NOT JUST POSSIBLE

Climate change makes West Nile virus outbreaks 'plausible' in UK

Risk of mosquito-borne pathogen spreading to the country will increase as temperatures rise, say scientists

UK CENTRE FOR ECOLOGY & HYDROLOGY

Research News

  

IMAGE: THE COMMON HOUSE MOSQUITO (CULEX PIPIENS) CAN TRANSMIT THE WEST NILE VIRUS view more 

CREDIT: FABRIZIO MONTARSI, CC BY 3.0

Climate change will make outbreaks of West Nile virus more likely in the UK within the next 20-30 years, scientists say.

West Nile virus is spread by mosquitoes and has no vaccine. Most people have no symptoms, but it can cause serious neurological disease.

Scientists from the UK Centre for Ecology & Hydrology (UKCEH), Biomathematics and Statistics Scotland (BioSS) and the University of Glasgow developed a new model to determine the risk of a West Nile virus outbreak in the UK.

They found the risk is low for the next two to three decades, but will increase as temperatures rise.

Dr Steven White, a theoretical ecologist at UKCEH, said: "Knowing if or when a new disease will affect us is vitally important.

"West Nile virus is currently absent in the UK, but we do harbour the Culex pipiens mosquito, which can transmit the disease and potentially lead to spill-over into humans.

"West Nile virus is now endemic in Italy and there have been outbreaks in Germany, so it is moving into more temperate climates.

"Our model shows that the risk will steadily increase and that future outbreaks are plausible in the UK."

The team's mathematical model looked at the effects of temperature on the biological processes affecting the Culex pipiens mosquito population in the UK. They were able to capture how these seasonal changes might interact with faster replication of the virus under higher temperatures to drive outbreaks.

Dr David Ewing from BioSS, formerly a UKCEH PhD student when most of the research was carried out, said: "Our model shows the predicted risk of an outbreak increases substantially if the biting season goes on longer, or if new viral strains are introduced that replicate at a higher rate than the ones already studied.

"Most other approaches are simplified, but we've built in complex biological relationships. This model could be adapted to look at other viruses and diseases, or other mosquito or insect species."

Dr Ewing says the study shouldn't be cause for alarm, but to help the UK prepare. "While there's relatively little immediate danger, we can take steps to prepare for future outbreaks.

This could be as simple as ensuring doctors are aware of the symptoms, testing and who's most at risk of becoming seriously ill."

The research was reported in the Journal of the Royal Society Interface - DOI: doi/10.1098/rsif.2021.0049

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Notes to editors

About West Nile virus

(From the World Health Organisation)

* West Nile virus can cause a fatal neurological disease in humans.

* However, approximately 80% of people who are infected will not show any symptoms.

* West Nile virus is mainly transmitted to people through the bites of infected mosquitoes.

* The virus can cause severe disease and death in horses.

* Vaccines are available for use in horses but not yet available for people.

* Birds are the natural hosts of West Nile virus.

* It is commonly found in Africa, Europe, the Middle East, North America and West Asia. WNV is maintained in nature in a cycle involving transmission between birds and mosquitoes. Humans, horses and other mammals can be infected.

About the Culex pipiens mosquito

* Culex pipiens is the most common mosquito species in the UK.

* In more northerly latitudes, such as the UK, they mainly feed on birds, not humans.

* Only females feed on blood (male Culex pipiens consume carbohydrate food sources) and are most active around sunset.

* Mosquito population levels tend to increase over the summer months, particularly in hot and wet summers which facilitate faster development and an increase in breeding sites.

* Over winter in the UK, the mosquito species stops taking blood meals and instead survives on sugary food sources as they enter diapause (akin to hibernation) as adults, inhabiting sheltered locations.

* The species is found in both temperate and tropical climates.

* Alongside West Nile virus, Culex pipiens are carriers of other diseases such as avian malaria.

About the UK Centre for Ecology & Hydrology (UKCEH)

The UK Centre for Ecology & Hydrology is a centre for excellence in environmental science across water, land and air. Our 500 scientists work to understand the environment, how it sustains life and the human impact on it - so that together, people and nature can prosper.

We have a long history of investigating, monitoring and modelling environmental change, and our science makes a positive difference in the world. The issues our science addresses include: air pollution, biodiversity, biosecurity, chemical risks, extreme weather events, droughts, floods, greenhouse gas emissions, land use, soil health, sustainable agriculture, sustainable ecosystems, sustainable macronutrient use, and water resources management.

The UK Centre for Ecology & Hydrology is a strategic delivery partner for the Natural Environment Research Council, part of UK Research and Innovation.

http://www.ceh.ac.uk @UK_CEH

About BioSS

BioSS specialises in the development and application of the quantitative methods needed to enhance scientific knowledge and impact. We are recognised internationally for our work at the interface between the mathematically-based sciences and a wide span of applied sciences covering agriculture and the rural economy, the environment, food and health.

