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Climate services are intended to improve climate-sensitive decisions by making climate information ‘useful, useable and used’. Here, we analyse 27 expert interviews to evaluate whether this user-driven model of climate science has been successfully implemented in the public sector. We show that, although climate services promise better decision-making, they mainly focus on delivering better data. The norms and institutions of climate science produce three key tensions in operationalizing climate services: a focus on products rather than processes, services based on broad assumptions about demand rather than being demand-driven, and the narrow economic valuation of products rather than evaluation of improvements in decision-making. These tensions help explain why climate services often generate nominal changes in climate science where transformations are promised. Transformational change requires that climate services account for diverse social structures, behaviours and contexts. Integrating social science is no panacea for demand-driven climate services, but it is certainly a prerequisite. Climate services aim to make climate data and information accessible for climate-sensitive decision-making. However, the grounding of climate services in the norms and institutions of climate science creates tensions that reduce the impact of climate services.

Incorporating species’ ability to adaptively respond to climate change is critical for robustly predicting persistence. One such example could be the adaptive role of algal symbionts in setting coral thermal tolerance under global warming and ocean acidification. Using a global ecological and evolutionary model of competing branching and mounding coral morphotypes, we show symbiont shuffling (towards taxa with increased heat tolerance) was more effective than symbiont evolution in delaying coral-cover declines, but stronger warming rates (high emissions scenarios) outpace the ability of these adaptive processes and limit coral persistence. Acidification has a small impact on reef degradation rates relative to warming. Global patterns in coral reef vulnerability to climate are sensitive to the interaction of warming rate and adaptive capacity and cannot be predicted by either factor alone. Overall, our results show how models of spatially resolved adaptive mechanisms can inform conservation decisions. The authors model the role of algal symbiont shuffling and evolution in coral resilience to warming and ocean acidification, globally. They find that shuffling is more effective than evolution, and show global patterns of vulnerability due to the interaction of warming rate and adaptive capacity.

Summary Elections represent infrequent, high-leverage opportunities for everyday individuals to contribute to climate change mitigation. In this perspective, we present two ways of thinking about the climate impact of voting in elections. The first, “emissions responsibility,” intuitively apportions emissions to voters according to popular principles in carbon accounting and can be calculated for elections where there is a clear difference between major candidates (as in the 2019 Canadian federal election). The second approach, “expected emissions value,” is more probabilistic and can be used to investigate the rationality of participating in an election for climate-motivated voters. Building on these ideas, we discuss the possibility that “political carbon offsets” (donations to pro-climate politicians) could constitute a more effective and more equitable alternative to traditional, voluntary carbon offsets.

Misunderstandings in the relative efficacy of pro-environmental behaviors may have important consequences for climate mitigation efforts. In this study, we evaluate the ability to perceive the carbon footprint associated with individual actions, known as “carbon numeracy,” in 965 members of the North American public using ranking and tradeoff questions. The questions are designed to independently assess the role of knowledge, ability to do tradeoffs, and basic numeracy skills in determining carbon numeracy. We report multiple lines of evidence suggesting that people underestimate greenhouse gas emissions associated with air travel and, to a lesser extent, meat consumption. They are also largely incapable of making tradeoffs between different actions (e.g., the number of hamburgers that would be equivalent to a trans-Atlantic flight in terms of climate impact). Concern for climate change, political orientation, and education were not significant predictors of accuracy in making tradeoffs, but basic numeracy was linked with increased accuracy. The results suggest that further education may be necessary to improve carbon numeracy by providing the public with a basic hierarchy of actions according to carbon reduction efficacy. Consumers seeking to balance their carbon budgets may benefit from external aids (e.g., carbon labels associated with actions) to guide emission-related decision-making.

Warm-water growth and survival of corals are constrained by a set of environmental conditions such as temperature, light, nutrient levels and salinity. Water temperatures of 1 to 2°C above the usual summer maximum can trigger a phenomenon known as coral bleaching, whereby disruption of the symbiosis between coral and dinoflagellate micro-algae, living within the coral tissue, reveals the white skeleton of coral. Anomalously cold water can also lead to coral bleaching but has been the subject of limited research. Although cold-water bleaching events are less common, they can produce similar impacts on coral reefs as warm-water events. In this study, we explored the effect of temperature and light on the likelihood of cold-water coral bleaching from 1998-2017 using available bleaching observations from the Eastern Tropical Pacific and the Florida Keys. Using satellite-derived sea surface temperature, photosynthetically available radiation and light attenuation data, cold temperature and light exposure metrics were developed and then tested against the bleaching observations using logistic regression. The results show that cold-water bleaching can be best predicted with an accumulated cold-temperature metric, i.e. ‘degree cooling weeks’, analogous to the heat stress metric ‘degree heating weeks’, with high accuracy (90%) and fewer Type I and Type II errors in comparison with other models. Although light, when also considered, improved prediction accuracy, we found that the most reliable framework for cold-water bleaching prediction may be based solely on cold-temperature exposure.

