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Science

Toward a world that values insects

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Science  28 Jun 2019:
Vol. 364, Issue 6447, pp. 1230-1231
DOI: 10.1126/science.aaw7071

Insects make up the bulk of terrestrial diversity (1). Reports of insect declines, best documented in Europe and North America, suggest that 40% of insect species in temperate countries may face extinction over the next few decades (2), although this figure is probably inflated (3). Other studies have highlighted falling insect biomass in Germany and Puerto Rico (4, 5), as well as threats to many insect taxa in Europe (5) and insect pollinators worldwide (6) that support food production (7). To protect insects, it is crucial that they are considered as separate species with distinct responses to threats, with particular attention to tropical insects and their habitats. Bees and butterflies may serve as an initial focus, but conservation efforts must go far beyond these iconic species. Halting habitat loss and fragmentation, reducing pesticide use, and limiting climate change are all required if insect populations are to be preserved.

The Main Threats

Trends in biodiversity decline are more severe for invertebrates than for vertebrates (4), because the former are highly specialized in terms of food resources and microhabitats. About half of insect species are herbivores and have intimate relationships with their host plants; the slightest alteration to plant abundance or phenology may therefore have severe consequences for insect populations. Multiple interacting threats affect insects, often with negative consequences not just for the insect species themselves but also for other species that rely on them and for overall ecosystem functioning. However, little is known about the identity, genomics, or ecological role of most insect species.

Habitat loss and fragmentation are probably the most serious threats to temperate and tropical insects, particularly to rare, endemic, and specialized species, resulting in reduced and homogeneous assemblages of generalist species across space (8). Habitat loss is fueled by agricultural expansion and intensification, which involves substantial use of chemical pesticides (insecticides and herbicides). The latter are another substantial threat to insect species; insecticides have been linked to insect decline in temperate countries (2, 4) and to global pollinator decline (6). The increasing introduction of large-scale agriculture in the tropics may similarly cause substantial harm to insect populations through the impacts of pesticides beyond agricultural systems (9). The use of fertilizers and herbicides may also shift plant composition, altering the population dynamics of host plants and dependent insects (3).

Climate change, and especially the frequency of extreme climatic anomalies, may be especially detrimental to tropical insects, which tend to have narrow geographic ranges and low tolerance to changes in temperature and rainfall (5, 10). Invasive species and pathogens may also threaten local populations, as can light pollution (2, 3).

Improving Knowledge

Insects are the central component of the living world, and their protection is crucial to maintaining functioning ecosystems and ensuring food security (4, 7). However, scientific knowledge is limited because of insufficient funding for entomological science and the resulting scarcity of adequate field studies. Many past studies have relied on overall insect biomass measurements, which are relatively easy to conduct (2, 5). However, insect biomass greatly varies in space and time and provides little information about the population dynamics of specific species. Instead, population trends can be summarized by combining insect species into different functional groups (10), which may help to identify which species are coping better or worse with anthropogenic changes (3).

Furthermore, many studies are resurveys—that is, snapshots taken at specific time intervals rather than continuous monitoring. The latter is crucial for evaluating how insects respond to individual threats. Comparison of snapshots is further complicated by habitat changes, does not accurately capture which species are present or absent, and may yield misleading trends (3).

Assemblages monitored in the long term must be representative of local insect populations and reasonably diverse. Findings of low insect densities and rates of local extinction must be corroborated with independent studies, particularly in the tropics, where many species subsist at low densities (10). Further, contrasting insect responses to threats must be acknowledged and scrutinized (3, 10). For example, many native species may be declining in temperate forests, but several pest species are expanding their geographical range in response to climate change (7). Efficient monitoring programs can benefit from recently developed technologies involving molecular methods (11) or bioacoustics, as well as from citizen participation (6).

