Climate Change Hotspot Research Articles

Five Years of Dust Episodes at the Southern Italy GAW Regional Coastal Mediterranean Observatory: Multisensors and Modeling Analysis

The Mediterranean area is a climate-change hotspot because of the natural and anthropogenic pollution pressure. The presence of natural aerosols, such as dust, influences solar radiation and contributes to the detection, in storm episodes, of significant concentrations of PM10 in Southern Italy, where generally fresh and clean air is due to local circulation, and particulate matter concentrations are very low. We present the results of medium-term observations (2015–2019) at Lamezia Terme GAW (Global Atmospheric Watch) Regional Observatory, with the purpose of identifying the dust incursion events by studying the aerosol properties in the site. To achieve this goal, the experimental data, collected by several instruments, have been also correlated with the large-scale atmospheric patterns derived by the ERA5 reanalysis dataset, in order to study the meteorological conditions that strongly influence dust outbreaks and their spatio-temporal behavior. An intense dust-outbreak episode, which occurred on 23–27 April 2019, was chosen as a case study; a detailed analysis was carried out considering surface and column optical properties, chemical properties, large-scale pattern circulation, air-quality modeling/satellite products, and back-trajectory analysis, to confirm the capability of the modeled large-scale atmospheric fields to correctly simulate the conditions mainly related to the desert dust-outbreak events.

Extreme events are more likely to affect the breeding success of lesser kestrels than average climate change

Climate change is predicted to severely impact interactions between prey, predators and habitats. In Southern Europe, within the Mediterranean climate, herbaceous vegetation achieves its maximum growth in middle spring followed by a three-month dry summer, limiting prey availability for insectivorous birds. Lesser kestrels (Falco naumanni) breed in a time-window that matches the nestling-rearing period with the peak abundance of grasshoppers and forecasted climate change may impact reproductive success through changes in prey availability and abundance. We used Normalised Difference Vegetation Index (NDVI) as a surrogate of habitat quality and prey availability to investigate the impacts of forecasted climate change and extreme climatic events on lesser kestrel breeding performance. First, using 14 years of data from 15 colonies in Southwestern Iberia, we linked fledging success and climatic variables with NDVI, and secondly, based on these relationships and according to climatic scenarios for 2050 and 2070, forecasted NDVI and fledging success. Finally, we evaluated how fledging success was influenced by drought events since 2004. Despite predicting a decrease in vegetation greenness in lesser kestrel foraging areas during spring, we found no impacts of predicted gradual rise in temperature and decline in precipitation on their fledging success. Notwithstanding, we found a decrease of 12% in offspring survival associated with drought events, suggesting that a higher frequency of droughts might, in the future, jeopardize the recent recovery of the European population. Here, we show that extreme events, such as droughts, can have more significant impacts on species than gradual climatic changes, especially in regions like the Mediterranean Basin, a biodiversity and climate change hotspot.

Environmental drivers and indicators of change in habitat and fish assemblages within a climate change hotspot

Climate-driven environmental change is predicted to accelerate over the coming decades. Anticipating the ecological consequences requires a fundamental understanding of how environmental variables influence key habitats and species. Southeastern Australia is a marine climate change hotspot, characterised by rapidly increasing sea surface temperatures, strengthening currents and increasing storm frequency. To understand ecosystem responses to environmental drivers in this region, and to anticipate future climate-driven change, we examined the spatial distribution and environmental relationships of key marine habitats, fish assemblages, and the ecologically important urchin Centrostephanus rodgersii along ∼1000 km of reef off southeastern Australia using towed video transects. We also identified potential biological indicators of climate-driven changes to rocky reef ecosystems, based on ecological importance, ease of measurement, and sensitivity to one or more climate-affected environmental drivers. Significant latitudinal gradients were identified for biota, with habitats, fish assemblages and urchin densities all varying latitudinally with sea surface temperature and current strength. Wave energy and distance offshore were identified as drivers of biota at local-scales (100–1000 m). These results indicate that climate-driven changes to various environmental factors will alter the composition and distribution of marine biota, at a variety of scales. The average thermal niche for fish assemblages varied significantly with changing mean sea surface temperature and may be a sentinel indicator of climate-driven changes. Coverage of the kelp Ecklonia radiata, densities of the urchin C. rodgersii, and coral cover were also confirmed as potential valuable biological indicators of climate-driven changes. These indicators, and the widespread baseline data assembled in this study, will facilitate detection of future changes to rocky reef ecosystems in southeastern Australia.

