Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts and Response Strategies. Moss, R., Babiker, M., Brinkman, S., Calvo, E., Carter, T., Edmonds, J., Elgizouli, I., Emori, S., Erda, L., Hibbard, K., Jones, R., Kainuma, M., Kelleher, J., Lamarque, J. F., Manning, M., Matthews, B., Meehl, J., Meyer, L., Mitchell, J., Nakicenovic, N., O'Neill, B., Pichs, R., Riahi, K., Rose, S., Runci, P., Stouffer, R., van Vuuren, D., Weyant, J., Wilbanks, T., van Ypersele, J. P., & Zurek, M. Intergovernmental Panel on Climate Change.
Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts and Response Strategies [link]Paper  abstract   bibtex   
[Excerpt: Conclusion] This section summarizes the ways in which the parallel process for development of climate change scenarios described in this report relates to the six general questions introduced in Section I. [::1. Can new integrated scenarios that meet user needs be produced with the available resources and completed in time for consideration in a possible future IPCC assessment?] Earlier approaches to the use of scenarios in climate change science have followed the sequence of development of a complete set of emissions scenarios, development of the corresponding complete set of climate change simulations, and finally development of a range of matching impact and adaptation analyses. This stepwise process involved delays of many years in transferring information between the relevant IAM, CM, and IAV communities. The parallel process now planned by these science communities will reduce the time required for such transfers through better coordination at all stages so that each community can start to work within the same overall framework as soon as possible. [] In addition, the early agreement on RCPs and generation of the corresponding climate simulations using ESMs will open the way to using pattern scaling as a means to construct climate change scenarios corresponding to additional socioeconomic and emissions scenarios as those are subsequently developed, without requiring the very time-consuming ESM runs. While the full validity of pattern scaling in this context requires further research (see question 3 below) the parallel process will clearly be able to provide more consistent analyses across the different disciplines than have been available for an IPCC assessment at any stage in the past. [] The timetable discussed in this report has been set following extensive interdisciplinary discussions. It will require strict limits on the number of scenarios to be considered by the CM community, which has indicated that there are only resources for comprehensive runs for two to four RCPs within the necessary time frame. However, the focus by the CM community on larger ensembles for fewer emissions scenarios will provide better information for subsequent IAV analyses, as it will allow probabilistic estimation of uncertainties in future climate change (e.g., due to uncertainties in climate parameters such as climate sensitivity), and in particular will enable more robust analyses of changes in extreme events that are critical to impacts. [] Although the research community is confident that the parallel approach and the timetable given here will provide a better framework for future IPCC assessments, it is important to recognize that the approach now planned is untested and by its nature involves new types of interdisciplinary interactions. There remain significant underlying differences of approach in different areas of climate change science and the extent to which these may limit the effectiveness of the parallel process remains to be seen. Given this exploratory nature of what is now being planned in the science community, it should be understood that interdisciplinary consistency and synthesis is more likely to be available for a comprehensive IPCC assessment in 2014 or later, than in 2013. [::2. To what extent can concentration pathways be usefully abstracted from underlying emissions and socioeconomic changes?] Although a very large number of emissions scenarios now exist, from a physical climate perspective these can be spanned by a much smaller number of radiative forcing pathways. This suggests that many different socioeconomic and technological pathways may map to climate change scenarios that are indistinguishable within natural climate variability and ESM uncertainties. However, as noted earlier, only a relatively small number of emissions scenarios provide details for all the species now required in ESMs. In addition, the prescription of regional-scale evolution of land use/land cover, aerosol emissions, tropospheric ozone precursors, and other factors influencing climate now introduces potentially tighter linkages to socioeconomic and technological factors than has been the case when only global-scale long-lived GHG emissions were used for climate modeling. [] The emergence of new dependencies between what is required by ESM simulations and the underlying socioeconomic assumptions means that we cannot assume that significantly different socioeconomic pathways could produce effectively equal climate scenarios, particularly at the regional scale that is important for IAV studies. As a result, the range of socioeconomic pathways that may be consistent with a particular pathway for radiative forcing or global and regional climate change can only be identified through further research. The parallel modeling