Elevated ocean temperatures can cause coral bleaching, the loss of colour from reef-building corals because of a breakdown of the symbiosis with the dinoflagellate Symbiodinium. Recent studies have warned that global climate change could increase the frequency of coral bleaching and threaten the long-term viability of coral reefs. These assertions are based on projecting the coarse output from atmosphere-ocean general circulation models (GCMs) to the local conditions around representative coral reefs. Here, we conduct the first comprehensive global assessment of coral bleaching under climate change by adapting the NOAA Coral Reef Watch bleaching prediction method to the output of a low- and high-climate sensitivity GCM. First, we develop and test algorithms for predicting mass coral bleaching with GCM-resolution sea surface temperatures for thousands of coral reefs, using a global coral reef map and 1985-2002 bleaching prediction data. We then use the algorithms to determine the frequency of coral bleaching and required thermal adaptation by corals and their endosymbionts under two different emissions scenarios. The results indicate that bleaching could become an annual or biannual event for the vast majority of the world's coral reefs in the next 30-50 years without an increase in thermal tolerance of 0.2-1.0°C per decade. The geographic variability in required thermal adaptation found in each model and emissions scenario suggests that coral reefs in some regions, like Micronesia and western Polynesia, may be particularly vulnerable to climate change. Advances in modelling and monitoring will refine the forecast for individual reefs, but this assessment concludes that the global prognosis is unlikely to change without an accelerated effort to stabilize atmospheric greenhouse gas concentrations.

The increasing frequency of mass coral bleaching and associated coral mortality threaten the future of warmwater coral reefs. Although thermal stress is widely recognized as the main driver of coral bleaching, exposure to light also plays a central role. Future projections of the impacts of climate change on coral reefs have to date focused on temperature change and not considered the role of clouds in attenuating the bleaching response of corals. In this study, we develop temperature- and light-based bleaching prediction algorithms using historical sea surface temperature, cloud cover fraction and downwelling shortwave radiation data together with a global-scale observational bleaching dataset observations. The model is applied to CMIP6 output from the GFDL-ESM4 Earth System Model under four different future scenarios to estimate the effect of incorporating cloudiness on future bleaching frequency, with and without thermal adaptation or acclimation by corals. The results show that in the low emission scenario SSP1-2.6 incorporating clouds into the model delays the bleaching frequency conditions by multiple decades in some regions, yet the majority (>70%) of coral reef cells still experience dangerously frequent bleaching conditions by the end of the century. In the moderate scenario SSP2-4.5, however, the increase in thermal stress is sufficient to overwhelm the mitigating effect of clouds by mid-century. Thermal adaptation or acclimation by corals could further shift the bleaching projections by up to 40 years, yet coral reefs would still experience dangerously frequent bleaching conditions by the end of century in SPP2-4.5. The findings show that multivariate models incorporating factors like light may improve the near-term outlook for coral reefs and help identify future climate refugia. Nonetheless, the long-term future of coral reefs remains questionable if the world stays on a moderate or higher emissions path.

Despite long-standing assertions that climate change creates new risk management challenges, the climate change adaptation literature persists in assuming, both implicitly and explicitly, that weather and climate variability are suitable proxies for climate change in evaluating farmers’ risk perceptions and predicting their adaptive responses. This assumption persists in part because there is surprisingly little empirical evidence either way, although case studies suggest that there may be important differences. Here, we use a national survey of South Africa’s commercial grain farmers (n = 389)—similar to their peers in higher-income countries (e.g., North America, Europe, Australia), but without subsidies—to show that they treat weather and climate change risks quite differently. We find that their perceptions of climate change risks are distinct from and, in many regards, oppositional to their perceptions of weather risks. While there seems to be a temporal element to this distinction (i.e., differing concern for short-term vs long-term risks), there are other differences that are better understood in terms of normalcy (i.e., normal vs abnormal relative to historical climate) and permanency (i.e., temporary vs permanent changes). We also find an interaction effect of education and political identity on concern for climate change that is at odds with the well-publicized cultural cognition thesis based on surveys of the American public. Overall, studies that use weather and climate variability as unqualified proxies for climate change are likely to mislead researchers and policymakers about how farmers perceive, interpret, and respond to climate change stimuli.

Lowering the growth in greenhouse gas emissions from air travel may be critical for avoiding dangerous levels of climate change, and yet some individuals perceive frequent air travel to be critical to their professional success. Using a sample of 705 travellers at the University of British Columbia, we investigated the influence of career stage, research productivity, field of expertise, and other variables on academic air travel and the associated emissions. This is the first time that research has evaluated the link between observed air travel and academic success. First, we compared air travel behaviour at different career stages and found that individuals at the start of their careers were responsible for fewer emissions from air travel than senior academics. Second, since career advancement may depend on an academic’s ability to form partnerships and disseminate their research abroad, we investigated the relationship between air travel emissions and publicly available bibliometric measurements. We found no relationship between air travel emissions and metrics of academic productivity including hIa (h-index adjusted for academic age and discipline). There was, however, a relationship between emissions and salary that remains significant even when controlling for seniority. Finally, based on the premise that academics studying topics related to sustainability may have greater responsibility or motivation to reduce their emissions, we coded 165 researchers in our sample as either “Green” or “Not-green.” We found no significant difference between Green and Not-green academics in total air travel emissions, or in the types of emissions that might be easiest to avoid. Taken together, this preliminary evidence suggests that there may be opportunities, especially for academics who study topics related to climate and sustainability, to reduce their emissions from air travel while maintaining productive careers.