 GREEN MILITARISM

Scientists develop transparent electrode that boosts solar cell efficiency

PENN STATE

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IMAGE: SCIENTISTS FOUND USING A CHROMIUM SEED LAYER ALLOWED THEM TO GROW ULTRATHIN GOLD FILM THAT SERVES AS A TRANSPARENT ELECTRODE WITH GOOD CONDUCTIVITY FOR PEROVSKITE SOLAR CELLS. view more 

CREDIT: PENN STATE

UNIVERSITY PARK, Pa. -- Developing new ultrathin metal electrodes has allowed researchers to create semitransparent perovskite solar cells that are highly efficient and can be coupled with traditional silicon cells to greatly boost the performance of both devices, said an international team of scientists. The research represents a step toward developing completely transparent solar cells.

"Transparent solar cells could someday find a place on windows in homes and office buildings, generating electricity from sunlight that would otherwise be wasted," said Kai Wang, assistant research professor of materials science and engineering at Penn State and co-author on the study. "This is a big step -- we finally succeeded in making efficient, semitransparent solar cells."

Traditional solar cells are made from silicon, but scientists believe they are approaching the limits of the technology in the march to create ever more efficient solar cells. Perovskite cells offer a promising alternative and stacking them on top of the traditional cells can create more efficient tandem devices, the scientists said.

"We've shown we can make electrodes from a very thin, almost few atomic layers of gold," said Shashank Priya, associate vice president for research and professor of materials science and engineering at Penn State. "The thin gold layer has high electrical conductivity and at the same time it doesn't interfere with the cell's ability to absorb sunlight."

The perovskite solar cell that the team developed achieved 19.8% efficiency, a record for a semitransparent cell. And when combined with a traditional silicon solar cell, the tandem device achieved 28.3% efficiency, up from 23.3% from the silicon cell alone. The scientists reported their findings in the journal Nano Energy.

"A 5% improvement in efficiency is giant," Priya said. "This basically means you are converting about 50 watts more sunlight for every square meter of solar cell material. Solar farms can consist of thousands of modules, so that adds up to a lot of electricity, and that's a big breakthrough."

In previous research, ultrathin gold film showed promise as a transparent electrode in perovskite solar cells, but issues in creating a uniform layer resulted in poor conductivity, the scientists said.

The team found that chromium used as a seed layer allowed the gold to form on top in a continuous ultrathin layer with good conductive properties.

"Normally, if you grow a thin layer of something like gold, the nanoparticles will couple together and gather like small islands," said Dong Yang, assistant research professor of materials science and engineering at Penn State. "Chromium has a large surface energy that provides a good place for the gold to grow on top of, and it actually allows the gold to form a continuous thin film."

Perovskite solar cells are composed of five layers and other materials tested as transparent electrodes damaged or degraded layers of the cells. The scientists said solar cells made with the gold electrodes are stable and maintain high efficiencies over time in laboratory tests.

"This breakthrough in the design of tandem cell architecture based on a transparent electrode offers an efficient route toward the transition to perovskite and tandem solar cells," said Yang.

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Also contributing to this research from Penn State were Tao Ye and Jungjin Yoon, postdoctoral scholars; and Yuchen Hou, a doctoral student.

Xiaorong Zhang, Shaanxi Normal University, China; Shengzhong Liu, Chinese Academy of Sciences; Congcong Wu, Hubei University, China; and Mohan Sanghadasa, U.S. Army Combat Capabilities Development Command, also contributed to the research.

The Office of Naval Research, the Army Rapid Innovation Fund, and the Air Force Office of Scientific Research provided funding for this research.

CAUSE THEY HAVE ALL THE MONEY

READY FOR SUMMER 2050

Research shows potential new sunscreen is coral-safe and provides more UVB/UVA protection

Scientists find that Methylene Blue could be an effective alternative to sunscreens that cause coral damage

MBLUE LABS

Research News

 

(Bethesda, MD - May 25, 2021) A new study published in Nature Scientific Reports has found that Methylene Blue, a century old medicine, has the potential to be a highly effective, broad-spectrum UV irradiation protector that absorbs UVA and UVB, repairs ROS and UV irradiation induced DNA damages, and is safe for coral reefs. The study suggests that Methylene Blue could become an alternative sunscreen ingredient that supports the environment and protects human skin health.

80% of today's sunscreens use Oxybenzone as a chemical UV blocker, despite multiple studies that have shown it expedites the destruction of coral reefs. Several states and countries have now banned the use of Oxybenzone and its derivatives to stop the devastating effects on the world's marine ecosystem. In addition, consumers focus primarily on the Sun Protection Factor (SPF) to prevent sunburns and potentially dangerous long-term health issues. However, SPF only measures UVB exposure, leaving sunscreen users vulnerable to UVA-triggered oxidative stress and photo-aging.

