How Will Earth Respond to Plans for Carbon Dioxide Removal?

Abstract. The recent IPCC reports state that continued anthropogenic greenhouse gas emissions are changing the climate threatening "severe, pervasive and irreversible" impacts. Slow progress in emissions reduction to mitigate climate change is resulting in increased attention on what is called Geoengineering, Climate Engineering, or Climate Intervention – deliberate interventions to counter climate change that seek to either modify the Earth's radiation budget or remove greenhouse gases such as CO2 from the atmosphere. When focused on CO2, the latter of these categories is called Carbon Dioxide Removal (CDR). The majority of future emission scenarios that stay well below 2 °C, and nearly all emission scenarios that do not exceed 1.5 °C warming by the year 2100, require some form of CDR. At present, there is little consensus on the impacts and efficacy of the different types of proposed CDR. To address this need the Carbon Dioxide Removal Model Intercomparison Project (or CDR-MIP) was initiated. This project brings together models of the Earth system in a common framework to explore the potential, impacts, and challenges of CDR. Here, we describe the first set of CDR-MIP experiments that are designed to address questions concerning CDR-induced climate "reversibility", the response of the Earth system to direct atmospheric CO2 removal (direct air capture and storage), and the CDR potential and impacts of afforestation/reforestation, as well as ocean alkalinization.

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The Carbon Dioxide Removal Model Intercomparison Project (CDRMIP): rationale and experimental protocol for CMIP6

Geoscientific Model Development ◽

10.5194/gmd-11-1133-2018 ◽

2018 ◽

Vol 11 (3) ◽

pp. 1133-1160 ◽

Cited By ~ 29

Author(s):

David P. Keller ◽

Andrew Lenton ◽

Vivian Scott ◽

Naomi E. Vaughan ◽

Nico Bauer ◽

...

Keyword(s):

Climate Change ◽

Carbon Dioxide ◽

Carbon Dioxide Removal ◽

Atmospheric Co2 ◽

Earth System ◽

Emission Scenarios ◽

Model Intercomparison ◽

The Earth ◽

Intercomparison Project ◽

Removal Model

Abstract. The recent IPCC reports state that continued anthropogenic greenhouse gas emissions are changing the climate, threatening severe, pervasive and irreversible impacts. Slow progress in emissions reduction to mitigate climate change is resulting in increased attention to what is called geoengineering, climate engineering, or climate intervention – deliberate interventions to counter climate change that seek to either modify the Earth's radiation budget or remove greenhouse gases such as CO2 from the atmosphere. When focused on CO2, the latter of these categories is called carbon dioxide removal (CDR). Future emission scenarios that stay well below 2 °C, and all emission scenarios that do not exceed 1.5 °C warming by the year 2100, require some form of CDR. At present, there is little consensus on the climate impacts and atmospheric CO2 reduction efficacy of the different types of proposed CDR. To address this need, the Carbon Dioxide Removal Model Intercomparison Project (or CDRMIP) was initiated. This project brings together models of the Earth system in a common framework to explore the potential, impacts, and challenges of CDR. Here, we describe the first set of CDRMIP experiments, which are formally part of the 6th Coupled Model Intercomparison Project (CMIP6). These experiments are designed to address questions concerning CDR-induced climate reversibility, the response of the Earth system to direct atmospheric CO2 removal (direct air capture and storage), and the CDR potential and impacts of afforestation and reforestation, as well as ocean alkalinization.>

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Atmospheric methane removal: a research agenda

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2020.0454 ◽

2021 ◽

Vol 379 (2210) ◽

pp. 20200454 ◽

Cited By ~ 1

Author(s):

Robert B. Jackson ◽

Sam Abernethy ◽

Josep G. Canadell ◽

Matteo Cargnello ◽

Steven J. Davis ◽

...