Frequent occurrences of coral bleaching and associated coral mortality over recent decades have raised concerns about the survival of coral reefs in a warming planet. The El Niño-influenced coral reefs in the central Gilbert Islands of the Republic of Kiribati, which experience years with prolonged heat stress more frequently than 99% of the world’s reefs, may serve as a natural model for coral community response to frequent heat stress. Here we use nine years of survey data (2004–2012) and a suite of remote sensing variables from sites along gradients of climate variability and human disturbance in the region to evaluate the drivers of coral community response to, and recovery from, multiple heat stress events. The results indicate that the extent of bleaching was limited during the 2009–2010 El Niño event, in contrast to a similar 2004–2005 event, and was correlated with incoming light and historical temperature variability, rather than heat stress. Spatial and temporal patterns in benthic cover suggest growing resistance to bleaching-level heat stress among coral communities subject to high inter-annual temperature variability and local disturbance, due to the spread of “weedy” and temperature-tolerant species (e.g., Porites rus) and the cloudy conditions in the region during El Niño events.

Marine heatwaves (MHWs), periods of anomalously warm sea surface temperature (SST) which can have significant impacts on marine ecosystems, have increased in frequency and severity over recent decades. Many coastal systems (e.g. coral reefs) are particularly vulnerable to warm-season heat stress when temperature can exceed organisms’ thermal thresholds and lead to mass mortality. While many studies have examined the change of the warm-season heat stress occurrence over time, e.g., for coral reefs, there has been less analysis of the thermal structure of heat stress events. Here we examined the trend in the characteristics of warm-season heat stress (referred to as warm-season MHWs) at the global-scale from 1985 to 2019, using multiple metrics for each of duration, peak intensity, accumulated heat stress, heating rates and level of intensity. The results showed that warm-season MHWs have become more frequent, longer-lasting, featured higher peak intensity and accumulated heat stress across most of the ocean over the past four decades. Furthermore, decomposition of the trends in warm-season MHWs structure showed that the increased accumulated heat stress was predominantly driven by the increased duration rather than the increased intensity, especially in the western and central equatorial Pacific. The results contribute to improving the understanding of warm-season MHWs, which may help inform the prediction of their impacts on marine ecosystems as well as marine conservation and management under climate change.

Climate change and warming ocean temperatures are a threat to coral reef ecosystems. Since the 1980s, there has been an increase in mass coral bleaching and associated coral mortality due to more frequent and severe thermal stress. Although most research has focused on the role of temperature, coral bleaching is a product of the interacting effects of temperature and other environmental variables such as solar radiation. High light exacerbates the effects of thermal stress on corals, whereas reductions in light can reduce sensitivity to thermal stress. Here, we use an updated global dataset of coral bleaching observations (n = 35,769) from 1985 to 2017 and satellite-derived datasets of SST and clouds to examine for the first time at a global scale the influence of cloudiness on the likelihood of bleaching from thermal stress. We find that among coral reefs exposed to severe bleaching-level heat stress (Degree Heating Weeks >8°Cˑweek), bleaching severity is inversely correlated with the interaction of heat stress and cloud fraction anomalies (p < 0.05), such that higher cloudiness implies reduced bleaching response. A Random Forest model analysis employing different set of environmental variables shows that a model employing Degree Heating Weeks and the 30-day cloud fraction anomaly most accurately predicts bleaching severity (Accuracy = 0.834; Cohen's Kappa = 0.769). Based on these results and global warm-season cloudiness patterns, we develop a 'cloudy refugia' index which identifies the central equatorial Pacific and French Polynesia as regions where cloudiness is most likely to protect corals from bleaching. Our findings suggest that incorporating cloudiness into prediction models can help delineate bleaching responses and identify reefs which may be more resilient to climate change.

Background Each spring, thousands of Canadian medical students travel across the country to interview for residency positions, a process known as the CaRMS tour. Despite the large scale of travel, the CaRMS tour has received little environmental scrutiny. Purpose To estimate the national carbon footprint of flights associated with the CaRMS tour, as well as reductions in emissions achievable by transitioning to alternative models. Methods We developed a three-question online commuter survey to collect the unique travel itineraries of applicants in the 2020 CaRMS tour. We calculated the emissions associated with all flights and modelled expected emissions for two alternative in-person interview models, and two virtual interview models. Results We collected 960 responses out of 2943 applicants across all 17 Canadian medical schools. We calculated the carbon footprint of flights for the 2020 CaRMS as 4239 tCO2e (tonnes of carbon dioxide equivalents), averaging 1.44 tCO2e per applicant. The average applicant's tour emissions represent 35.1% of the average Canadian's annual household carbon footprint, and the emissions of 26.7% of respondents exceeded their entire annual '2050 carbon budget.' Centralized in-person interviews could reduce emissions by 13.7% to 74.7%, and virtual interviews by at least 98.4% to 99.9%. Conclusions Mandatory in-person residency interviews in Canada contribute significant emissions and reflect a culture of emissions-intensive practices. Considerable decarbonization of the CaRMS tour is possible, and transitioning to virtual interviews could eliminate the footprint almost entirely.

In an incredible story of human adaptation, the aggregate global risk of mortality to extreme weather declined by over two orders of magnitude over the past century. Yet the data show that large losses of lives to extreme weather disasters persist in nations typified by poor economic development, weak institutions, and political instability. And currently we are seeing spikes in mortality from extreme heat events in rich nations, including a wave of new reported deaths in Japan, Europe, and Canada during 2018. These events and future projections of increasing exposure suggest that we need to revisit adaptation strategies to deal with the adverse effects of extreme weather disasters across the world.