"Our work suggests that Methylene Blue is an effective UVB blocker with a number of highly desired characteristics as a promising ingredient to be included in sunscreens. It shows a broad spectrum absorption of both UVA and UVB rays, promotes DNA damage repair, combats reactive oxygen species (ROS) induced by UVA, and most importantly, poses no harm to coral reefs." says the study's senior author Dr. Kan Cao, Founder of Mblue Labs, Bluelene Skincare and a Professor at the University of Maryland Department of Cell Biology and Molecular Genetics.

The research team, which included scientists from Mblue Labs and the University of Maryland, looked at the UV protection benefits of Methylene Blue from several angles in primary human keratinocytes and skin fibroblasts from young and old donors and compared those results with Oxybenzone. They concluded that Methylene Blue not only absorbs UVA & UVB as the traditional sunscreen actives do, it also helps repair the DNA damage caused by UV irradiation, thereby leading to better cell survival. They also exposed the same amounts of Methylene Blue or Oxybenzone in Xenia umbellate, a soft coral species, in isolated tanks and monitored coral reefs' growth and responses to these chemicals. They reported drastic coral bleaching and death in Oxybenzone-treated Xenia corals in less than a week, while Methylene Blue does not have any negative effects on coral health even at a relatively high concentration (1 micro molar).

They also compared Methylene Blue with other well-known skincare antioxidants such as Vitamin A (Retinol) and Vitamin C in their ability to reduce cellular oxidative stress. "We are extremely excited to see that skin fibroblasts, derived from both young and old individuals, have improved so much in terms of proliferation and cellular stress in a methylene blue-containing cell culture medium." Dr. Cao shares. "Most surprisingly," according to Dr. Cao," we found that the combination of Methylene Blue and Vitamin C could deliver amazing anti-aging effects, particularly in skin cells from older donors, suggesting a strong synergistic reaction between these two beneficial antioxidants."

"Altogether, our study suggests that Methylene Blue has the potential to be a coral reef-friendly sunscreen active ingredient that can provide broad-spectrum protection against UVA and UVB." The team concludes in the abstract.

The researchers are so confident in their findings that Methylene Blue is an effective UV blocking agent that also delays skin aging and promotes DNA damage repair, that they have filed a patent application and have started developing sunscreen prototypes containing Methylene Blue. In addition, Mblue Lab (Bluelene) recently launched the first multifunctional skincare product that combines Methylene Blue and Vitamin C to deliver the optimal anti-aging effects (Bluelene's Night Plus+).

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This research was supported by a National Science Foundation (NSF) Small Business Technology Transfer Grant (Grant: 1842745) This press release does not necessarily represent the views of the NSF. This study was conducted jointly by researchers at Mblue Labs and the University of Maryland.

The research paper, "Ultraviolet radiation protection potentials of Methylene Blue for human skin and coral reef health " was published in Nature's Scientific Reports on May 28, 2021. www.nature.com/articles/s41598-021-89970-2.

About Mblue Labs + Bluelene:

The research team at the University of Maryland, led by Dr. Kan Cao, has measured the effectiveness of Methylene Blue for increased skin hydration, expanded thickness of the dermis, and improved skin texture when compared to products that have mitochondrial-targeting antioxidants. Methylene Blue outperformed MitoQ, NAC and MTemp in this experiment, as a more effective way to enhance mitochondrial health and delay senescence of the cells. It's with our steadfast research that in 2019 we introduced Bluelene, an anti-aging face and body skincare line infused with Methylene Blue to deliver lasting results. http://www.mbluelabs.com, http://www.bluelene.com

Contact: Jasmin El Kordi (CEO, Mblue Labs) - Email: Jasmin@mbluelabs.com, Phone: 703-628-2956, Rachel Johnson Burns (PR) - Email: rjohnson@rljpr.com, Phone: 410-530-5857.

 

Reef-building corals and the microscopic algae within their cells evolve together

Genetics of coral-algal partnerships may have conservation implications

PENN STATE

Research News

IMAGE: REEF-BUILDING CORALS, SUCH AS ELKHORN CORAL (ACROPORA PALMATA) STAGHORN CORAL (ACROPORA CERVICORNIS), AND THEIR HYBRID, ALL PICTURED HERE, COEVOLVE WITH THE MICROSCOPIC ALGAE THAT LIVE WITHIN THEIR CELLS, ACCORDING TO... view more 

CREDIT: LISA CARNE, FRAGMENTS OF HOPE BELIZE

UNIVERSITY PARK, Pa. -- The microscopic algae that live inside and provide nutrients to their reef-building coral hosts may be evolving in tandem with the corals they inhabit, so each partner is fine-tuned to meet one another's needs. A new study by Penn State biologists reveals that genetic differences within a species of these microalgal symbionts correspond to the coral species they inhabit, a discovery that could have implications for the conservation of these endangered corals.

