Posts Tagged climate change

Apr 8 2015

Oceans might take 1,000 years to recover from climate change, study suggests

la-sci-sn-oceans-climate-change-20150331-001Sea urchins disappeared for thousands of years during ancient warming periods that could be a model of future climate change, a new study shows. Here, the shells of modern sea urchins lie in a tide pool in Corona del Mar. (Glenn Koenig / Los Angeles Times)

 

Naturally occurring climate change lowered oxygen levels in the deep ocean, decimating a broad spectrum of seafloor life that took some 1,000 years to recover, according to a study that offers a potential window into the effects of modern warming.

Earth’s recovery from the last glacial period, in fact, was slower and more brutal than previously thought, according to the study, published online Monday in the journal Proceedings of the National Academy of Sciences.

Researchers deciphered that plotline from a 30-foot core of sea sediments drilled from the Santa Barbara Basin containing more than 5,000 fossils spanning nearly 13,000 years.

“The recovery does not happen on a century scale; it’s a commitment to a millennial-scale recovery,” said Sarah Moffitt, a marine ecologist at UC Davis’ Bodega Marine Laboratory and lead author of the study. “If we see dramatic oxygen loss in the deep sea in my lifetime, we will not see a recovery of that for many hundreds of years, if not thousands or more.”

Studies already have chronicled declines in dissolved oxygen in some areas of Earth’s oceans. Such hypoxic conditions can expand when ocean temperatures rise and cycles that carry oxygen to deeper areas are interrupted.

As North American glaciers retreated during a warming period 14,700 years ago, an oxygen-sensitive community of  seafloor invertebrates that included sea stars, urchins, clams and snails nearly vanished from the fossil record within about 130 years, the researchers found.

“We found incredible sensitivity across all of these taxonomic groups, across organisms that you would recognize, that you could hold in your hand, organisms that build and create ecosystems that are really fundamental to the way ecosystems function,” Moffitt said. “They were just dramatically wiped out by the abrupt loss of oxygen.”

That highly diverse community soon was replaced with a relatively narrow suite of bizarre and extreme organisms similar to those found near deep-ocean vents and methane seeps in modern oceans, Moffitt said.

Evidence of that transition was confined to such a narrow band of sediments that the turnover could have been “nearly instantaneous,” the study concluded.

Then, beginning around 13,500 years ago, the seafloor community began a slow recovery with the rise of grazers that fed on bacterial mats. Recovery eventually was driven by a fluctuation back toward glaciation during the Younger Dryas period, a cooling sometimes called the Big Freeze.

“The biological community takes 1,000 years to truly recover to the same ecological level of functioning,” Moffitt said. “And the community progresses through really interesting and bizarre states before it recovers the kind of biodiversity that was seen prior to the warming.”

That relatively brief freeze also ended abruptly around 11,700 years ago, virtually wiping out all the seafloor metazoans, the study found. They were gone within 170 years and did not appear again for more than 4,000 years, according to the study.

The climate changes chronicled in the study arose from natural cycles involving Earth’s orbit of the sun, and the oxygen declines that ensued were more extreme than those that have occurred in modern times, the study noted.

Still, the abrupt fluctuations offer a glimpse at the duration of the effects of climate change driven by human activity pumping more planet-warming gases into Earth’s atmosphere, Moffitt said.

“What this shows us is that there are major biomes on this planet that are on the table, that are on the chopping block for a future of abrupt climate warming and unchecked greenhouse gas emissions,” Moffitt said. “We as a society and civilization have to come to terms with the things that we are going to sacrifice if we do not reduce our greenhouse gas footprint.”


Read original post: http://www.latimes.com

Mar 19 2015

Sea lion pup strandings may hit 2,000, but don’t blame climate change (yet)

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California sea lion pups keep washing up on the state’s coastline at abnormally high numbers: more than 1,800 starving pups have been brought into rescue facilities already this year, officials reported Tuesday.

The average yearly intake for stranded pups is about 200.

Justin Viezbicke, California Stranding Network coordinator for the National Marine Fisheries Service, said that he’s asking the public to be patient when it comes to rescue attempts for emaciated pups.

He said that the network won’t be able to rescue all pups and efforts to do so would hurt its ability to treat animals already in house. About 750 sea lions are being held for treatment in facilities right now.

