Damages from extreme events like floods are even more relevant than the mean sea level itself when it comes to the costs of climate impacts for coastal regions. However, while it is now rather well understood how sea-levels will rise in the future, only small progress has been made estimating how the implied damage for cities at the coasts will increase during the next decades. A team of scientists from the Potsdam Institute for Climate Impact Research (PIK) now provides a method to quantify monetary losses from coastal floods under sea-level rise. For the first time, the scientists show that the damage costs consistently increase at a higher rate than the sea-level rise itself.
"When sea levels rise, damage costs rise even faster, our analyses show," explains Markus Boettle, lead author of the study published in the journal Natural Hazards and the Earth System. Rising sea levels as a major impact of climate change pose a risk for coastal regions - the mean regional sea level rise takes effect by more frequent and more intense coastal flood events. "At the same time, the severity of flood impacts is not only determined by environmental factors, but also to a significant extent by human decisions: flood defense measures can counteract the increasing flood risk," says Boettle. "Our study illustrates that the complexity of climate change, adaptation, and flood damage can be disentangled by surprisingly simple mathematical functions to provide estimates of the average annual costs of sea-level rise over a longer time period."
The scientists developed a method that translates the occurrence probability of flood events into the probability of inundation damage. Expected regional sea level rise is taken into account by separating two components, namely the increasing number of events and the increasing severity of each one. Moreover, potential flood defense measures like dikes or sea walls can be included into the calculations as they prevent or mitigate damages from storm surges.
Flood risks, damages, adaptation
Although coastal cities are different around the world and also flood-related threats have their own characteristics at different coasts, the scientists found general results. "Our equations basically work in Mumbai, New York, Hamburg - Pacific, Atlantic, or North Sea. In any location worldwide the same simple and universal expressions hold true," says co-author Jürgen Kropp, deputy chair of PIK research domain Climate Impacts & Vulnerabilities. For an exemplary implementation of their method, the scientists applied it to the city of Copenhagen in Denmark: They found that a moderate mean sea level rise of 11 centimeters until mid-century would in the same period double economic losses in this city, given no action is taken.
"A concise assessment of potential economic consequences is indispensable for appraising the efficiency of adaptation measures," explains co-author Diego Rybski. "Even when temperatures stabilize, sea levels will continue to rise and shape our coastlines for future generations. So, additional preventive measures need to be considered in addition to the mitigation of greenhouse gas emissions, to help coastal regions especially in transition and developing countries to adapt and to limit damage costs."
A large share of the world population lives in coastal regions
Nevertheless, some constraints of the methodology remain, which was developed in the broader context of the European-funded RAMSES project. For instance, extreme events and attributed damages are not evenly distributed in time - there are years without any damage at all and others when quite unlikely floods may occur. The approach cannot forecast single events and associated damages, but estimates damage expectations over longer time-spans. Despite of the lack of knowledge regarding the timing of the extreme events, the statistical spreading of damage over years has been quantified by the researchers.
"A large share of the world population lives in coastal regions," says Jürgen Kropp, director of the RAMSES project. "In the light of limited funds for adaptation it is an asset to provide comparable cost assessments. While mitigation remains of vital importance to keep climate impacts on a still manageable scale, an adaptation perspective can help to limit damage costs in the right places."
Mr. Gore was elected to the U.S. House of Representatives in 1976, 1978, 1980 and 1982 and the U.S. Senate in 1984 and 1990. He was inaugurated as the 45th Vice President of the United States on January 20, 1993, and served eight years.
Al Gore has three questions about climate change and our future. First: Do we have to change? Each day, global-warming pollution traps as much heat energy as would be released by 400,000 Hiroshima-class atomic bombs. This trapped heat is leading to stronger storms and more extreme floods, he says: "Every night on the TV news now is like a nature hike through the Book of Revelation." Second question: Can we change? We've already started. So then, the big question: Will we change? In this challenging, inspiring talk, Gore says yes. "When any great moral challenge is ultimately resolved into a binary choice between what is right and what is wrong, the outcome is foreordained because of who we are as human beings," he says. "That is why we're going to win this."