"Acroporid corals are some of the primary reef-building species in the Caribbean, providing protection to coastlines and habitat for economically important species," said Iliana Baums, professor of biology at Penn State and leader of the research team. "However, these corals are critically endangered due to warming waters, pollution, and other human-induced changes, and their survival is in part tied to the symbionts that live inside them. Understanding the relationships between the coral and their symbionts may help us improve conservation efforts."

Reef-building corals such as Acroporids obtain nutrients from the microalgae symbionts that live inside their cells. The research team compared genetic differences among members of the symbiont species Symbiodinium 'fitti' collected from either elkhorn coral (Acropora palmata), the closely related staghorn coral (Acropora cervicornis), or the hybrid that results when the two species breed, called fused staghorn coral. The researchers collected symbiont samples from each coral species in several locations spanning the Caribbean Sea. Their results appear online in the journal Molecular Ecology.

"The genetic differences we saw within the symbiont were primarily explained by the species of host we collected them from," said Hannah Reich, a graduate student at Penn State at the time of the research and currently a postdoctoral researcher at the University of Rhode Island. "Each coral species is a unique micro-habitat for their symbionts. For example, the limestone skeletons of the two coral species are distinct and reflect sunlight differently. So the symbionts must adapt to the conditions created by each host to best harness solar energy and convert it to food. They then provide this nourishment to their hosts which rely on it for most of their nutrition."

The researchers suspect that each of the coral species has coevolved with a subset of the strains of S. 'fitti'. Over generations, they have formed more specialized relationships. This specialization even occurred in the natural coral hybrid that has a relatively recent origin.

"Some of the genetic differences we observed among S. 'fitti' strains were in genes predicted to cause downstream effects on the symbiont's metabolism and physiology," said Sheila Kitchen, a postdoctoral researcher at Penn State at the time of the research and currently a postdoctoral researcher at the California Institute of Technology. "These changes may enable the symbiont to adapt to the unique metabolic and nutritional demands imposed by each host's microenvironment."

The fidelity between the coral species and their symbionts could be reinforced if symbionts are selective about which coral species they colonize, and/or if the coral hosts are selective about which symbiont strain is allowed to remain in their cells, though the mechanisms of partner selectivity remain unclear. The researchers note that environmental factors may also play a role in genetic differences among the symbiont strains, for example by influencing the symbionts before they have colonized a coral or indirectly by influencing the microenvironment inside the coral host.

"Some conservation efforts are exploring ways to help corals colonize new habitats and adapt to changing environments," said Reich. "However, if symbionts and their corals hosts have coevolved and formed preferential relationships with each other, it may not be enough to focus conservation efforts just on the coral host. Continuing to study these relationships will provide important information about how we can best approach conservation efforts."

CAPTION

Genetic differences between strains of the microscopic algae that live within reef-building coral correspond to the coral species they inhabit. Some of the observed differences occur in genes related to the algae's metabolism and physiology, which could enable the algae to adapt to the unique demands imposed by each host's microenvironment.

CREDIT

Lisa Carne, Fragments of Hope Belize

In addition to Baums, Reich, and Kitchen, the research team at Penn State includes Kathryn Stankiewicz, graduate student in biology, and Meghann Devlin-Durante, senior research technologist at the time of the research. The team also includes Nicole Fogarty at the University of North Carolina, Wilmington. This work was supported by the National Science Foundation.

 

Climate change-resistant corals could provide lifeline to battered reefs

Corals that withstood a severe bleaching event and were transplanted to a different reef maintained their resilient qualities, according to a new study led by Katie Barott of the University of Pennsylvania

UNIVERSITY OF PENNSYLVANIA

Research News

IMAGE: UNIVERSITY OF PENNSYLVANIA BIOLOGIST KATIE BAROTT AND COLLEAGUES FOUND THAT CORALS MAINTAIN THEIR ABILITY TO RESIST BLEACHING EVEN WHEN TRANSPLANTED TO A NEW REEF. view more 

CREDIT: S. MATSUDA

In 2015, nearly half of Hawai?i's coral reefs were affected by the most severe bleaching event to date. Coral bleaching occurs when warmer-than-normal ocean temperatures prompt corals to expel the algae that normally live inside them and on which the corals rely for food.

Bleaching events are dismaying, but corals can sometimes recover, while others resist bleaching altogether. In a new study in the journal Proceedings of the National Academy of Sciences, researchers led by Katie Barott of the University of Pennsylvania found that these battle-tested, resilient corals could thrive, even when transplanted to a different environment and subjected to additional heat stress. The findings offer hope that hardy corals could serve as a founding population to restore reefs in the future.

"The big thing that we were really interested in here was trying to experimentally test whether you an take a coral that seems to be resistant to climate chage and use that as the seed stock to propagate and put out on a different reef that might be degraded," Barott says. "The cool thing was we didn't see any differences in their bleaching response after this transplant."

