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Cumulative carbon as a policy framework for achieving climate stabilization.

Matthews HD, Solomon S, Pierrehumbert R - Philos Trans A Math Phys Eng Sci (2012)

Bottom Line: We show first that both atmospheric CO(2) concentration at a given year and the associated temperature change are generally associated with a unique cumulative carbon emissions budget that is largely independent of the emissions scenario.Non-CO(2) emissions therefore contribute to uncertainty in the cumulative carbon budget associated with near-term temperature targets, and may suggest the need for a mitigation approach that considers separately short- and long-lived gas emissions.By contrast, long-term temperature change remains primarily associated with total cumulative carbon emissions owing to the much longer atmospheric residence time of CO(2) relative to other major climate forcing agents.

View Article: PubMed Central - PubMed

Affiliation: Department of Geography, Planning and Environment, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec, Canada H3G 1M8. dmatthew@alcor.concordia.ca

ABSTRACT
The primary objective of the United Nations Framework Convention on Climate Change is to stabilize greenhouse gas concentrations at a level that will avoid dangerous climate impacts. However, greenhouse gas concentration stabilization is an awkward framework within which to assess dangerous climate change on account of the significant lag between a given concentration level and the eventual equilibrium temperature change. By contrast, recent research has shown that global temperature change can be well described by a given cumulative carbon emissions budget. Here, we propose that cumulative carbon emissions represent an alternative framework that is applicable both as a tool for climate mitigation as well as for the assessment of potential climate impacts. We show first that both atmospheric CO(2) concentration at a given year and the associated temperature change are generally associated with a unique cumulative carbon emissions budget that is largely independent of the emissions scenario. The rate of global temperature change can therefore be related to first order to the rate of increase of cumulative carbon emissions. However, transient warming over the next century will also be strongly affected by emissions of shorter lived forcing agents such as aerosols and methane. Non-CO(2) emissions therefore contribute to uncertainty in the cumulative carbon budget associated with near-term temperature targets, and may suggest the need for a mitigation approach that considers separately short- and long-lived gas emissions. By contrast, long-term temperature change remains primarily associated with total cumulative carbon emissions owing to the much longer atmospheric residence time of CO(2) relative to other major climate forcing agents.

No MeSH data available.


Related in: MedlinePlus

Summary figure showing the relationship between cumulative emissions, CO2 concentrations and temperature change. (a) Cumulative emission values, (b) CO2 scenarios and (c) the central value for the year-2100 temperature changes corresponding to the UVic ESCM model simulations as shown in figure 1. The red-bar temperature range represents the 5–95% uncertainty range for the temperature response to cumulative emissions [14,16]. In (b) the purple shaded region represents an estimate (for 550 CO2 scenario) of the uncertainty in the carbon cycle response to cumulative emissions, based on the C4MIP model simulations [36].2 Also shown in (b), for the year 2005 as well as for the year 2100 of the 400, 450 and 550 scenarios, are additional ranges corresponding to the CO2-equivalent values of CO2 plus non-CO2 greenhouse gases and aerosols (green cross symbols and uncertainty ranges, as plotted in figure 5c). Finally, for the scenarios where we included an estimate of the CO2-equivalent, we have included an additional range for the temperature response to cumulative emissions (thin green bars), shifted upward to match to the best estimate of the CO2-equivalent concentration for each of the 400, 450 and 550 ppm scenarios. The grey shaded region at the bottom of the plot shows total cumulative emissions to date, and the correspondingly inaccessible climate targets, assuming positive future cumulative emissions. Figure adapted from Solomon et al. [6, figs 3–8].
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RSTA20120064F6: Summary figure showing the relationship between cumulative emissions, CO2 concentrations and temperature change. (a) Cumulative emission values, (b) CO2 scenarios and (c) the central value for the year-2100 temperature changes corresponding to the UVic ESCM model simulations as shown in figure 1. The red-bar temperature range represents the 5–95% uncertainty range for the temperature response to cumulative emissions [14,16]. In (b) the purple shaded region represents an estimate (for 550 CO2 scenario) of the uncertainty in the carbon cycle response to cumulative emissions, based on the C4MIP model simulations [36].2 Also shown in (b), for the year 2005 as well as for the year 2100 of the 400, 450 and 550 scenarios, are additional ranges corresponding to the CO2-equivalent values of CO2 plus non-CO2 greenhouse gases and aerosols (green cross symbols and uncertainty ranges, as plotted in figure 5c). Finally, for the scenarios where we included an estimate of the CO2-equivalent, we have included an additional range for the temperature response to cumulative emissions (thin green bars), shifted upward to match to the best estimate of the CO2-equivalent concentration for each of the 400, 450 and 550 ppm scenarios. The grey shaded region at the bottom of the plot shows total cumulative emissions to date, and the correspondingly inaccessible climate targets, assuming positive future cumulative emissions. Figure adapted from Solomon et al. [6, figs 3–8].