Governments around the world last year struck a landmark climate-change deal: to keep global temperature increases no more than 2 degrees Celsius above pre-industrial levels. The European Commission says this means a global reduction in greenhouse-gas emissions from energy, with a shift towards renewables widely expected. What prospects and opportunities does this agreement bring for an EU that still gets almost half of its energy from fossil fuels?
How will the EU follow up on the promises it made in Paris? What opportunities lie ahead for Europe? What needs to be done to deliver on the COP21 agreement? Can the EU maintain its role as a leader in the fight against climate change? Why should other countries follow? What will inspire investments in a new clean-energy system? What will COP21 change for EU climate and energy policy? How far will the new deal move Europeans along the path they have already taken? How far will the world shift away from fossil fuels this century – and how can industry adapt? How much will global geopolitical news affect the successful implementation of the objectives set out last year? And in the absence of a global emissions-reduction target, how will governments and companies be judged for the action they take to deliver on Paris?
Emily Waterfield, Chief Correspondent – Energy for MLex, is joined by Elina Bardram, Head of Unit for International & Inter-Institutional Relations, European Commission, Miriam Dalli MEP, S&D Group, Rosalind Cook, Senior Policy Advisor working on EU climate and energy policy in E3G’s Brussels office and Charlotte Wolff-Bye, Vice-President Sustainability, Statoil, to debate the question: “COP21: What opportunities does the Paris agreement bring for Europe?”
On February 19, 2016, the crew Sea Shepherd's research vessel of R/V Martin Sheen spotted a humpback whale entangled in a gillnet in the Vaquita Refuge in the Gulf of California, Baja California, Mexico. While Captain Oona Layolle, campaign leader and captain of the M/V Farley Mowat, notified the Mexican Navy and the Federal Attorney for Environmental Protection (PROFEPA), the crew began the rescue operation. The whale was estimated to be 35 feet long and crews from both vessels worked to free the whale by cutting the gillnet off the whale's head and torso.
This is not the first humpback whale entangled in an illegal gillnet found by Sea Shepherd crew. On Christmas Eve, the crew of the R/V Martin Sheen spotted a humpback whale weighed down by a gillnet. Upon further investigation, the crew determined that the humpback whale was a calf and was already dead. Sea Shepherd then sought permission from the Mexican government to be able to begin removing gillnets; that permission was granted on December 31, 2015.
Sea Shepherd's newest vessel, the M/V Farley Mowat, a retired United States Coast Guard interceptor ship, joined the R/V Martin Sheen, in January 2016. On its first day of Operation Milagro, the crew of the M/V Farley Mowat spotted an illegal gillnet and spent six hours removing it. The Mexican Navy were notified and seized the illegal gillnet. Since then, the crews of both vessels have developed net retrieval devices to trail behind the R/V Martin Sheen and the M/V Farley Mowat's speedboat the Wolf. The use of these devices has already resulted in removal of seven gillnets and three longlines in just the past few weeks. Three totoaba, seven rays, one whale, and dozens of juvenile sharks have been saved by the recent removals of illegal fishing equipment. This total does not taken into account the countless animals who will not become trapped and die in the illegal gillnets and illegal fishing lines.
The Sea Shepherd M/V Farley Mowat
The crew of the M/V Farley Mowat was recently joined by Survivorman Les Stroud. Upon assisting in freeing the whale, he commented, “This is true conservation in action. Today, we were able to save the whale and remove another illegal gillnet. It is an honor to be a crew member with Sea Shepherd Conservation Society. Cutting that net and freeing the whale was a life changing experience.”
