We could see changes to the prevalence of crop and human pests, like locust plagues set off by drought conditions; forest fire frequency; the dynamics of the predator-prey food chain; the identification and productivity of reliably arable land, and the predictability of agriculture output.
Historians of the next century will grasp the importance of this decline in our ability to predict the future. They may mark the coming decades of this century as the period during which humanity, despite rapid technological and scientific advances, achieved “peak knowledge” about the planet it occupies. They will note that many decades may pass before society again attains the same level.
One exception to this pattern-based knowledge is the weather, whose underlying physics governs how the atmosphere moves and adjusts. Because we understand the physics, we can replicate the atmosphere with computer models. Monitoring by weather stations and satellites provides the starting point for the models, which compute a forecast for how the weather will evolve. Today, forecast accuracy based on such models is generally good out to a week, sometimes even two.
But farmers need to think a season or more ahead. So do infrastructure planners as they design new energy and water systems. It may be feasible to develop the science and make the observations necessary to forecast weather a month or even a season in advance. We are also coming to understand enough of the physics to make useful global and regional climate projections a decade or more ahead.
The intermediate time period is our big challenge. Without substantial scientific breakthroughs, we will remain reliant on pattern-based methods for time periods between a month and a decade. The problem is, as the planet warms, these patterns will become increasingly difficult to discern. This will present a troubling issue for regions of the world subject to El Niño, monsoon cycles and other long-term weather variability. Predicting extreme weather may become even more trying than it is today.
The oceans, which play a major role in global weather patterns, will also see substantial changes as global temperatures rise. Ocean currents and circulation patterns evolve on time scales of decades and longer, and fisheries change in response. We lack reliable, physics-based models to tell us how this occurs. Our best knowledge is built on what we have seen in the past, like how fish populations respond to El Niño’s cycle. Climate change will further undermine our already limited ability to make these predictions. Anticipating ocean resources from one year to the next will become harder.
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Civilization’s understanding of Earth has expanded enormously in recent decades, making humanity safer and more prosperous. As the patterns that we have come to expect are disrupted by warming temperatures, we will face huge challenges feeding a growing population and prospering within our planet’s finite resources. New developments in science offer our best hope for keeping up, but this is by no means guaranteed.
Our grandchildren could grow up knowing less about the planet than we do today. This is not a legacy we want to leave them. Yet we are on the verge of ensuring this happens.
William B. Gail is a founder of the Global Weather Corporation, a past president of the American Meteorological Society and the author of “Climate Conundrums: What the Climate Debate Reveals About Us.”