Coral reefs are increasingly affected by a combination of acute and chronic disturbances from climate change and local stressors. The coral reefs of the Republic of Kiribati’s Gilbert Islands are exposed to frequent heat stress caused by central-Pacific type El Niño events, and may provide a glimpse into the future of coral reefs in other parts of the world, where the frequency of heat stress events will likely increase due to climate change. Reefs in the Gilbert Islands experienced a series of acute disturbances over the past fifteen years, including mass coral bleaching in 2004–2005 and 2009–2010, and an outbreak of the corallivorous sea starAcanthastercfsolaris, or Crown-of-Thorns (CoTs), in 2014. The local chronic pressures including nutrient loading, sedimentation and fishing vary within the island chain, with highest pressures on the reefs in urbanized South Tarawa Atoll. In this study, we examine how recovery from acute disturbances differs across a gradient of human influence in neighboring Tarawa and Abaiang Atolls from 2012 through 2018. Benthic cover and size frequency data suggests that local coral communities have adjusted to the heat stress via shifts in the community composition to more temperature-tolerant taxa and individuals. In densely populated South Tarawa, we document a phase shift to the weedy and less bleaching-sensitive coralPorites rus, which accounted for 81% of all coral cover by 2018. By contrast, in less populated Abaiang, coral communities remained comparatively more diverse (with higher percentages ofPocilloporaand the octocoralHeliopora)after the disturbances, but reefs had lower overall hard coral cover (18%) and were dominated by turf algae (41%). The CoTs outbreak caused a decline in the cover and mean size of massivePorites, the only taxa that was a ‘winner’ of the coral bleaching events in Abaiang. Although there are signs of recovery, the long-term trajectory of the benthic communities in Abaiang is not yet clear. We suggest three scenarios: they may remain in their current state (dominated by turf algae), undergo a phase shift to dominance by the macroalgaeHalimeda, or recover to dominance by thermally tolerant hard coral genera. These findings provide a rare glimpse at the future of coral reefs around the world and the ways they may be affected by climate change, which may allow scientists to better predict how other reefs will respond to increasing heat stress events across gradients of local human disturbance.

Urgent reductions in greenhouse gas emissions depend on governments implementing and enforcing rigorous climate policy. Individuals in democracies seeking to persuade government officials to reduce greenhouse gas emissions can take steps such as voting, protesting, and contacting officials directly, but it is unclear how effective each of these actions is in changing the behavior of elected officials. Here we take advantage of the public nature of social media to evaluate the actual efficacy of climate campaign emails using an original, real-world experiment where 335 Members of Canadian Parliament were asked by constituents to post a pro-climate message to their Twitter account. Only one Member of Parliament posted the exact text suggested by the campaign. After scraping and coding 18,776 tweets, we first find no evidence that a public health messaging frame is more effective than a standard environmental frame in eliciting pro-climate posts. Furthermore, we find only a marginally significant relationship between volume of constituent contact and increased pro-climate tweeting from Members of Parliament. Follow-up interviews with political staffers suggest that analog alternatives may be more effective than campaign emails in some cases. Interview findings also reveal that some offices receive low levels of constituent communication on climate change, indicating that increased pressure from constituents could still be consequential. Supplementary Information The online version contains supplementary material available at 10.1007/s10584-021-03215-9.

Future sediment dynamics may be affected by changing climates or hydrological regimes because of the close link between hydrology and sediment erosion, deposition, and transport. Previously, investigations of these potential changes have been constrained by a combination of limited observational data, hydrological drivers, and appropriate mechanistic models. Additionally, there is often ambiguity regarding how to disentangle the impacts of climate and hydrology from direct human factors such as reservoirs and land‐use change, which often exert more control over sediment dynamics. In this study, we utilize a recently developed, large‐scale, distributed, mechanistic sediment transport model to project future sediment erosion, deposition, and transportation within the Fraser River Basin in British Columbia, Canada—a basin with historical water flux and sediment load observations and limited anthropogenic influences upstream of its delta. The sediment model is driven by synthetic land‐surface hydrology derived from Scenarios A1B, A2, and B1 of the Special Report on Emissions Scenarios, which were provided by the Pacific Climate Impacts Consortium. Resulting simulations of water flux and sediment load from 1965 to 1994 are first validated against observational data then compared with future projections. Future projections show an overall increase in annual hillslope erosion and in‐channel transportation, a shift towards earlier spring peak erosion and transportation, and longer persistence of the sediment signal through the year. These shifts in timing and annual yield may have deleterious effects on spawning sockeye salmon and are insufficient to counteract future coastal retreat caused by sea‐level rise.

How climate-sensitive actors—like commercial farmers—perceive, understand, and react to weather and climate stimuli will ultimately determine the success or failure of climate change adaptation policies. Many studies have characterized farmers’ climate risk perceptions or farming practices, but few have evaluated the in situ decision-making processes that link (or fail to link) risk perceptions to adaptive behaviors. Here, we use a novel methodology to reveal patterns in climate-sensitive decision-making by commercial grain farmers in South Africa. We structure, linguistically code, and statistically analyze causal relationships described in 30 mental models interviews. We show that farmers’ framing of weather and climate risks strongly predicts their adoption of conservation agriculture (CA)—climate-resilient best practices that reduce shorter-term financial and weather risks and longer-term agronomic risks. These farmers describe weather and climate risks using six exhaustive and mutually exclusive languages: agricultural, cognitive, economic, emotional, political, and survival. The prevalence of agricultural and economic language only weakly predicts CA practice, whereas emotional and farm survival language strongly limits CA adoption. The framing of weather risks in terms of farm survival impedes adaptations that are likely to improve such survival in the longer term. But this survival framing is not necessarily indicative of farmers’ current economic circumstances. It represents a consequential mindset rather than a financial state and it may go undetected in more conventional studies relying on direct survey or interview questions.

