WASHINGTON, DC – Climate change will pose a number of challenges to food safety in the coming decades, from boosting the rates of food- and water-borne illnesses to enabling the spread of pathogens, researchers reported Monday at the annual meeting of the American Association for the Advancement of Science.

Depending on the greenhouse gas emissions scenario, global average temperature is expected to rise between 1.1° and 6.8° Celsius by the end of the century. And warmer temperatures are known to increase rates of some diseases: According to a recent study of salmonellosis in Europe, frequency of the ailment rises about 12 percent for every 1°C that air temperature increases beyond a baseline of 6°C, said Cristina Tirado, an environmental scientist at the University of California, Los Angeles. The precise cause for this trend isn’t clear, said Ewen Todd, a bacteriologist at Michigan State University in East Lansing. It’s possible that warmer temperatures cause bacteria to grow more quickly, or people may prepare food differently in warmer weather (grilling outdoors vis-à-vis cooking in a kitchen, for example).

Climate change can increase disease risks in several ways, Tirado added. The concentration of methyl mercury in fish increases about 3.5 percent for every 1°C rise in water temperature. Warmer sea-surface temperatures can boost the frequency of harmful algal blooms, leading to an increased incidence of paralytic shellfish poisoning. Higher water temperatures also enable the spread of pathogens to higher latitudes: An outbreak of vibriosis on an Alaskan cruise ship in 2005, later linked to oysters that had been harvested near one of the ship’s ports of call, represents the spread of the disease-causing Vibrio parahaemolyticus to a locale more than 1,000 kilometers north of its previous known range. Dust storms, which are expected to increase in some regions due to climate change, could wreak their own havoc, because iron-rich mineral dust can drive a 10- to 1,000-fold increase in the growth rate of Vibrio bacteria.

Indirect effects of climate change abound as well. For instance, an increased frequency of intense storms and floods means that water purification systems could be overwhelmed more often, leading to a more-frequent incidence of waterborne diseases, says Sandra Hoffman of the U.S. Department of Agriculture’s Economic Research Service in Washington, D.C. Increased temperatures, particularly in the summer, may lead to longer and more-frequent electrical blackouts, during which food may be more susceptible to the growth of disease-causing agents. Climate-driven changes in the production, processing and transport of food could also boost the incidence of disease, she noted.

But some changes in behavior could trim the increased incidence of disease, Hoffman noted. If people begin to buy more of their foods locally rather than purchasing items transported long distances — either by conscious decision or in response to rising energy prices — the incidence of transport-related diseases may be reduced. One of the challenges to future food safety will be maintaining and improving disease surveillance, especially in developing nations, says Hoffman. While deaths attributable to food- and water-borne illnesses in industrialized nations are measured only in the hundreds each year, in developing nations the annual death tally for the same diseases is around 2.2 million.

WASHINGTON, DC – Although no one knows the ultimate effects of climate change on marine ecosystems, scientists know enough about the oceans to proceed with adaptation, researchers reported Saturday at the annual meeting of the American Association for the Advancement of Science. And while many previous studies have focused on minimizing detriments to single species of economic importance, future efforts should shift to preserving ecosystems and their capacity to adapt, they suggest.

While many people recognize the warming effects of climate change on Earth’s atmosphere, the oceans are sucking up heat too. Only 4 percent of the excess energy absorbed by the planet in the past 40 years has gone into heating the atmosphere, but 84 percent has gone into the oceans, a larger and much more effective reservoir of heat, said Chad English, director of science policy outreach at the Communication Partnership for Science and the Sea (COMPASS) in Silver Spring, Maryland. (The rest of that energy imbalance has gone into warming Earth’s landmasses and melting ice, he notes.) Meanwhile, oceans are acidifying (by the end of this century, they’ll reach a pH lower than any experienced in the last 20 million years), sea levels are rising, and waves are getting bigger, driven by faster winds. The changes seen so far are just a preview of coming attractions, he suggests: “We’ve only seen [Earth’s] transient response to warming, and we don’t yet know at what point ecosystems will break down.”

Indeed, a wide variety of holes exist in scientists’ knowledge about when —and how — ecosystems will respond to climate change. While many studies have assessed the individual effects of warmer waters, increasing levels of ocean acidity, and lower levels of dissolved oxygen on various marine species, the combined effects of multiple stressors are largely unknown, said James Barry of the Monterey Bay Aquarium Research Institute in Moss Landing, California.