Mentions: The cumulative carbon framework is summarized in figure 6. Read sequentially from left to right, this figure connects cumulative carbon emissions at the year 2100 with CO2 concentrations and temperature changes at that date. Uncertainties in temperature changes (red bars) reflect our estimate of the very likely (5–95%) range of temperature responses to the associated level of cumulative carbon emissions, based on carbon cycle and climate feedback uncertainties [6,14,16]. The uncertainty associated with the carbon cycle alone is indicated by the purple shaded region around the 550 ppm CO2 scenario at the year 2100, reflecting inter-model differences in the carbon cycle response to emissions and climate changes [36].2 The CO2-equivalent of all greenhouse gases and aerosols, along with the uncertainty on this estimate, is plotted on the CO2 concentration profiles with green cross symbols and error bars at year 2005, and at year 2100 for the three intermediate CO2 scenarios. For these scenarios (400, 450 and 550 ppm CO2 concentrations at 2100), we have also given a modified temperature response, which reflects the slight increase in the year-2100 CO2-equivalent concentration (relative to the CO2-only concentration) associated with a given level of cumulative carbon emissions (thin green vertical bars).Figure 6.


Cumulative carbon as a policy framework for achieving climate stabilization.

Matthews HD, Solomon S, Pierrehumbert R - Philos Trans A Math Phys Eng Sci (2012)

Summary figure showing the relationship between cumulative emissions, CO2 concentrations and temperature change. (a) Cumulative emission values, (b) CO2 scenarios and (c) the central value for the year-2100 temperature changes corresponding to the UVic ESCM model simulations as shown in figure 1. The red-bar temperature range represents the 5–95% uncertainty range for the temperature response to cumulative emissions [14,16]. In (b) the purple shaded region represents an estimate (for 550 CO2 scenario) of the uncertainty in the carbon cycle response to cumulative emissions, based on the C4MIP model simulations [36].2 Also shown in (b), for the year 2005 as well as for the year 2100 of the 400, 450 and 550 scenarios, are additional ranges corresponding to the CO2-equivalent values of CO2 plus non-CO2 greenhouse gases and aerosols (green cross symbols and uncertainty ranges, as plotted in figure 5c). Finally, for the scenarios where we included an estimate of the CO2-equivalent, we have included an additional range for the temperature response to cumulative emissions (thin green bars), shifted upward to match to the best estimate of the CO2-equivalent concentration for each of the 400, 450 and 550 ppm scenarios. The grey shaded region at the bottom of the plot shows total cumulative emissions to date, and the correspondingly inaccessible climate targets, assuming positive future cumulative emissions. Figure adapted from Solomon et al. [6, figs 3–8].
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Related In: Results  -  Collection

