Posts Tagged 'Policy'

Exploring coastal acidification and oyster restoration activities on the United States Atlantic coast

Executive Summary

The global ocean mediates the effect of climate change and anthropogenic carbon emissions by absorbing atmospheric carbon dioxide (Ellis et al., 2017). The ocean’s absorption of carbon dioxide results in a change in ocean chemistry and decline in seawater pH known as ocean acidification (Kapsenberg and Cyronak, 2018). Changes in ocean chemistry and pH may also be driven by primary production activity, upwelling, and river runoff into marine environments (Richards et al., 2014). Ocean acidification has the potential to adversely affect numerous marine organisms (Kapsenberg and Cyronak, 2018), however, it can be especially problematic for calcifying shellfish species (Swezey et al., 2020) like the Eastern Oyster and larval or juvenile stage organisms (Mangi et al., 2018). Temperature, salinity, dissolved oxygen levels, and acidification impact the health and longevity of oysters and oyster reefs. Oyster reefs offer numerous ecosystem services. These reefs provide habitat for benthic invertebrates, seabirds and fish that rely on reefs for feeding, nursery, and breeding grounds (Burrows et al., 2005). The Eastern Oyster (Crassostrea virginica) is a native oyster species of the U.S. Atlantic Coast. Although oysters reefs support coastal livelihoods and offer numerous ecosystem services, many reefs have been degraded by anthropogenic activities (Burrows et al., 2005). Pollution, over-harvest, and an increase in loading of suspended sediments are key threats to oyster reef health (Burrows et al., 2005). Oyster reef restoration projects focus on returning reefs to their natural state. Given the role of oysters as ecosystem engineers, and the many benefits that may be derived from healthy oyster reefs, restoration projects are a priority for communities throughout the U.S. Atlantic Coast.

Cooley et al. 2016 recommends several effective community actions that may be taken to help address ocean acidification today. This project focuses on two non-legislative actions discussed by Cooley et al. 2016. These are public education related to coastal acidification and resilience management through oyster reef restoration projects. The purpose of this project is to support coastal resource-reliant communities on the U.S. Atlantic Coast in preparing for the potential future impacts of ocean acidification on C. virginica. The project examines trends in the oyster reef restoration projects presently underway at the state and local level along the U.S. Atlantic Coast, and it considers how coastal acidification may affect the longevity of the region’s oyster reefs. Finally, the project considers the future research and management considerations needed to adequately protect oyster reefs under changing climatic conditions.

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CO2 capture by pumping surface acidity to the deep ocean

The majority of IPCC scenarios call for active CO2 removal (CDR) to remain below 2oC of warm- ing. On geological timescales, ocean uptake regulates atmospheric CO2 concentration, with two homeostats driving CO2 uptake: dissolution of deep ocean calcite deposits and terrestrial weathering of silicate rocks, acting on 1ka to 100ka timescales, respectively. Many current ocean-based CDR proposals effectively act to accelerate the latter. Here we present a method which relies purely on the redistribution and dilution of acidity from a thin layer of the surface ocean to a thicker layer of deep ocean, with the aim of reducing surface acidification and accelerating the former carbonate homeostasis. This downward transport could be seen analogous to the action of the natural biological carbon pump. The method offers advantages over other ocean CDR methods and direct air capture approaches (DAC): the conveyance of mass is minimized (acidity is pumped in situ to depth), and expensive mining, grinding and distribution of alkaline material is eliminated. No dilute substance needs to be concentrated, avoiding the Sherwood’s Rule costs typically encountered in DAC. Finally, no terrestrial material is added to the ocean, avoiding significant alteration of seawater ion concentrations or issues with heavy metal toxicity encountered in mineral-based alkalinity schemes. The artificial transport of acidity accelerates the natural deep ocean compensation by calcium carbonate. It has been estimated that the total compensation capacity of the ocean is on the order of 1500GtC. We show through simulation that pumping of ocean acidity could remove up to 150GtC from the atmosphere by 2100 with- out excessive increase of local ocean pH. For an acidity release below 2000m, the relaxation half-life of CO2 return to the atmosphere was found to be ∼2500 years (∼1000yr without account- ing for carbonate dissolution), with ∼85% retained for at least 300 years. The uptake efficiency and residence time were found to vary with the location of acidity pumping, and optimal areas were determined. Requiring only local resources (ocean water and energy), this method could be uniquely suited to utilize otherwise-unusable open ocean energy sources at scale. We examine technological pathways that could be used to implement it and present a brief techno-economic estimate of 130-250$/tCO2 at current prices and as low as 93$/tCO2 under modest learning-curve assumptions.