Looking to save ecosystems by preserving a single species of importance probably won’t work, said Nancy Knowlton, a marine biologist at the Smithsonian Institution’s National Museum of Natural History in Washington, D.C. Such a “California condor” approach – a massive effort dedicated to preserving just one, usually charismatic species – ignores the fact that ecosystems are finely-tuned biological networks composed of numerous interacting species. In the case of coral reefs, Knowlton’s specialty, those ecosystems are home to more than 1,000 species of corals and between 1 million and 9 million species of fish and other organisms.

While researchers are now developing detailed simulations of many marine ecosystems, models that include anything other than the lowest levels of the ocean’s food chain won’t be ready for three to five years, said Anne Hollowed, a fisheries ecologist with the National Oceanic and Atmospheric Administration in Seattle, Washington. And when those models eventually arrive, scientists will also need to consider factors such as fishing pressure and how climate change will cause shifts in the habitats suitable for various species.

A far better approach than saving a few keystone species would be to preserve an entire ecosystem’s ability to adapt, says Andrew Rosenberg of Conservation International in Arlington, Virginia. While long-term efforts to mitigate climate change might address carbon dioxide emissions, the root cause of climate change, in the short term people can preserve the ocean’s biodiversity at local levels by reducing overfishing, nutrient runoff and pollution. “Reasonably simple things can be done, and many steps can be taken before the results of detailed [ecosystem] modeling are in,” he said.

“The choices we make in the next decade will be with us for millennia,” said English. “Today’s choices affect tomorrow’s options.”

WASHINGTON, DC – Climate change will dramatically alter marine ecosystems, wreaking havoc on many fisheries and exacting a huge economic toll, researchers reported today at the annual meeting of the American Association for the Advancement of Science.

Despite being overexploited, the world’s fisheries are still profitable: In 2003, they generated more than $24 billion in wages for fishermen, profits for companies and payments to resource owners, says Rashid Sumaila, an economist at the University of British Columbia in Vancouver. Yet those profits – and in some cases the fisheries themselves – are threatened by a variety of ill effects brought about by climate change, he notes. Warming seas and rising atmospheric concentrations of carbon dioxide will cause oceans to acidify, the habitable ranges of many species to shift substantially, and the size of adult fish to decline, to name just a few.

Climate models suggest that by the year 2100, sea-surface temperatures will be between 1.9° and 2.8° Celsius higher than they were in the 1890s, says Jorge Sarmiento, a marine biogeochemist at Princeton University in Princeton, New Jersey. As a result, changes in the patterns and rates of upwelling that bring nutrients to the surface, among other factors, will cause primary productivity – the amount of biomass generated by the ocean’s food chain – to decline between 2 and 16 percent by the end of the century. While some areas, such as the Southern Ocean surrounding Antarctica, will see slight increases in biological productivity, many areas, including much of the tropical and temperate seas, will see substantial decreases, the models suggest. For example, he notes, in 2090 the combined productivity of North Atlantic fisheries will be about half what it was in 1860.

As has been noted for large numbers of land-based species of plants and animals, the habitable ranges of many fish species will shift poleward as climate warms. At high latitudes, where warming tends to be greatest, those shifts will be dramatic, says William Cheung, a marine ecologist at the University of East Anglia in Norwich, England. For example, in the North Sea and the Arctic Ocean north of Scandinavia, ranges will shift northward, on average, more than 40 kilometers per decade between now and 2050, he reports. Such shifts could have a dramatic influence on fishing grounds, causing local extinctions of species along the southern fringes of some fisheries, for example.

Cheung also noted that warmer seas will cause the size of adult cod to decline about 10 percent by 2050. If the potential effects of ocean acidification and decreases in dissolved oxygen content are included, body size could drop as much as 40 percent. Altogether, effects of climate change could trim yields from fisheries in tropical latitudes and many areas of the Southern Ocean in half by 2055.

Although yields from Arctic fisheries will increase in coming years, those in other areas will drop off woefully. Due to changes in ocean chemistry and declines in fish body size, more than 70 percent of fishing nations will see declines in the tonnage of fish netted. As a result, about 60 percent of those countries will see declines in the profitability of their fisheries, says Vicky Lam, a fisheries economist at the University of British Columbia in Vancouver. In some cases, countries will see declines in profitability of as much as 40 percent.

