Thanks, Andrew. From the paper: "Management options Limiting the effects of ocean warming and acid- ification is critical considering the widespread risks of impacts facing natural and human sys- tems, even under a stringent emissions scenario (RCP2.6; Fig. 2). A growing body of literature presents options for action in response to climate change and ocean acidification (143–145). Draw- ing on Billé et al. (146), these actions can be clus- tered in four groups (Fig. 4): reducing the drivers of climate change and ocean acidification (mit- igate), building or maintaining resilience in eco- systems (protect), adapting human societies (adapt), and repairing damage that has already occurred (repair). At present, only one of these (reducing CO2 emissions) addresses the fundamental prob- lem; the others merely delay or decrease impacts (e.g., protecting reefs from major disturbances such as coral mining). Some actions rely on readi- ly available technologies (e.g., sewage treatment plants to reduce exacerbating effects of coastal nutrient pollution) and socioeconomic mecha- nisms (e.g., coastal setback zones), whereas more engineering-intensive techniques are being devel- oped and will require testing (e.g., removal of CO2 from the atmosphere). These options inter- act. For example, reducing secondary environmen- tal stressors so as to retain ecosystem resilience works over some range of PCO2 values but is ul- timately relevant only if ocean warming and acidification are drastically limited. One cannot manage coral reef resilience, for example, if there are no healthy reefs remaining (46). Importantly, some policy options are antagonistic: For exam- ple, solar radiation management could limit the increase of surface temperature but would reduce the incentive to cut greenhouse gases emissions, including CO2, thereby providing no relief from ocean acidification (147). A positive development is that a widening range of stakeholders are testing new practices or reviving old ones, including CO2 extraction from seawater (148), assisted evolution of corals (149), coral farming (150), and customary local management (151). Such field tests provide use- able information and tools for decision-makers and climate negotiators as to the costs, benefits, and timing of management options. Aquaculture, for example, has shown some potential to reduce the risk of impacts from climate change and ocean acidification through societal adaptation, such as improved monitoring and changing cultured species or farm locations (127, 152). However, the cost of adaptation measures—such as real- time monitoring of water chemistry—can be prohibitive and not within the reach of most aquaculture operations, especially those in the developing world. Ecosystem-based adaptation— or using ecosystems to reduce the vulnerability of people—appears to offer cost-efficient solu- tions bringing multiple co-benefits, especially for developing countries and marginalized commu- nities (153). Stimulating ecosystem resilience by reducing the number and magnitude of local stressors and setting up marine protected areas (154) with strictly enforced no-take areas and limited pollutant inputs also stand out as tract- able priorities. Moreover, some regions and local areas that are relatively less exposed to warming, hypoxia, and acidification could be climate change refugia, where more favorable environmental con- ditions would enable survival under CO2-driven impacts (155). Thus, identifying these climate change refugia and conserving biodiversity there contribute to building resilience to climate change (156). Nevertheless, all of these options require ap- propriate policy frameworks and financial com- mitments to cover transaction and opportunity costs, surveillance, and enforcement and moni- toring and likely offer only limited protection in the face of persistent climate change and ocean acidification. As the ocean warms and acidifies, the range of protection, adaptation, and repair options—and our confidence in those options—dwindles, while the cost of remaining options skyrockets. Lower- emissions scenarios such as RCP2.6 leave society with a greater number of effective options for safeguarding marine ecosystems and the services they provide. Therefore, actions that do not re- duce carbon emissions are meaningful ocean management options only if the future climate regime entails ambitious national contributions toward the phaseout of global CO2 emissions as well as a strong funding mechanism and a rele- vant framework to support on-the-ground imple- mentation of these options."
GR - Basically downplays alternative CO2/climate management methods in order make the case that drastic emissions reduction - adhering to RCP 2.6 or better - is our only option. Instead, what needs to be said is that it is now very unlikely that we can or will achieve RCP 2.6 regardless of what happens at COP 21, that additional, new mitigation/management methods are needed, and immediate R&D investments in these are required. Apparently, a global catastrophe is needed before this line of thinking becomes mainstream, which by then will be too late. Indeed, "One cannot manage coral reef resilience, for example, if there are no healthy reefs remaining". So if one truly values the ocean, isn't time to stop clinging to the hope that emissions reduction is going to singlehandedly save the day, and start actively searching for additional remedies, not downplaying their relevance? "As the ocean warms and acidifies, the range of protection, adaptation, and repair options—and our confidence in those options—dwindles, while the cost of remaining options skyrockets." Since so little research has been conducted, how do we know that these options will be too expensive (relative to the alternative - failed emissions reduction?) and don't deserve our confidence? Even if the quote is true, isn't this a clarion call to search for and test out better, cheaper, faster, higher capacity options?