Mass coral bleaching events are getting increasingly frequent, raising worries that corals will become victims of climate change in the near future. Yet Barott and colleagues have been studying the corals that resist bleaching, with an eye toward buying corals more time to hang on in the face of warming and acidifying ocean waters.

One strategy they and others have envisioned, and which has been trialed in areas such as the Great Barrier Reef, is coral transplantation. Researchers could replenish reefs damaged by climate change--or other anthropogenic insults, such as sedimentation or a ship grounding--with corals that had proved sturdy and able to survive in the face of tough conditions.

For this to work, however, would require the coral "survivors" to continue to display their resilient characteristics after being moved to a new environment.

"If you take a coral that is resistant to bleaching in its native habitat, it could be that the stress of moving to a new place might make them lose that ability," Barott says.

Just as a fern that grew well in the shade might wilt if moved to a sunny plot, the conditions of a new environment, including water flow rate, food access, light, and nutrient availability, could could affect the resilience of transplanted corals.

Barott and colleagues went after this question with an experiment in two reefs in Hawai?i's Ka?ne?ohe Bay on the island of O?ahu: one closer to shore with more stagnant waters and another farther from shore with higher flow. In each area, the researchers identified coral colonies that had resisted bleaching during the 2015 bleaching event and collected samples from them the following year. Corals are clonal organisms, and so a chunk taken from a colony can regrow and will have the same genetics as the "mother" coral. For each colony, they kept some samples on their native reef and transplanted others to the second reef.

After the corals had spent six months at their new location, the biologists also put coral samples from each site in tanks in the lab and simulated another bleaching event by raising the water temperature over a period of several days.

Carefully tracking the corals' health and the conditions of the surrounding environment, the team measured photosynthesis rates, metabolism, and calcification rates, as well as the health of the symbiotic algae. They found that bleaching-resistant corals stayed that way, even in a new environment.

"What was really novel is that we had this highly replicated experiment," Barott says, "and we saw no change in the coral's bleaching response."

The researchers also looked at how well the corals reproduced the summer that followed their collection. A coral's native site conditions had an impact on their future reproductive fitness, they discovered.

"The corals from the 'happy' site--the outer lagoon that had higher growth rates prior to the bleaching event--generally seemed a little happier and their fitness was higher," Barott says. "That tells us that, if you're going to have a coral nursery, you should pick a site with good conditions because there seems to be some carryover benefit of spending time at a nicer site even after the corals are outplanted to a less 'happy' site."

The "happy" site, the lagoon farther from shore, had higher flow rates than the other reef, which is closer to shore, less salty, and more stagnant. "Higher flow rates are really important for helping corals get rid of waste and get food," Barott says.

Barott, who started the work as a postdoc at the Hawai?i Institute of Marine Biology, is continuing to pursue research on coral resiliency in her lab at Penn, including an investigation of the effects of heat stress and bleaching on reproductive success and the function of coral sperm.

While the results of the transplantation study are promising, she says that it would only be a temporary solution to the threat of climate change.

"I think techniques like this can buy us a little bit of time, but there isn't a substitute for capping carbon emissions," she says. "We need global action on climate change because even bleaching-resistant corals aren't going to survive forever if ocean warming keeps increasing as fast as it is today."

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Katie L. Barott is an assistant professor in the Department of Biology in the University of Pennsylvania School of Arts & Sciences.

Barott's coauthors on the work were Penn's Teegan Innis and the University of Hawai?i's Ariana S. Huffmyer, Jennifer M. Davidson, Elizabeth Lenz, Shayle B. Matsuda, Joshua R. Hancock, Crawford Drury, Hollie M. Putnam, and Ruth D. Gates.

The study was supported by the Paul G. Allen Family Foundation, the University of Pennsylvania, and the National Science Foundation (grants 1923743 and 1323822).

Lessening the cost of strategies to reach the Paris Agreement

Balancing CO2 and methane mitigation actions progressively along the way

NATIONAL INSTITUTE FOR ENVIRONMENTAL STUDIES

Research News

 

IMAGE: TEMPERATURE STABILIZATION AND OVERSHOOT PATHWAYS AND BEST AVAILABLE CONVERSION FACTORS FOR METHANE UNDER EACH ILLUSTRATIVE PATHWAY. view more 

CREDIT: NIES

Five researchers shed new light on a key argument to reduce greenhouse gases (GHG): they provided the first economic analysis of conversion factors of other GHG like methane into their CO2 equivalent in overshoot scenarios. Although the United Nations Framework Convention on Climate Change (UNFCCC) considers settling for one value of reference (known as "Common Metric") to make this conversion among the Paris Agreement, the models presented here show the economic advantage of flexibility between various factors of conversion. "A key notion in the UNFCCC is to reduce GHG emissions in the least costly way so as to ensure global benefits" highlights Katsumasa Tanaka, primary author of the Science Advances study.

