scholarly journals Methane removal and the proportional reductions in surface temperature and ozone

2021 ◽  
Vol 379 (2210) ◽  
pp. 20210104 ◽  
Author(s):  
S. Abernethy ◽  
F. M. O'Connor ◽  
C. D. Jones ◽  
R. B. Jackson
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Surface Temperature ◽  
Surface Ozone ◽  
Carbon Dioxide Removal ◽  
System Model ◽  
Future Research ◽  
Removal Technologies ◽  
Surface Ozone Concentration ◽  
Global Surface

Mitigating climate change requires a diverse portfolio of technologies and approaches, including negative emissions or removal of greenhouse gases. Previous literature focuses primarily on carbon dioxide removal, but methane removal may be an important complement to future efforts. Methane removal has at least two key benefits: reducing temperature more rapidly than carbon dioxide removal and improving air quality by reducing surface ozone concentration. While some removal technologies are being developed, modelling of their impacts is limited. Here, we conduct the first simulations using a methane emissions-driven Earth System Model to quantify the climate and air quality co-benefits of methane removal, including different rates and timings of removal. We define a novel metric, the effective cumulative removal, and use it to show that each effective petagram of methane removed causes a mean global surface temperature reduction of 0.21 ± 0.04°C and a mean global surface ozone reduction of 1.0 ± 0.2 parts per billion. Our results demonstrate the effectiveness of methane removal in delaying warming thresholds and reducing peak temperatures, and also allow for direct comparisons between the impacts of methane and carbon dioxide removal that could guide future research and climate policy. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.

scholarly journals The regulation of the air: a hypothesis

2011 ◽  
Vol 3 (2) ◽  
pp. 769-788 ◽  
Author(s):  
E. G. Nisbet ◽  
C. M. R. Fowler ◽  
R. E. R. Nisbet
Keyword(s):  
Carbon Dioxide ◽  
Natural Selection ◽  
Surface Temperature ◽  
Atmospheric Pressure ◽  
Nitrogen Fixing ◽  
Bisphosphate Carboxylase ◽  
Global Surface Temperature ◽  
Global Surface ◽  
Evolution Of Photosynthesis

Abstract. We propose the hypothesis that natural selection, acting on the specificity of rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) for carbon dioxide over oxygen, has controlled the CO2:O2 ratio of the atmosphere since the evolution of photosynthesis and has also sustained the Earth's greenhouse-set surface temperature. Rubisco works in partnership with the nitrogen-fixing enzyme nitrogenase to control atmospheric pressure. Together, these two enzymes control global surface temperature and indirectly the pH and oxygenation of the ocean. Thus, the co-evolution of these two enzymes may have produced clement conditions on the Earth's surface, allowing life to be sustained.

scholarly journals The Climate Sensitivity of the Community Climate System Model Version 3 (CCSM3)

2006 ◽  
Vol 19 (11) ◽  
pp. 2584-2596 ◽  
Author(s):  
Jeffrey T. Kiehl ◽  
Christine A. Shields ◽  
James J. Hack ◽  
William D. Collins
Keyword(s):  
Carbon Dioxide ◽  
High Resolution ◽  
Surface Temperature ◽  
Climate Sensitivity ◽  
Horizontal Resolution ◽  
System Model ◽  
Climate Response ◽  
Community Climate System Model ◽  
Transient Climate Response ◽  
Climate System Model

Abstract The climate sensitivity of the Community Climate System Model (CCSM) is described in terms of the equilibrium change in surface temperature due to a doubling of carbon dioxide in a slab ocean version of the Community Atmosphere Model (CAM) and the transient climate response, which is the surface temperature change at the point of doubling of carbon dioxide in a 1% yr−1 CO2 simulation with the fully coupled CCSM. For a fixed atmospheric horizontal resolution across model versions, we show that the equilibrium sensitivity has monotonically increased across CSM1.4, CCSM2, to CCSM3 from 2.01° to 2.27° to 2.47°C, respectively. The transient climate response for these versions is 1.44° to 1.09° to 1.48°C, respectively. Using climate feedback analysis, it is shown that both clear-sky and cloudy-sky processes have contributed to the changes in transient climate response. The dependence of these sensitivities on horizontal resolution is also explored. The equilibrium sensitivity of the high-resolution (T85) version of CCSM3 is 2.71°C, while the equilibrium response for the low-resolution model (T31) is 2.32°C. It is shown that the shortwave cloud response of the high-resolution version of the CCSM3 is anomalous compared to the low- and moderate-resolution versions.