In April 2015, President Enrique Peña Nieto announced a two year ban on the use of gillnets in the Gulf of California. The intent was to protect the vaquita porpoise, the world's most endangered marine mammal. Vaquita are the unintended victims of gillnets used to catch the totoaba bass, another endangered species. The totoaba are targeted for their swim bladders for sale on the black markets in Asian. Vaquita are native only to the northernmost part of the Gulf of California.
Chief of Naval Research Rear Adm. Mat Winter, right, talks with Rear Adm. Veijo Taipalus, commander of the Finnish navy. Both attended the International Cooperative Engagement Program for Polar Research (ICE-PPR), a first-ever gathering of senior defense officials to coordinate science and technology research in high latitudes. US Navy photo by: Lt. Marten Coulter
To address the need for collaborative research in the Polar Regions, Chief of Naval Research Rear Adm. Mat Winter met in Finland last week with counterparts from five nations in a first-ever gathering of senior defense officials to coordinate science and technology research in high latitudes.
Dubbed the International Cooperative Engagement Program for Polar Research (ICE-PPR), defense officials and scientists from partner nations with Arctic and Antarctic interests--including the U.S., Canada, Denmark, Finland, Norway and Sweden--met in Helsinki to advance collaboration on polar research that could prove pivotal to not only scientific understandings but also U.S. and international naval operations.
While the U.S. Navy has long experience with polar operations, changing climates present new challenges--particularly for surface ships, as new water passages open up.
"Cooperative polar research is essential to ensuring safe maritime operations in these rapidly changing regions," said Winter. "ICE-PPR will allow the U.S. Navy and our partners to outline and coordinate our respective needs and priorities moving forward.
"The longstanding research and operational experience of our polar partners will play a key role in advancing U.S. knowledge and capabilities in these extremely challenging regions of the world."
The meeting answers the recent call from Chief of Naval Operations Adm. John Richardson to rapidly accelerate learning and provide new capabilities to the fleet. The Design for Maintaining Maritime Superiority specifically calls for expanding and strengthening the Navy and Marine Corps network of partners--including a directive to "prioritize key international partnerships through information sharing, interoperability initiatives and combined operations."
Ongoing research sponsored by the Office of Naval Research (ONR) is increasing the world's understanding of the changing environment in the Arctic, documenting a steady reduction in summer sea ice--with the resultant opening up of previously inaccessible waterways for extended periods of time each year.
At the gathering, representatives from each nation presented an overview of ongoing polar research activities, and outlined their top research priorities that could benefit from increased international science and technology collaboration.
Officials say the research collaboration will run the gamut from long-term fundamental research partnerships to applied research and even system prototypes--enabling more immediate opportunities to provide new technologies and capabilities to the fleet, a CNO priority.
The results could enhance capability for the Navy to support the U.S. Coast Guard in search and rescue operations, as well as the ability to more swiftly provide humanitarian and disaster relief around the world.
Long-term U.S. priorities discussed at the gathering included the enhancement of polar platforms, including surface ships and autonomous vehicles; the improvement of remote sensing in polar regions; and the exploration of how to enhance human performance in some of the most physically challenging regions of the world.
"The mutual sharing of science and technology will be essential, both short-term and long-term, to the U.S. Navy and Marine Corps, to the Department of Defense and to our international partners," said Winter.
ICE-PPR was developed by ONR Global and other Navy partners.
By 2030, more energy will be saved than the amount of energy consumed deriving from oil, according to a JRC analysis. Energy savings can thus be considered as "an energy source in its own right", in line with the European Commission strategy for a resilient energy union. As Europe is likely to miss the intermediary 2020 target of 20% of energy saved, the authors recommend scaling up private investments and introducing a guarantee fund to remove the perceived risk by investors.
The report examines the importance of energy efficiency for the EU's security of energy supply and import dependency in 2030, using projections made by the Commission's Directorate-General for Energy. It provides scientific evidence that transforming energy efficiency into a mechanism to reduce energy demand will ensure that the EU meets its objectives on security of supply, climate change and competitiveness in a decarbonising economy.