Policy: Global cooperation game

International cooperation on technological development might be a crucial part of the much-needed breakthrough in tackling climate change.

Original paper: Golombek, R. & Hoel, M. International cooperation on climate-friendly technologies. Environ. Res. Econ. doi:10.1007/s10640-010-9442-x (2010).

Ecology: Downhill drive

Climate change can cause vegetation to move up- or down-slope depending on water availability.

Original paper: Crimmins, S. M., Dobrowski, S. Z., Greenburg, J. A., Abatzoglou, J. T. & Mynsberge, A. R. Changes in climatic water balance drive downhill shifts in plant species’ optimum elevations. Science doi:10.1126/science.1199040 (2011).

Atmospheric science: Sun’s energy output

Accurately estimating the Sun’s energy output is vital for attributing climate change correctly. Improved measurements have now been obtained from a space-based instrument.

Original paper: Kopp, G. & Lean, J. L. A new, lower value of total solar irradiance: Evidence and climate significance. Geophys. Res. Lett. 38, L01706 (2011).

In the coming decades, the world’s coral reefs will suffer a variety of indignities, from global threats such as warming seas and ocean acidification to local and regional problems such as overfishing and nutrient-rich runoff. If carbon dioxide emissions remain high until the end of the century, reef coverage may drop by 50 percent or more even if local threats are addressed aggressively, a new study suggests. Despite this bad news, another study provides a glimmer of hope for long-suffering reefs: In some cases, the coral ecosystems that rise to replace ones blighted by climate change may actually be more resistant to disease.

In a paper to be published in Global Change Biology, Kenneth Anthony, a marine ecologist at the University of Queensland in Brisbane, Australia and his colleagues modeled how reefs of branching corals of the genus Acropora would fare under various levels of climate change and fishing. In the team’s model simulations, ocean acidification and warming impair the growth and boost the mortality of corals, elevated nutrients in runoff fuels the growth of coral-stifling Lobophora seaweed, and more intense fishing drives down the numbers of herbivores that help to keep the seaweed under control.

Unsurprisingly, under the most extreme climate scenario — the IPCC’s A1FI scenario, in which atmospheric concentrations of carbon dioxide rise to exceed 900 parts per billion by 2100, compared to around 390 ppb today — reefs suffer the most. By the end of the century, even if fish graze about 60 percent of the seaweed each year and the nutrient content of runoff remains relatively low, the area covered by Acropora corals could drop to half today’s amount. If increased fishing drives the grazing rate below 40 percent, however, coral coverage plummets to near zero and the area occupied by seaweed rises to 40 percent or higher. A rise in nutrient-rich runoff would boost the growth of seaweed even higher, Anthony says.

The new analysis doesn’t include effects of non-nutrient pollution and coral disease, and it doesn’t account for any synergetic effects among global and local threats that would amplify known detriments from individual threats, says Anthony. “In that sense, our figures may quite possibly paint an overly optimistic picture.” Nevertheless, he adds, “coral reefs can survive climate change if they’re treated well at the local scale, but many people would consider a nearly 50 percent drop in coral coverage a significant deterioration.”

If there’s any positive aspect to be seen in the ecological havoc wrought by climate change, it’s this: The coral ecosystems that replace old-growth reefs could, in some instances, be more resistant to disease outbreaks, according to a study published online on January 17 in Proceedings of the National Academy of Sciences. In that paper, Laith Yakob and Peter Mumby of the University of Queensland in Brisbane, Australia propose a model in which climate change affects disease resistance in corals in two contradictory ways.

First, says Mumby, warming waters will render individual corals more susceptible to disease (by stressing the corals and possibly boosting the abundance or virulence of pathogens). Second, by increasing the frequency of coral bleaching events and coral mortality, warming will lead to faster turn over of coral populations within a reef, leading to an overall decline in the risk of disease. In such a scenario, disease resistance doesn’t arise due to evolution-driven immunity; instead it arises when the old reef, composed primarily of one or two dominant species of corals, is replaced by a mixture of new, fast-growing species in which a critical mass of disease-susceptible corals forms less often. The net outcome of these conflicting trends will vary from one situation and one reef to another, the researchers report.

