Climate change on a live Earth

Els líders mundials consideren que les conclusions del Grup Intergovernamental d'Experts sobre el Canvi Climàtic (GIECC) són fiables; tant és així que les prediccions obtingudes s'utilitzen per a formular lleis i polítiques. No obstant això, el GIECC no ha sobreestimat el canvi climàtic, sinó que ha subestimat la gravetat de l'escalfament global, principalment perquè ha prestat massa atenció a les emissions de diòxid de carboni i no la suficient a la resposta de la Terra. Al llarg dels últims quaranta-quatre anys he treballat observant la Terra d'una manera diferent, com un sistema dinàmic que regula activament el clima i la composició atmosfèrica per mantenir el planeta habitable. La Terra no accepta passivament l'acció humana. Respon al canvi climàtic d'una manera molt més mortífera que el petit canvi que estem provocant. La teoria de Gaia sosté que el sistema Terra pot actuar com un amplificador i les petites modificacions, ja siguin cap a la calor o al fred, s'intensifiquen, fet que podria ser la causa dels canvis erràtics de temperatura. En aquest article intentaré demostrar que aturar el canvi climàtic pot ser més difícil del que creuen els governs. La nostra tasca, en cas que l'escalfament global continuï, és adaptar-nos a la nova situació i preparar-nos per a sobreviure.The findings of the Intergovernmental Panel on Climate Change (IPCC) are taken by world leaders as authoritative, so much so that their predictions are used to frame legislation and policy. However, the IPCC has not overestimated climate change, they have, instead, underestimated the severity of global heating mainly because they paid too much attention to our emissions of carbon dioxide and not enough to the Earth’s response. For the past 44 years I have worked on a different way of looking at the Earth, seeing it as a dynamic system that actively regulates the climate and the atmospheric composition to keep the planet habitable. The Earth does not passively accept what we do to it. It responds to climate change and that response is far more deadly than the small change that we are making. Gaia theory teaches that the Earth system can act as an amplifier and small changes either to heat or cold are intensified and this could be the cause of the erratic shifts of temperature. In this article I will try to show that stopping climate change may be more difficult than our governments believe. Our task, should global heating continue, is to adapt and prepare to survive

Modeled CO2 Emissions from Coastal Wetland Transitions to Other Land Uses: Tidal Marshes, Mangrove Forests, and Seagrass Beds

The sediments of coastal wetlands contain large stores of carbon which are vulnerable to oxidation once disturbed, resulting in high levels of CO2 emissions that may be avoided if coastal ecosystems are conserved or restored. We used a simple model to estimate CO2 emissions from mangrove forests, seagrass beds, and tidal marshes based on known decomposition rates for organic matter in these ecosystems under either oxic or anoxic conditions combined with assumptions of the proportion of sediment carbon being deposited in either oxic or anoxic environments following a disturbance of the habitat. Our model found that over 40 years after disturbance the cumulative CO2 emitted from tidal marshes, mangrove forests, and seagrass beds were ∼70–80% of the initial carbon stocks in the top meter of the sediment. Comparison of our estimates of CO2 emissions with empirical studies suggests that (1) assuming 50% of organic material moves to an oxic environment after disturbance gives rise to estimates that are similar to CO2 emissions reported for tidal marshes; (2) field measurements of CO2 emissions in disturbed mangrove forests were generally higher than our modeled emissions that assumed 50% of organic matter was deposited in oxic conditions, suggesting higher proportions of organic matter may be exposed to oxic conditions after disturbance in mangrove ecosystems; and (3) the generally low observed rates of CO2 emissions from disturbed seagrasses compared to our estimates, assuming removal of 50% of the organic matter to oxic environments, suggests that lower proportions may be exposed to oxic conditions in seagrass ecosystems. There are significant gaps in our knowledge of the fate of wetland sediment carbon in the marine environment after disturbance. Greater knowledge of the distribution, form, decomposition, and emission rates of wetland sediment carbon after disturbance would help to improve models

Rolling covenants to protect coastal ecosystems in the face of sea-level rise

This article considers how “rolling covenants” (i.e., covenants on land title that can operate in a “rolling” geographic area to keep pace with sea-level rise) can be used to permit productive use of land in the short term, while ensuring land use can shift over time to allow for coastal ecosystem migration in the medium to long term. We use Australia as a case study, and through analysis of legislation and a series of semistructured interviews, we demonstrate how land title-based covenants can be used to give legal effect to “rolling covenant” arrangements where land is subject to existing use and occupation. We then consider practical issues associated with drafting a rolling covenant arrangement, including an analysis of the types of events or scenarios that could be used as a basis for land use changing (e.g., projected sea-level rise, actual ecosystem migration), and the advantages and disadvantages of each. We conclude that rolling covenants are a viable option for land management in the coastal zone, especially in circumstances where funding sources are available to incentivize uptake. Rolling covenants may provide opportunities for coastal wetlands to be maintained and even enhanced in cover, thereby delivering important ecosystem services (e.g., blue carbon) into the future

The effects of elevated CO2 and eutrophication on surface elevation gain in a European salt marsh.