Furthermore, the analysis compares scenarios on improved energy efficiency of 27%, 30% and 40% and shows that if a 40% target is adopted, the sum of energy savings and renewables would overtake the sum of energy from imported fossil fuels all together (oil, gas and solid fuels) in 2030. Member States would hence not increase their dependency on fossil fuels imports.
The work presented in the report supports the upcoming Commission revision of the EU legislation framework on energy efficiency, foreseen for the autumn, and a new directive on renewables, planned in winter 2016.
For the revision round on energy efficiency, JRC scientists recommend including a framework for de-risking energy efficiency investments. The objective is to stimulate and scale-up private investments in energy efficiency projects and to ensure that energy savings compete on equal terms with generation capacity as foreseen by the Energy Union strategy. The report provides evidence that the objective to transform the EU economy from fossil fuels-based to a low-carbon one is possible if energy savings are made the niche fuel for investors, especially when energy prices are low.
Young adult herring from Washington state's Puget Sound. Credit: Margaret Siple/University of Washington.
A wise investor plays the financial market by maintaining a variety of stocks. In the long run, the whole portfolio will be more stable because of the diversity of the investments it contains.
It's this mindset that resource managers should adopt when considering Pacific herring, one of the most ecologically significant fish in Puget Sound and along the entire West Coast, argue the authors of a paper appearing in the January 2016 print edition of the journal Oecologia.
Just like a financial portfolio contains shares from different companies, the diverse subpopulations of herring from different bays and beaches around Puget Sound collectively keep the total population more stable, the study's authors found.
"This paper shows that all of these little subpopulations are important to the stability of Puget Sound herring as a whole," said lead author Margaret Siple, a University of Washington doctoral student in aquatic and fishery sciences.
"If you're a manager and you need to invest in multiple pieces of a natural resource, it's helpful to know what the impact will be of diversifying your efforts instead of just focusing on a few spots."
Pacific herring swim close to shore to spawn in eelgrass or seaweed, and each subpopulation usually returns to the same area year after year. This life pattern has traditionally created a close relationship between the herring and First Nations peoples and tribes who harvest herring and their eggs on Pacific Northwest beaches, as well as the marine mammals and larger fish that feed on these small, silvery fish.
Puget Sound herring eggs on seaweed. Credit: Margaret Siple/University of Washington.
Siple and senior author Tessa Francis, lead ecosystem ecologist with the Puget Sound Institute at UW Tacoma, analyzed 40 years of herring biomass data in Puget Sound to try to understand how the nearly 21 distinct subpopulations behave and relate to each other.
They found that each smaller group varied out of synch with the others -- despite sometimes spawning near each other. They also found that high year-to-year variability, which is common in forage fish such as herring, was dampened by the existence of many distinct subpopulations, buffering the wellbeing of the entire Puget Sound herring population from the failures of any single group.
"This paper shows that the local variability of herring helps ensure stability of the population," Francis said. "While biologists have recognized local variation in herring anecdotally, not all management has adapted to the 'local matters' perspective yet. This work shows that if you're interested in overall sustainability of the resource, protecting that local diversity is a good strategy."
In Puget Sound, the commercial herring fishery is limited and targets juvenile fish in South and Central Puget Sound, mainly caught to be used as bait in sport fisheries, primarily salmon. Concern about overfishing has resulted in relatively light fishing for herring since around the late 1980s, compared with other regions.
The Puget Sound herring stock is managed at a relatively fine scale, meaning all of the distinct subpopulations that spawn at various beaches in Puget Sound are known and counted by the Washington Department of Fish and Wildlife.
In Alaska and British Columbia, where the commercial herring fisheries are much larger, management doesn't yet account for what happens among smaller groups at individual beaches. But that local, beach-to-beach level is really how people and other animals most readily interact with herring, the researchers said, so it's important information to consider.