“If we go over too many animals, the care really is lessened for all of those animals, and they all have decreased chances of survival,” Viezbicke said “Whereas, if we can focus on the ones we know we can give the best care and have the best chance of survival, we at least are giving them the best shot.”

Even reaching treatment centers is no guarantee of survival for the pups. Some are judged to be too far gone and are euthanized. Others die while undergoing treatment.

Even the ones that are successfully treated and released face difficult survival prospects. Unusually warm water off the coast holds less prey for the sea lions to forage.

“The reality is we’re putting them back into a very challenging situation, so there’s no guarantee that these animals that are being rehabbed are going to survive. It’s something we’ll be watching and monitoring for the future,” Viezbicke said.

The warm water is believed to be the cause of the high number of strandings in the first place.

As nursing mothers spend more time away on hunting trips seeking out that ever elusive prey, starving young leave their rookeries far earlier than they normally would.

Scientists said that the population of California sea lions is still strong, with estimates of total size at around 300,000 individuals.

The population has doubled from decades ago and the increased competition may be contributing to the poor feeding conditions, according to Nate Mantua, a climatologist with NOAA Fisheries.

Climate change not culpable … yet

He said the warm water isn’t likely caused by global warming because its development was too recent and too regional.

“It doesn’t look to me like a global warming pattern. It’s a direct response to the regional wind patterns that have been so persistent — including the pattern that brought us drought,” Mantua said. “I don’t really see the hallmarks of a global warming signature.”

A lack of winds from the north has kept surface water from being pushed out from the coast. That has lessened the amount of nutrient-rich upwelling of colder water.

101938-eightThe sea surface temperature map shows the unusually warm ocean water encompassing the West Coast. Darker red indicates temperatures farther above average. Credit: NOAA Fisheries/Southwest Fisheries Science Center.

No end in sight

Mantua said the northerly winds that normally accompany the start of spring are beginning to appear in Northern California. If they persist, he said some colder water could emerge nearer to land. That could help.

But he said the effect would be localized and that a recently declared El Niño appears to be strengthening — a combination that means the warm water could last for another year.

“The bigger picture, you step back and look at the whole broad region of the Northeast Pacific Ocean, it’s likely to stay warm for much of this year,” he said.

“Unless we get a winter next year that’s more normal and a lot stormier,” he added, “I think that it might persist. And if the El Niño develops, then it becomes even more likely to persist all the way to the end of the year and to next spring.”

Even though climate change isn’t a large factor in the current water temperature rise, Mantua said models predict it will become the major cause for future warmer water.

“When we get towards the middle of this century, human-caused climate change is going to be equal and then dominant for the warming trends along the West Coast,” Mantua said.

 

2013 was bad, too

This is the second time in a few years that California sea lion pups have stranded at abnormally high rates. In 2013, NOAA declared an unusual mortality event for the species.

Viezbicke, of the California Stranding Network, said it would take several years of similar mass deaths to reduce numbers to a threatened level because sea lion populations are so big right now.

In fact, events like this may even strengthen the remaining population.

“Even in naturally occurring situations like this, Mother Nature can kind of control the population size out there, and those that are doing well — that are currently in this warm water situation — will probably continue to do ok,” Viezbicke said. “And those that don’t, will kind of be weeded out from the gene pool.”

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Read the original post: www.scpr.org

Dec 18 2014

Climate change projected to drive marine species northward

New study predicts eastern Pacific species shifting poleward by 30 km per decade

Contributed by Michael Milstein December 10, 2014

Anticipated changes in climate will push West Coast marine species from sharks to salmon northward an average of 30 kilometers per decade, shaking up fish communities and shifting fishing grounds, according to a new study published in Progress in Oceanography.

The study suggests that shifting species will likely move into the habitats of other marine life to the north, especially in the Gulf of Alaska and Bering Sea. Some will simultaneously disappear from areas at the southern end of their ranges, especially off Oregon and California.

“As the climate warms, the species will follow the conditions they’re adapted to,” said Richard Brodeur, a NOAA Fisheries senior scientist at the Northwest Fisheries Science Center’s Newport Research Station and coauthor of the study. “We’re going to see more interactions between species and there will be winners and losers that we cannot foresee.”
Climate models used to project species shifts

The study, led by William Cheung of the University of British Columbia, estimated changes in the distribution of 28 near-surface fish species commonly collected by research surveys in the northeast Pacific Ocean. The researchers used established global climate models to project how the distribution of the fish would shift by 2050 as greenhouse gases warm the atmosphere and, in turn, the ocean surface.