21st Century Projections of Extreme Precipitation Indicators for Cyprus

According to observational and model-based studies, the eastern Mediterranean region is one of the most prominent climate-change hotspots in the world. The combined effect of warming and drying is expected to augment the regional impacts of global warming. In addition to changes in mean climatic conditions, global warming is likely to induce changes in several aspects of extreme rainfall such as duration and magnitude. In this context, we explore the impact of climate change on precipitation with the use of several indicators. We focus on Cyprus, a water-stressed island located in the eastern Mediterranean Basin. Our results are derived from a new high-resolution simulation for the 21st century, which is driven by a “business-as-usual” scenario. In addition to a strong temperature increase (up to 4.1 °C), our analysis highlights that, on average for the island, most extreme precipitation indicators decrease, suggesting a transition to much drier conditions. The absolute daily rainfall maxima exhibit strong local variability, indicating the need for high resolution simulations to understand the potential impacts on future flooding.

Twenty-First-Century Climate Change Hot Spots in the Light of a Weakening Sun

AbstractSatellite measurements over the last three decades show a gradual decrease in solar output, which can be indicative as a precursor to a modern grand solar minimum (GSM). Using a chemistry–climate model, this study investigates the potential of two GSM scenarios with different magnitude to counteract the climate change by projected anthropogenic greenhouse gas (GHG) emissions through the twenty-first century. To identify regions showing enhanced vulnerability to climate change (hot spots) and to estimate their response to a possible modern GSM, a multidimensional metric is applied that accounts for—in addition to changes in mean quantities—seasonal changes in the variability and occurrence of extreme events. We find that a future GSM in the middle of the twenty-first century would temporarily mitigate the global mean impact of anthropogenic climate change by 10%–23% depending on the GSM scenario. A future GSM would, however, not be able to stop anthropogenic global warming. For the GHG-only scenario, our hot-spot analysis suggests that the midlatitudes show a response to rising GHGs below global average, while in the tropics, climate change hot spots with more frequent extreme hot seasons will develop during the twenty-first century. A GSM would reduce the climate change warming in all regions. The GHG-induced warming in Arctic winter would be dampened in a GSM due to the impact of reduced solar irradiance on Arctic sea ice. However, even an extreme GSM could only mitigate a fraction of the tropical hot-spot pattern (up to 24%) in the long term.

Climate change vulnerability, water resources and social implications in North Africa

North Africa is considered a climate change hot spot. Existing studies either focus on the physical aspects of climate change or discuss the social ones. The present article aims to address this divide by assessing and comparing the climate change vulnerability of Algeria, Egypt, Libya, Morocco, and Tunisia and linking it to its social implications. The vulnerability assessment focuses on climate change exposure, water resources, sensitivity, and adaptive capacity. The results suggest that all countries are exposed to strong temperature increases and a high drought risk under climate change. Algeria is most vulnerable to climate change, mainly due to the country’s high sensitivity. Across North Africa, the combination of climate change and strong population growth is very likely to further aggravate the already scarce water situation. The so-called Arab Spring has shown that social unrest is partly caused by unmet basic needs of the population for food and water. Thus, climate change may become an indirect driver of social instability in North Africa. To mitigate the impact of climate change, it is important to reduce economic and livelihood dependence on rain-fed agriculture, strengthen sustainable land use practices, and increase the adaptive capacity. Further, increased regional cooperation and sub-national vulnerability assessments are needed.