* Greg * http://www.nature.com/nclimate/journal/v2/n10/full/nclimate1555.html http://link.springer.com/referenceworkentry/10.1007%2F978-94-007-5784-4_54 http://www.pgafamilyfoundation.org/oceanchallenge/ -------------------------------------------- On Fri, 7/3/15, Andrew Lockley <[email protected]> wrote: Subject: [geo] Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios Carbon emissions and their ocean impacts To: "geoengineering" <[email protected]> Date: Friday, July 3, 2015, 12:45 AM Poster's note : relevant to CDR particularly, but also somewhat to SRM, and marine BECCS. http://m.sciencemag.org/content/349/6243/aac4722.abstract?sid=4d57e97f-8860-4a5d-8863-9d80373ed461 Science 3 July 2015: Vol. 349 no. 6243 DOI: 10.1126/science.aac4722 Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios Carbon emissions and their ocean impacts Anthropogenic CO2 emissions directly affect atmospheric chemistry but also have a strong influence on the oceans. Gattuso et al. review how the physics, chemistry, and ecology of the oceans might be affected based on two CO2 emission trajectories: one business as usual and one with aggressive reductions. Ocean warming, acidification, sea-level rise, and the expansion of oxygen minimum zones will continue to have distinct impacts on marine communities and ecosystems. The path that humanity takes regarding CO2 emissions will largely determine the severity of these phenomena. Structured Abstract BACKGROUND Although the ocean moderates anthropogenic climate change, this has great impacts on its fundamental physics and chemistry, with important consequences for ecosystems and people. Yet, despite the ocean’s critical role in regulating climate—and providing food security and livelihoods for millions of people—international climate negotiations have only minimally considered impacts on the ocean. Here, we evaluate changes to the ocean and its ecosystems, as well as to the goods and services they provide, under two contrasting CO2 scenarios: the current high-emissions trajectory (Representative Concentration Pathway 8.5, RCP8.5) and a stringent emissions scenario (RCP2.6) consistent with the Copenhagen Accord of keeping mean global temperature increase below 2°C in the 21st century. To do this, we draw on the consensus science in the latest assessment report of the Intergovernmental Panel on Climate Change and papers published since the assessment. ADVANCES Warming and acidification of surface ocean waters will increase proportionately with cumulative CO2 emissions (see figure). Warm-water corals have already been affected, as have mid-latitude seagrass, high-latitude pteropods and krill, mid-latitude bivalves, and fin fishes. Even under the stringent emissions scenario (RCP2.6), warm-water corals and mid-latitude bivalves will be at high risk by 2100. Under our current rate of emissions, most marine organisms evaluated will have very high risk of impacts by 2100 and many by 2050. These results—derived from experiments, field observations, and modeling—are consistent with evidence from high-CO2 periods in the paleorecord. Impacts to the ocean’s ecosystem services follow a parallel trajectory. Services such as coastal protection and capture fisheries are already affected by ocean warming and acidification. The risks of impacts to these services increase with continued emissions: They are predicted to remain moderate for the next 85 years for most services under stringent emission reductions, but the business-as-usual scenario (RCP8.5) would put all ecosystem services we considered at high or very high risk over the same time frame. These impacts will be cumulative or synergistic with other human impacts, such as overexploitation of living resources, habitat destruction, and pollution. Fin fisheries at low latitudes, which are a key source of protein and income for millions of people, will be at high risk. OUTLOOK Four key messages emerge. First, the ocean strongly influences the climate system and provides important services to humans. Second, impacts on key marine and coastal organisms, ecosystems, and services are already detectable, and several will face high risk of impacts well before 2100, even under the low-emissions scenario (RCP2.6). These impacts will occur across all latitudes, making this a global concern beyond the north/south divide. Third, immediate and substantial reduction of CO2 emissions is required to prevent the massive and mostly irreversible impacts on ocean ecosystems and their services that are projected with emissions greater than those in RCP2.6. Limiting emissions to this level is necessary to meet stated objectives of the United Nations Framework Convention on Climate Change; a substantially different ocean would result from any less-stringent emissions scenario. Fourth, as atmospheric CO2 increases, protection, adaptation, and repair options for the ocean become fewer and less effective. The ocean provides compelling arguments for rapid reductions in CO2 emissions and eventually atmospheric CO2 drawdown. Hence, any new global climate agreement that does not minimize the impacts on the ocean will be inadequate. Changes in ocean physics and chemistry and impacts on organisms and ecosystem services according to stringent (RCP2.6) and high business-as-usual (RCP8.5) CO2 emissions scenarios. Changes in temperature (∆T) and pH (∆pH) in 2090 to 2099 are relative to preindustrial (1870 to 1899). Sea level rise (SLR) in 2100 is relative to 1901. RCP2.6 is much more favorable to the ocean, although important ecosystems, goods, and services remain vulnerable, and allows more-efficient management options. l, m, h: low, mid-, and high latitudes, respectively. Abstract The ocean moderates anthropogenic climate change at the cost of profound alterations of its physics, chemistry, ecology, and services. Here, we evaluate and compare the risks of impacts on marine and coastal ecosystems—and the goods and services they provide—for growing cumulative carbon emissions under two contrasting emissions scenarios. The current emissions trajectory would rapidly and significantly alter many ecosystems and the associated services on which humans heavily depend. A reduced emissions scenario—consistent with the Copenhagen Accord’s goal of a global temperature increase of less than 2°C—is much more favorable to the ocean but still substantially alters important marine ecosystems and associated goods and services. The management options to address ocean impacts narrow as the ocean warms and acidifies. Consequently, any new climate regime that fails to minimize ocean impacts would be incomplete and inadequate. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
