Posts Tagged 'Arctic'

Climate in Svalbard 2100 – a knowledge base for climate adaptation

This report was commissioned by the Norwegian Environment Agency in order to provide basic information for climate change effect studies and climate change adaptation in Svalbard. It includes descriptions of historical, as well as projections for future climate development in the atmosphere, hydrosphere, cryosphere and ocean, and it includes effects on the physical nature, e.g. risks associated with landslides and avalanches. The projections for future climate are based on the global climate models used in the IPCCs fifth assessment report (IPCC, 2013). Dependent on availability of model data, three scenarios for emissions of greenhouse gases are used: “RCP8.5” (“business as usual”; “high emissions”), “RCP4.5” (reductions after 2040; “medium emissions”) and “RCP2.6” (drastic cuts from 2020; “low emissions”). Climate change in the atmosphere and land surface are projected up to the year 2100 and in the ocean up to the year 2070.

The report is to a large degree an assessment of existing literature and model results, e.g. the Arctic CORDEX regional climate models. In addition, a fine scale atmospheric regional climate model (COSMO-CLM) has been run, and the results were applied for estimating changes in e.g. heavy rainfall, frost days, snow, permafrost and glaciers. Further, a hydrological model has been run for Svalbard for present and projected future climate, based on input data from Arctic CORDEX. Also for the ocean, new analyses have been performed, based on the best available model data. Below follows a summary based on a combination of the assessment and results from new analyses.

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Predicting which species succeed in climate-forced polar seas

Understanding the mechanisms which determine the capacity of any species to adapt to changing environmental conditions is one of the foremost requirements in accurately predicting which populations, species and clades are likely to survive ongoing, rapid climate change. The polar oceans are amongst the most rapidly changing environments on Earth with reduced regional sea ice duration and extent, and their fauna’s expected sensitivity to warming and acidification. These changes potentially pose a significant threat to a number of polar fauna. There is, therefore, a critical need to assess the vulnerability of a wide range of species to determine the tipping points or weak links in marine assemblages. Knowledge of the effect of multiple stressors on polar marine fauna has advanced over the last 40 years, but there are still many data gaps. This study applies ecological risk assessment techniques to the increasing knowledge of polar species’ physiological capacities to identify their exposure to climate change and their vulnerability to this exposure. This relatively rapid, semi-quantitative assessment provides a layer of vulnerability on top of climate envelope models, until such times as more extensive physiological data sets can be produced. The risk assessment identified more species that are likely to benefit from the near-future predicted change (the winners), especially predators and deposit feeders. Fewer species were scored at risk (the losers), although animals that feed on krill scored consistently as under the highest risk.

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Northern cod species face spawning habitat losses if global warming exceeds 1.5°C

Rapid climate change in the Northeast Atlantic and Arctic poses a threat to some of the world’s largest fish populations. Impacts of warming and acidification may become accessible through mechanism-based risk assessments and projections of future habitat suitability. We show that ocean acidification causes a narrowing of embryonic thermal ranges, which identifies the suitability of spawning habitats as a critical life-history bottleneck for two abundant cod species. Embryonic tolerance ranges linked to climate simulations reveal that ever-increasing CO2 emissions [Representative Concentration Pathway (RCP) 8.5] will deteriorate suitability of present spawning habitat for both Atlantic cod (Gadus morhua) and Polar cod (Boreogadus saida) by 2100. Moderate warming (RCP4.5) may avert dangerous climate impacts on Atlantic cod but still leaves few spawning areas for the more vulnerable Polar cod, which also loses the benefits of an ice-covered ocean. Emissions following RCP2.6, however, support largely unchanged habitat suitability for both species, suggesting that risks are minimized if warming is held “below 2°C, if not 1.5°C,” as pledged by the Paris Agreement.

Continue reading ‘Northern cod species face spawning habitat losses if global warming exceeds 1.5°C’

Aerobic capacities and swimming performance of polar cod (Boreogadus saida) under ocean acidification and warming conditions