Brodeur cautioned that like any models, climate models carry uncertainty. While they provide a glimpse of the most likely changes in global climate, they may be less accurate when estimating more fine-scale, local changes.

“Nothing is certain,” he said, “but we think we have a picture of the most likely changes.”

Some species shifts are already being documented as West Coast waters are warming: predatory Humboldt squid from Central and South America have invaded the West Coast of North America in recent years, albacore have shifted to more northerly waters and eulachon have disappeared from warming waters at the southern end of their range.
Effects on the marine ecosystem

“Thinking more broadly, this re-shuffling of marine species across the whole biological community may lead to declines in the beneficial functions of marine and coastal ecosystems,” said Tom Okey, a Pew Fellow in Marine Conservation at the University of Victoria and a coauthor of the study. “These declines may occur much more rapidly and in more surprising ways than our expected changes in species alone.”

The study anticipates warm-water species such as thresher sharks and chub mackerel becoming more prominent in the Gulf of Alaska and off British Columbia. Some predators such as sea lions and seabirds, which rear their young in fixed rookeries or colonies, may find the fish they usually prey on moving beyond predators’ usual foraging ranges.

“If their prey moves farther north, they either have to travel farther and expend more energy to get to them, or find something else to eat,” Brodeur said. “It’s the same thing for fishermen. If it gets warmer, the fish they depend on are going to move up north and that means more travel time and more fuel will be needed to follow them, or else they may need to switch to different target species. It may not happen right away but we are likely to see that kind of a trend.”

El Nino years, when tropical influences temporarily warm the eastern Pacific, offer a preview of what to expect as the climate warms.

Shifts in marine communities may be most pronounced in high-latitude regions such as the Gulf of Alaska and Bering Sea, which the study identifies as “hotspots” of change. Cold-water species such as salmon and capelin have narrower temperature preferences than warmer water species, making them more sensitive to ocean warming and likely to respond more quickly.

An intrusion of warm-water species into cooler areas could lead to significant changes in marine communities and ecosystems. The diversity of northern fish communities, now often dominated by a few very prolific species such as walleye pollock, may increase as southern species enter the region, leading to new food web and species interactions.

alabacore_NOAAFishWatchAlbacore tuna have shifted to more northerly waters.

eulachon_NOAA_AFSCEulachon have disappeared from warming waters at the southern end of their range.

humboldtsquid_noaa_oceanexploreHumboldt squid from Central and South America have invaded the West Coast of North America in recent years.

ThresherShark.SWFSCAccording to the study, thresher sharks may become more prominent in the Gulf of Alaska and off British Columbia.


Read the original post here.

Nov 18 2014

Why isn’t anyone talking about Ocean Acidification?

acidification

Climate change is not the only outcome of increased greenhouse gas concentrations. The oceans have absorbed a lot of the excess carbon in the atmosphere, reducing the impacts of climate change to date, but at a cost. Higher concentrations of carbon dioxide (CO2) in the atmosphere have led to an increase in acidity of ocean water, a process known as ocean acidification. The process of acidification is laid out by Cheryl Logan in a user-friendly 2010 summary in the journal Bioscience.

Ocean acidification occurs when CO2 dissolves in ocean water, undergoing a chemical reaction that produces carbonic acid. The rate of this reaction is completely predictable and as a result the progression of acidification as CO2 levels increase is completely predictable. Unlike climate change, ocean acidification is not controversial at all—basically nobody disputes that it is happening—and happening rapidly.

As Logan explains, acidity is measured through the concentration of hydrogen ions—called the pH scale, for power of hydrogen—more hydrogen equals greater acidity. Since the late 19th century, the concentration of hydrogen ions in the ocean has increased by 30%, and that will increase another 150% by 2100, according to common emissions projections.

That is a massive change to ocean chemistry in a short amount of time, and many of the ocean’s inhabitants are struggling to adapt. The shells of many marine organisms are made of calcium carbonate, which is highly susceptible to acid. Logan explains how some organisms are starting to have trouble forming new shells, and in extreme cases, existing shells are getting thinner.