Conservation efforts cannot succeed without sound ecological knowledge of the role of insects in ecosystem maintenance and functioning and of the complex processes, such as adaptive strategies, food behavior, or cascading trophic interactions, that may be disrupted by threats (5). Because even small ecosystem fragments have conservation value for insect biodiversity and ecosystem services, studies should focus on how to preserve forest heterogeneity, enhance the values of fragments by increasing forest connectivity, and promote habitat restoration favorable to insects. Experiments should investigate the consequences of extreme temperatures, which may reduce the fitness of predatory and parasitoid species. A better understanding and delineation of the species that need to be protected is also important. Taxonomic knowledge can be advanced by training more taxonomists and by developing DNA barcode libraries, which provide tractable and testable taxonomic frameworks (11).

Protection Measures

Insects are of crucial importance for ecosystem functioning (including pollination and forest regeneration), for mitigation of pests, and as a source of protein for animals and humans (7). Effective protection measures can be implemented now to mitigate insect decline by examining the evidence available for temperate insects. If decision-makers fulfill their commitments toward the implementation of the 2015 Paris Agreement to mitigate global warming, threats to insect populations resulting directly from global climate change will be alleviated. In urban areas, policies that favor organic agriculture and insect-friendly gardens can greatly support insect species (12). Planting native species in urban environments such as parks, roofs, and backyards can also help to protect insect populations and deliver pollination services.

In rural areas, insect species would benefit from support for organic agriculture and permaculture, the reduction and more efficient use of pesticides, use of integrated pest management (7), and local-scale farming practices that nurture insect populations. Boosting the abundance, diversity, and continuity of floral resources and providing nesting sites are efficient ways to mitigate pollinator decline (6).

Efficient, appropriate, and permanent conservation measures for natural habitats (such as old-growth forests) and human-influenced areas of even very small sizes can support high insect diversity (3). National coordination, informed by scientific results, can lead to better conservation management, such as supporting effective landscape-scale ecological networks (13). Funding of long-term research activities on habitat conservation in general, and specifically on insect science and taxonomy, is especially important to evaluate and mitigate future changes in insect communities, obtain reliable insect time series, and discover species before they go extinct (1).

Engaging the Public

In general, the public tends to appreciate aesthetic insects such as butterflies and the beneficial role of pollinators (6). These perceptions can be used to strengthen the conservation value of insects. However, bee and butterfly species represent only <4% of the insect species described worldwide (1). Many people have negative perceptions of insects in general and do not perceive them as separate species (14). Further, the roles of insects in ecosystem services can be difficult to comprehend (except for pollinators), as are the consequences of insect species loss and overall attrition of biodiversity.

Although public interest in insects varies from one country to another, biological education about the conservation of insects and their natural habitats is urgently needed at all levels of society, starting with field education programs (14). The extraordinary natural history of insects offers many opportunities in biological education and citizen science (14). Field surveys and experiments help the public to appreciate the importance of insects in terrestrial biodiversity (14). Such activities may promote greater empathy and curiosity toward insects and their habitats. Finally, promoting science through traditional and social media can spread enthusiasm and respect for insects and those who study them.

Embedded Image

A male weevil (Rhinostomus barbirostris) protects an egg-laying female in Panama.

PHOTO: YVES BASSET

Tropical Data Gaps

In the tropics, where most insect species live, circumstantial data exist, but long-term records are too sparse to support the conclusion of a global insect decline. Most tropical datasets (see supplementary materials) were collected in locations buffered from the effects of agricultural practices and habitat disturbance. Most of these studies do not unequivocally suggest a decline in insect abundance or species richness; rather, they point to contrasting patterns in population dynamics and to the possible impact of climate change. This may reflect an initial positive effect of rising temperatures or merely the dynamics of common species (see fig. S1 in supplementary materials). For example, the species richness of a community of leaf litter ants in Ecuador remained constant for a study period of 11 years, with little or no evidence of directional change toward a new community (15).

Longer time series including diverse taxa are urgently required to understand what is going on. However, tropical regions mostly composed of developing countries can only devote limited funds to research on nature conservation. Successful examples of conservation planning and public outreach in temperate regions could be shared with tropical regions and could help to guide insect conservation in those locations. International collaborations involving scientists from both developed and developing nations will be key to expertise sharing, as will be the development of global databases with open access.