Remotely-Sensed Identification of a Transition for the Two Ecosystem States Along the Elevation Gradient: A Case Study of Xinjiang Tianshan Bogda World Heritage Site

The alpine treeline, as an ecological transition zone between montane coniferous forests and alpine meadows (two ecosystem states), is a research hotspot of global ecology and climate change. Quantitative identification of its elevation range can efficiently capture the results of the interaction between climate change and vegetation. Digital extraction and extensive analysis in such a critical elevation range crucially depend on the ability of monitoring ecosystem variables and the suitability of the experimental model, which are often restricted by the weak intersection of disciplines and the spatial-temporal continuity of the data. In this study, the existence of two states was confirmed by frequency analysis and the Akaike information criterion (AIC) as well as the Bayesian information criterion (BIC) indices. The elevation range of a transition for the two ecosystem states on the northern slope of the Bogda was identified by the potential analysis. The results showed that the elevation range of co-occurrence for the two ecosystem states was 2690–2744 m. At the elevation of 2714 m, the high land surface temperature (LST) state started to exhibit more attraction than the low LST state. This elevation value was considered as a demarcation where abrupt shifts between the two states occurred with the increase of elevation. The identification results were validated by a field survey and unmanned aerial vehicle data. Progress has been made in the transition identification for the ecosystem states along the elevation gradient in mountainous areas by combining the remotely-sensed index with a potential analysis. This study also provided a reference for obtaining the elevation of the alpine tree line quickly and accurately.

Management options to reduce the environmental impact of dairy goat milk production

Although numbers are still low compared to cattle rearing, intensive dairy goat farms have been widely spreading in the Italian livestock systems. Since goats are quite rustic, they can easily adapt to different management practices; however, improving the efficiency can make the difference, both in productivity and on the environmental impact attributed to goat milk production.In the present study, the Life Cycle Assessment (LCA) approach was used to quantify the potential environmental impact of goat milk production system in 17 farms in Lombardy (Northern Italy). Together with the environmental assessment, statistical analysis was carried out in order to determine whether it was possible to identify any relation among the variables that characterise this farming system.From an environmental point of view, it has been shown that the lower the individual milk production, the more it affects the environmental impact: specifically, the carbon footprint appears higher than the one emitted by cattle milk production. Climate Change resulted, on average, equal to 2.67 kg CO2 eq/kg Fat and Protein Corrected Milk (FPCM) with a wide variability (min: 1.12 kg CO2 eq/kg FPCM; max: 5.05 kg CO2 eq/kg FPCM). Purchased feed was the main hotspot for several environmental impact categories (such as freshwater eutrophication, land use and mineral, fossil and renewable resources depletion). Enteric emissions and emissions from manure storage were hotspots for climate change, particulate matter and terrestrial acidification. The C sequestration during crop cultivation was not considered. As shown by the statistical analysis, the main driver which influenced the 6 main impact categories was, in fact, individual milk production. The environmental assessment was also performed considering a second Functional Unit (FU) (i.e. 1 ha of land) and the statistical analysis conducted on this FU showed the relevance of livestock intensity. In addition to this, the statistical analysis also showed how a restricted land availability can negatively affect the environmental outcome. This study represents one of the first studies on the environmental impact assessment of dairy goat milk production. Additionally, studying two FUs and using a statistical analysis approach helped to identify the main management options to which farmers should pay attention to improve goat milk production from an environmental point of view.

A qualitative comparative analysis of women’s agency and adaptive capacity in climate change hotspots in Asia and Africa

There is growing concern about sustainable and equitable adaptation in climate change hotspots, commonly understood as locations that concentrate high climatic variability, societal vulnerability and negative impacts on livelihood systems. Emphasizing gender within these debates highlights how demographic, socioeconomic and agro-ecological contexts mediate the experiences and outcomes of climate change. Drawing on data from 25 qualitative case studies across three hotspots in Africa and Asia, analysed using qualitative comparative analysis, we show how and in what ways women’s agency, or the ability to make meaningful choices and strategic decisions, contributes to adaptation responses. We find that environmental stress is a key depressor of women’s agency even when household structures and social norms are supportive or legal entitlements are available. These findings have implications for the effective implementation of multilateral agreements such as the United Nations Framework Convention on Climate Change, the Sendai Framework on Disaster Risk Reduction and the Sustainable Development Goals. Qualitative comparative analysis of 25 case studies across climate change hotspots in Africa and Asia shows that male migration and women’s poor working conditions combine with either institutional failure or poverty to constrain women’s agency, which limits their adaptive capacity.