scholarly journals How to most effectively expand the global surface ozone observing network

2016 ◽  
Vol 16 (3) ◽  
pp. 1445-1457 ◽  
Author(s):  
E. D. Sofen ◽  
D. Bowdalo ◽  
M. J. Evans
Keyword(s):  
Quality Control ◽  
Air Quality ◽  
Surface Ozone ◽  
Tropospheric Chemistry ◽  
Model Assessment ◽  
Data Set ◽  
Air Masses ◽  
The World ◽  
The Impact ◽  
Global Surface

Abstract. Surface ozone observations with modern instrumentation have been made around the world for more than 40 years. Some of these observations have been made as one-off activities with short-term, specific science objectives and some have been made as part of wider networks which have provided a foundational infrastructure of data collection, calibration, quality control, and dissemination. These observations provide a fundamental underpinning to our understanding of tropospheric chemistry, air quality policy, atmosphere–biosphere interactions, etc. brought together eight of these networks to provide a single data set of surface ozone observations. We investigate how representative this combined data set is of global surface ozone using the output from a global atmospheric chemistry model. We estimate that on an area basis, 25 % of the globe is observed (34 % land, 21 % ocean). Whereas Europe and North America have almost complete coverage, other continents, Africa, South America, Australia, and Asia (12–17 %) show significant gaps. Antarctica is surprisingly well observed (78 %). Little monitoring occurs over the oceans, with the tropical and southern oceans particularly poorly represented. The surface ozone over key biomes such as tropical forests and savanna is almost completely unmonitored. A chemical cluster analysis suggests that a significant number of observations are made of polluted air masses, but cleaner air masses whether over the land or ocean (especially again in the tropics) are significantly under-observed. The current network is unlikely to see the impact of the El Niño–Southern Oscillation (ENSO) but may be capable of detecting other planetary-scale signals. Model assessment and validation activities are hampered by a lack of observations in regions where the models differ substantially, as is the ability to monitor likely changes in surface ozone over the next century. Using our methodology we are able to suggest new sites which would help to close the gap in our ability to measure global surface ozone. An additional 20 surface ozone monitoring sites (a 20 % increase in the World Meteorological Organization Global Atmosphere Watch (WMO GAW) ozone sites or a 1 % increase in the total background network) located on 10 islands and in 10 continental regions would almost double the area observed. The cost of this addition to the network is small compared to other expenditure on atmospheric composition research infrastructure and would provide a significant long-term benefit to our understanding of the composition of the atmosphere, information which will also be available for consideration by air quality control managers and policy makers.

scholarly journals Carbon dioxide removal technologies are not born equal

2021 ◽  
Author(s):  
Jessica Strefler ◽  
Nico Bauer ◽  
Florian Humpenöder ◽  
David Klein ◽  
Alexander Popp ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Removal ◽  
Removal Technologies

Overshooting warming targets – temperature reversibility and implications for impacts, adaptation needs and near-term mitigation

2021 ◽  
Author(s):  
Carl-Friedrich Schleussner ◽  
Quentin Lejeune ◽  
Philippe Ciais ◽  
Thomas Gasser ◽  
Joeri Rogelj ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Global Warming ◽  
Large Scale ◽  
Carbon Dioxide Removal ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Removal Technologies ◽  
Near Term ◽  
The Impact ◽  
Global Mean