Just in case the plight of a few snails seems like a relatively minor concern, the issue goes well beyond snails. Corals, sea urchins, many species of plankton- organisms crucial to marine habitats and food webs- all rely on calcium carbonate as part of their structure. Some research even suggests that acidification can disrupt the ability of plants to perform photosynthesis. As marine organisms are responsible for much of the Earth’s oxygen production, this might one day threaten our very survival.

Acidification has the potential to completely disrupt the ocean’s—and perhaps even the planet’s—ecosystem before climate change has a chance to do so. Despite the urgency Logan describes, the American public is largely unaware of the issue. Public awareness notwithstanding, the solution to ocean acidification is straightforward: burn less carbon. Efforts to curb the climate change will address acidification as well, but progress is slow. It is astounding that such a key issue, one that might genuinely threaten our survival as a species, is still so little-known.


JSTOR Citations:

A Review of Ocean Acidification and America’s Response
Cheryl A. Logan
BioScience
Vol. 60, No. 10 (November 2010), pp. 819-828
Published by: Oxford University Press

Marine and Coastal Science: Will Ocean Acidification Erode the Base of the Food Web?
Carol Potera
Environmental Health Perspectives
Vol. 118, No. 4 (APRIL 2010), p. A157
Published by: The National Institute of Environmental Health Sciences (NIEHS)


View original post: JSTOR|Daily

Oct 3 2014

Massive Pacific Coast die off of starfish continues, may be harbinger of climate change

Reposted by permission from: SEAFOODNEWS.COM [Newsweek] By Megan Scudellari – October 2, 2014

starfishdieoffPhoto Credit: WordPress – Dive.Roko

A grisly horror show is playing out along the West Coast of North America. Remains of millions of dead and dying sea stars, commonly known as starfish, litter the shoreline from Vancouver to San Diego.

Those stars are the victims of a swift and brutal illness. First, the animal’s body deflates, as if drained of all its water. Then the trademark arms begin to curl, detaching from rocks. White lesions appear, like festering canker sores. Then the star explodes as organs rupture though the body wall. The arms fall off. Ultimately, the sea star dissolves, as if melted by acid, disintegrating into goo.

Researchers in Washington state first noticed signs of the so-called “wasting syndrome” in June 2013 during routine monitoring of populations of bright purple and orange Pisaster ochraceus sea stars. The outbreak continued through the summer, spreading down into California’s central and southern coasts. Scientists hoped it would subside during the winter. It did not.

This summer, the outbreak morphed into a full-scale epidemic: Dead stars, of over 20 species, can now be found from Mexico all the way up to Alaska. It’s hard to find even a single group of stars that isn’t affected, says professor Drew Harvell of Cornell University, who spent the last year tracking the outbreak around the San Juan Islands near Seattle. The die-off is so bad that researchers have lost count of how many stars are lost. They estimate millions.

“It’s the largest epidemic we’ve ever seen with marine wildlife,” says Harvell. “We watched our populations go from thousands of stars to none over the space of a month.” The wasting syndrome has also been reported in populations along the East Coast, from New Jersey to Maine, though fewer monitoring programs exist there to quantify its spread.

Sea stars are voracious predators at the top of the coastal food chain, key members of the environment that chomp away on mussels, barnacles and more. Without sea stars, food webs are being upended: In Howe Sound, northwest of Vancouver, for example, green sea urchins, one of the sea stars’ prey, are flourishing and devouring large amounts of seaweed, once home to young spot prawns. The prawns used the seaweed as a nursery; without it, young prawns cannot flourish. And shorelines that used to be dotted with sea stars and other species are now blanketed with barnacles growing with abandon, a sign of the loss of biodiversity on the coast.

No one yet knows the exact causes of the epidemic. Some evidence suggests the outbreak is linked to warming ocean temperatures or other changes in the ocean due to climate change. It wouldn’t be the first time: Climate-related disease spread has been documented in corals and shellfish, although on a smaller scale than sea star wasting syndrome. This may be because infectious microorganisms thrive in warmer temperatures. Last year, for example, scientists found that ocean warming is promoting the growth and persistence of pathogenic bacteria in the North Sea in Europe.