A fast-moving target: achieving marine conservation goals under shifting climate and policies.

In the Anthropocene, marine ecosystems are rapidly shifting to new ecological states. Achieving effective conservation of marine biodiversity has become a fast‐moving target because of both global climate change and continuous shifts in marine policies. How prepared are we to deal with this crisis? We examined EU Member States Programs of Measures designed for the implementation of EU marine environmental policies, as well as recent European Marine Spatial Plans, and discovered that climate change is rarely considered operationally. Further, our analysis revealed that monitoring programs in marine protected areas are often insufficient to clearly distinguish between impacts of local and global stressors. Finally, we suggest that while the novel global Blue Growth approach may jeopardize previous marine conservation efforts, it can also provide new conservation opportunities. Adaptive management is the way forward (e.g., preserving ecosystem functions in climate change hotspots, and identifying and targeting climate refugia areas for protection) using Marine Spatial Planning as a framework for action, especially given the push for Blue Growth.

Assessing the Changing Rationale of the Fisher Youth in Climate Change Hotspots of Kerala

The Indian fisheries and aquaculture statistics seems fail largely to capture the youth and children working in the sector. A detailed study in the area related to the rising interest of fishermen, especially the younger generation to move out of fisheries in search of new opportunities in other fields and the reasons for the same has not been carried out. Taking this into consideration, to throw insights into the changing rationale of fisher youth, and their preferences in the context of climate change and depletion in fish catch over the years, a study was conducted in three coastal villages of Ernakulam district with the objectives of assessing the socio-economic profile of the fishermen community, younger generations interest in choosing fisheries as a livelihood option, generational shift in fishing operations and reasons for the disinterest of the younger generation in choosing fisheries as an occupation. Low status job, low profit and income, poor working conditions, high capital investment and operating cost and seasonal nature of occupation was reported as the five major reasons because of which the younger generation is not interested in choosing fisheries as an occupation and a considerable generational shift in social, economic and professional status was observed.

A century of conservation: The ongoing recovery of Svalbard reindeer

ABSTRACTSeveral caribou and reindeer (Rangifer tarandus) populations have experienced recent population declines, often attributed to anthropogenic stressors such as harvesting, landscape fragmentation, and climate change. Svalbard reindeer (R. t. platyrhynchus), the wild reindeer subspecies endemic to the high‐Arctic Svalbard archipelago, was protected in 1925, after most subpopulations had been eradicated by harvest. Although direct pressure from harvest has ceased, indirect anthropogenic stressors from environmental changes have increased in this climate change hot spot. An assessment of the current distribution and abundance is therefore urgently needed. We combined distance sampling (300 km transects, n = 489 reindeer groups) and total counts (1,350 km2, n = 1,349 groups) to estimate the Svalbard reindeer distribution and abundance across its entire range, which we compared with historical data from the literature and radiocarbon‐dated bones. Reindeer have now recolonized nearly all non‐glaciated land (i.e., areas occupied prior to human presence), and their spatial variation in abundance reflects vegetation productivity. Independent of vegetation productivity, however, recently recolonized areas have lower reindeer densities than areas not subject to past extirpation. This suggests that recovery from past overharvesting is still in progress. These incompletely recovered areas are potential targets for increased monitoring frequency and maintaining strict conservation to follow the Svalbard management goal (i.e., virtually untouched wilderness areas). Because of such ongoing recolonization, possibly combined with vegetation greening effects of recent warming, our status estimate of Svalbard reindeer abundance (22,435 [95% CI = 21,452–23,425]) is more than twice a previous estimate based on opportunistic counts. Thus, although our study demonstrates the successful outcome of strict harvesting control implemented a century ago, current and future population trajectories are likely shaped by climate change. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Subsurface ocean flywheel of coupled climate variability in the Barents Sea hotspot of global warming