Outlook

No matter whether the insect apocalypse is global or not, immediate actions are necessary to mitigate insect decline. Here, more insect-friendly agricultural practices are key. Scientific research into the cost effectiveness of pesticide use will help to reduce unnecessary pesticide applications (9). Redistribution of eco-friendly subsidies to favor insect protection (5) can target integrated pest management, the use of pesticide and fertilizers only when necessary for food security and the protection of remaining natural habitats from land-use conversion. Changes of laws can be implemented quickly using bees or butterflies as the focus of attention, as recently demonstrated in Bavaria, Germany, where a grassroots citizen campaign and a state referendum led to a law necessitating drastic changes in agricultural practice to protect biodiversity.

Efforts to mitigate the effects of climate change, such as the boycott of harmful chemical products by both the public and governments, will also help insect populations to recover. To allow insect populations to prosper in both temperate and tropical areas, scientists and policy-makers need to rethink scientific and public priorities to reach out to the public and develop effective protection measures. We need a bioliterate society that protects insects to ensure humanity’s own survival.

References and Notes

Acknowledgments: Supported by ForestGEO and SENACYT (FID2016-070) (Y.B.) and by GAČ R (19-15645Y) and ERC (669609) (G.P.A.L.).

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EurekAlert/ AAAS

Public Release: 

Coffee and bees: New model of climate change effects

Overcoming doomsday scenarios depends on biological intelligence

Smithsonian Tropical Research Institute

Areas in Latin America suitable for growing coffee face predicted declines of 73-88 percent by 2050. However, diversity in bee species may save the day, even if many species in cool highland regions are lost as the climate warms. The research, co-authored by David Roubik, senior scientist at the Smithsonian Tropical Research Institute, will be published in an early online Proceedings of the National Academy of Sciences edition between Sept. 11-15.

“For my money, we do a far superior job of predicting the future when we consider both plants and animals (or in this case the bees) and their biology,” Roubik said. “Traditional models don’t build in the ability of organisms to change. They’re based on the world as we know it now, not on the way it could be as people and other organisms adapt.”

A research team modeled impacts for Latin America, the largest coffee-growing region under several global-warming scenarios–considering both the plants and the bees. The team consisted of experts from the Smithsonian in Panama; the International Center for Tropical Agriculture in Vietnam; the Tropical Agricultural Research and Higher Education Center in Costa Rica; Conservation International and the University of Vermont in the U.S.; CIRAD in France; and CIFOR in Peru.

Despite predicted declines in total bee species, in all scenarios at least five bee species were left in future coffee-suitable areas; in about half of the areas, 10 bee species were left.

For land no longer suitable for coffee production, the team recommended management strategies to help farmers switch to other crops or production systems. In areas where bee diversity is expected to decrease, but coffee can still be grown, adaptation strategies may include increasing bee habitat and maintaining native bees. Many coffee types prefer to grow in the shade of tall trees. Choosing tree species that favor bees is a win-win strategy, according to the authors.

Roubik’s favorite example of a potentially huge environmental change that did not play out as predicted is the case of Africanized honey bees, which were accidentally released in Brazil in 1957. Roubik’s studies in Panama of coffee pollination taking native rainforest bees into consideration began in the 1970s as the aggressive non-native Africanized honey bees swarmed north through Latin America. Doomsayers predicted the worst: that the killer bees would disrupt the delicate balance between tropical forest species and their native pollinators. Roubik discovered the opposite to be true. In lowland tropical forests in Mexico, plants pollinated by very busy Africanized bees ended up producing more flowers, thus making more pollen and nectar available to native bees.

“Africanized honey bees in the Western Hemisphere both regulate their nest temperature and their own body temperature using water,” Roubik said. “When the climate is hotter–unless it’s too dry–they’re better adapted to endure climate change and pollinate coffee–an African plant.”

By paying attention to biological processes and managing coffee for maximum pollination depending upon the effects of climate on both the plants and the bees, as well as strategically adjusting shade, rotating crops and conserving natural forests, it may be possible for coffee producers to adapt to climate change.

###

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The Institute furthers the understanding of tropical biodiversity and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Website: http://www.stri.si.edu/. Promo video: https://www.youtube.com/watch?v=M9JDSIwBegk.