Salt marshes can play a vital role in mitigating the effects of global environmental change by dissipating incident storm wave energy and, through accretion, tracking increasing water depths consequent upon sea level rise. Atmospheric CO2 concentrations and nutrient availability are two key variables that can affect the biological processes that contribute to marsh surface elevation gain. We measured the effects of CO2 concentrations and nutrient availability on surface elevation change in intact mixed-species blocks of UK salt marsh using six open-top chambers receiving CO2 -enriched (800 ppm) or ambient (400 ppm) air. We found more rapid surface elevation gain in elevated CO2 conditions: an average increase of 3.4 mm over the growing season relative to ambient CO2 . Boosted regression analysis to determine the relative influence of different parameters on elevation change identified that a 10% reduction in microbial activity in elevated CO2 -grown blocks had a positive influence on elevation. The biomass of Puccinellia maritima also had a positive influence on elevation, while other salt marsh species (e.g. Suaeda maritima) had no influence or a negative impact on elevation. Reduced rates of water use by the vegetation in the high CO2 treatment could be contributing to elevation gain, either directly through reduced soil shrinkage or indirectly by decreasing microbial respiration rates due to lower redox levels in the soil. Eutrophication did not influence elevation change in either CO2 treatment despite doubling aboveground biomass. The role of belowground processes (transpiration, root growth and decomposition) in the vertical adjustment of European salt marshes, which are primarily minerogenic in composition, could increase as atmospheric CO2 concentrations rise and should be considered in future wetland models for the region. Elevated CO2 conditions could enhance resilience in vulnerable systems such as those with low mineral sediment supply or where migration upwards within the tidal frame is constrained.Marie Curie Incoming International Fellowship (Grant ID: FP7-PEOPLE-IIF 623720 STORM)This is the author accepted manuscript. The final version is available from Wiley via https://doi.org/10.1111/gcb.1339

Seagrass meadows as a globally significant carbonate reservoir

There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha(-1), with an average of 654 +/- 24 Mg PIC ha(-1), exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of -8 +/- 2 Mg PIC ha(-1) per degree of latitude (general linear model, GLM; p \u3c 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 +/- 31.05 g PIC m(-2) yr(-1). Based on the global extent of seagrass meadows (177 000 to 600 000 km(2)), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr(-1), representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrated by the comparison of carbon (PIC and POC) stocks between vegetated and adjacent un-vegetated sediments

Financial incentives for large-scale wetland restoration: beyond markets to common asset trusts

Wetlands provide $47.4 trillion/year worth of ecosystem services globally and support immense biodiversity, yet face widespread drainage and pollution, and large-scale wetlands restoration is urgently needed. Payment for ecosystem service (PES) schemes provide a viable avenue for funding large-scale wetland restoration. However, schemes around the globe differ substantially in their goals, structure, challenges, and effectiveness in supporting large-scale wetland restoration. Here, we suggest wetland-based PES schemes use common asset trusts (CATs) to build investment portfolios of wetlands across landscapes that sustain and enhance overall provision of multiple ecosystem services. CATs can meet the needs of multiple investors, permit bundled payments, and provide flexibility to invest in the restoration of numerous services/values, all using a coordinated, highly collaborative, prioritized, and transparent process. CATs would support financial viability, facilitate efficiency to reduce administrative burdens, and enable credibility and social licence building to restore wetland values and services globally

Braneworld holography in Gauss-Bonnet gravity

We investigate holography on an (n-1)-dimensional brane embedded in a background of AdS black holes, in n-dimensional Gauss-Bonnet gravity. We demonstrate that for a critical brane near the AdS boundary, the Friedmann equation corresponds to that of the standard cosmology driven by a CFT dual to the AdS bulk. We show that there is no holographic description for non-critical branes, or when the brane is further away from the AdS boundary. We then derive a Cardy-Verlinde formula for the dual CFT on the critical brane near the boundary. This gives us insight into the remarkable correspondence between Cardy-Verlinde formulae and Friedmann equations in Einstein gravity.Comment: 24 pages, no figures; references added, minor changes, version to appear in CQ

Improving the Quality of Dentistry (IQuaD):a cluster factorial randomised controlled trial comparing the effectiveness and cost-benefit of oral hygiene advice and/or periodontal instrumentation with routine care for the prevention and management of periodontal disease in dentate adults attending dental primary care

Acknowledgements The authors wish to thank Mark Forrest and the programming team at CHaRT; Cynthia Fraser, our information specialist, for assistance with referencing; Moira Swan, who was the dental research nurse and part of the OA team in Newcastle upon Tyne; Louise Campbell for secretarial support and data management; our original statistician in the group, Andy Elders; senior IT manager Gladys Macpherson; senior trial administrator at the TCOD Marilyn Laird; Luke Vale for his involvement with the design of the health economic analysis at the inception of the trial; Maria Dimitrova, who assisted the health economists in the collection of unit costs; staff of the Scottish Primary Care Research Network, who assisted with screening eligible patients at dental practices; staff of the North East Commissioning Support Unit who assisted with research payments to dental practices in the north-east; members of the TMC and Periodontal Advisory Group for their ongoing advice and support of the trial; the independent members of the TSC and DMC; and the staff at recruitment sites who facilitated recruitment, treatment and follow-up of trial participants. The Health Services Research Unit and the Health Economics Research Unit is core funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorate.Peer reviewedPublisher PD