Accelerated shrinkage of the Arctic sea ice cover is the main reason for the recent Arctic amplification of global warming. There is growing evidence that the ocean is involved in this phenomenon, but to what extent remains unknown. Here, a unique dataset of hydrographic profiles is used to infer the regional pattern of recent subsurface ocean warming and construct a skillful predictor for surface climate variability in the Barents Sea region - a hotspot of the recent climate change. It is shown that, in the era of satellite observations (1981–2018), summertime temperature anomalies of Atlantic water heading for the Arctic Ocean explain more than 80% of the variance of the leading mode of variability in the following winter sea ice concentration over the entire Northern Hemisphere, with main centers of action just in the Barents Sea region. Results from empirical forecast experiments demonstrate that predictability of the wintertime sea ice cover in the Barents Sea from subsurface ocean heat anomalies might have increased since the Arctic climate shift of the mid-2000s. In contrast, the corresponding predictability of the sea ice cover in the nearby Greenland Sea has been lost.

Photo voice as a participatory approach to influence climate related health policy in the Sundarbans

The IPCC Fifth Assessment Report highlights community-based strategies to drive effective and ecologically sustainable local adaptation strategies. A climate change hot spot, Sundarbans, India, needs collective action between communities and for local level health and non-health decision makers to find sustainable solutions to combat the impacts of climate change on child health. In our photovoice study, mothers examined mediating factors by which climate change was impacting their child's health. Over 80 mothers with at least one child aged 0–6 years took photographs to document the impact of climate change on factors affecting child health. During facilitated fortnightly group meetings, mothers identified and categorised the major factors affecting their children's health. Participants collectively selected the photographs most reflective of the mediating factors and presented their findings to the local and state health administrations to identify mutually agreeable solutions. Mothers identified five mediating factors. These included food security, livelihood, water and sanitation, accessibility of the health-care system, and breaching of embankments. The findings were presented by the mothers to community-level and state-level policy makers. The interactions resulted in the initiation of resilient road infrastructure, increased human resource availability in primary health centres during floods, and local government representatives demanding long-term adaptation strategies to address climate impacts. Child health is affected by climate change through multiple pathways. Participatory approaches like photo voice can be used effectively to reflect ground level experiences of climate-vulnerable communities, empower them, and provide a collaborative and inclusive platform to design policies and initiatives for the creation of climate resilient health systems and communities. Funding Future Health System Research consortium funded by DFID. Contributors UG drafted the abstract which was modified by BS and SB. UG and SB are the co-investigators of the study. BS is the supervising author. Declaration of interests We declare no competing interests.

Usage of Agricultural Intensification Practices by Smallholder Farmers in Kenyan Rapidly Developing Dry Areas

Developing countries, Kenya included are mostly affected by food problems and poverty as a result of high dependence on agriculture. In Kenya agriculture contributes to 27.3% of the Gross Domestic Product. Agriculture in Kenya is dominated by smallholder farmers, whose production is hampered by climate variability, declining land sizes and low agricultural technologies. Agricultural intensification is aimed at solving the problem of low agricultural productivity and poverty through increasing farm output per unit land area. Makueni and Nyando Sub-County were considered as hotspots of climate change by CCAFS. A total of 320 households were sampled from the two sub-counties. From the scope farmers were engaged in 16 agricultural intensification practices, some practices were substitutes others complementary so they were highly correlated. Principal Component Analysis (PCA) was then used to group them into clusters called principal components. PCA helped in creating levels of agricultural intensifications. From the results, the number of components (Levels of agricultural intensification) of users was ranging from one to five. That is from low users of strategy 1, partial users of 2, 3 and 4 to full users of 5. The result revealed that 56% of farmers used 5 sets of strategies while 31%, 8%, 3% and 1% of farmers’ used 4, 3, 2 and 1 levels of agricultural intensification practices respectively. The results implied that there was need for smallholder farmers to increase agricultural intensification which leads to improved smallholder farmers livelihood outcomes and helps in building their resilience to harsh climatic conditions. Keywords: Agricultural intensification practices, Kenya, Principal Component Analysis, Smallholder farmer DOI : 10.7176/JESD/10-18-04 Publication date :September 30 th 2019

