Posts Tagged 'mitigation'

La terminologie de la géoingénierie marine. Une contribution au projet IATE-CvT (in French)

Pour la première fois mentionnée dans la politique en 1965 par le comité consultatif scientifique du président des États-Unis, la géoingénierie (ou : ingénierie climatique) est une préoccupation relativement nouvelle. Plus de cinquante ans plus tard, le sujet reste néanmoins une topique controversée. La question reste : jusqu’où peut-on intervenir dans le climat afin de contrebalancer le changement climatique d’origine anthropocène ? La géoingénierie fait référence aux techniques développées pour lutter contre le changement climatique en supprimant les gaz à effet de serre de l’atmosphère de l’un côté et de l’autre en augmentant la quantité de lumière solaire réfléchie vers l’espace à partir de la terre et des océans (Shepherd, J. G. 2009). C’est un domaine actuel qui peut éventuellement impliquer chacun sur terre. Le domaine se trouve au cœur de nombreux sommets internationaux (p. ex. le COP21 de 2015 à Paris) et suscite non seulement des questions au niveau de la technologie, mais également au niveau éthique (jusqu’où peut-on altérer la nature ?), politique (protocole de Kyoto, 1997), philosophique (« on est Dieu »), sociologique (les conséquences pour les habitants), biologique (les conséquences pour les espèces) et économique (qui paye ?). Comme la géoingénierie est une préoccupation relativement nouvelle, la terminologie internationale laisse encore à désirer. Le domaine étant en pleine voie de développement, les scientifiques du domaine ne se préoccupent guère avec les mots qu’ils appliquent. Reste la tâche aux terminologues de décrire, nommer et normer les termes. Dans ce travail sont traités dix termes venant de la géoingénierie marine. Les termes ont été rencontrés dans des publications scientifiques anglaises, puis décrits en anglais, français et néerlandais de manière à les intégrer dans les bases de données terminologiques IATE et la base terminologique du Centrum voor Terminologie (CvT ; Centre pour Terminologie).

Continue reading ‘La terminologie de la géoingénierie marine. Une contribution au projet IATE-CvT (in French)’

Algal communities: an answer to global climate change

Human activities and resultant changes in global climate have profound consequences for ecosystems and economic and social systems, including those that are dependent upon marine systems. The increasing concentration of atmospheric greenhouse gases (GHGs) has resulted in gradual modification of multiple aspects of marine ecosystem properties such as salinity, temperature, and pH. It is well known that temporal and spatial variations in environmental properties determine the composition and abundance of different algal populations in a region. Within the present study the evidence for algal compatibility to changing environmental conditions is surveyed. The unique ability of algal communities to play a role in promotion of CO2 sequestration technologies, biorefinery approaches, as well as transition to CO2‐neutral renewable energy has gained traction with environmentalists and economists in a view to mitigation of climate change using algae. The next step is to re‐evaluate the assumption of a steady‐state oceanic carbon cycle and the role of biological activities in response to future climate changes.

Continue reading ‘Algal communities: an answer to global climate change’

Increasing seawater alkalinity using fly ash to restore the pH and the effect of temperature on seawater flue gas desulfurization

Wet type flue gas desulfurization (FGD) using lime or limestone is popular because of its operational simplicity and the availability of lime and limestone. Seawater FGD (SWFGD) utilizes the alkalinity of seawater, and its efficiency varies depending on the seawater alkalinity. This study examined the effects of temperature, gas/water ratio, and total alkalinity of the absorbing solution on the removal efficiency of SO2 from flue gas by seawater. In addition, this study showed the possibility of increasing the total alkalinity of seawater using fly ash from coal power plants. The experimental results showed a 8% increase in removal efficiency, while temperature decreased by 10 °C from 25 °C under the conditions of a gas/water ratio of 100 and a resultant pH of 3. The increase in removal efficiency with increasing alkalinity was measured as 0.27%/ppm of bicarbonate alkalinity. This study showed that fly ash has the ability to increase the total alkalinity of seawater. The pH restoration experiment was conducted using fly ash and limestone. The conceptual design processes of SWFGD using NaOH, fly ash, and limestone for a 400 MW coal power plant were developed, and the material balance was calculated using ASPEN Plus software.

Continue reading ‘Increasing seawater alkalinity using fly ash to restore the pH and the effect of temperature on seawater flue gas desulfurization’

The potential environmental response to increasing ocean alkalinity for negative emissions

The negative emissions technology, artificial ocean alkalinization (AOA), aims to store atmospheric carbon dioxide (CO2) in the ocean by increasing total alkalinity (TA). Calcium carbonate saturation state (ΩCaCO3) and pH would also increase meaning that AOA could alleviate sensitive regions and ecosystems from ocean acidification. However, AOA could raise pH and ΩCaCO3 well above modern-day levels, and very little is known about the environmental and biological impact of this. After treating a red calcifying algae (Corallina spp.) to elevated TA seawater, carbonate production increased by 60% over a control. This has implication for carbon cycling in the past, but also constrains the environmental impact and efficiency of AOA. Carbonate production could reduce the efficiency of CO2 removal. Increasing TA, however, did not significantly influence Corallina spp. primary productivity, respiration, or photophysiology. These results show that AOA may not be intrinsically detrimental for Corallina spp. and that AOA has the potential to lessen the impacts of ocean acidification. However, the experiment tested a single species within a controlled environment to constrain a specific unknown, the rate change of calcification, and additional work is required to understand the impact of AOA on other organisms, whole ecosystems, and the global carbon cycle.