"Salmon rely heavily on herring as a prey source. We also know that indigenous people connect to herring locally and are using the resource at a very local scale. Herring beaches are in their villages, they're walking distance from their homes," Francis said.
This Puget Sound-focused study comes on the heels of a West Coast-wide effort last summer to bring together everyone who has a stake in Pacific herring -- from tribes, First Nations peoples and commercial fishers to fishery managers, nonprofits and scientists. The goal of the three-day summit in British Columbia was to capture the various roles herring plays in the ecosystem and understand how the species fits into the social, economic and ecological landscape.
Now, a smaller working group is tasked with creating a way to bring social and cultural knowledge of herring into actual management of the fishery. As a starting point, the first day of the June summit was dedicated to hearing stories of how tribes and First Nations peoples interact closely with the fish. That intimate knowledge is lost to the existing herring management process, Francis said.
"These social metrics are currently not used in fisheries management for herring, and yet herring is the forage fish of the people -- they come to shore to spawn and are tightly connected to people," she said.
The working group's first paper that discusses the June meeting and initial findings was accepted in the journal Ecosystem Health and Sustainability this month. The team of about 20 people, the second working group of the Ocean Modeling Forum of which Francis is the managing director, will meet three more times, drawing inspiration from communities in Haida Gwaii, British Columbia, and Sitka, Alaska.
Ultimately, the group plans to construct a framework that agencies can adopt when they are ready to incorporate human dimensions, such as the cultural significance of fishing, into fisheries management.
A new study in Nature Climate Change contends that traditional assessment methods overestimate the vulnerability of salt marshes to sea-level rise because they don't fully account for processes that allow the marshes to grow vertically and migrate landward as water levels increase.
The persistence of salt marshes despite rising seas would be a rare bit of good news for coastal ecosystems, which are under threat from a host of factors including nutrient pollution, invasive species, and development. Healthy marshes buffer coasts from storms, improve water quality, provide habitat for commercial fisheries, and help fight global warming by trapping carbon.
Lead author Matt Kirwan, a professor at the Virginia Institute of Marine Science, says "Catastrophic predictions of marsh loss appear alarming, but they stem from simple models that don't simulate the dynamic feedbacks that allow marshes to adapt not only to present rates of sea-level rise but the accelerated rates predicted for coming decades. Marsh soils actually build much faster as marshes become more flooded."
More frequent flooding carries more mud into the marsh and also encourages the growth of several common marsh plants. Together, these processes raise the marsh soil in concert with rising waters.
By not accounting for these feedbacks, Kirwan and his co-authors argue, traditional assessments greatly underestimate marsh resilience. Joining Kirwan on the study were Stijn Temmerman of the University of Antwerpen, Emily Skeehan of VIMS, Glenn Guntenspergen of the U.S. Geological Survey, and Sergio Fagherazzi of Boston University.
The team conducted their study by compiling and re-analyzing 179 previously published records of change in marsh elevation from sites in North America and Europe. "Our study shows that soil accretion rates more than double as marshes become more flooded, suggesting a strong ability for marshes to survive accelerations in sea-level rise," says Kirwan.
"The most common models greatly overestimate marsh vulnerability to sea-level rise," adds Guntenspergen. "These models assume that marshes rise, but only at a rate equal to recent measurements of marsh accretion. This approach leads inevitably to marsh drowning, and predictions that most tidal wetlands will be inundated by the end of the current century."
The researchers say the few models that do incorporate dynamic feedbacks indicate that marshes can generally survive 10 to 50 millimeters of sea-level rise per year. That far exceeds current annual rates of about 3 millimeters of globally averaged sea-level rise, and mostly exceeds even the higher-end rates of 8 to 17 millimeters per year predicted by U.N. climate scientists for 2100.
The team suggests that use of these more advanced models will help ecosystem managers assess marsh vulnerability more accurately, and should be encouraged. They also recommend that researchers expand their current focus on the vertical adaptability of marshes by mounting studies that help clarify the processes that control the horizontal migration of marsh boundaries through time.