Morphological characterization of cactus pear (Opuntia ficus-indica) accessions from Agadir, Morocco

The North Africa region falls under arid and semi-arid climate and it is considered as a hot spot for climate change. To face feed shortage, increase income of the rural poor and to mitigate the effect of climate change, around 1 million ha of cactus crop has been planted in Tunisia, Algeria and Morocco. Aware of the importance of germplasm, in-situ collections are being initiated in the region where promising accessions have been introduced from many countries. The objective of this contribution was to assess the genetic diversity of 20 cactus pear accessions from the in-situ collection located in the INRA Morocco research station of Agadir using morphological characterization based on FAO-Cactusnet descriptor. The data were subjected to Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) using XLSTAT 2015 package. The results showed that the accessions can be discriminated by the morphological descriptors. Many of these morphological descriptors are significantly correlated as the number of cladodes and the number of fruits (r=0.73), the number of cladodes and the plant diameter (r=0.73), the length of the cladode and the plant height (r=0.7), the length of the spine and the number of areoles (r=0.67). The cladode shape and the number of spines and areoles are the recommended descriptors, and are capable to discriminate accessions with a suitable accuracy. Other descriptors do not seem to influence the morphological characterization as the cladode thickness, the number of spine, the plant height and the cladode shape index. Therefore, Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) are good tools to segregate accessions using a reduced number of morphological descriptors. Another important finding is that the number of morphological descriptors may be reduced without potential risk of reducing the accuracy of the phenotypic characterization.

Climate drivers of malaria at its southern fringe in the Americas.

In this work we analyze potential environmental drivers of malaria cases in Northwestern Argentina. We inspect causal links between malaria and climatic variables by means of the convergent cross mapping technique, which provides a causality criterion from the theory of dynamic systems. Analysis is based on 12 years of weekly malaria P. vivax cases in Tartagal, Salta, Argentina—at the southern fringe of malaria incidence in the Americas—together with humidity and temperature time-series spanning the same period. Our results show that there are causal links between malaria cases and both maximum temperature, with a delay of five weeks, and minimum temperature, with delays of zero and twenty two weeks. Humidity is also a driver of malaria cases, with thirteen weeks delay between cause and effect. Furthermore we also determined the sign and strength of the effects. Temperature has always a positive non-linear effect on cases, with maximum temperature effects more pronounced above 25°C and minimum above 17°C, while effects of humidity are more intricate: maximum humidity above 85% has a negative effect, whereas minimum humidity has a positive effect on cases. These results might be signaling processes operating at short (below 5 weeks) and long (over 12 weeks) time delays, corresponding to effects related to parasite cycle and mosquito population dynamics respectively. The non-linearities found for the strength of the effect of temperature on malaria cases make warmer areas more prone to higher increases in the disease incidence. Moreover, our results indicate that an increase of extreme weather events could enhance the risks of malaria spreading and re-emergence beyond the current distribution. Both situations, warmer climate and increase of extreme events, will be remarkably increased by the end of the century in this hot spot of climate change.