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Large-scale interventions may delay decline of the Great Barrier Reef

On the iconic Great Barrier Reef (GBR), the cumulative impacts of tropical cyclones, marine heatwaves and regular outbreaks of coral-eating crown-of-thorns starfish (CoTS) have severely depleted coral cover. Climate change will further exacerbate this situation over the coming decades unless effective interventions are implemented. Evaluating the efficacy of alternative interventions in a complex system experiencing major cumulative impacts can only be achieved through a systems modelling approach. We have evaluated combinations of interventions using a coral reef meta-community model. The model consisted of a dynamic network of 3753 reefs supporting communities of corals and CoTS connected through ocean larval dispersal, and exposed to changing regimes of tropical cyclones, flood plumes, marine heatwaves and ocean acidification. Interventions included reducing flood plume impacts, expanding control of CoTS populations, stabilizing coral rubble, managing solar radiation and introducing heat-tolerant coral strains. Without intervention, all climate scenarios resulted in precipitous declines in GBR coral cover over the next 50 years. The most effective strategies in delaying decline were combinations that protected coral from both predation (CoTS control) and thermal stress (solar radiation management) deployed at large scale. Successful implementation could expand opportunities for climate action, natural adaptation and socioeconomic adjustment by at least one to two decades.

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Slow-onset events: a review of the evidence from the IPCC special reports on land, oceans and cryosphere

This paper reviews the evidence on slow-onset events presented in the Special Report on Climate Change and Land (SRCCL) and the Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), both published in 2019. It analyses how the reports, and recent literature cited in them, deal with the eight types of slow-onset events, specified by the UNFCCC: increasing temperatures, sea level risesalinizationocean acidification, glacial retreat, land degradationdesertification and loss of biodiversity. The authors used qualitative data analysis software to analyse the reports, and for each of the SOEs, they coded and analysed information about the state, rate of change, timescale, geography, drivers, impacts, management responses, adaptation limits and residual losses and damages. The paper provides an overview of the state of the art on SOEs and helps to identify gaps and challenges in understanding the nature of SOEs, their impact and effective management approaches.

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Conserve and sustainably use the oceans, seas, and marine resources

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Global ocean governance and ocean acidification

Among many other impacts, the rising levels of atmospheric carbon dioxide (CO2), primarily induced by increased rates of fossil fuel combustion, are changing the ocean’s chemistry (Guidetti and Danavaro 2018). The resulting increased uptake of more CO2 by the ocean is making the ocean more acidic leading to deleterious harm to marine ecosystems. This ocean acidification problem needs to be seen as an increased pressure on marine living resources, which are already under intense physicochemical and biological stress due to increased ocean warming (IPCC 2013), changes in their ecosystems (Milazzo et al. 2019), and the introduction of alien, competing species (Essl et al. 2020). For example, one of the well-known effects of ocean acidification is the lowering of calcium carbonate saturation states, which negatively impacts shell-forming marine organisms that range widely from plankton to benthic molluscs, echinoderms, and corals. The potential for marine organisms to adapt to…

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Climate change impacts on corals in the UK overseas territories of BIOT and the Pitcairn Islands

BIOT

The British Indian Ocean Territory (BIOT) consists of five atolls of low-lying islands, including the largest atoll in the world, Great Chagos Bank, and a number of submerged atolls and banks. Diego Garcia is the only inhabited island. The BIOT Marine Protected Area (MPA) was designatedin 2010. It covers the entire maritime zone and coastal waters, an approximate area of 640,000 km2. The marine environment is rich and diverse, attracting sea birds, sharks, cetaceans and sea turtles and with extensive seagrass and coral reef habitats. It includes the endangered Chagos brain coral (Ctenella chagius), an endemic massive coral unique to BIOT. BIOT reefs have suffered extensive bleaching and mortality, and they remain vulnerable to current and future climate change and other pressures, including:

Bleaching
The heavy mortality has been caused by recurrent marine heatwaves since the 1970s. Reefs have not yet recovered from the most severe bleaching in 2016 and 2017, with increasingly severe events expected. Deeper fore-reefs may act as refuges, but those colonies are likely to be more sensitive to temperature change. Limiting other pressures will not guarantee resilience to future bleaching.