Bruce Menge, an ocean ecologist at Oregon State University, has been studying sea stars along the Oregon coast for over 30 years. Now, at some of his study sites, he can no longer find even a single star. “Deep down, I worry this might be a harbinger of some impending, major problem resulting from climate change,” Menge says. “If what we’re seeing in this marine environment is any indication of what we might see in the future,” he adds, “it could lead to a complete alteration of coastal ecosystems,” ultimately affecting fish populations and the people that rely on them.

On the other hand, the death of captive sea stars in aquariums in both Seattle and Vancouver—in tanks that had maintained healthy populations for 40 years—suggests the cause is an infectious microorganism able to travel through water. Aquariums maintain constant temperatures in their tanks but fill them with circulating ocean water, so perhaps something in the water made the captive stars sick.

A team of eight pathologists, led by Alisa Newton of the Wildlife Conservation Society, closely examined slides of tissues harvested from dead or dying sea stars from both aquariums and the wild. “We haven’t seen, on slides, any parasite or fungus or specific organisms in the tissues,” Newton says. However, that rules out only infectious agents that are large enough to be seen with a light microscope.

To try to detect smaller microorganisms, Ian Hewson of Cornell, one of the few scientists in the world specializing in viruses that infect marine invertebrates, sequenced the DNA of hundreds of sea star samples to look for genetic evidence of a virus or small bacteria. He has recently found “quite conclusive” evidence for the involvement of at least one virus or bacteria, Harvell says, but until other scientists review that research, the Cornell team is declining to reveal the identity of the culprit.

Still, even if a virus or bacterium is implicated, Newton, Harvell and others agree the extent of the current wasting syndrome is most likely the result of multiple factors. Harvell’s team, for instance, detected a correlation between sea star deaths and warmer waters, so she and her team took sea stars into the lab, where they could control the environment, and found that the stars deteriorated faster at warmer temperatures. If warmer temperatures increase the speed or spread of the disease, that doesn’t bode well for the coming months: The National Oceanic and Atmospheric Administration is predicting that El Niño, a period of unusually warm sea surface temperatures in the Pacific, is likely to begin this fall and run into the winter.

On the flip side, the wasting syndrome appeared on the Oregon coast at the same time that deep, cold water rose up and filled the area, says Menge, so perhaps it is not warming waters but other effects of climate change, such as ocean acidification or lack of oxygen in the water, that led to the outbreak.

Either way, if the epidemic was exacerbated by climate change, similar widespread illnesses in other marine life may soon occur. Sea stars are, in a way, the canary in the coal mine of the ocean. “Honestly, if this had been a small worm or small crab, the whole thing could have happened and we never would have even known about it,” says Harvell. “Epidemics in the ocean are definitely out of sight and out of mind. As it was, it took a while for us to understand the scale of this.” Now, though, awareness is growing. In mid-September, for example, Rep. Denny Heck, D-Washington, introduced the Marine Disease Emergency Act to Congress,with the goal of creating a national response strategy to sea star wasting syndrome and future marine disease emergencies.

At the University of California, Santa Cruz, professor Pete Raimondi and his colleagues have been assessing the impact of the loss of the sea stars. They continue to monitor coastal areas to see if the absence of this top predator will cause predicted effects, such as increasing mussel populations and a loss of biodiversity. If so, that doesn’t bode well for the ecosystem.

But recently, Raimondi’s team saw small twinkles of hope dotting the rocky shore. Little juvenile stars, about the size of a thumbnail, are latching on to the coastline. Raimondi doesn’t know yet if these babies are susceptible to the disease. If they are, the new sea stars won’t live long enough to breed, and sea star populations may not recover next year. “This year might be the best, last chance for the animals,” says Menge.

But if the young stars are resistant to the epidemic and survive, there is hope—both for the stars and the ecosystems in which they live. “We should know in the next six months,” Raimondi says. “We’re tracking them. We’ll see whether the little guys grow.”


Seafood News

 

Ken Coons
SeafoodNews.com 1-781-861-1441
Email comments to kencoons@seafood.com

Copyright © 2014 Seafoodnews.com

Feb 22 2014

El Niño may make 2014 the hottest year on record

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Hold onto your ice lollies. Long-term weather forecasts are suggesting 2014 might be the hottest year since records began. That’s because climate bad-boy El Niño seems to be getting ready to spew heat into the atmosphere.