Experts recommend that decision-makers in climate-vulnerable sectors integrate, or ‘mainstream’, climate change adaptation into their decision-making. Farmers are often thought to do so intuitively, because many climate change impacts will manifest in similar ways to the weather and climate variability that farmers have always faced. However, there is little evidence to suggest whether farmers are already doing this, how they should go about it, and how hard it might be. Here we show that commercial grain farmers in South Africa (N = 90), as a uniquely informative group, are struggling to mainstream climate change risk management despite their apparent incentive, capacity and willingness to adapt. They perform large-scale, highly mechanized, input-intensive grain farming like their peers in higher-income countries (e.g., the United States, Canada, Europe and Australia), but without the government subsidies, crop insurance and irrigation more common in other regions. They are therefore motivated to adapt proactively because they are more vulnerable to the financial harms of weather and climate risks. Our data show that they are explicitly sensitive to the risks of climate change, generally expressing concern for its potential impacts, reporting observed changes, proposing possible adaptations, and expressing the desire to adapt proactively. However, their mental models of climate change (n = 30) are linguistically and structurally isolated from their mental models of weather and other ‘normal’ risks. They are therefore implicitly insensitive to climate change, making it unlikely that they will adapt proactively and rationally to this uncertain risk that they otherwise appear well-equipped to manage.

Within the last two centuries, the Mississippi River basin has been transformed by changes in land use practices, dam construction and training of the rivers for navigation. Here we analyze the contemporary patterns of fluvial sediment yield in the Mississippi River basin using all available data in order to assess the influence of regional land condition on the variation of sediment yield within the basin. We develop regional scale relations between specific sediment yield (yield per unit area) and drainage area to reveal contemporary regional sediment yield patterns and source areas of riverine sediments. Extensive upland erosion before the development of soil conservation practices exported large amounts of sediment to the valleys and floodplains [Trimble, 1981; Belmont et al., 2011]. We show that sediment today is sourced primarily along the river valleys from arable land, and from stream bank and channel erosion, with sediment yields from areas dominated by arable land two orders of magnitude greater than that of grassland dominated areas. Comparison with the “T factor”, a commonly quoted measure of agricultural soil resilience suggests that the latter may not reflect contemporary soil loss from the landscape.

Decades of fertilizer and manure applications have led to a buildup of phosphorus (P) in agricultural soils and sediments, commonly referred to as legacy P. Legacy P can provide a long-term source of P to surface waters where it causes eutrophication. Using a suite of numerical models, we investigated the influence of legacy P on water quality in the Yahara Watershed of southern Wisconsin, USA. The suite included Agro-IBIS, a terrestrial ecosystem model; THMB, a hydrologic and nutrient routing model; and the Yahara Water Quality Model which estimates water quality indicators in the Yahara chain of lakes. Using five alternative scenarios of antecedent P storage (legacy P) in soils and channels under historical climate conditions, we simulated outcomes of P yield from the landscape, lake P loading, and three lake water quality indicators. Legacy P had a significant effect on lake loads and water quality. Across the five scenarios for Lake Mendota, the largest and most upstream lake, average P yield (kg ha−1) varied by −41 to +22%, P load (kg y−1) by −35 to +14%, summer total P (TP) concentration (mg l−1) by −25 to +12%, Secchi depth (m) by −7 to +3%, and the probability of hypereutrophy by −67 to +34%, relative to baseline conditions. The minimum storage scenario showed that a 35% reduction in present-day loads to Lake Mendota corresponded with a 25% reduction in summer TP and smaller reductions in the downstream lakes. Water quality was more vulnerable to heavy rainfall events at higher amounts of P storage and less so at lower amounts. Increases in heavy precipitation are expected with climate change; therefore, water quality could be protected by decreasing P reserves.

Este artículo contiene 10 páginas, 5 figuras., Without drastic efforts to reduce carbon emissions and mitigate globalized stressors, tropical coral reefs are in jeopardy. Strategic conservation and management requires identification of the environmental and socioeconomic factors driving the persistence of scleractinian coral assemblages—the foundation species of coral reef ecosystems. Here, we compiled coral abundance data from 2,584 Indo-Pacific reefs to evaluate the influence of 21 climate, social and environmental drivers on the ecology of reef coral assemblages. Higher abundances of framework-building corals were typically associated with: weaker thermal disturbances and longer intervals for potential recovery; slower human population growth; reduced access by human settlements and markets; and less nearby agriculture. We therefore propose a framework of three management strategies (protect, recover or transform) by considering: (1) if reefs were above or below a proposed threshold of >10% cover of the coral taxa important for structural complexity and carbonate production; and (2) reef exposure to severe thermal stress during the 2014–2017 global coral bleaching event. Our findings can guide urgent management efforts for coral reefs, by identifying key threats across multiple scales and strategic policy priorities that might sustain a network of functioning reefs in the Indo-Pacific to avoid ecosystem collapse.