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RSTA20120064F6: Summary figure showing the relationship between cumulative emissions, CO2 concentrations and temperature change. (a) Cumulative emission values, (b) CO2 scenarios and (c) the central value for the year-2100 temperature changes corresponding to the UVic ESCM model simulations as shown in figure 1. The red-bar temperature range represents the 5–95% uncertainty range for the temperature response to cumulative emissions [14,16]. In (b) the purple shaded region represents an estimate (for 550 CO2 scenario) of the uncertainty in the carbon cycle response to cumulative emissions, based on the C4MIP model simulations [36].2 Also shown in (b), for the year 2005 as well as for the year 2100 of the 400, 450 and 550 scenarios, are additional ranges corresponding to the CO2-equivalent values of CO2 plus non-CO2 greenhouse gases and aerosols (green cross symbols and uncertainty ranges, as plotted in figure 5c). Finally, for the scenarios where we included an estimate of the CO2-equivalent, we have included an additional range for the temperature response to cumulative emissions (thin green bars), shifted upward to match to the best estimate of the CO2-equivalent concentration for each of the 400, 450 and 550 ppm scenarios. The grey shaded region at the bottom of the plot shows total cumulative emissions to date, and the correspondingly inaccessible climate targets, assuming positive future cumulative emissions. Figure adapted from Solomon et al. [6, figs 3–8].
Mentions: The cumulative carbon framework is summarized in figure 6. Read sequentially from left to right, this figure connects cumulative carbon emissions at the year 2100 with CO2 concentrations and temperature changes at that date. Uncertainties in temperature changes (red bars) reflect our estimate of the very likely (5–95%) range of temperature responses to the associated level of cumulative carbon emissions, based on carbon cycle and climate feedback uncertainties [6,14,16]. The uncertainty associated with the carbon cycle alone is indicated by the purple shaded region around the 550 ppm CO2 scenario at the year 2100, reflecting inter-model differences in the carbon cycle response to emissions and climate changes [36].2 The CO2-equivalent of all greenhouse gases and aerosols, along with the uncertainty on this estimate, is plotted on the CO2 concentration profiles with green cross symbols and error bars at year 2005, and at year 2100 for the three intermediate CO2 scenarios. For these scenarios (400, 450 and 550 ppm CO2 concentrations at 2100), we have also given a modified temperature response, which reflects the slight increase in the year-2100 CO2-equivalent concentration (relative to the CO2-only concentration) associated with a given level of cumulative carbon emissions (thin green vertical bars).Figure 6.

Bottom Line: We show first that both atmospheric CO(2) concentration at a given year and the associated temperature change are generally associated with a unique cumulative carbon emissions budget that is largely independent of the emissions scenario.Non-CO(2) emissions therefore contribute to uncertainty in the cumulative carbon budget associated with near-term temperature targets, and may suggest the need for a mitigation approach that considers separately short- and long-lived gas emissions.By contrast, long-term temperature change remains primarily associated with total cumulative carbon emissions owing to the much longer atmospheric residence time of CO(2) relative to other major climate forcing agents.

View Article: PubMed Central - PubMed

Affiliation: Department of Geography, Planning and Environment, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec, Canada H3G 1M8. dmatthew@alcor.concordia.ca

ABSTRACT
The primary objective of the United Nations Framework Convention on Climate Change is to stabilize greenhouse gas concentrations at a level that will avoid dangerous climate impacts. However, greenhouse gas concentration stabilization is an awkward framework within which to assess dangerous climate change on account of the significant lag between a given concentration level and the eventual equilibrium temperature change. By contrast, recent research has shown that global temperature change can be well described by a given cumulative carbon emissions budget. Here, we propose that cumulative carbon emissions represent an alternative framework that is applicable both as a tool for climate mitigation as well as for the assessment of potential climate impacts. We show first that both atmospheric CO(2) concentration at a given year and the associated temperature change are generally associated with a unique cumulative carbon emissions budget that is largely independent of the emissions scenario. The rate of global temperature change can therefore be related to first order to the rate of increase of cumulative carbon emissions. However, transient warming over the next century will also be strongly affected by emissions of shorter lived forcing agents such as aerosols and methane. Non-CO(2) emissions therefore contribute to uncertainty in the cumulative carbon budget associated with near-term temperature targets, and may suggest the need for a mitigation approach that considers separately short- and long-lived gas emissions. By contrast, long-term temperature change remains primarily associated with total cumulative carbon emissions owing to the much longer atmospheric residence time of CO(2) relative to other major climate forcing agents.

No MeSH data available.


Related in: MedlinePlus