Keyword(s):

Carbon Dioxide ◽

Methane Oxidation ◽

Research Agenda ◽

The Arctic ◽

Anthropogenic Emissions ◽

Atmospheric Methane ◽

Model Intercomparison ◽

Intercomparison Project ◽

Removal Model

Atmospheric methane removal (e.g. in situ methane oxidation to carbon dioxide) may be needed to offset continued methane release and limit the global warming contribution of this potent greenhouse gas. Because mitigating most anthropogenic emissions of methane is uncertain this century, and sudden methane releases from the Arctic or elsewhere cannot be excluded, technologies for methane removal or oxidation may be required. Carbon dioxide removal has an increasingly well-established research agenda and technological foundation. No similar framework exists for methane removal. We believe that a research agenda for negative methane emissions—‘removal' or atmospheric methane oxidation—is needed. We outline some considerations for such an agenda here, including a proposed Methane Removal Model Intercomparison Project (MR-MIP). This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.

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Contribution of the coupled atmosphere–ocean–sea ice–vegetation model COSMOS to the PlioMIP2

Climate of the Past ◽

10.5194/cp-16-2275-2020 ◽

2020 ◽

Vol 16 (6) ◽

pp. 2275-2323

Author(s):

Christian Stepanek ◽

Eric Samakinwa ◽

Gregor Knorr ◽

Gerrit Lohmann

Keyword(s):

Carbon Dioxide ◽

Sea Ice ◽

Boundary Conditions ◽

Surface Temperature ◽

Arctic Ocean ◽

Carbon Dioxide Concentration ◽

Boreal Summer ◽

Earth System ◽

Model Intercomparison ◽

Intercomparison Project

Abstract. We present the Alfred Wegener Institute's contribution to the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) wherein we employ the Community Earth System Models (COSMOS) that include a dynamic vegetation scheme. This work builds on our contribution to Phase 1 of the Pliocene Model Intercomparison Project (PlioMIP1) wherein we employed the same model without dynamic vegetation. Our input to the PlioMIP2 special issue of Climate of the Past is twofold. In an accompanying paper we compare results derived with COSMOS in the framework of PlioMIP2 and PlioMIP1. With this paper we present details of our contribution with COSMOS to PlioMIP2. We provide a description of the model and of methods employed to transfer reconstructed mid-Pliocene geography, as provided by the Pliocene Reconstruction and Synoptic Mapping Initiative Phase 4 (PRISM4), to model boundary conditions. We describe the spin-up procedure for creating the COSMOS PlioMIP2 simulation ensemble and present large-scale climate patterns of the COSMOS PlioMIP2 mid-Pliocene core simulation. Furthermore, we quantify the contribution of individual components of PRISM4 boundary conditions to characteristics of simulated mid-Pliocene climate and discuss implications for anthropogenic warming. When exposed to PRISM4 boundary conditions, COSMOS provides insight into a mid-Pliocene climate that is characterised by increased rainfall (+0.17 mm d−1) and elevated surface temperature (+3.37 ∘C) in comparison to the pre-industrial (PI). About two-thirds of the mid-Pliocene core temperature anomaly can be directly attributed to carbon dioxide that is elevated with respect to PI. The contribution of topography and ice sheets to mid-Pliocene warmth is much smaller in contrast – about one-quarter and one-eighth, respectively, and nonlinearities are negligible. The simulated mid-Pliocene climate comprises pronounced polar amplification, a reduced meridional temperature gradient, a northwards-shifted tropical rain belt, an Arctic Ocean that is nearly free of sea ice during boreal summer, and muted seasonality at Northern Hemisphere high latitudes. Simulated mid-Pliocene precipitation patterns are defined by both carbon dioxide and PRISM4 paleogeography. Our COSMOS simulations confirm long-standing characteristics of the mid-Pliocene Earth system, among these increased meridional volume transport in the Atlantic Ocean, an extended and intensified equatorial warm pool, and pronounced poleward expansion of vegetation cover. By means of a comparison of our results to a reconstruction of the sea surface temperature (SST) of the mid-Pliocene we find that COSMOS reproduces reconstructed SST best if exposed to a carbon dioxide concentration of 400 ppmv. In the Atlantic to Arctic Ocean the simulated mid-Pliocene core climate state is too cold in comparison to the SST reconstruction. The discord can be mitigated to some extent by increasing carbon dioxide that causes increased mismatch between the model and reconstruction in other regions.