Ocean acidification
There has been a low impact of ocean acidification on coral reefs so far, but when combined with future bleaching therisk of decalcification and erosion will increase. Under high emissions scenarios, BIOT is projected to become less suitable for corals by the end of the century.

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How to destroy a planet

The focus of climate change research has been with the anthropogenic production of carbon dioxide and the impact of
increasing concentrations of carbon dioxide in the atmosphere on; the climate, marine biological productivity and
biodiversity. Climate change is an equation, what goes into the atmosphere must be removed. Over the last 70 years since the chemical revolution, starting in the 1950’s, we have been destroying natural ecosystems with toxic-for-ever chemicals and plastic. The oceans represent our greatest carbon bank with a potential to sequester most of the carbon generated from the burning of fossil fuels, but productivity and biodiversity in the oceans are declining, and we could be faced with a trophic cascade collapse of the entire marine ecosystem. All life of earth depends upon a healthy ocean ecosystem, and we cannot solve climate change without protecting the oceans. This report details the sequence of events that are likely to occur and the actions that need to happen to prevent the collapse of the marine ecosystem and to avoid the worst of climate change.

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Aiding ocean development planning with SDG relationships in small island developing states

Promoting the Sustainable Development Goals (SDGs) must contend with the often siloed nature of governance institutions, making the identification of cooperative institutional networks that promote SDG targets a priority. We develop and apply a method that combines SDG interaction analysis, which helps determine prerequisites for SDG attainment, with the transition management framework, which helps align policy goals with institutional designs. Using Aruba as a case study, we show that prioritizing increased economic benefits from sustainable marine development, including those of tourism, provides the greatest amount of direct co-benefits to other SDGs. When considering indirect co-benefits, reducing marine pollution emerged as a key supporting target to achieve SDGs. The results also show that, as in many other small island states, sustainable ocean development in Aruba depends on international partnerships to address global issues—including climate change mitigation—over which it has little control. Using SDG relationships as a guide for institutional cooperation, we find that the institutions with the most potential to coordinate action for sustainable ocean development are those that address economic, social and international policy, rather than institutions specifically focused on environmental policy. Our results provide key methodologies and insights for sustainable marine development that require coordinated actions across institutions.

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Climate change and its impact on the ocean

Increased human activities—in particular energy generation and land use—have led to atmospheric pollution by the significant emission of greenhouse gases such as carbon dioxide (CO2) and methane. The associated climate change is also affecting the ocean while, at the same time, the ocean plays a fundamental role in mitigating climate change by serving as a major heat and carbon sink. We highlight some of the most salient aspects of climate change impacting the ocean as articulated in the Special Report on the Ocean and Cryosphere in a Changing Climate by the Intergovernmental Panel on Climate Change (IPCC) released in 2019. It shows that the ocean is warming, the global sea level is rising, ocean heatwaves are more frequent, the ocean is becoming more acidic, marine ecology is shifting, levels of dissolved oxygen are reducing and the melting of ocean-terminating glaciers and ice sheets around Greenland and Antarctica is rapidly increasing. From the perspective of meeting the United Nations Sustainable Development Goals, in particular SDG 14, there are strong synergies between promoting climate mitigation and adaptation strategies, which are enshrined in SDG 13 and outlined in more detail by the Paris Agreement. Scientific research and solution-oriented knowledge generation require the growth and transformation of the science system. Specifically, they will require more freely shared ocean data, new and more effective ways of analyzing observational data fused with ocean and climate models, and enhanced timely assessment, predictions and scenario development of future ocean conditions. At the same time, knowledge from natural and social sciences, as well as informal knowledge, must be considered. Ocean science must be in a position to support decision makers by providing knowledge and frameworks to weigh the ecological, environmental and human impacts with an expected increase in use of the ocean for different sustainable development pathways. In recognition of this challenge, the United Nations declared 2021–2030 as the Decade of Ocean Science for Sustainable Development in order to advance “the science that we need for the ocean we want”. The ocean decade seeks to catalyze a change towards more international, shared and solution-oriented ocean science.

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Ocean acidification in the IPCC AR5 WG II

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