35 research outputs found
Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing
Changes to climate-carbon cycle feedbacks may significantly affect the Earth Systemâs response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth System Models (ESMs). Here, we construct a stylized global climate-carbon cycle model, test its output against complex ESMs, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon-cycle feedbacks and the operation of the carbon cycle. We use our results to analytically study the relative strengths of different climate-carbon cycle feedbacks and how they may change in the future, as well as to compare different feedback formalisms. Simple models such as that developed here also provide "workbenches" for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the Planetary Boundaries, that are currently too uncertain to be included in complex ESMs
Potential feedbacks between loss of biosphere integrity and climate change
Non-technical abstract
Individual organisms on land and in the ocean sequester massive amounts of the carbon emitted into the atmosphere by humans. Yet the role of ecosystems as a whole in modulating this uptake of carbon is less clear. Here, we study several different mechanisms by which climate change and ecosystems could interact. We show that climate change could cause changes in ecosystems that reduce their capacity to take up carbon, further accelerating climate change. More research on â and better governance of â interactions between climate change and ecosystems is urgently required.
Technical abstract
Individual responses of terrestrial and marine species to future climate change will affect the capacity of the land and ocean to store carbon. How system-level changes in the integrity of the biosphere interact with climate change is more uncertain. Here, we explore the consequences
of different hypotheses on the interactions between the climateâcarbon system and the integrity of the terrestrial and marine biospheres. We investigate mechanisms including impairment of terrestrial ecosystem functioning due to lagged ecosystem responses, permafrost thaw, terrestrial biodiversity loss and impacts of changes in marine biodiversity on the marine biological pump. To investigate climateâbiosphere interactions involving complex concepts such as biosphere integrity, we designed and implemented conceptual representations of these climateâbiosphere interactions in a stylized climateâcarbon model. We find that all four classes of interactions amplify climate change, potentially contributing up to an additional 0.4°C warming across all representative concentration pathway scenarios by the year 2100 and potentially turning the terrestrial biosphere into a net carbon source,
although uncertainties are large. The results of this preliminary quantitative study call for more research on â and better integrated governance of â the interactions between climate change and biosphere integrity, the two core âplanetary boundariesâ.The research leading to these results has received funding from the Stordalen Foundation via the Planetary Boundary Research Network (PB.net), the Earth Leagueâs EarthDoc programme, the Leibniz Association (project DOMINOES), European Research Council Synergy project Imbalance-P (grant ERC-2013-SyG-610028), European Research Council Advanced Investigator project ERA (grant ERC-2016-ADG-743080), Deutsche Forschungsgemeinschaft (DFG BE 6485/1-1), Project Grant 2014-589 from the Swedish Research Council Formas and a core grant to the Stockholm Resilience Centre by Mistra
Potential feedbacks between loss of biosphere integrity and climate change
Individual organisms on land and in the ocean sequester massive amounts of the carbon emitted into the atmosphere by humans. Yet the role of ecosystems as a whole in modulating this uptake of carbon is less clear. Here, we study several different mechanisms by which climate change and ecosystems could interact. We show that climate change could cause changes in ecosystems that reduce their capacity to take up carbon, further accelerating climate change. More research on â and better governance of â interactions between climate change and ecosystems is urgently required
Trajectories of the Earth System in the Anthropocene
This is the final version of the article. Available from National Academy of Sciences via the DOI in this record.We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a "Hothouse Earth" pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System-biosphere, climate, and societies-and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.W.S. and C.P.S. are members of the Anthropocene Working Group.