In their paper, Yakob and Mumby used a model to better explain how reefs near Key West, Florida responded after an outbreak of a disease dubbed White Plague type II. Previous studies couldn’t duplicate the pattern of death and recovery seen there, says Mumby. he team’s study “is a refreshing look at the future of coral reefs and their potential to evolve and adapt to environmental change,” says Kim Ritchie, manager of the Marine Microbiology Program at the Mote Marine Laboratory in Summerland Key, Florida.

The analysis also points out that “we just can’t assume that coral reefs will continue to function as they have in the past,” says Alastair Harborne, a reef ecologist at the University of Exeter in the United Kingdom (now on short-term assignment to the University of Queensland, where he works with both Anthony and Mumby). Still, he notes, “the overall picture is not a good one for reefs in general.”

Image: © ISTOCKPHOTO / LEE CHIN YONG

Media: Reporters get it right

Accurate reporting of sea-level rise is a welcome success story at the sometimes fraught interface of climate science and mass media.

Original paper: Rick, U. K. et al. Effective media reporting of sea level rise projections: 1989–2009. Environ. Res. Lett. (in the press).

Ecology: Pikas’ pain

Rising temperatures may be to blame for the disappearance of a mountain-dwelling mammal.

Original paper: Beever, E. A. et al. Contemporary climate change alters the pace and drivers of extinction. Glob. Change Biol. doi:10.1111/j.1365-2486.2010.02389.x (2010).

Energy: A carbon-free future?

Large-scale deployment of wind, water and solar power could decarbonize our energy system by 2050, academics say.

Original papers: Jacobson, M. Z. & Delucchi, M. A. Providing all global energy with wind, water, and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure, and materials. Energy Policy. doi:10.1016/j.enpol.2010.11.040 (2010).

Delucchi, M. A. & Jacobson, M. Z. Providing all global energy with wind, water, and solar power, Part II: Reliability, system and transmission costs, and policies. Energy Policy. doi:10.1016/j.enpol.2010.11.045 (2010).

Read these highlights in full on our homepage.

Built environment: Cities to suffer

The world’s most populated port cities will be three times more likely to suffer from an extreme weather event by 2070, a study suggests.

Original paper: Hanson, S. et al. A global ranking of port cities with high exposure to climate extremes. Climatic Change doi:10.1007/s10584-010-9977-4 (2010

Agriculture: Insights on adaptation

A historical look at grain growth in North America shows that past generations of farmers have coped with significant climate changes.

Original paper: Olmstead, A. L. & Rhode, P. W. Adapting North American wheat production to climatic challenges, 1839-2009. Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1008279108 (2010).

Ecology: Climate relief

Plant leaf growth is boosted by carbon dioxide, but can, in turn, slow global warming, shows research.

Original paper: Bounoua, L. et al. Quantifying the negative feedback of vegetation to greenhouse warming: A modeling approach. Geophys. Res. Lett. 37, L23701 (2010

Read these highlights in full on our homepage.

A well-designed scientific experiment shouldn’t affect the behavior of its subjects or cause them harm. Yet that’s exactly the result of using flipper bands to identify individual penguins during field studies, one team of researchers now contends.

In recent years, scientists have increasingly looked to penguins as a source of data about climate change. The new evidence comes from a long-term field experiment conducted on a remote island in the southern Indian Ocean that was designed to do just that. From 1998 through 2008, a team led by Yvon Le Maho, an ecophysiologist at the University of Strasbourg in France, monitored 100 king penguins on Possession Island, a 150-square-kilometer landmass in the windswept Crozet archipelago. Le Maho and his colleagues implanted the penguins with transponder tags — similar to those implanted in pet dogs and cats — that allowed researchers to track the comings and goings of the majestic birds in the breeding colony there. But 50 of the birds in this experiment were also tagged with a metallic band around one flipper, the standard technique scientists have used to monitor penguins for decades.

Over the course of the team’s 10-year study, unbanded penguins fared much better than their banded brethren. Birds tagged with flipper bands had a lower long-term survival rate — dropping by 16 percentage points, or about 44 percent overall (note this was incorrectly reported in the original paper, a point picked up by AP journalist Seth Borenstein). Banded birds also had about 40 percent fewer chicks than unbanded birds did, the researchers report in the January 13 issue of Nature.