Continue reading ‘The potential environmental response to increasing ocean alkalinity for negative emissions’

The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve (updated)

Coastal ecosystems can experience acidification via upwelling, eutrophication, riverine discharge, and climate change. While the resulting increases in pCO2 can have deleterious effects on calcifying animals, this change in carbonate chemistry may benefit some marine autotrophs. Here, we report on experiments performed with North Atlantic populations of hard clams (Mercenaria mercenaria), eastern oysters (Crassostrea virginica), bay scallops (Argopecten irradians), and blue mussels (Mytilus edulis) grown with and without North Atlantic populations of the green macroalgae, Ulva. In six of seven experiments, exposure to elevated pCO2 levels ( ∼ 1700µatm) resulted in depressed shell- and/or tissue-based growth rates of bivalves compared to control conditions, whereas rates were significantly higher in the presence of Ulva in all experiments. In many cases, the co-exposure to elevated pCO2 levels and Ulva had an antagonistic effect on bivalve growth rates whereby the presence of Ulva under elevated pCO2 levels significantly improved their performance compared to the acidification-only treatment. Saturation states for calcium carbonate (Ω) were significantly higher in the presence of Ulva under both ambient and elevated CO2 delivery rates, and growth rates of bivalves were significantly correlated with Ω in six of seven experiments. Collectively, the results suggest that photosynthesis and/or nitrate assimilation by Ulva increased alkalinity, fostering a carbonate chemistry regime more suitable for optimal growth of calcifying bivalves. This suggests that large natural and/or aquacultured collections of macroalgae in acidified environments could serve as a refuge for calcifying animals that may otherwise be negatively impacted by elevated pCO2 levels and depressed Ω.

Continue reading ‘The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve (updated)’

Bio-buffering to combat ocean acidification?

Atmospheric carbon dioxide (CO2) concentration is rising faster than ever before, due to continuous surge in burning fossil fuel. According to the ‘State of the Climate in 2017’ report from the National Oceanic and Atmospheric Administration (NOAA) and the American Meteorological Society, the global growth rate of atmospheric CO2 concentration was approximately 0.6 ± 0.1 ppm/year in the 1960s [3]. However, in the last decade, the growth rate has jumped to 2.3 ppm/year. The estimated atmospheric CO2 concentration is expected to reach 800–1000 ppm by the end of this century [6]. Oceans absorb nearly 30% of the global CO2 emissions [8], resulting in decrease in ocean pH, known as ocean acidification (OA). While atmospheric CO2 is the major contributor to OA globally, other anthropogenic activities influence OA on a local level. These include acid rain from vehicle emissions and industry in urban areas, inflow of organic carbon to the oceans in the form of sewage, and nutrient loading into the oceans from agricultural runoff; all of which contribute to OA [7].

Ocean acidification not only lowers the pH of ocean water, but also decreases dissolved carbonate ion (CO32−) concentration and alters the saturation states of calcium carbonate minerals. Calcifying organisms, such as corals, mollusks, and shellfishes, which use CO32− ions along with calcium ions to produce their calcium carbonate skeletons and shells, are negatively impacted by decreased CO32− levels. In addition, OA causes changes in habitat quality and nutrient cycling, which have numerous effects on food web interactions. Overall, complex changes occur in populations, communities, and the entire ecosystem; the scope of which is yet to be fully understood.

Continue reading ‘Bio-buffering to combat ocean acidification?’

Ocean solutions to address climate change and its effects on marine ecosystems

The Paris Agreement target of limiting global surface warming to 1.5–2C compared to pre-industrial levels by 2100 will still heavily impact the ocean. While ambitious mitigation and adaptation are both needed, the ocean provides major opportunities for action to reduce climate change globally and its impacts on vital ecosystems and ecosystem services. A comprehensive and systematic assessment of 13 global- and local-scale, ocean-based measures was performed to help steer the development and implementation of technologies and actions toward a sustainable outcome. We show that (1) all measures have tradeoffs and multiple criteria must be used for a comprehensive assessment of their potential, (2) greatest benefit is derived by combining global and local solutions, some of which could be implemented or scaled-up immediately, (3) some measures are too uncertain to be recommended yet, (4) political consistency must be achieved through effective cross-scale governance mechanisms, (5) scientific effort must focus on effectiveness, co-benefits, disbenefits, and costs of poorly tested as well as new and emerging measures.

Continue reading ‘Ocean solutions to address climate change and its effects on marine ecosystems’


Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,284,648 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book