Importance of snow and glacier meltwater for agriculture on the Indo-Gangetic Plain

Densely populated floodplains downstream of Asia’s mountain ranges depend heavily on mountain water resources, in particular for irrigation. An intensive and complex multi-cropping irrigated agricultural system has developed here to optimize the use of these mountain water resources in conjunction with monsoonal rainfall. Snow and glacier melt thereby modulate the seasonal pattern of river flows and, together with groundwater, provide water when rainfall is scarce. Climate change is expected to weaken this modulating effect, with potentially strong effects on food production in one of the world’s breadbaskets. Here we quantify the space-, time- and crop-specific dependence of agriculture in the Indo-Gangetic Plains on mountain water resources, using a coupled state-of-the-art, high-resolution, cryosphere–hydrology–crop model. We show that dependence varies strongly in space and time and is highest in the Indus basin, where in the pre-monsoon season up to 60% of the total irrigation withdrawals originate from mountain snow and glacier melt, and that it contributes an additional 11% to total crop production. Although dependence in the floodplains of the Ganges is comparatively lower, meltwater is still essential during the dry season, in particular for crops such as sugar cane. The dependency on meltwater in the Brahmaputra is negligible. In total, 129 million farmers in the Indus and Ganges substantially depend on snow and glacier melt for their livelihoods. Snow and glacier melt provides enough water to grow food crops to sustain a balanced diet for 38 million people. These findings provide important information for agricultural and climate change adaptation policies in a climate change hot spot where shifts in water availability and demand are projected as a result of climate change and socio-economic growth. Climate change will affect Himalayan water resources. This study quantifies the importance of snow and glacier melt for agriculture on the Indo-Gangetic plain, finding that 129 million farmers depend on it, especially for rice and cotton, and that meltwater supports crops feeding 38 million people.

The role of stratospheric ozone for Arctic-midlatitude linkages

Arctic warming was more pronounced than warming in midlatitudes in the last decades making this region a hotspot of climate change. Associated with this, a rapid decline of sea-ice extent and a decrease of its thickness has been observed. Sea-ice retreat allows for an increased transport of heat and momentum from the ocean up to the tropo- and stratosphere by enhanced upward propagation of planetary-scale atmospheric waves. In the upper atmosphere, these waves deposit the momentum transported, disturbing the stratospheric polar vortex, which can lead to a breakdown of this circulation with the potential to also significantly impact the troposphere in mid- to late-winter and early spring. Therefore, an accurate representation of stratospheric processes in climate models is necessary to improve the understanding of the impact of retreating sea ice on the atmospheric circulation. By modeling the atmospheric response to a prescribed decline in Arctic sea ice, we show that including interactive stratospheric ozone chemistry in atmospheric model calculations leads to an improvement in tropo-stratospheric interactions compared to simulations without interactive chemistry. This suggests that stratospheric ozone chemistry is important for the understanding of sea ice related impacts on atmospheric dynamics.

Climate change, biological invasions, and the shifting distribution of Mediterranean fishes: A large-scale survey based on local ecological knowledge.

Climate change and biological invasions are rapidly reshuffling species distribution, restructuring the biological communities of many ecosystems worldwide. Tracking these transformations in the marine environment is crucial, but our understanding of climate change effects and invasive species dynamics is often hampered by the practical challenge of surveying large geographical areas. Here, we focus on the Mediterranean Sea, a hot spot for climate change and biological invasions to investigate recent spatiotemporal changes in fish abundances and distribution. To this end, we accessed the local ecological knowledge (LEK) of small-scale and recreational fishers, reconstructing the dynamics of fish perceived as "new" or increasing in different fishing areas. Over 500 fishers across 95 locations and nine different countries were interviewed, and semiquantitative information on yearly changes in species abundance was collected. Overall, 75 species were mentioned by the respondents, mostly warm-adapted species of both native and exotic origin. Respondents belonging to the same biogeographic sectors described coherent spatial and temporal patterns, and gradients along latitudinal and longitudinal axes were revealed. This information provides a more complete understanding of the shifting distribution of Mediterranean fishes and it also demonstrates that adequately structured LEK methodology might be applied successfully beyond the local scale, across national borders and jurisdictions. Acknowledging this potential through macroregional coordination could pave the way for future large-scale aggregations of individual observations, increasing our potential for integrated monitoring and conservation planning at the regional or even global level. This might help local communities to better understand, manage, and adapt to the ongoing biotic transformations driven by climate change and biological invaders.