W.S., J.R., K.R., S.E.C., J.F.D., I.F., S.J.L., R.W. and H.J.S. are members of the
Planetary Boundaries Research Network PB.net and the Earth Leagueâs EarthDoc
Programme supported by the Stordalen Foundation. T.M.L. was supported by
a Royal Society Wolfson Research Merit Award and the European Union
Framework Programme 7 Project HELIX. C.F. was supported by the Erlingâ
Persson Family Foundation. The participation of D.L. was supported by the
Haury Program in Environment and Social Justice and National Science
Foundation (USA) Decadal and Regional Climate Prediction using Earth
System Models Grant 1243125. S.E.C. was supported in part by Swedish Research
Council Formas Grant 2012-742. J.F.D. and R.W. were supported by
Leibniz Association Project DOMINOES. S.J.L. receives funding from Formas
Grant 2014-589. This paper is a contribution to European Research Council
Advanced Grant 2016, Earth Resilience in the Anthropocene Project 743080
Modulation of the thalamus by microburst vagus nerve stimulation: a feasibility study protocol
Vagus nerve stimulation (VNS) was the first device-based therapy for epilepsy, having launched in 1994 in Europe and 1997 in the United States. Since then, significant advances in the understanding of the mechanism of action of VNS and the central neurocircuitry that VNS modulates have impacted how the therapy is practically implemented. However, there has been little change to VNS stimulation parameters since the late 1990s. Short bursts of high frequency stimulation have been of increasing interest to other neuromodulation targets e.g., the spine, and these high frequency bursts elicit unique effects in the central nervous system, especially when applied to the vagus nerve. In the current study, we describe a protocol design that is aimed to assess the impact of high frequency bursts of stimulation, called âMicroburst VNSâ, in subjects with refractory focal and generalized epilepsies treated with this novel stimulation pattern in addition to standard anti-seizure medications. This protocol also employed an investigational, fMRI-guided titration protocol that permits personalized dosing of Microburst VNS among the treated population depending on the thalamic blood-oxygen-level-dependent signal. The study was registered on clinicaltrials.gov (NCT03446664). The first subject was enrolled in 2018 and the final results are expected in 2023
Planetary boundaries: guiding human development on a changing planet
The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth System. Here, we revise and update the planetary boundaries framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundariesâclimate change and biosphere integrityâhave been identified, each of which has the potential on its own to drive the Earth System into a new state should they be substantially and persistently transgressed
Analytically tractable climate–carbon cycle feedbacks under 21st century anthropogenic forcing
Changes to climateâcarbon cycle feedbacks may significantly affect
the Earth system's response to greenhouse gas emissions. These
feedbacks are usually analysed from numerical output of complex and
arguably opaque Earth system models. Here, we construct a
stylised global climateâcarbon cycle model, test its output against
comprehensive Earth system models, and investigate the strengths of its
climateâcarbon cycle feedbacks analytically. The analytical
expressions we obtain aid understanding of carbon cycle feedbacks
and the operation of the carbon cycle. Specific results include
that different feedback formalisms measure fundamentally the same
climateâcarbon cycle processes; temperature dependence of the
solubility pump, biological pump, and CO2 solubility all
contribute approximately equally to the ocean climateâcarbon
feedback; and concentrationâcarbon feedbacks may be more sensitive
to future climate change than climateâcarbon feedbacks. Simple
models such as that developed here also provide workbenches for
simple but mechanistically based explorations of Earth system
processes, such as interactions and feedbacks between the planetary
boundaries, that are currently too uncertain to be included in
comprehensive Earth system models
Analytically tractable climateâcarbon cycle feedbacks under 21st century anthropogenic forcing
Changes to climateâcarbon cycle feedbacks may ignificantly affect the Earth system's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth system models. Here, we construct a stylised global climateâcarbon cycle model, test its output against comprehensive Earth system models, and investigate the strengths of its climateâcarbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon cycle feedbacks and the operation of the carbon cycle. Specific results include that different feedback formalisms measure fundamentally the same climateâcarbon cycle processes; temperature dependence of the solubility pump, biological pump, and CO2 solubility all contribute approximately equally to the ocean climateâcarbon feedback; and concentrationâcarbon feedbacks may be more sensitive to future climate change than climateâcarbon feedbacks. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the planetary boundaries, that are currently too uncertain to be included in comprehensive Earth system models.The research leading to these results has
received funding from the Stordalen Foundation via the Planetary
Boundary Research Network (PB.net), the Earth Leagueâs EarthDoc
programme, the Leibniz Association (project DOMINOES),
European Research Council Synergy project Imbalance-P (grant
ERC-2013-SyG-610028), project grant 2014-589 from the Swedish
Research Council Formas, and a core grant to the Stockholm
Resilience Centre by Mistra
Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing
Paper contact with cynthia festin: [email protected]ĂŻments: The research leading to these results has received funding from the Stordalen Foundation via the Planetary Boundary Research Network (PB.net), the Earth League's EarthDoc programme, the Leibniz Association (project DOMINOES), Project Grant 2014-589 from the Swedish Research Council Formas, and a core grant to the Stockholm Resilience Centre by Mistra. We thank Malin Ădalen for her comments on the manuscript.Changes to climate-carbon cycle feedbacks may significantly affect the Earth System's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth System Models (ESMs). Here, we construct a stylized global climate-carbon cycle model, test its output against complex ESMs, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon-cycle feedbacks and the operation of the carbon cycle. We use our results to analytically study the relative strengths of different climate-carbon cycle feedbacks and how they may change in the future, as well as to compare different feedback formalisms. Simple models such as that developed here also provide 'workbenches' for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the Planetary Boundaries, that are currently too uncertain to be included in complex ESMs