An El Niño occurs when warm water buried below the surface of the Pacific rises up and spreads along the equator towards America. For nine months or more it brings rain and flooding to areas around Peru and Ecuador, and drought and fires to Indonesia and Australia. It is part of a cycle called the El Niño-Southern Oscillation.

It is notoriously hard to make a prediction before the “spring barrier” as to whether there will be an El Niño in a given year. “The El Niño-Southern Oscillation cycle more or less reboots around April-May-June each calendar year,” says Scott Power from the Bureau of Meteorology in Melbourne, Australia.

The problem is that there is so much background variability in the atmosphere and ocean that it is hard to see any signal amidst the noise, says Wenju Cai from the CSIRO, Australia’s national research agency in Melbourne. “Even if there is a developing El Niño, it is hard to predict.”

Read the full article here.

Aug 27 2013

Ocean Acidification Will Make Climate Change Worse

TIME Science TIME ecocentric
Given that they cover 70% of the Earth’s surface—and provide about 90% of the planet’s habitable space by volume—the oceans tend to get short shrift when it comes to climate change. The leaked draft of the forthcoming coming new report from the Intergovernmental Panel on Climate Change highlighted the atmospheric warming we’re likely to see, the rate of ice loss in the Arctic and the unprecedented (at least within the last 22,000 years) rate of increase of concentrations of greenhouse gases like carbon dioxide and methane. But when it came to the oceans, press reports only focused on how warming would cause sea levels to rise, severely inconveniencing those of us who live on land.

Some of that ignorance is due to the out of sight, out of mind nature of the underwater world—a place human beings have only seen about 5% of. But it has more to do with the relative paucity of data on how climate change might impact the ocean. It’s not that scientists don’t think it matters—the reaction of the oceans to increased levels of CO2 will have an enormous effect on how global warming impacts the rest of us—it’s that there’s still a fair amount of uncertainty around the subject.

But here’s one thing they do know: oceans are absorbing a large portion of the CO2 emitted into the atmosphere—in fact, oceans are the largest single carbon sink in the world, dwarfing the absorbing abilities of the Amazon rainforest. But the more CO2 the oceans absorb, the more acidic they become on a relative scale, because some of the carbon reacts within the water to form carbonic acid. This is a slow-moving process—it’s not as if the oceans are suddenly going to become made of hydrochloric acid. But as two new studies published yesterday in the journal Nature Climate Change shows, acidification will make the oceans much less hospitable to many forms of marine life—and acidification may actually to serve to amplify overall warming.

The first study, by the German researchers Astrid Wittmann and Hans-O. Portner, is a meta-analysis looking at the specific effects rising acid levels are likely to have on specific categories of ocean life: corals, echinoderms, molluscs, crustaceans and fishes. Every category is projected to respond poorly to acidification, which isn’t that surprising—pH, which describes the relative acidity of a material, is about as basic a function of the underlying chemistry of life as you can get. (Lower pH indicates more acidity.) Rapid changes—and the ocean is acidifying rapidly, at least on a geological time scale—will be difficult for many species to adapt to.

Corals are likely to have the toughest time. The invertebrate species secretes calcium carbonate to make the rocky coastal reefs that form the basis of the most productive—and beautiful—ecosystems in the oceans. More acidic oceans will interfere with the ability of corals to form those reefs. Some coral have already shown the ability to adapt to lower pH levels, but combined with direct ocean warming—which can lead to coral bleaching, killing off whole reefs—many scientists believe that corals could become virtually extinct by the end of the century if we don’t reduce carbon emissions.

Read the full article here.

Bleaches corals off the coast of Indonesia. Ocean acidification could have disastrous impacts on sealife—and the climate |  Reinhard Dirscherl via Getty Images

Bleaches corals off the coast of Indonesia. Ocean acidification could have disastrous impacts on sealife—and the climate |
Reinhard Dirscherl via Getty Images

Feb 1 2013

Major climate changes looming

Washington — In his inaugural address last Monday, President Obama made climate change a priority of his second term. It might be too late.

Within the lifetimes of today’s children, scientists say, the climate could reach a state unknown in civilization.

In that time, global carbon dioxide emissions from burning fossil fuels are on track to exceed the limits that scientists believe could prevent catastrophic warming. CO{-2} levels are higher than they have been in 15 million years.