The research provides series of dynamic variations of conversion factors depending on possible trajectories of global warming to lessen the economic cost while maintaining some stability to anticipate the implementation of policies. They took into consideration different scenarios, one in which we reach the Paris Agreement's objectives of stabilization at 2°C and 1.5°C and others in which we would overshoot these objectives and need to strengthen efforts later on. These overshoot scenarios are a violation of the Paris Agreement, but the authors argued that such possibilities cannot be ruled out, in view of the near-term climate policies currently. They further noted that the feasibility of these scenarios still depends on very deep mitigation needed later in this century. They applied conversion factors in the numerical model and simulated the additional mitigation costs in all these scenarios to target the most favourable values.

The choice of a common conversion factor

A conversion system into CO2 equivalent is used to determine the participation of different GHG on a given time to prioritize actions. A well-known example is the global warming potential (GWP). To enable comparison among the parties of the Paris Agreement, the 100-year global warming potential (GWP100) was chosen as a reference. Greenhouse gases having very different lifespan and radiative impact, this conversion system is dependent on the choice of a time horizon.

"With GWP100 we look at the cumulative greenhouse effect on a 100-year period, which for methane gives a conversion factor of 28. This means 1 kilogram of methane is 28 times more potent than a kilogram of CO2" explains Johannes Morfeldt, a collaborator of this study joined from Sweden. Yet, since methane has a shorter lifespan and a higher radiative impact than CO2, the cumulative effect on 20 years (GWP20) is much more significant: 84 times more than 1 kilogram of CO2.

Changing the time horizon changes the conversion factor, and therefore influences which gas gets high on the agenda. If a kilogram of methane is 84 times more important than one of CO2, it will be more efficient to lower the global emissions by reducing methane. A debate is in motion since the nineties regarding which conversion factor should be used, and this team of researchers meant to bring additional information on their economic cost in light of possible pathways of global warming.

"We realized with our model that GWP100 is good for the coming decades, but is far from ideal in the long run" says Philippe Ciais, one of the co-authors of the study. "We don't see much variation in an optimal scenario of stabilization at 2°C. But in the event of an overshoot scenario we observe a high discrepancy among ideal conversion factors for today and when we reach 2°C of global warming. If we do not have a dynamic approach to change these values along the way, then society will bear an additional cost to mitigate climate change" adds Olivier Boucher, another co-author.

An optimal agenda

The researchers then modelled these additional costs to estimate which conversion factor would be ideal at a given time for different temperature trajectories. They showed that setting in stone GWP100 would bring about additional mitigation costs that could be avoided by switching to a dynamic factor. In a scenario of stabilization at 2°C these additional costs round up near 2%, but in high overshoot scenarios it goes up to 5%. "This shows that the ideal factors of conversion depend on a time horizon but are also primarily determined by the pathway, and strongly influenced by a temperature overshoot" underlines Daniel Johansson, a Swedish co-author.

This study shows that adapting to possible trajectories by switching from GWP100 to shorter time-horizons in the future could spare additional mitigation costs compared to the sole use of GWP100. The researchers also understand that these values cannot continuously change to enable policies to be anticipated and implemented. Thus, they put forward series of simple combinations of cost-effective conversion factors depending on the possible pathways. The authors suggest that "the UNFCCC and Parties to the Paris Agreement consider adapting the choice of conversion factors to the future pathway as it unfolds, to implement the cheapest options to reduce greenhouse gases emissions."

As we do not know yet the long-term pathway, the matter of the cost-effectiveness could be included in the technical assessment supporting the global stocktake within the UNFCCC. This key element of the Paris Agreement evaluates every five years the countries' collective progress toward long-term goals and aims at increasing the level of ambition of national policies. An inclusion of cost-effectiveness of factors of conversion on this recurring stocktaking process could allow the necessary assessment in time to inform following sessions as the long-term pathway unfolds.

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Declining biodiversity in wild Amazon fisheries threatens human diet

Similar trends are seen around the world

EARTH INSTITUTE AT COLUMBIA UNIVERSITY

Research News

 

IMAGE: LANDING A CATCH ALONG THE UCAYALI RIVER IN THE LORETO DEPARTMENT OF THE PERUVIAN AMAZON. THE BOY IS HOLDING A BOQUICHICO, A COMMONLY CONSUMED SPECIES. (ALL PHOTOS: SEBASTIAN HEILPERN) view more 

CREDIT: SEBASTIAN HEILPERN

A new study of dozens of wild fish species commonly consumed in the Peruvian Amazon says that people there could suffer major nutritional shortages if ongoing losses in fish biodiversity continue. Furthermore, the increasing use of aquaculture and other substitutes may not compensate. The research has implications far beyond the Amazon, since the diversity and abundance of wild-harvested foods is declining in rivers and lakes globally, as well as on land. Some 2 billion people globally depend on non-cultivated foods; inland fisheries alone employ some 60 million people, and provide the primary source of protein for some 200 million. The study appears this week in the journal Science Advances.