and integration phases of the parallel process described in Section II of this report will provide an initial basis for such research. [::3. To what extent can climate changes be interpolated between forcing levels?] As noted earlier, the later stages of the parallel process envisaged here will use pattern scaling between climate change scenarios developed for the RCPs to generate climate change scenarios corresponding to new emissions scenarios that fall between the high and low RCPs. The robustness of this patternscaling approach has been tested to some extent for AOGCMs (e.g., Mitchell et al., 1999), but is likely to be reconsidered in light of new results from the more complex ESMs. Major tools for such work are simple and regional CMs and models of intermediate complexity (e.g., Mitchell, 2003; Ruosteenoja et al., 2007) and further research will be needed to ensure that these can be calibrated or matched to ESMs. To date, pattern scaling techniques have employed linear assumptions about the scaler (e.g., annual global mean temperature) and the pattern of response at the regional scale (see above references). At this stage, it is generally expected that pattern scaling will be more reliable for climate variables such as average temperature than for variables such as precipitation or for identifying extreme or rare events. Although the AR4 model runs suggest that broad patterns of precipitation change are common to different scenarios used in AOGCMs, these generally reflect the effect of atmospheric water vapor increases. Higher spatial resolution in future simulations may introduce greater local dependence on orography and regional-scale feedbacks, (e.g., soil moisture loss, frost days, and land cover change), which are less likely to scale linearly with the applied radiative forcing (Ruosteenoja et al., 2007). [] Regions where significant feedbacks occur, such as on the margins of snow and ice cover or where significant land cover change occurs, may also show temperature changes that do not scale with radiative forcing. In addition, there are potential thresholds in the physical climate system, such as the transition from positive to negative surface mass balance of the Greenland Ice Sheet, whose effects are unlikely to be captured by a simple linear scaling approach. Finally, the introduction of an overshoot scenario for the low RCP raises the prospect of physical and biological systems switching their responses from a warming world to a cooling world over a range of quite different time scales. The applicability of linear scaling in such circumstances is untested but appears likely to be less robust than scaling between climates in which the responses are all occurring in the same direction. [] Thus, although there is an expectation that some climate variables will scale linearly in some regions, the overall robustness of the pattern-scaling approach will need to be re-evaluated when new model results are available. This can be performed to some extent using an RCP intermediate between the high and low cases, and can be done by specific research projects in the CM and IAV communities. [::4. What information can be provided in the form of downscaled climate and socioeconomic information for use by the IAV community?] The physical climate variables to be diagnosed by ESMs are well defined and the issues involved in downscaling these from the resolution of global ESMs to regional and local scales more appropriate for IAV studies are generally understood. In some respects such downscaling raises similar issues to those of scaling with radiative forcing as discussed above and many of the same caveats occur. Downscaling the magnitude and frequency of extreme events is particularly important for determining impacts and this merits further research, for example, working from the existing archive of AOGCM results for the AR4. Downscaling of physical climate variables may be advanced by further reviews of the techniques, agreement on best practice, and improving the accessibility of archived products for IAV analyses. [] Issues that are more difficult are raised in relation to downscaling the major socioeconomic and technological assumptions that determine the RCPs from the macro scale, where they are prescribed or diagnosed in the IAM community, to the regional and local scales where they influence adaptive capacity. In this regard, a merging of bottom-up and top-down perspectives as discussed below for question 5 will be helpful. For example, consistency across different scales can be improved by the development of regional storylines that are compatible with one another and with the global scenario underlying the RCPs. [] Further work on downscaling for physical variables will require collaboration between the CM and IAV communities, and for socioeconomic factors will require collaboration between the IAV and IAM communities. In both cases, primary responsibility rests with the IAV community, which is in the best position to judge the type of results required and the value and robustness of what can be produced. The TGICA and the DDC are well placed to provide the necessary organizational and archival infrastructure to support such collaborations. [::5. How can disaggregated analyses of mitigation opportunities at the scales of large countries (e.g., China, India, and the United States) or regions (e.g., European Union) be undertaken in