Looking at recent history, the researchers note that the feedbacks built into the dynamic models also help explain the observed stability of many salt marshes in the mid-Atlantic and elsewhere during recent decades, and the relative rarity of marshes that have already drowned. Where drowned marshes do occur--think the Mississippi delta or Venice lagoon--the culprit is a reduced sediment supply, due to dam or levee building, or increased subsidence due to groundwater withdrawal and other factors.
"Marshes fail to survive current rates of sea-level rise only where people have restricted sediment delivery or where the tidal range is very low," says Kirwan.
The researchers temper their optimism regarding vertical marsh growth with a cautionary note about the importance of allowing salt marshes to migrate horizontally as rising seas push them landward. They note that in low-lying areas of the U.S. Atlantic Coast, migration into nearby forests could offset most of the loss of existing salt marshes.
But marsh migration isn't possible where obstructed by coastal cliffs or human barriers. "Almost 20% of the Chesapeake Bay shoreline is hardened by riprap, seawalls, and other structures," says Kirwan, "and similar structures border almost all marsh areas in northwest Europe. We suggest that the availability of low-lying land for wetland migration is a first-order determinant of marsh fate."
Ross Sea. Since pre-industrial times, the world’s oceans have absorbed 41 percent of the carbon dioxide humans have released into the atmosphere. In a new paper, a research team headed by Galen McKinley describes the best approach to date for determining how efficiently the oceans will continue to soak up what we emit. Ross Sea in the Southern Ocean was among the regions the researchers modeled. Photo Credit: Juan Botella.
Since pre-industrial times, the world's oceans have absorbed 41 percent of the carbon dioxide humans have released into the atmosphere. The remainder stays airborne, warming the planet.
The relationship between our future carbon dioxide emissions and future climate change depends strongly on the capacity of the ocean-carbon sink. How efficiently will it continue to soak up what we emit?
That is a question climate scientists have so far been unable to answer because of limited opportunities to take robust ocean-atmosphere measurements around the planet and because of inherent challenges in existing computer models.
In a new paper published in Nature Thursday, Feb. 25, 2016, a research team headed by Galen McKinley, professor in the University of Wisconsin-Madison Department of Atmospheric and Oceanic Sciences, describes the best modeling approach to date for arriving at an answer to this and other crucial climate questions.
"It's an evolution in our ability to use climate models to make predictions, particularly on timescales of a few decades," says McKinley, also an affiliate of the Center for Climatic Research at UW-Madison's Nelson Institute for Environmental Studies.
This improved predictive capacity could allow scientists to better understand what changes to expect, where to expect them, and their magnitude. It could also lead to better allocation of limited resources to enhance monitoring efforts, or to the creation of specific policies to mitigate change.
McKinley will present the Community Earth System Model findings on Tuesday, Feb. 23, at the 2016 Ocean Sciences Meeting, which is co-sponsored by the Association for the Sciences of Limnology and Oceanography, The Oceanography Society and the American Geophysical Union.
A variety of natural factors influence global climate, from solar variation to volcanoes, but anthropogenic greenhouse gas emissions also change the nature of the planet. Researchers want to distinguish the difference, especially in the context of large fluctuations in annual weather. They want to discern the role humans play in a changing climate.
"In Wisconsin, we might have a winter that is very cold, even though the overall climate is slowly and steadily warming," McKinley explains. "The swing to a very cold year is natural variability, and what we want to be able to uncover and understand is the magnitude of the slow and steady trend occurring at the same time as these large swings."
Prior climate models have lacked the fundamental computing power necessary to find the human signal above the noise of a variable climate system, McKinley says. This has been particularly true of the ocean-carbon sink.
The new study employed massive computing resources at the National Center for Atmospheric Research (NCAR), funded by the National Science Foundation (NSF), to perform a large number of simulations using a single model. This meant any variability detected would be inherent to the modeled climate system itself and not because of differences between models.