Imbach, P., Fung, E., Hannah, L. et al. 2017 Coffee, bees, and climate: Coupling of pollination services and agriculture under climate change. PNAS. http://www.pnas.org/cgi/doi/10.1073/pnas.1617940114

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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Reblogged from The Economic Times BENGALURU: While India reaped the benefits of the Green Revolution in the 1960s, her neighbour China is now taking the lead in another area of sustainable agriculture — developing crops that meet the challenges posed by global warming. Chinese agricultural scientists are working to convert seasonal crops into perennial crops […]

via Could perennial crops be an answer to climate change? — The Plantwise Blog

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theguardian

Maize, rice, wheat: alarm at rising climate risk to vital crops

Simultaneous harvest failures in key regions would bring global famine, says the Met Office

A villager lifts up fallen corn plants after a flood at a farm in Jianhe county, Guizhou province, China in July 2017.
A villager lifts up fallen corn plants after a flood at a farm in Jianhe county, Guizhou province, China in July 2017. Photograph: Reuters

Maize, rice, wheat: alarm at rising climate risk to vital crops

Simultaneous harvest failures in key regions would bring global famine, says the Met Office

Governments may be seriously underestimating the risks of crop disasters occurring in major farming regions around the world, a study by British researchers has found.

The newly published research, by Met Office scientists, used advanced climate modelling to show that extreme weather events could devastate food production if they occurred in several key areas at the same time. Such an outcome could trigger widespread famine.

The scientists, led by Chris Kent, of the Met Office, focused their initial efforts on how extreme weather would affect maize, one of the world’s most widely grown crops. Heat and drought were the prime risks, although flooding was also included in the analysis.

The group found there is a 6% chance every decade that a simultaneous failure in maize production could occur in China and the US – the world’s main growers – which would result in widespread misery, particularly in Africa and south Asia, where maize is consumed directly as food.

“The impact would be felt at a global scale,” Kent told the Observer. “This is the first time we have been able to quantify the risk. It hasn’t been observed in the last 30 years, but the indications are that it is possible in the current climate.”

An example of the kind of disaster that could occur is provided by the maize harvests that failed last year in Africa. Communities in Zambia, Congo, Zimbabwe, Mozambique and Madagascar were affected and six million people were left on the brink of starvation. A joint failure of China and America’s maize harvest would have a far greater impact.

Drought-damaged corn stalks at a farm in Missouri Valley, Iowa.
Pinterest
Drought-damaged corn stalks at a farm in Missouri Valley, Iowa. Photograph: Larry Downing/Reuters

Having studied the risks facing maize production, the group is now following up this work by studying climate impacts on the world’s other staple crops – in particular rice, wheat and soya beans – in order to assess how weather extremes could affect their production.

According to the UN Food and Agriculture Organisation, maize, rice and wheat together make up 51% of the world’s calorie intake. Billions of people rely on these crops for survival. Any disruption to their production would have calamitous consequences.

The trouble is that crop-growing methods and locations have changed considerably over time, as has the climate and the probability of extreme events, Kent told the Observer. “This means the number of relevant observations to the present-day growing of stable crops has been reduced, and that limits our ability to have useful estimates of the risks to the growing of these crops.”

To get round this problem, the team ran 1,400 climate model simulations on the Met Office’s new supercomputer to understand how climate might vary in the next few years and found that the probability of severe drought was higher than if estimated solely from past observations. The scientists concluded that current agricultural policies could considerably underestimate the true risk of climate-related shocks to maize growing and food supply.

The particular risk outlined by the study envisaged simultaneous catastrophic disruptions in China and the US. In 2014 total world production of maize was around 1 billion tonnes, with the US producing 360 million tonnes and China growing 215 million. If production in these two countries were hit by simultaneous extreme weather events, most likely droughts, more than 60% of global maize production would be hit.

A double whammy like this has never happened in the past, but the work by the Met Office indicates that there is now a real risk. In addition, there may be risks of similar events affecting rice, wheat or soya harvests. These are now being studied by the Met Office, which is also working with researchers in China in a bid to understand climate risks that might affect agricultural production.