The authors studied the vast, rural Loreto department of the Peruvian Amazon, where most of the 800,000 inhabitants eat fish at least once a day, or an average of about 52 kilograms (115 pounds) per year. This is their primary source not only of protein, but fatty acids and essential trace minerals including iron, zinc and calcium. Unfortunately, it is not enough; a quarter of all children are malnourished or stunted, and more than a fifth of women of child-bearing age are iron deficient.

Threats to Amazon fisheries, long a mainstay for both indigenous people and modern development, are legion: new hydropower dams that pen in big migratory fish (some travel thousands of miles from Andes headwaters to the Atlantic estuary and back); soil erosion into rivers from deforestation; toxic runoff from gold mines; and over-exploitation by fishermen themselves, who are struggling to feed fast-growing populations. In Loreto, catch tonnages are stagnating; some large migratory species are already on the decline, and others may be on the way. It is the same elsewhere; globally, a third of freshwater fish species are threatened with extinction, and 80 are already known to be extinct, according to the World Wildlife Fund.

Different species of animals and plants contain different ratios of nutrients, so biodiversity is key to adequate human nutrition, say the researchers. "If fish decline, the quality of the diet will decline," said the study's senior coauthor, Shahid Naeem, director of Columbia University's Earth Institute Center for Environmental Sustainability. "Things are definitely declining now, and they could be on the path to crashing eventually."

To study the region's fish, the study's lead author, then-Columbia PhD. student Sebastian Heilpern, made numerous shopping trips to the bustling Belén retail market in the provincial capital of Iquitos. He also visited the city's Amazon River docks, where wholesale commerce begins at 3:30 in the morning. He and another student bought multiple specimens of as many different species as they could find, and ended up with 56 of the region's 60-some main food species. These included modest-size scale fish known locally as ractacara and yulilla; saucer-shaped palometa (related to piranha); and giant catfish extending six feet or more. (The researchers settled for chunks of the biggest ones.)

The fish were flown on ice to a government lab in Lima, where each species was analyzed for protein, fatty acids and trace minerals. The researchers then plotted the nutritional value of each species against its probability of surviving various kinds of ongoing environmental degradation. From this, they drew up multiple scenarios of how people's future diet would be affected as various species dropped out of the mix.

Overall, the biomass of fish caught has remained stable in recent years. However, large migratory species, the most vulnerable to human activities, comprise a shrinking portion, and as they disappear, they are being replaced by smaller local species. Most fish contain about the same amount of protein, so this has not affected the protein supply. And, the researchers found, many smaller fish in fact contain higher levels of omega-3 fatty acids, so their takeover may actually increase those supplies. On the other hand, as species compositions lean more to smaller fish, supplies of iron, zinc are already going down, and will continue to decline, they say.

"Like any other complex system, you see a tradeoff," said Heilpern. "Some things are going up while other things are going down. But that only lasts up to a point." Exactly which species will fill the gaps left when others decline is difficult to predict--but the researchers project that the overall nutritional value of the catch will nosedive around the point where 40 of the 60 food species become scarce or extinct. "You have a tipping point, where the species that remain can be really lousy," said Heilpern.

One potential solution: in many places around the world where wild foods including fish and bush meat (such as monkeys and lizards) are declining, people are turning increasingly to farm-raised chicken and aquaculture--a trend encouraged by the World Bank and other powerful organizations. This is increasingly the case in Loreto. But in a separate study published in March, Heilpern, Naeem and their colleagues show that this, too, is undermining human nutrition.

The researchers observed that chicken production in the region grew by about three quarters from 2010 to 2016, and aquaculture nearly doubled. But in analyzing the farmed animals' nutritional values, they found that they typically offer poorer nutrition than a diverse mix of wild fish. In particular, the move to chicken and aquaculture will probably exacerbate the region's already serious iron deficiencies, and limit supplies of essential fatty acids, they say. "Because no single species can offer all key nutrients, a diversity of species is needed to sustain nutritionally adequate diets," they write.

Besides this, chicken farming and aquaculture exert far more pressure on the environment than fishing. In addition to encouraging clearing of forests to produce feed for the animals, animal farming produces more more greenhouse gases, and introduces fertilizers and other pollutants into nearby waters, says Heilpern.

"Inland fish are fundamental for nutrition in many low-income and food-deficit countries, and of course landlocked countries," said John Valbo Jørgensen, a Rome-based expert on inland fisheries with the UN Food and Agriculture Organization. "Many significant inland fisheries, including those of Peru, take place in remote areas with poor infrastructure and limited inputs. It will not be feasible to replace those fisheries with farmed animals including fish."

Heilpern is now working with the Wildlife Conservation Society to produce an illustrated guide to the region's fish, including their nutritional values, in hopes of promoting a better understanding of their value among both fishermen and consumers.