"What this does is let us determine how big that variability is and how it changes as timescales lengthen. We're better able to see when human activity begins to affect the ocean-carbon sink," she explains. "This is really a first step in using this new technique to understand a host of issues in terms of climate change, and it's not restricted to ocean carbon or biogeochemistry or physics. People are also using it to look at precipitation and temperature changes."
For assessing the global ocean-carbon sink, McKinley and her co-authors from the National Oceanic and Atmospheric Administration (NOAA)Pacific Marine Environmental Laboratory, NCAR and the University of Colorado Boulder used the model to establish a long-running climate scenario from historical data. Then, on model date Jan. 1, 1920, the researchers created a "slight perturbation" within the system: a slight rounding of the calculations for air temperature. Then, they looked at what happened.
"It was just a butterfly effect, a small change in the atmospheric temperature fields," McKinley says. "You perturb it oh-so-slightly and the model takes distinct paths of variation."
With this single, slight change the researchers elicited 32 different simulations -- built on all the same assumptions -- that represented some of the different ways the same climate system could evolve.
Ocean-carbon sink map. The colors on the globe correspond to how long it would take to see the difference between natural variability and the influence of humans on the ocean-carbon sink (aka, the time of emergence). The blue stars indicate seven sites where direct measurements of the ocean-carbon sink are made on a regular basis. Credit: Galen McKinley/University of Wisconsin-Madison.
"It's like a swirl of creamer in your coffee cup," says McKinley. "You can stir it today and it will look like this, but you stir it tomorrow and the pattern is different. You're using the same spoon, the same cup, the same coffee, the same creamer, but the swirls look different. This is how our climate system works."
And yet, she says, regardless of the shape the swirl initially takes, the coffee will still end up the same lighter color, unless something else changes, like pouring in additional creamer.
"We know that if we put carbon in the atmosphere, we will get an ancillary effect, the climate will warm," she says. "But how we get there are those swirls ... we are now starting to realize that variability is still strong on timescales of decades and we don't have as much ability as we would like to predict it."
In using the model to assess the ocean-carbon sink, the researchers assumed a "business as usual" carbon dioxide emissions trajectory, the Representative Concentration Pathway 8.5 scenario found in the Intergovernmental Panel on Climate Change for 2006-2010, where emissions continue to rise throughout the 21st century.
The model also accounted for natural drivers of change, including the direct influence of increased carbon dioxide on ocean-carbon uptake and the indirect effect that a changing climate has on the physical state of the ocean and its relationship to atmospheric carbon dioxide. For example, carbon dioxide is less soluble in water in a warmer climate.
The model showed that regions of the subpolar and equatorial Atlantic Ocean are undergoing changes that can already be detected through the noise of variability. Here, the ocean-carbon sink has increased, absorbing more carbon dioxide. However, changes to the sink in the Pacific and Indian Ocean subtropical regions will be too low-resolution to detect before at least 2050.
The researchers also checked the model against actual ocean observations. "What we find is that observations today are not sufficient to be able to see change in the ocean-carbon sink," McKinley explains. "We can see that there is a sink, but at any one location, we don't have enough data to say that the sink is increasing or decreasing."
The ability of any particular ocean or region of an ocean to absorb carbon dioxide depends in part on local features like how much exchange there is between surface and deep sea water. Taking measurements in some of these areas can be complicated. The model may help guide efforts to focus on particular regions and devote resources to these areas.
But the models themselves aren't easy to develop, which is why they are another step in the process and an improvement upon the tools previously available.
"If you want to calculate how all the wind moves, how the ocean circulates, how the chemistry in the atmosphere happens, the productivity on land, that's a lot of computer code and you want to do it at the highest resolution possible," McKinley says. "What we're really trying to do is represent all the complexity of planet Earth with a computer, so you can imagine how complicated that would be."