“We have found that we are not as resilient as we thought when it comes to crop growing,” said Kirsty Lewis, science manager for the Met Office’s climate security team. “We have to understand the risks we face or there is a real danger we could get caught out. For now we don’t have the means to quantity the risks. We have to put that right.”

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A plant assistant of Plant Clinic in Rohal Suong is recently recruited as an agricultural extension worker for her commune. Women can help reach more sectors in the communities. Photo: Dyna Eam (WorldFish)

Greater involvement of women in plant clinics has improved the climate resilience of the farmers in Rohal Suong village, Cambodia. Women farmers play a critical role in agricultural production and food security, as well as household welfare in most Southeast Asian countries. According to a Census of Agriculture in Cambodia in 2013, of the 82% of Cambodians engaged in the agriculture sector, at least half of them were women.

Female youth and women, however, have limited access to education, agricultural extension services and social events, as they often have low education backgrounds, and are frequently busy with household activities and other unpaid work. They are historically underrepresented in agriculture decision-making and community leadership as well.

Agricultural development projects are now seeking to increase women’s involvement. The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), aims to improve gender equality and women farmers’ decision-making in agriculture through the establishment of Climate-Smart Villages (CSVs). Rohal Suong Village in Battambang, Cambodia is one of the six CSVs in Southeast Asia.

As such, the Rohal Suong CSV has emphasized the inclusion of women farmers in its activities and strategies, such as the Plant Clinic. Operating since June 2016, it is a meeting place where plant advisors and assistants help farmers who are faced with issues of plant pests and diseases. The Clinic has been supported by WorldFish and Center for Agriculture and Bioscience International Southeast Asia (CABI-SEA). Plant advisors and assistants, who are trained through CABI’s Plantwise program, provide diagnoses, treatment advice and recommendations to farmers. Women farmers are encouraged to join the program.

Training and field practices on rice pest and diseases provided by Cambodia’s General Directorate of Agriculture and CABI’s Plantwise program.  Women farmers join the program. Photo: Dyna Eam (WorldFish)

The Plant Clinic is currently led by plant advisors from Battambang Provincial Department of Agriculture and Aphivat Strey (AS), a local NGO, and supported by plant assistants. Plant assistants who are recruited from local farmers play an important role in engaging local farmers to bring their crop issues to the clinic and also in following up with client farmers.

One woman farmer, Ms Savet, was recruited to join the Plant Clinic as a plant assistant. Through her involvement in the project, she has learned several things, such as plant disease identification, plant treatment, and community engagement. She has also had more opportunities to work closely with other community committees and to deliver services to local farmers, particularly other women. Ms Savet was not only able to help local farmers to improve their plant management technique, but has also applied the techniques and treatment methods she learned on her own farm.

I am so happy to work as a plant assistant because I have learned many things about plant disease, pest and treatment methods from the plant advisers and trainings, such as training in Phnom Penh. Now I can provide the advice on some plant diseases to my villagers,” said Ms Savet.

As a result of her experience in the project, Ms Savet has been recruited as an agricultural extension worker for her commune. Now, she is organizing groups of community members for an agricultural demonstration project run by the Battambang Provincial Department of Agriculture, Forestry and Fisheries, and the Agriculture Services Programme for Innovation Resilience and Extension (ASPIRE). ASPIRE is a program of the Ministry of Agriculture, Forestry, and Fisheries, and is funded by the International Fund for Agricultural Development.

I thought that I was recruited as a commune extension worker because I could answer well the questions from examination committees, actually this knowledge came from my experiences at Plant Clinic,” added Ms Savet.

She is now trying to understand the common and different needs of women and men famers in agriculture. Ms Savet is keen to learn more about agricultural technologies and extension service methods, and to transfer her knowledge to her villagers.

Engaging local farmers through the Plant Clinic and extension work is an approach that has helped to successfully build local farmers’ capacities and also help local farmers, particularly women farmers, to get better access to agricultural services. In doing so, the project has helped improve the livelihoods of farming households and increase the resilience of agriculture-dependent communities.