CAPTION

People in the Loreto region commonly eat 60-some fish species. Left to right: a diminutive palometa, a relative of the piranha; a doncella, a type of catfish that migrates thousands of miles; three boquichicos; a larger palometa; two sardinas; and a fasaco. The ruler shows sizes in centimeters.

CREDIT

Sebastian Heilpern

The other authors of the new study are Ruth deFries and Maria Uriarte of the Earth Institute; and Kathryn Fiorella, Alexander Flecker and Suresh Sethi of Cornell University.

The Earth Institute, Columbia University mobilizes the sciences, education and public policy to achieve a sustainable earth. http://www.earth.columbia.edu

CAPTION

At the Belén Market in Iquitos, a fishmonger takes apart a dorado catfish. A long-distant migrant, the dorado is highly vulnerable to dams and overfishing.

CREDIT

Sebastian Heilpern

 

A fiery past sheds new light on the future of global climate change

Ice core samples reveal significant smoke aerosols in the pre-industrial Southern Hemisphere

HARVARD JOHN A. PAULSON SCHOOL OF ENGINEERING AND APPLIED SCIENCES

Research News

 

Centuries-old smoke particles preserved in the ice reveal a fiery past in the Southern Hemisphere and shed new light on the future impacts of global climate change, according to new research published in Science Advances.

"Up till now, the magnitude of past fire activity, and thus the amount of smoke in the preindustrial atmosphere, has not been well characterized," said Pengfei Liu, a former graduate student and postdoctoral fellow at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and first author of the paper. "These results have importance for understanding the evolution of climate change from the 1750s until today, and for predicting future climate."

One of the biggest uncertainties when it comes to predicting the future impacts of climate change is how fast surface temperatures will rise in response to increases in greenhouse gases. Predicting these temperatures is complicated since it involves the calculation of competing warming and cooling effects in the atmosphere. Greenhouse gases trap heat and warm the planet's surface while aerosol particles in the atmosphere from volcanoes, fires and other combustion cool the planet by blocking sunlight or seeding cloud cover. Understanding how sensitive surface temperature is to each of these effects and how they interact is critical to predicting the future impact of climate change.

Many of today's climate models rely on past levels of greenhouse gasses and aerosols to validate their predictions for the future. But there's a problem: While pre-industrial levels of greenhouse gasses are well documented, the amount of smoke aerosols in the preindustrial atmosphere is not.

To model smoke in the pre-industrial Southern Hemisphere, the research team looked to Antarctica, where the ice trapped smoke particles emitted from fires in Australia, Africa and South America. Ice core scientists and co-authors of the study, Joseph McConnell and Nathan Chellman from the Desert Research Institute in Nevada, measured soot, a key component of smoke, deposited in an array of 14 ice cores from across the continent, many provided by international collaborators.

"Soot deposited in glacier ice directly reflects past atmospheric concentrations so well-dated ice cores provide the most reliable long-term records," said McConnell.

What they found was unexpected.

"While most studies have assumed less fire took place in the preindustrial era, the ice cores suggested a much fierier past, at least in the Southern Hemisphere," said Loretta Mickley, Senior Research Fellow in Chemistry-Climate Interactions at SEAS and senior author of the paper.

To account for these levels of smoke, the researchers ran computer simulations that account for both wildfires and the burning practices of indigenous people.

"The computer simulations of fire show that the atmosphere of the Southern Hemisphere could have been very smoky in the century before the Industrial Revolution. Soot concentrations in the atmosphere were up to four times greater than previous studies suggested. Most of this was caused by widespread and regular burning practiced by indigenous peoples in the pre-colonial period," said Jed Kaplan, Associate Professor at the University of Hong Kong and co-author of the study.

This result agrees with the ice core records that also show that soot was abundant before the start of the industrial era and has remained relatively constant through the 20th century. The modelling suggests that as land use changes decreased fire activity, emissions from industry increased.

What does this finding mean for future surface temperatures?

By underestimating the cooling effect of smoke particles in the pre-industrial world, climate models might have over-estimated the warming effect of carbon dioxide and other greenhouse gasses in order to account for the observed increases in surface temperatures.

"Climate scientists have known that the most recent generation of climate models have been over-estimating surface temperature sensitivity to greenhouse gasses, but we haven't known why or by how much," said Liu. "This research offers a possible explanation."

"Clearly the world is warming but the key question is how fast will it warm as greenhouse gas emissions continue to rise. This research allows us to refine our predictions moving forward," said Mickley.

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The research was co-authored by Yang Li, Monica Arienzo, John Kodros, Jeffrey Pierce, Michael Sigl, Johannes Freitag, Robert Mulvaney and Mark Curran.

It was funded by the National Science Foundation's Geosciences Directorate under grants AGS-1702814 and 1702830, with additional support from 0538416, 0538427, and 0839093.