Polar cod (Boreogadus saida) is an important prey species in the Arctic ecosystem, yet its habitat is changing rapidly: climate change, through rising seawater temperatures and CO2 concentrations, is projected to be most pronounced in Arctic waters. This study aimed to investigate the influence of ocean acidification and warming on maximum performance parameters of B. saida as indicators for the species’ acclimation capacities under environmental conditions projected for the end of this century. After 4 months at four acclimation temperatures (0, 3, 6, 8°C) each combined with two PCO2 levels (390 and 1170 µatm), aerobic capacities and swimming performance of B. saida were recorded following a Ucrit protocol. At both CO2 levels, standard metabolic rate (SMR) was elevated at the highest acclimation temperature indicating thermal limitations. Maximum metabolic rate (MMR) increased continuously with temperature, suggesting an optimum temperature for aerobic scope for exercise (ASex) at 6°C. Aerobic swimming performance (Ugait) increased with acclimation temperature irrespective of CO2 levels, while critical swimming speed (Ucrit) did not reveal any clear trend with temperature. Hypercapnia evoked an increase in MMR (and thereby ASex). However, swimming performance (both Ugait and Ucrit) was impaired under elevated near-future PCO2 conditions, indicating reduced efficiencies of oxygen turnover. The contribution of anaerobic metabolism to swimming performance was very low overall, and further reduced under hypercapnia. Our results revealed high sensitivities of maximum performance parameters (MMR, Ugait, Ucrit) of B. saida to ocean acidification. Impaired swimming capacity under ocean acidification may reflect reduced future competitive strength of B. saida.

Continue reading ‘Aerobic capacities and swimming performance of polar cod (Boreogadus saida) under ocean acidification and warming conditions’

Using natural analogues to investigate the effects of climate change and ocean acidification on Northern ecosystems

Northern oceans are in a state of rapid transition. Still, our knowledge of the likely effects of climate change and ocean acidification on key species in the food web, functionally important habitats and the structure of Arctic and sub-Arctic ecosystems is limited and based mainly on short-term laboratory studies on single species. This review discusses how tropical and temperate natural analogues of carbonate chemistry drivers, such as CO2 vents, have been used to further our knowledge of the sensitivity of biological systems to predicted climate change, and thus assess the capacity of different species to show long-term acclimation and adaptation to elevated levels of pCO2. Natural analogues have also provided the means to scale-up from single-species responses to community and ecosystem level responses. However, to date the application of such approaches is limited in high latitude systems. A range of Arctic and sub-Arctic sites, including CO2 vents, methane cold seeps, estuaries, up-welling areas, and polar fronts, that encompass gradients of pH, carbonate saturation state, and alkalinity, are suggested for future high latitude, in-situ ocean acidification research. It is recommended that combinations of monitoring of the chemical oceanography, observational, and experimental (in situ and laboratory) studies of organisms around these natural analogues be used to attain better predictions of the impacts of ocean acidification and climate change on high latitude species and ecosystems.

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AMAP assessment 2018: Arctic ocean acidification

Ocean acidification, resulting from changes in ocean chemistry induced by increasing seawater carbon dioxide concentrations, is one of the growing challenges to marine organisms, ecosystems and biogeochemical cycling. Some of the fastest rates of ocean acidification currently observed are in the Arctic Ocean, with important physiological and geochemical thresholds already surpassed. Projections indicate that large parts of the Arctic Ocean are undergoing marine carbonate system changes that will incur significant shifts in ecological status over the coming decades unless global carbon emissions are drastically curtailed. These changes in water chemistry and biology will have significant socio-ecological and economic consequences at the local to global level.

The first AMAP Arctic Ocean acidification report (AMAP, 2013) presented a scientific assessment on the changing state of ocean acidification in the Arctic and provided an Arctic-wide perspective on the rapid increase in seawater acidity. The report concluded that ocean acidification was affecting the Arctic marine environment and ecosystems.

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Experimental study of the influence of thawing permafrost on the chemical properties of sea water

In a warming environment, permafrost thawing can play a significant role in the chemical composition of coastal waters in the Arctic region. It is a potential source of organic and inorganic forms of nutrients, as well as heavy metals and pollutants. To estimate the permafrost thawing influence on the chemical properties of the sea water, an experimental study was conducted as part of a Norwegian-Russian expedition to Svalbard 11–17 June 2017. Permafrost (PF) samples were collected at an abrasive cliff 10 km west of Longyearbyen, after that, the experiment was performed at the University of Svalbard laboratory. The experiment was focused on identifying the possible changes in concentrations of nutrients, carbonate system parameters, and pollutant composition related to permafrost thawing. During the experiment, the samples of permafrost were added to the seawater. Then, the solution was exposed to natural conditions outdoors for 24 hours while water samples from the solution were taken at specified time intervals. Data from the experiment allowed for estimating the rate and change in concentrations of chemical substances due to permafrost thawing. This study shows the importance of permafrost thawing in the coastal areas chemical regime, affecting the metals supply, ocean acidification, and nutrient inputs; therefore, coastal ecosystems could be exposed to new impacts of numerous stresses associated with global warming.

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Ocean acidification in the IPCC AR5 WG II

OUP book