By Dyna Eam. Reblogged from the CGIAR CCAFS blog. Read the original here→

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In the busy streets of Hanoi, history was made last month. CABI Southeast Asia (CABI-SEA) signed a memorandum of understanding with Agricultural Multimedia Joint Stock Company (AgriMedia) – a private company working in the field of agriculture. As a pioneer in M2M applications in agriculture, AgriMedia was established in 2014 and aims to provide a […]

via Working with AgriMedia to address climate change in Vietnam — The Plantwise Blog

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MILTECH

Fires, storms, insects: climate change increases risks for forests worldwide

“When climate is changing, there are initially direct effects on the growth of the trees. But the chain of climate impacts is considerably longer: if, for instance, more rain saturates the soils or if soils are less frequently frozen, the trees will have less stability to withstand storms and damage will increase. The many dead and dying trees will then provide ideal breeding material for insects such as bark beetles to reproduce quickly. At the same time, the trees that are still alive will be weakened and will thus be more vulnerable to insect attacks,” explains lead author Rupert Seidl from the University of Natural Resources and Life Sciences in Vienna. “Our study shows that climate change significantly influences disruptive factors all around the world – and that a further increase of disturbances in forests has to be expected in the future.”

Stress is normal for the forests – while the increase of disturbances is not

“Whether in the giant boreal forests of Scandinavia and Russia or in the wide woodlands of North America – fundamentally, natural disturbances like fires, insect attacks or storms are normal aspects of these ecosystems,” says project leader Christopher Reyer of the Potsdam Institute for Climate Impact Research. To get shaken up a little through natural disturbances can even be good for forests, as the natural renewal for instance promotes a greater biological diversity.

“But through climate change, these usual disturbances have already changed in the last years”, explains Reyer. “This has impacts on the ability of the forests to provide services for us humans – for example in terms of their wood, in terms of protection against avalanches, or simply as recreational spaces. If climate change keeps on increasing disturbances, this clearly is a risk for the coping capacities of the forests – in the long run, ecosystems as we know them today might change profoundly.”

Climate change as a challenge for forest management

For the review study, forest experts from Austria, Germany, Switzerland, Finland, Italy, Spain, the Czech Republic, Scotland, Slovakia and Slovenia analyzed more than 1600 different findings from academic publications which establish links between disruptions and climate factors. Additionally, the scientists examined how indirect climate impacts, such as the alteration of tree species in the forests, influence the occurrence of disturbances. In particular the indirect effects and the interactions between different disruptive factors were collated in an unprecedentedly comprehensive manner in the research on forest disturbances.

Already today it is clear that risks caused by fires, pests and fungi will increase in the context of climate change – the devastating forest fires in Canada and Russia in the last years are an example of possible impacts. Fires are currently the most significant disruptive factor in many forests around the world, and will become an even more serious threat in the coming decades, according to the scientists. The forests of Northern and Central Europe, however, have until present primarily been impaired by storms such as Cyclone Kyrill in 2007, and the insect damage that follows them – a type of damage which will also increase under climate change. Damage caused by ice and snow were the only disruptive factors examined by the study that will likely decrease under continuing climate change. However, this positive effect cannot compensate the negative effects from other factors.

“Our analysis clearly shows that climate change brings enormous challenges for forests – the forest sector has to adapt and to increase its resilience, as it seems impossible to prevent damage completely”, says Seidl. “In the long term, reductions of greenhouse-gas emissions and effective climate protection measures will help the most,” adds Reyer.

Article:  Rupert Seidl, Dominik Thom, Markus Kautz, Dario Martin-Benito, Mikko Peltoniemi, Giorgio Vacchiano, Jan Wild, Davide Ascoli, Michal Petr, Juha Honkaniemi, Manfred J. Lexer, Volodymyr Trotsiuk, Paola Mairota, Miroslav Svoboda, Marek Fabrika, Thomas A. Nagel, and Christopher P. O. Reyer (2017): Forest disturbances under climate change. Nature Climate Change [10.1038/NCLIMATE3303]

Weblink to the article: https://www.nature.com/nclimate/journal/v7/n6/full/nclimate3303.html

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