a way that can be related to more highly aggregated global scenario studies using IAMs?] The rapidly growing interest of governments in determining strategic plans for emissions within their jurisdiction, and the many studies already being undertaken for regional initiatives that would reduce carbon intensity or increase energy efficiency, signal a clear need to keep such developments in mind when considering future emissions scenarios. Regional considerations can have significant implications for investment strategies (in relation to both adaptation and mitigation), the nature and scale of new infrastructure, the rate at which new technologies penetrate markets, and the governance structure that affects the balance between individual and communal decisions. One technique for ensuring consistency between the regional and global levels is through use of storylines that carry sufficient contextual detail to allow the matching of compatible changes across different regions and ultimately with a world view of each scenario considered. [] New institutional interactions may be needed to ensure that regional policy options are promptly and effectively considered in relation to emissions scenarios used for research purposes. Several international organizations are already involved in such work and could contribute their perspectives and knowledge base. However, it may be necessary to demonstrate more clearly to such organizations that their interests can be advanced through analyses of climate change impacts and vulnerability, or of regional- to global-scale economic interactions, by the international research communities. [] This is an area in which experts from DC/EIT countries should clearly play major roles. Such local experts provide the best means of linking their government strategies to international research, and provide the local credibility that one would expect international funding agencies to be looking for when considering new research initiatives. [::6. How can the proposed scenario process be strengthened to evaluate key dimensions of uncertainty (e.g., in our understanding of key natural processes or socioeconomic futures)?] Scenario analyses are themselves a primary tool for exploring uncertainties in future climate change. The parallel process envisaged here, through its early agreement on RCPs followed by its development of new scenarios, will extend the work undertaken for the SRES scenarios and provide new insights into the factors in socioeconomic development that are most influential in determining future climate change, its impacts, and human and natural vulnerabilities. [] The growing regional disaggregation of factors that underlie scenarios and the increasing sophistication and spatial resolution of ESMs should be used to provide additional information on those uncertainties that are common to all regions and those that are of more importance within particular areas or sectors. The strategy of covering the full range of plausible scenarios should also allow identification of the widest possible range of thresholds in the physical climate system as well as consideration of the key aspects and timing of socioeconomic and technological change that may act as bifurcation points in determining world futures. The introduction of an overshoot scenario for the low RCP will raise, for the first time, important issues of recovery of physical and biological systems. [] The focus on two or four RCPs that are well spaced in terms of radiative forcing, and the generation of large ensembles of simulations for these cases, should provide a better focus for future IAV studies in terms of reducing uncertainties in determining the impacts of extremes. It will also support new intercomparisons and assessments of the methodological and sectoral modeling uncertainties in IAV analyses. This focus on fewer and more clearly separated future climate scenarios should also enable better estimates of avoided impacts. [] The summary above indicates many areas in which future research is clearly needed to ensure that the parallel process is effective in bringing together a truly cross-disciplinary synthesis of research on climate change. By its nature, research can uncover new sources of uncertainty, however, through accelerating the transfer of information between disciplines, the parallel process described in this report should address currently known uncertainties more rapidly and comprehensively than would be possible otherwise. [] [...]
@book{mossNewScenariosAnalysis2008,
  title = {Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts and Response Strategies},
  author = {Moss, Richard and Babiker, Mustafa and Brinkman, Sander and Calvo, Eduardo and Carter, Tim and Edmonds, Jae and Elgizouli, Ismail and Emori, Seita and Erda, Lin and Hibbard, Kathy and Jones, Roger and Kainuma, Mikiko and Kelleher, Jessica and Lamarque, Jean F. and Manning, Martin and Matthews, Ben and Meehl, Jerry and Meyer, Leo and Mitchell, John and Nakicenovic, Nebojsa and O'Neill, Brian and Pichs, Ramon and Riahi, Keywan and Rose, Steven and Runci, Paul and Stouffer, Ron and van Vuuren, Detlef and Weyant, John and Wilbanks, Tom and van Ypersele, Jean P. and Zurek, Monika},
  date = {2008},
  publisher = {{Intergovernmental Panel on Climate Change}},
  location = {{Geneva, Switzerland}},
  url = {http://mfkp.org/INRMM/article/14172769},
  abstract = {[Excerpt: Conclusion]