Climate change and human disturbance threatens coral reefs across the Pacific, yet there is little consensus on what characterizes a "healthy" reef. Benthic cover, particularly low coral cover and high macroalgae cover, are often used as an indicator of reef degradation, despite uncertainty about the typical algal community compositions associated with either near-pristine or damaged reefs. In this study, we examine differences in coral and algal community compositions and their response to human disturbance and past heat stress, by analysing 25 sites along a gradient of human disturbance in Majuro and Arno Atolls of the Republic of the Marshall Islands. Our results show that total macroalgae cover indicators of reef degradation may mask the influence of local human disturbance, with different taxa responding to disturbance differently. Identifying macroalgae to a lower taxonomic level (e.g. the genus level) is critical for a more accurate measure of Pacific coral reef health.

It is critical that future sustainability leaders possess the skills and aptitudes needed to tackle increasingly ‘wicked’ challenges. While much has been done to identify this need, inadequate Leadership Training for graduate students in Sustainability (LTS) continues to plague even the most highly-resourced institutions. Collectively, the authors of this paper represent the small yet growing number of LTS programs across the United States and Canada working to close this training gap. In this paper, we describe the integrative approach we took to synthesize our collective knowledge of LTS with our diverse programmatic experiences and, ultimately, translate that work into concrete guidance for LTS implementation and design. We present a framework for the suite of key LTS aptitudes and skills yielded by our collaborative approach, and ground these recommendations in clear, real-world examples. We apply our framework to the creation of an open-access curricular database rich with training details, and link this database to an interactive network map focused on sharing programmatic designs. Together, our process and products transform many disparate components into a more comprehensive and accessible understanding of what we as LTS professionals do, with a view to helping others who are looking to do the same for the next generation of sustainability leaders.

The election as US President of Donald J Trump, who denies the scientific consensus on climate change, raises questions about the role of scientists in public discourse. How far should scientists wade into the waters of advocacy before risking their credibility of fair arbiters of knowledge? The new study by Kotcher, Myers, Vraga, Stenhouse, and Maibach [2017. Does engagement in advocacy hurt the credibility of scientists? Results from a randomized national survey experiment. Environmental Communication. doi:10.1080/17524032.2016.1275736] is a reminder that scientists are among the most trusted people in public life and have some freedom to engage publicly without harming their reputation. However, with the power to influence public debate comes the responsibility to carefully consider the impact of statements and actions. This commentary discusses the challenges facing scientists at a time of great potential for public engagement, and for a gap between perceived and actual intent of public statem...

The Athabasca River Basin, home to Canada's growing oil sands mining industry, faces challenging trade-offs between energy production and water security. Water demand from the oil sands mining industry is projected to increase as climate change is projected to alter the seasonal freshwater supply. In this study, a range of water management options are developed to investigate the potential trade-offs between the scale of bitumen production and industry growth, water storage requirements, and environmental protection for the aquatic ecosystems, under projections of mid-century climate change. It is projected that water storage will be required to supplement river withdrawals to maintain continuous bitumen production under the impacts of future climate warming. If high growth in future bitumen production and water demand is the priority, then building sufficient water storage capacity to meet industry demand will be comparable to a week of lost revenue because of interrupted production. If environmental protection is prioritized instead, it will require over nine times the water storage costs to maintain water demand under a high industry growth trajectory. Future water use decisions will need to first, determine the scale of industry and environmental protection, and second, balance the costs of water storage against lost revenue because of water shortages that limit bitumen production. This physically based assessment of future water trade-offs can inform water policy, water management decisions, and climate change adaptation plans, with applicability to other regions facing trade-offs between industrial development and ecosystem water needs. Copyright © 2016 John Wiley & Sons, Ltd.

The Republic of Kiribati is largely composed of infertile, low-lying atolls, and coral islands in the central Pacific. Kiribati’s geographical isolation and remoteness makes it difficult to access regional and global economic markets, and it is considered as one of the least developed countries in the Pacific. However, Kiribati has one of the largest exclusive economic zones with globally important tuna stocks. Many of the uninhabited atolls in the Line and Phoenix Island group boast excellent examples of healthy coral reefs without anthropogenic stresses, and are home to globally significant populations of seabirds. Recent deep-sea research suggests high biodiversity in benthic habitats below 200 ft., with many species new to science. The limited flora of Kiribati is ecologically critical to wildlife on the atolls, as well as for the culture and survival of the i-Kiribati people. Although there are few published scientific studies, a review of technical reports suggests localized pollution, destructive fishing practices, overfishing, and poorly planned coastal infrastructure have all contributed to the decline of coastal resources. Regionally, Kiribati has made significant commitments toward the protection of marine resources in the Pacific Ocean, the largest of which is the declaration of the 405,755 km2 Phoenix Islands Protected Area and World Heritage Area. There is growing interest to expanding their terrestrial protected areas to include complementary marine protected areas in the Line Islands.

Future bitumen production in the Athabasca Oil Sands, one of the largest remaining reserves of petroleum on the planet, is a key factor in global climate policy and politics. Climate warming in the Athabasca River Basin (ARB) has the potential to limit future streamflow availability for aquatic ecosystem needs, as well as for water withdrawals in oil sands mining operations. This study applies the land surface model IBIS and the hydrological routing algorithm THMB, with forced output from CMIP5 global climate models, to examine the response of streamflow in the ARB to climate change this century. In comparison to the small impact of water withdrawals on streamflow, climate change impacts are projected to be the primary driver of future low flow occurrences. Although winter flows are most sensitive to water withdrawals under the historical hydroclimatological regime, future climate change is projected to increase winter flows and decrease summer flows instead, with the frequency of summer low flows projected to rise by up to 85 % in the highest future emissions scenario by the end of the century. A decline in water availability due to more frequent low flows could interrupt oil sands water withdrawals and subsequent daily bitumen production for an additional 2–3 months each year by mid-century. Adaptation to climate warming in the ARB will need to recognize these changing seasonal patterns of flow in order to maintain available flows for ecological needs and water withdrawals.