The Arctic, melting rapidly and probably irreversibly, has reached a state that the Vikings would not recognize.

“We are poised right at the edge of some very major changes on Earth,” said Anthony Barnosky, a UC Berkeley professor of biology who studies the interaction of climate change with population growth and land use. “We really are a geological force that’s changing the planet.”

 
Read more here

 

Sep 14 2012

Sea Level’s Rise Focus of Summit

Projections of dramatic change draw group to UCSD to strategize about vulnerabilities of affected areas

LA JOLLA — Climate researchers, social scientists and policy experts from across the Pacific Rim convened at UC San Diego last week to get ahead of seas projected to rise so dramatically that they could create some of the most visible effects of global warming.

Representatives from about 20 leading research universities and nonprofit groups in South Korea, Russia, Indonesia and elsewhere met to prepare for potentially catastrophic effects on 200 million people and trillions of dollars of coastal assets.

Sea levels off most of California are expected to rise about 3 feet by 2100, according to recent projections by the National Research Council. Higher seas create challenges for port cities from San Diego to Singapore, including the potential for dramatically increased damage to coastal roads, homes and beaches — especially during storms.

“All future development has to be assessed in regards to future rises in sea level,” Steffen Lehmann, professor of sustainable design at the University of South Australia, said during the conference. “Reducing the vulnerabilities of urban (areas) is the big topic, the big task ahead of us now.”

Potential responses include managing a retreat from eroding bluffs and reshaping coastal areas to buffer development from higher water levels. “The missing link (is) between the science and those guys in planning offices and architecture firms and city municipal offices,” Lehmann said.

David Woodruff, director of the University of California San Diego’s Sustainability Solutions Institute, organized the workshop to address that problem with cross-disciplinary discussions that move toward international action.

“We are trying to affect societal change,” he said. “The sooner we start scoping options, the less expensive it will be to save current infrastructure.”

The workshop was sponsored by the Association of Pacific Rim Universities, a consortium of 42 leading research institutions. Participants drafted a report about rising sea levels for top university leaders so they can make the topic a priority with national-level leaders around the Pacific Rim.

“I really think universities can play a key role,” said UC San Diego’s Charles Kennel. “They are right at the pivot point between connecting knowledge to action. … One of the places they need to transfer their knowledge to is adaptation to climate change.”

A warming climate causes sea levels to rise primarily by heating the oceans — which causes the water to expand — and by melting land ice, which drains water to the ocean. Sea levels at any given spot depend on a complex interaction of factors, such as ocean and atmospheric circulation patterns and tectonic plate movements.

Global sea level has risen about 7 inches during the 20th century, the National Research Council said.

While sea-level-rise projections aren’t a sure thing, they are widely accepted by mainstream scientists. Skeptics see it as a waste of money to plan for problems that may not materialize for decades, or may be more modest than predicted.

Read more on the Union-Tribune San Diego.

 
Mar 6 2012

Oceans’ acidic shift may be fastest in 300 million years

 

Written by Deborah Zabarenko | Environment Correspondent

The world’s oceans are turning acidic at what could be the fastest pace of any time in the past 300 million years, even more rapidly than during a monster emission of planet-warming carbon 56 million years ago, scientists said on Thursday.

Looking back at that bygone warm period in Earth’s history could offer help in forecasting the impact of human-spurred climate change, researchers said of a review of hundreds of studies of ancient climate records published in the journal Science.

Quickly acidifying seawater eats away at coral reefs, which provide habitat for other animals and plants, and makes it harder for mussels and oysters to form protective shells. It can also interfere with small organisms that feed commercial fish like salmon.

The phenomenon has been a top concern of Jane Lubchenco, the head of the U.S. National Oceanic and Atmospheric Administration, who has conducted demonstrations about acidification during hearings in the U.S. Congress.

Oceans get more acidic when more carbon gets into the atmosphere. In pre-industrial times, that occurred periodically in natural pulses of carbon that also pushed up global temperatures, the scientists wrote.

Human activities, including the burning of fossil fuels, have increased the level of atmospheric carbon to 392 parts per million from about 280 parts per million at the start of the industrial revolution. Carbon dioxide is one of several heat-trapping gases that contribute to global warming.

Read the rest of the article on Reuters.