McKinley's goals are to continue to build upon the capabilities of the model. "What does Wisconsin look like 10 years from now? That's really hard to say," she says. "But we can provide ranges of expectations with broad variability, and use these techniques to quantify it."
"You know you can't be sure on any given day that it's going to be too cold to go skiing, or there's going to be enough snow," she adds. "But we want to know: What is the likelihood that we'll have winters where skiing isn't doable or ice fishing on the lake is a lot less possible?"
The colorful diversity of coral found at One Tree Island. The structure and diversity of coral we see today is already at risk of dissolution from ocean acidification. Photo by Kennedy Wolfe
New findings from fieldwork undertaken at the University of Sydney's One Tree Island Research Station provide evidence ocean acidification resulting from carbon dioxide emissions is already slowing coral reef growth. Their findings were published in Nature today.
It is estimated that 40 percent of carbon dioxide released into the atmosphere as the result of human activities - including the burning of fossil fuels - is absorbed by the ocean. There, the chemistry of seawater becomes more acidic and corrosive to coral reefs, shellfish, and other marine life. This process is known as 'ocean acidification'.
Coral reefs are particularly vulnerable to the ocean acidification process, because reef architecture is built by the accretion of calcium carbonate, called calcification, which becomes increasingly difficult as acid concentrations increase and the surrounding water's pH decreases.
Scientists predict that reefs could switch from carbonate calcification to dissolution within the century due to this acidification process.
In the first experiment to manipulate the chemistry of seawater in the ocean, a team of researchers brought the pH of a reef on One Tree Island closer to what it would have been in pre-industrial times, based on estimates of atmospheric carbon dioxide from that era. They then measured the reef's calcification in response to this pH increase. They found calcification rates under these manipulated pre-industrial conditions were higher than today.
The team was led by Rebecca Albright and Ken Caldeira from Stanford University and included University of Sydney PhD candidate Kennedy Wolfe, who was instrumental to the fieldwork undertaken to create these findings.
Ken Caldeira, Jana Maclaren and Kennedy Wolfe watching the seawater treatment (dyed yellow) being pumped from the pool behind boat and washing across the coral reef. Photo by Lillian Caldeira.
Previous studies have demonstrated large-scale declines in coral reefs over recent decades. Work from another team led by Professor Caldeira found rates of reef calcification were 40 percent lower in 2008 and 2009 than during the same season in 1975 and 1976. However, it has been hard to pinpoint exactly how much of the decline is due to acidification and how much is caused by other anthropogenic stressors like ocean warming, pollution, and over-fishing.
"Our work provides the first strong evidence from experiments on a natural ecosystem that ocean acidification is already causing reefs to grow more slowly than they did 100 years ago," Dr Albright said.
"Ocean acidification is already taking its toll on coral reef communities. This is no longer a fear for the future; it is the reality of today."
Increasing the alkalinity of ocean water around coral reefs has been proposed as a geoengineering measure to save shallow marine ecosystems. These results show this idea could be effective. However, the practicality of implementing such measures would be almost impossible at all but the smallest scales.
"The only real, lasting way to protect coral reefs is to make deep cuts in our carbon dioxide emissions," Professor Caldeira said.
"If we don't take action on this issue very rapidly, coral reefs--and everything that depends on them, including both wildlife and local communities--will not survive into the next century."
One Tree Island is a unique reef ecosystem that, at low tide, forms a ponded lagoon surrounded by a coral reef edge. "This habitat is ideal for experiments like these, allowing researchers to monitor reef response to changes in seawater conditions enclosed within the lagoon", Mr Wolfe said.
"We manipulated the current conditions of seawater by scooping 15,000 litres of water into a tank similar in shape to a large inflatable pool. We then pumped the water onto the reef, measuring the difference in response between present-day water and pre-industrial conditions."
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. He is the subject of the Oscar-winning documentary An Inconvenient Truth and is the co-recipient, with the Intergovernmental Panel on Climate Change, of the