There could be any number of reasons for the dramatic disparity, says Rory Wilson, an aquatic biologist at Swansea University in England who was not involved in the research. For one thing, the glint from a metallic flipper band may actually attract the attention of predators. Prior research shows that penguins tagged with a flipper band use 24 percent more power when swimming than unbanded birds do, a measure of the drag caused in part by turbulence in water flow over the penguins’ flippers. Because of the increased drag, the birds deplete their oxygen supply more quickly when diving, chasing prey or eluding predators.

Some previous field studies have found no detrimental effects of flipper bands on penguins, but data gathered by Le Maho and his team help explain why. In years when food is overly plentiful, all birds can get by, and in lean years all birds suffer. Only in normal years do the injurious effects of the flipper bands become statistically apparent, the team found.

Results of the new study call into question the use of flipper bands in penguin studies and cast doubt on many data gathered during such field experiments, says Le Maho.

Check out Nature’s video of the penguins that took part in the study here.

Next spring will bring a much-awaited and exciting new addition to the family of Nature journals. The newest of Nature’s research journals, Nature Climate Change will dedicate its coverage to one of the greatest challenges for science and society.

By and large, society now accepts that climate change is happening. But the science of global climate change is far from settled — large uncertainties remain regarding the rate of change and the scale and distribution of impacts. Less certain still is how we will respond as individuals and collectively to the problem. Although ample cause for concern, such uncertainty also brings the opportunity for new discovery.

Nature Climate Change, which becomes available in print from April 2011, aims to be the world’s leading research journal for documenting new scientific discoveries about how we will experience and respond to the challenges of a changing climate. With our online submission system now open, we are calling for original research articles from the natural and social science communities, in subject areas from atmospheric physics to psychology and policy. Central to the journal’s mission, and to addressing climate change, is reaching beyond traditional academic boundaries, and bringing together diverse expertise and perspectives. As such, Nature Climate Change especially encourages the submission of interdisciplinary climate research. Further details can be found in our Guide to Authors.

Committed to a rigorous peer-review process, we will publish original research in Article and Letter format, selecting papers for their novelty and broad interest to those working in climate change. As with our sister journals, we will rely on the expertise and good will of the research community to assist us in evaluating the science submitted to us, such that only the highest quality research makes it through to publication. By ensuring that our authors make their data available to readers on request, the editorial team at Nature Climate Change will commit itself wholeheartedly to promoting transparency in climate research.

In addition to calling for papers, over the next six months we will be keeping readers informed of the latest developments in climate research published elsewhere. Reflecting the breadth of topics we will publish in print from April 2011, our research highlights will be available online weekly from 26 October 2010. Readers can receive an electronic update simply by signing up online. Those who enjoyed Nature Reports Climate Change, an online forerunner of the journal, can continue to access archived content from the website freely.

Some readers may question our decision to move our climate-related content into print in launching a journal. Although we strive to make our content just as accessible and enjoyable in html and pdf format, the simple fact is that print remains the medium of choice for most of our readers. Until readers’ preferences change and we can move fully into the digital domain, we are working to ensure that we produce the print version of our journal as sustainably as possible.

Nature Climate Change will offer something truly different from any existing journal: the very best of new climate research spanning the breadth of natural and social science, reviews of key questions in climate science, opinion and analysis, and unique reporting from renowned journalists. Authors who have traditionally submitted their papers to Nature and Nature Geosciencenow have another outlet to consider, one that extends beyond academia and is geared towards the wider climate community.

With this new journal, we aim to take the discussion on climate change both to a new level and to a broader range of readers. In achieving this, we ask for your input, as authors, reviewers and commentators, whether long-standing or new contributors to Nature journals. Between now and next spring, we look forward to hearing from you, to receiving your papers, your ideas for reviews and your honest feedback.

The blog will be back up and running regularly once the journal launches, and in the meantime, our website will go live in October. Once we are live, we will open our doors for submissions from the research community, and will be accepting original research papers, both in article and letter format, on climate change across the natural and social sciences. Until then, readers can find out more about the journal here.

From October right up until the first print issue of Nature Climate Change in April 2011, we will be highlighting the latest developments in climate research on a weekly basis online. We will also be commenting on climate change, its impacts and implications on Twitter, on Facebook, and here.