This section summarizes the ways in which the parallel process for development of climate change scenarios described in this report relates to the six general questions introduced in Section I.

[::1. Can new integrated scenarios that meet user needs be produced with the available resources and completed in time for consideration in a possible future IPCC assessment?]

Earlier approaches to the use of scenarios in climate change science have followed the sequence of development of a complete set of emissions scenarios, development of the corresponding complete set of climate change simulations, and finally development of a range of matching impact and adaptation analyses. This stepwise process involved delays of many years in transferring information between the relevant IAM, CM, and IAV communities. The parallel process now planned by these science communities will reduce the time required for such transfers through better coordination at all stages so that each community can start to work within the same overall framework as soon as possible.

[] In addition, the early agreement on RCPs and generation of the corresponding climate simulations using ESMs will open the way to using pattern scaling as a means to construct climate change scenarios corresponding to additional socioeconomic and emissions scenarios as those are subsequently developed, without requiring the very time-consuming ESM runs. While the full validity of pattern scaling in this context requires further research (see question 3 below) the parallel process will clearly be able to provide more consistent analyses across the different disciplines than have been available for an IPCC assessment at any stage in the past.

[] The timetable discussed in this report has been set following extensive interdisciplinary discussions. It will require strict limits on the number of scenarios to be considered by the CM community, which has indicated that there are only resources for comprehensive runs for two to four RCPs within the necessary time frame. However, the focus by the CM community on larger ensembles for fewer emissions scenarios will provide better information for subsequent IAV analyses, as it will allow probabilistic estimation of uncertainties in future climate change (e.g., due to uncertainties in climate parameters such as climate sensitivity), and in particular will enable more robust analyses of changes in extreme events that are critical to impacts.

[] Although the research community is confident that the parallel approach and the timetable given here will provide a better framework for future IPCC assessments, it is important to recognize that the approach now planned is untested and by its nature involves new types of interdisciplinary interactions. There remain significant underlying differences of approach in different areas of climate change science and the extent to which these may limit the effectiveness of the parallel process remains to be seen. Given this exploratory nature of what is now being planned in the science community, it should be understood that interdisciplinary consistency and synthesis is more likely to be available for a comprehensive IPCC assessment in 2014 or later, than in 2013.

[::2. To what extent can concentration pathways be usefully abstracted from underlying emissions and socioeconomic changes?]

Although a very large number of emissions scenarios now exist, from a physical climate perspective these can be spanned by a much smaller number of radiative forcing pathways. This suggests that many different socioeconomic and technological pathways may map to climate change scenarios that are indistinguishable within natural climate variability and ESM uncertainties. However, as noted earlier, only a relatively small number of emissions scenarios provide details for all the species now required in ESMs. In addition, the prescription of regional-scale evolution of land use/land cover, aerosol emissions, tropospheric ozone precursors, and other factors influencing climate now introduces potentially tighter linkages to socioeconomic and technological factors than has been the case when only global-scale long-lived GHG emissions were used for climate modeling.

[] The emergence of new dependencies between what is required by ESM simulations and the underlying socioeconomic assumptions means that we cannot assume that significantly different socioeconomic pathways could produce effectively equal climate scenarios, particularly at the regional scale that is important for IAV studies. As a result, the range of socioeconomic pathways that may be consistent with a particular pathway for radiative forcing or global and regional climate change can only be identified through further research. The parallel modeling and integration phases of the parallel process described in Section II of this report will provide an initial basis for such research.