The long-term threat of sea-level rise to coral atoll and reef island communities in Kiribati, Tuvalu and other nations has raised the possibility of international migration. Historical resettlements in the Pacific may provide valuable insight into the long-term effect of future climate change-related migration on communities. This study evaluates the challenges faced by Gilbertese people resettled from modern-day Kiribati to Ghizo in the Solomon Islands by the British colonial administration in the mid-1900s. Drawing upon field interviews (n = 45) conducted in 2011 and the available historical literature, the study examines the circumstances of the initial failed resettlement in the equatorial Phoenix Islands, the subsequent relocation to Ghizo, and the recent concerns of the Gilbertese in Ghizo. Focus is placed on the struggle to recover from the 2007 tsunami that devastated the unprepared community. The analysis reveals that uncertainty about land tenure (raised by 61% of respondents) persists 60 years after resettlement, and is linked to the ability to recover from the tsunami, tensions with the Melanesian population, concerns over political representation, cultural decline, and education and employment opportunities. The Gilbertese experience can serve as a cautionary tale for policymakers considering mechanisms for facilitating climate change-related migration.

In our paper describing a new coral record from Butaritari, we hypothesized that comparing the temporal trends in our records to coral records from farther east in the equatorial Pacific may support the evidence for a weakening of a Walker circulation, documented elsewhere in the literature [Power and Smith, 2007; Tokinaga et al., 2012]. Weakening of the Walker circulation is expected under global warming due to an imbalance in the rate of change in different aspects of the hydrological cycle [Vecchi and Soden, 2007]. We thank Karnauskas et al. [2015] for recognizing the value of our Butaritari coral climate reconstruction, and we appreciate their critique of our study. The Karnauskas et al. [2015] analyses strengthen our argument regarding the utility of interisland coral-proxy derived sea surface temperature (SST) gradients as a Walker circulation metric, but we disagree with their interpretation of decadal variability in our records. Here we provide additional analyses, which confirm that our reconstruction [Carilli et al., 2014] shows a long-term weakening of the Walker circulation over 1972-1998. We also document that significant decadal variations in Walker circulation strength, and for particular choices of start and end years over which trends are calculated, are able to show slight Walker strengthening. Overall, we conclude that Walker circulation variations are more nuanced than either our original publication [Carilli et al., 2014] or the subsequent Karnauskas et al. [2015] comment would suggest. Karnauskas et al. [2015] also provide a detailed analysis of Equatorial Undercurrent (EUC) activity near the Gilbert Islands and argue that the EUC does not strongly affect Butaritari. Our original publication did not claim to find significant EUC/Butaritari linkages, and we appreciate the diligence of Karnauskas et al. [2015] for ruling this out as a possibility.

This work was supported by an Australian Nuclear Science and Technology Organization Postdoctoral Fellowship (J.C.), a Natural Sciences and Engineering Research Council of Canada Discovery Grant (S.D.), a National Science Foundation Ocean Sciences Postdoctoral Fellowship (S.S.), and ARC Discovery Project grant DP1092945 (H.V.M.), and an AINSE Fellowship grant (H.V.M.).

The ratio of key elements such as nitrogen, phosphorus, and silica determines nutrient limitations that are important to regulating primary productivity and species composition in aquatic ecosystems. The flux of these nutrients in streams, as dissolved constituents or as particulate matter, is sensitive to variability in flow conditions. Most previous research on nutrient flux and hydrologic variability has focused on the response of individual elements, especially nitrogen, to changes in flow over time. This study examines how the ratios of total nitrogen to total phosphorus (N:P) and total nitrogen to dissolved silica (N:Si) respond to hydrologic variability in the Mississippi-Atchafalaya River Basin. A doubling of the discharge by the Mississippi and Atchafalaya Rivers to the Gulf of Mexico is found to increase the N:P by 10% and the N:Si by 4%. Analysis of data from upstream stations indicates that the N:P increases with discharge in subbasins with intensive row crop agriculture and high fertilizer application rates but is less predictable in other subbasins. Conversely, the response of N:Si to discharge does not vary predictably with the land use characteristics of the subbasin. The response of the nutrient ratios to variability in flow may be linked to the different sources and sinks of each nutrient, as well as the difference between the dominant transport pathways of each nutrient. High-resolution data and models that describe the dissolved and particulate nutrient cycling are needed to assess the relative contribution of different drivers to these observed patterns and to identify the response of nutrient ratios to hydrologic variability under future land use and climate change.

The El Nino–Southern Oscillation is known to influence surface temperatures worldwide. El Nino conditions are thought to lead to anomalously warm global average surface temperature, absent other forcings. Recent research has identified distinct possible types of El Nino events based on the location of peak sea surface temperature anomalies. Here we analyze the relationship between the type of El Nino event and the global surface average temperature anomaly, using three historical temperature data sets. Separating El Nino events into types reveals that the global average surface temperatures are anomalously warm during and after traditional eastern Pacific El Nino events, but not central Pacific or mixed events. Historical analysis indicated that slowdowns in the rate of global surface warming since the late 1800s may be related to decadal variability in the frequency of different types of El Nino events.