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Contribution of the coupled atmosphere–ocean–sea ice–vegetation model COSMOS to the PlioMIP2

10.5194/cp-2020-10 ◽

2020 ◽

Cited By ~ 3

Author(s):

Christian Stepanek ◽

Eric Samakinwa ◽

Gerrit Lohmann

Keyword(s):

Carbon Dioxide ◽

Sea Ice ◽

Boundary Conditions ◽

Surface Temperature ◽

Arctic Ocean ◽

Carbon Dioxide Concentration ◽

Boreal Summer ◽

Earth System ◽

Model Intercomparison ◽

Intercomparison Project

Abstract. We present the Alfred Wegener Institute's contribution to the Pliocene Model Intercomparison Project, Phase 2 (PlioMIP2) where we employ the Community Earth System Models (COSMOS) that include a dynamic vegetation scheme. This work builds on our contribution to Phase 1 of the Pliocene Model Intercomparison Project (PlioMIP1) where we employed the same model without dynamic vegetation. Our input to the PlioMIP2 special issue of Climate of the Past is twofold. In an accompanying manuscript we compare results derived with the COSMOS in the framework of PlioMIP2 and PlioMIP1. With the manuscript on hand we present details of our contribution with COSMOS to PlioMIP2. We provide a description of the model and of methods employed to transfer reconstructed Mid-Pliocene geography, as provided by the Pliocene Reconstruction and Synoptic Mapping Initiative, Phase 4 (PRISM4), to model boundary conditions. We describe the spin-up procedure for creating the COSMOS PlioMIP2 simulation ensemble and present large scale climate patterns of the COSMOS PlioMIP2 Mid-Pliocene core simulation. Furthermore, we quantify the contribution of individual components of PRISM4 boundary conditions to characteristics of simulated Mid-Pliocene climate and discuss implications for anthropogenic warming. When exposed to PRISM4 boundary conditions, the COSMOS provide insight into a Mid-Pliocene climate that is characterized by increased rainfall (+0.17 mm d−1) and elevated surface temperature (+3.37 °C) in comparison to the Pre-Industrial (PI). About two-thirds of the Mid-Pliocene core temperature anomaly can be directly attributed to carbon dioxide that is elevated w.r.t. PI. The contribution of topography and ice sheets to Mid-Pliocene warmth is in contrast much smaller – about one-fourth and one-eighth, respectively. The simulated Mid-Pliocene climate comprises pronounced polar amplification, a reduced meridional temperature gradient, a northward shifted tropical rain belt, an Arctic Ocean that is nearly free of sea ice during boreal summer, as well as muted seasonality in Northern Hemisphere high latitudes. Simulated Mid-Pliocene precipitation patterns are defined by both carbon dioxide and PRISM4 paleogeography. The COSMOS confirm longstanding characteristics of the Mid-Pliocene Earth System, among these increased meridional volume transport in the Atlantic Ocean, an extended and intensified equatorial warm pool, as well as pronounced poleward expansion of vegetation cover. By means of a comparison of our results to a reconstruction of sea surface temperature (SST) of the Mid-Pliocene we find that the COSMOS reproduce reconstructed SST best if exposed to a carbon dioxide concentration of 400 ppmv. In the Atlantic to Arctic Ocean the simulated Mid-Pliocene core climate state is too cold in comparison to the SST reconstruction. The discord can be mitigated to some extent by increasing carbon dioxide that causes increased mismatch between model and reconstruction in other regions.

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