The role of closed ecological systems in carbon cycle modelling

AbstractThis paper examines the role of values in transformations toward sustainability. Values, generally defined as what people deem to matter, are increasingly gaining interest in and outside of academia. For example, sustainability aligns with specific values such as dignity, equality, safety, and harmony for people and nature. However, current approaches to values are mind-matter dualistic, and therefore failing to honor the inherently dynamic relations of socio-ecological systems. Drawing on new materialism, I explore values as part of the relations that make this world and propose to consider values as material-discursive practices. Ethnographic fieldwork was done in 2017 with coffee producers in Burundi who aimed to transform production by caring for the coffee and people that grow it. Based on interviews and participatory observation, I present how values were integral to transforming the relational aspects of coffee production. In this study, values of togetherness, care, dignity, and faith were dominant and were found to reconfigure the socio-ecological system of coffee production. I argue that values are inseparable from, and hence co-productive of, the material world that we experience and play a vital role in sustainability transformations.

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Theory and experiments to decipher the role of time and space in ecological systems, from populations to ecosystems

10.26904/rf-136-1476966800 ◽

2021 ◽

Keyword(s):

Ecological Systems ◽

Time And Space ◽

Theory And Experiments

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Reviews and syntheses: Flying the satellite into your model: on the role of observation operators in constraining models of the Earth system and the carbon cycle

Biogeosciences ◽

10.5194/bg-14-2343-2017 ◽

2017 ◽

Vol 14 (9) ◽

pp. 2343-2357 ◽

Cited By ~ 16

Author(s):

Thomas Kaminski ◽

Pierre-Philippe Mathieu

Keyword(s):

Data Assimilation ◽

Carbon Cycle ◽

Automatic Differentiation ◽

Satellite Observations ◽

Spectral Radiance ◽

Special Focus ◽

Earth System ◽

The Earth ◽

Retrieval Scheme

Abstract. The vehicles that fly the satellite into a model of the Earth system are observation operators. They provide the link between the quantities simulated by the model and the quantities observed from space, either directly (spectral radiance) or indirectly estimated through a retrieval scheme (biogeophysical variables). By doing so, observation operators enable modellers to properly compare, evaluate, and constrain their models with the model analogue of the satellite observations. This paper provides the formalism and a few examples of how observation operators can be used in combination with data assimilation techniques to better ingest satellite products in a manner consistent with the dynamics of the Earth system expressed by models. It describes commonalities and potential synergies between assimilation and classical retrievals. This paper explains how the combination of observation operators and their derivatives (linearizations) form powerful research tools. It introduces a technique called automatic differentiation that greatly simplifies both the development and the maintenance of code for the evaluation of derivatives. Throughout this paper, a special focus lies on applications to the carbon cycle.

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The Plio-Pleistocene climatic evolution as a consequence of orbital forcing on the carbon cycle

10.5194/cp-2017-3 ◽

2017 ◽

Author(s):

Didier Paillard

Keyword(s):

Carbon Cycle ◽

Ice Core ◽

Climate Science ◽

Atmospheric Concentration ◽

Sources And Sinks ◽

Climatic Evolution ◽

Astronomical Forcing ◽

The Antarctic ◽

Simple Dynamical Model

Abstract. Since the discovery of ice ages in the XIXth century, a central question of climate science has been to understand the respective role of the astronomical forcing and of greenhouse gases, in particular changes in the atmospheric concentration of carbon dioxide. Glacial-interglacial cycles have been shown to be paced by the astronomy with a dominant periodicity of 100 ka over the last million years, and a periodicity of 41 ka between roughly 1 and 3 million years before present (MyrBP). But the role and dynamics of the carbon cycle over the last 4 million years remain poorly understood. In particular, the transition into the Pleistocene about 2.8 MyrBP or the transition towards larger glaciations about 0.8 MyrBP (sometimes refered as the mid-pleistocene transition, or MPT) are not easily explained as direct consequences of the astronomical forcing. Some recent atmospheric CO2 reconstructions suggest slightly higher pCO2 levels before 1 MyrBP and a slow decrease over the last few million years (Bartoli et al., 2011; Seki et al., 2010). But the dynamics and the climatic role of the carbon cycle during the Plio-Pleistocene period remain unclear. Interestingly, the d13C marine records provide some critical information on the evolution of sources and sinks of carbon. In particular, a clear 400-kyr oscillation has been found at many different time periods and appears to be a robust feature of the carbon cycle throughout at least the last 100 Myr (eg. Paillard and Donnadieu, 2014). This oscillation is also visible over the last 4 Myr but its relationship with the eccentricity appears less obvious, with the occurrence of longer cycles at the end of the record, and a periodicity which therefore appears shifted towards 500-kyr (cf. Wang et al., 2004). In the following we present a simple dynamical model that provides an explanation for these carbon cycle variations, and how they relate to the climatic evolution over the last 4 Myr. It also gives an explanation for the lowest pCO2 values observed in the Antarctic ice core around 600–700 kyrBP. More generally, the model predicts a two-step decrease in pCO2 levels associated with the 2.4 Myr modulation of the eccentricity forcing. These two steps occur respectively at the Plio-Pleistocene transition and at the MPT, which strongly suggests that these transitions are astronomicaly forced through the dynamics of the carbon cycle.

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Role of volcanic forcing on future global carbon cycle

Earth System Dynamics Discussions ◽

10.5194/esdd-2-133-2011 ◽

2011 ◽

Vol 2 (1) ◽

pp. 133-159

Author(s):

J. F. Tjiputra ◽

O. H. Otterå

Keyword(s):

Climate Change ◽

Carbon Cycle ◽

21St Century ◽

Volcanic Eruptions ◽

Future Climate Change ◽

Small Scale ◽

Carbon Uptake ◽

Carbon Cycle Model ◽

Large Volcanic Eruptions

Abstract. Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller but more frequent eruptions, such as Pinatubo, would have a stronger impact on future climate change. In a scenario where the volcanic external forcings are prescribed with a five-year frequency, the induced cooling immediately lower the global temperature by more than one degree before return to the warming trend. Therefore, the climate change is approximately delayed by several decades and by the end of the 21st century, the warming is still below two degrees when compared to the present day period. The cooler climate reduces the terrestrial heterotrophic respiration in the northern high latitude and increases net primary production in the tropics, which contributes to more than 45% increase in accumulated carbon uptake over land. The increased solubility of CO2 gas in seawater associated with cooler SST is offset by reduced CO2 partial pressure gradient between ocean and atmosphere, which results in small changes in net ocean carbon uptake. Similarly, there is nearly no change in the seawater buffer capacity simulated between the different volcanic scenarios. Our study shows that even in the relatively extreme scenario where large volcanic eruptions occur every five-years period, the induced cooling only leads to a reduction of 46 ppmv atmospheric CO2 concentration as compared to the reference projection of 878 ppmv, at the end of the 21st century. With respect to sulphur injection geoengineering method, our study suggest that small scale but frequent mitigation is more efficient than the opposite. Moreover, the longer we delay, the more difficult it would be to counteract climate change.

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