The late founder of this journal, Stephen Schneider, argued that climate scientists must find the right balance between being honest about the limits of our knowledge and being effective in communicating the risks that climate change poses to society. The worlds of science and communications have changed dramatically in the years since Schneider first described this “double ethical bind”. Yet for most scientists, the core challenge of public communication remains. How do we choose between what we perceive as science – being honest – and what we perceive as advocacy – being effective? This essay suggests that scientists should view science and advocacy as opposite ends of a continuum with many possible positions. Drawing upon findings from psychology, communications, and science and technology studies, I describe how scientists can use research and critical self-analysis to be “scientific” about public engagement and to choose a suitable place for themselves on the science-advocacy continuum.

International aid is increasingly focused on adaptation to climate change. At recent meetings of the parties to the United Nations Framework Convention on Climate Change, the developed world agreed to rapidly increase international assistance to help the developing world respond to the impacts of climate change. In this paper, we examine the decision-making challenges facing internationally supported climate change adaptation projects, using the example of efforts to implement coastal protection measures (e.g. sea walls, mangrove planting) in Kiribati. The central equatorial Pacific country is home to the Kiribati Adaptation Project, the first national-level climate change adaptation project supported by the World Bank. Drawing on interview and document research conducted over an 8-year period, we trace the forces influencing decisions about coastal protection measures, starting from the variability and uncertainty in climate change projections, through the trade-offs between different measures, to the social, political, and economic context in which decisions are finally made. We then discuss how sub-optimal adaptation measures may be implemented despite years of planning, consultation, and technical studies. This qualitative analysis of the real-world process of climate change adaptation reveals that embracing a culturally appropriate and short-term (~20 years) planning horizon, while not ignoring the longer-term future, may reduce the influence of scientific uncertainty on decisions and provide opportunities to learn from mistakes, reassess the science, and adjust suboptimal investments. The limiting element in this approach to adaptation is likely to be the availability of consistent, long-term financing.

Episodes of mass coral bleaching have been reported in recent decades and have raised concerns about the future of coral reefs on a warming planet. Despite the efforts to enhance and coordinate coral reef monitoring within and across countries, our knowledge of the geographic extent of mass coral bleaching over the past few decades is incomplete. Existing databases, like ReefBase, are limited by the voluntary nature of contributions, geographical biases in data collection, and the variations in the spatial scale of bleaching reports. In this study, we have developed the first-ever gridded, global-scale historical coral bleaching database. First, we conducted a targeted search for bleaching reports not included in ReefBase by personally contacting scientists and divers conducting monitoring in under-reported locations and by extracting data from the literature. This search increased the number of observed bleaching reports by 79%, from 4146 to 7429. Second, we employed spatial interpolation techniques to develop annual 0.04° × 0.04° latitude-longitude global maps of the probability that bleaching occurred for 1985 through 2010. Initial results indicate that the area of coral reefs with a more likely than not (>50%) or likely (>66%) probability of bleaching was eight times higher in the second half of the assessed time period, after the 1997/1998 El Nino. The results also indicate that annual maximum Degree Heating Weeks, a measure of thermal stress, for coral reefs with a high probability of bleaching increased over time. The database will help the scientific community more accurately assess the change in the frequency of mass coral bleaching events, validate methods of predicting mass coral bleaching, and test whether coral reefs are adjusting to rising ocean temperatures.

Public opinion in the United States about human-caused climate change has varied over the past 20 years, despite an increasing consensus about the issue in the expert community. Attitudes about climate change have been attributed to a number of factors including personal values, political ideology, the media environment and personal experience. Recent studies have found evidence that the temperature can influence one’s opinion about climate change and willingness to change behaviour and/or support climate policy. Although there is some evidence that individual cool or warm years have influenced large-scale opinion about climate change, the extent to which temperature can explain the past variability in public opinion and public discourse about climate change at the national level is not known. Here we isolate the relationship between opinion about climate change and temperature at the national scale, using data from opinion polls, a discourse analysis of opinion articles from five major daily newspapers, and a national air temperature database. The fraction of respondents to national polls who express “belief in” or “worry about” climate change is found to be significantly correlated to U.S. mean temperature anomalies over the previous 3–12 months. In addition, the fraction of editorial and opinion articles which “agree” with the expert consensus on climate change is also found to be significantly correlated to U.S. mean temperature anomalies at seasonal and annual scales. These results suggest that a fraction of the past variance in American views about climate change could potentially be explained by climate variability.

This article examines the increasing emphasis amongst climate scientists and development professionals on providing ‘climate services’ in order to inform adaptation decisions in vulnerable countries. The climate service business model hopes to provide ‘on demand’ and ‘actionable’ information products that are useful for policy makers. Drawing from literature across the natural and social sciences, we outline potential benefits and limits of this model of providing climate information and products, as well as recommendations for improving climate services. We argue that a shift away from the commercialized model of climate services may be necessary to ensure the creation, and consistent delivery, of products that practitioners in the developing world are able to employ in making adaptation decisions. WIREs Clim Change 2017, 8:e424. doi: 10.1002/wcc.424 For further resources related to this article, please visit the WIREs website.

Comprehensive computer simulations show that coral reefs are likely to suffer extensive long-term degradation resulting from mass bleaching events even if the expected increase in global mean temperature can be kept well below 2 °C. Without major mitigation efforts to limit global warming significantly, the fate of coral reef ecosystems seems to be sealed.