<p>Limiting global mean temperature increase to politically agreed temperature limits such as the 1.5°C threshold in the Paris Agreement becomes increasingly challenging. This has given rise to a class of overshoot emissions pathways in the mitigation literature that limit warming to such thresholds only after allowing for a temporary overshoot. However, substantial biogeophysical uncertainties remain regarding the large-scale deployment of Carbon Dioxide Removal technologies required to potentially reverse global warming. Additionally, beyond global mean temperature very little is known about the benefits of declining temperatures on impacts and adaptation needs. Here we will provide an overview of the current state of understanding regarding the reversibility of global warming, as well as impacts and adaptation needs under overshoot pathways.</p><p>We highlight the characteristics of the overshoot scenarios from the literature, and especially those that are compatible with identified sustainability limits for Carbon Dioxide Removal deployment. We will compare those characteristics with uncertainties arising from the Earth System’s response which may complicate the efforts to achieve a decrease in Global Mean Temperature after peak warming is reached. This part will include latest results of the permafrost carbon feedback under stylized overshoot scenarios. Eventually, we will summarise the state-of-the-art knowledge and present new results regarding the impacts of overshoot scenarios for non-linear and time-lagged responses such as sea-level rise, permafrost and glaciers. This will allow for a preliminary assessment of the impact and adaptation benefits of early mitigation compatible with a no or low overshoot pathways.</p>

scholarly journals Cancel (Out) Emissions? The Envisaged Role of Carbon Dioxide Removal Technologies in Long-Term National Climate Strategies

2021 ◽  
Vol 3 ◽  
Author(s):  
Alexandra Buylova ◽  
Mathias Fridahl ◽  
Naghmeh Nasiritousi ◽  
Gunilla Reischl
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Carbon Dioxide Removal ◽  
Climate Mitigation ◽  
Low Emission ◽  
Climate Action ◽  
Removal Technologies ◽  
Barriers And Opportunities

Carbon dioxide removal (CDR) increasingly features in climate scenarios that hold global warming well below 2°C by 2100. Given the continuous gap between climate mitigation pledges and the emission pathways that are aligned with achieving the temperature goals of the Paris Agreement, we would expect countries to promote CDR in their long-term planning to achieve mid-century targets. Yet, countries may not consider it their responsibility to contribute to the global response to climate change using CDR. Thus, a study of the respective country's long-term climate plans is both timely and vital. Such a study could reveal the pledged collective ambition, the contribution of CDR to the pledged ambition, and how the envisaged role of CDR is described by the different countries. This paper explores the long-term low emission development strategies (LT-LEDS) of countries in order to map the role of CDR in addressing climate change. We also supplement our examination of strategies with the opinions of climate experts. Based on an inductive coding of the material and a literature review, the analytical focus of the analysis includes CDR targets and planning, types of CDR, barriers and opportunities to CDR implementation, as well as international cooperation. Our study of 25 national LT-LEDS submitted to the UN or to the EU, as well as 23 interviews with climate experts, shows that national plans for CDR vary substantially across countries and are generally lacking in detail. The findings also demonstrate that CDR is perceived to be necessary and desirable for achieving mid-century climate goals, but also reveal variation in the intended role of CDR. We use an interpretive approach to outline three possible visions of CDR in climate action: as a panacea, as a necessary fallback and as a chimera. We conclude by discussing what our findings of the envisaged roles of CDR in addressing climate change mean for climate governance. This research thereby contributes to the literature on governing CDR with new comprehensive insights into the long-term climate strategies of countries.

scholarly journals Impact of carbon dioxide removal technologies on deep decarbonization of the electric power sector

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
John E. T. Bistline ◽  
Geoffrey J. Blanford
Keyword(s):  
Carbon Dioxide ◽  
Capacity Planning ◽  
Carbon Capture ◽  
Carbon Dioxide Removal ◽  
Low Carbon ◽  
Carbon Removal ◽  
Electric Sector ◽  
Direct Air Capture ◽  
Air Capture ◽  
Removal Technologies

AbstractCarbon dioxide removal technologies, such as bioenergy with carbon capture and direct air capture, are valuable for stringent climate targets. Previous work has examined implications of carbon removal, primarily bioenergy-based technologies using integrated assessment models, but not investigated the effects of a portfolio of removal options on power systems in detail. Here, we explore impacts of carbon removal technologies on electric sector investments, costs, and emissions using a detailed capacity planning and dispatch model with hourly resolution. We show that adding carbon removal to a mix of low-carbon generation technologies lowers the costs of deep decarbonization. Changes to system costs and investments from including carbon removal are larger as policy ambition increases, reducing the dependence on technologies like advanced nuclear and long-duration storage. Bioenergy with carbon capture is selected for net-zero electric sector emissions targets, but direct air capture deployment increases as biomass supply costs rise.

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