ORCID Profile
0000-0003-4186-2136
Current Organisation
Météo France Toulouse
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Publisher: Copernicus GmbH
Date: 06-07-2020
Abstract: Abstract. Anthropogenic climate change is projected to lead to ocean warming, acidification, deoxygenation, reductions in near-surface nutrients, and changes to primary production, all of which are expected to affect marine ecosystems. Here we assess projections of these drivers of environmental change over the twenty-first century from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under the CMIP6 Shared Socioeconomic Pathways (SSPs). Projections are compared to those from the previous generation (CMIP5) forced under the Representative Concentration Pathways (RCPs). A total of 10 CMIP5 and 13 CMIP6 models are used in the two multi-model ensembles. Under the high-emission scenario SSP5-8.5, the multi-model global mean change (2080–2099 mean values relative to 1870–1899) ± the inter-model SD in sea surface temperature, surface pH, subsurface (100–600 m) oxygen concentration, euphotic (0–100 m) nitrate concentration, and depth-integrated primary production is +3.47±0.78 ∘C, -0.44±0.005, -13.27±5.28, -1.06±0.45 mmol m−3 and -2.99±9.11 %, respectively. Under the low-emission, high-mitigation scenario SSP1-2.6, the corresponding global changes are +1.42±0.32 ∘C, -0.16±0.002, -6.36±2.92, -0.52±0.23 mmol m−3, and -0.56±4.12 %. Projected exposure of the marine ecosystem to these drivers of ocean change depends largely on the extent of future emissions, consistent with previous studies. The ESMs in CMIP6 generally project greater warming, acidification, deoxygenation, and nitrate reductions but lesser primary production declines than those from CMIP5 under comparable radiative forcing. The increased projected ocean warming results from a general increase in the climate sensitivity of CMIP6 models relative to those of CMIP5. This enhanced warming increases upper-ocean stratification in CMIP6 projections, which contributes to greater reductions in upper-ocean nitrate and subsurface oxygen ventilation. The greater surface acidification in CMIP6 is primarily a consequence of the SSPs having higher associated atmospheric CO2 concentrations than their RCP analogues for the same radiative forcing. We find no consistent reduction in inter-model uncertainties, and even an increase in net primary production inter-model uncertainties in CMIP6, as compared to CMIP5.
Publisher: Research Square Platform LLC
Date: 09-01-2023
DOI: 10.21203/RS.3.RS-2230847/V1
Abstract: Anthropogenic warming of the oceans and associated deoxygenation are altering marine ecosystems. Current knowledge suggests that these changes might be reversible in the centennial timescale in the ocean surface and irreversible at deeper depth if global warming were to decline. However, knowledge on the persistence of their combined effects on marine ecosystems remains limited. Here we explore to what extent global warming will drive alterations on marine habitats by following the evolution of a metabolic index that captures the ecophysiological response of marine organisms to both changes in temperature and oxygen, through an idealised r -up r -down atmospheric CO 2 concentration experiment. Using a multi-model approach, we find that changes in ocean temperature and oxygen drives a centuries-long irreversible loss of ~4% in the habitable volume of the upper 1000 m of the world ocean. These results suggest the combined effect of warming and deoxygenation will diminish the capability of the ocean to hold life far after recovering from a temperature overshoot.
Publisher: Springer Science and Business Media LLC
Date: 19-09-2021
DOI: 10.1186/S12992-021-00761-W
Abstract: In the nearly half century since it began lending for population projects, the World Bank has become one of the largest financiers of global health projects and programs, a powerful voice in shaping health agendas in global governance spaces, and a mass producer of evidentiary knowledge for its preferred global health interventions. How can social scientists interrogate the role of the World Bank in shaping ‘global health’ in the current era? As a group of historians, social scientists, and public health officials with experience studying the effects of the institution’s investment in health, we identify three challenges to this research. First, a future research agenda requires recognizing that the Bank is not a monolith, but rather has distinct inter-organizational groups that have shaped investment and discourse in complicated, and sometimes contradictory, ways. Second, we must consider how its influence on health policy and investment has changed significantly over time. Third, we must analyze its modes of engagement with other institutions within the global health landscape, and with the private sector. The unique relationships between Bank entities and countries that shape health policy, and the Bank’s position as a center of research, permit it to have a formative influence on health economics as applied to international development. Addressing these challenges, we propose a future research agenda for the Bank’s influence on global health through three overlapping objects of and domains for study: knowledge-based (shaping health policy knowledge), governance-based (shaping health governance), and finance-based (shaping health financing). We provide a review of case studies in each of these categories to inform this research agenda. As the COVID-19 pandemic continues to rage, and as state and non-state actors work to build more inclusive and robust health systems around the world, it is more important than ever to consider how to best document and analyze the impacts of Bank’s financial and technical investments in the Global South.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Sumegha Asthana.