[::3. To what extent can climate changes be interpolated between forcing levels?]

As noted earlier, the later stages of the parallel process envisaged here will use pattern scaling between climate change scenarios developed for the RCPs to generate climate change scenarios corresponding to new emissions scenarios that fall between the high and low RCPs. The robustness of this patternscaling approach has been tested to some extent for AOGCMs (e.g., Mitchell et al., 1999), but is likely to be reconsidered in light of new results from the more complex ESMs. Major tools for such work are simple and regional CMs and models of intermediate complexity (e.g., Mitchell, 2003; Ruosteenoja et al., 2007) and further research will be needed to ensure that these can be calibrated or matched to ESMs. To date, pattern scaling techniques have employed linear assumptions about the scaler (e.g., annual global mean temperature) and the pattern of response at the regional scale (see above references). At this stage, it is generally expected that pattern scaling will be more reliable for climate variables such as average temperature than for variables such as precipitation or for identifying extreme or rare events. Although the AR4 model runs suggest that broad patterns of precipitation change are common to different scenarios used in AOGCMs, these generally reflect the effect of atmospheric water vapor increases. Higher spatial resolution in future simulations may introduce greater local dependence on orography and regional-scale feedbacks, (e.g., soil moisture loss, frost days, and land cover change), which are less likely to scale linearly with the applied radiative forcing (Ruosteenoja et al., 2007).

[] Regions where significant feedbacks occur, such as on the margins of snow and ice cover or where significant land cover change occurs, may also show temperature changes that do not scale with radiative forcing. In addition, there are potential thresholds in the physical climate system, such as the transition from positive to negative surface mass balance of the Greenland Ice Sheet, whose effects are unlikely to be captured by a simple linear scaling approach. Finally, the introduction of an overshoot scenario for the low RCP raises the prospect of physical and biological systems switching their responses from a warming world to a cooling world over a range of quite different time scales. The applicability of linear scaling in such circumstances is untested but appears likely to be less robust than scaling between climates in which the responses are all occurring in the same direction.

[] Thus, although there is an expectation that some climate variables will scale linearly in some regions, the overall robustness of the pattern-scaling approach will need to be re-evaluated when new model results are available. This can be performed to some extent using an RCP intermediate between the high and low cases, and can be done by specific research projects in the CM and IAV communities.

[::4. What information can be provided in the form of downscaled climate and socioeconomic information for use by the IAV community?]

The physical climate variables to be diagnosed by ESMs are well defined and the issues involved in downscaling these from the resolution of global ESMs to regional and local scales more appropriate for IAV studies are generally understood. In some respects such downscaling raises similar issues to those of scaling with radiative forcing as discussed above and many of the same caveats occur. Downscaling the magnitude and frequency of extreme events is particularly important for determining impacts and this merits further research, for example, working from the existing archive of AOGCM results for the AR4. Downscaling of physical climate variables may be advanced by further reviews of the techniques, agreement on best practice, and improving the accessibility of archived products for IAV analyses.

[] Issues that are more difficult are raised in relation to downscaling the major socioeconomic and technological assumptions that determine the RCPs from the macro scale, where they are prescribed or diagnosed in the IAM community, to the regional and local scales where they influence adaptive capacity. In this regard, a merging of bottom-up and top-down perspectives as discussed below for question 5 will be helpful. For example, consistency across different scales can be improved by the development of regional storylines that are compatible with one another and with the global scenario underlying the RCPs.

[] Further work on downscaling for physical variables will require collaboration between the CM and IAV communities, and for socioeconomic factors will require collaboration between the IAV and IAM communities. In both cases, primary responsibility rests with the IAV community, which is in the best position to judge the type of results required and the value and robustness of what can be produced. The TGICA and the DDC are well placed to provide the necessary organizational and archival infrastructure to support such collaborations.

[::5. How can disaggregated analyses of mitigation opportunities at the scales of large countries (e.g., China, India, and the United States) or regions (e.g., European Union) be undertaken in a way that can be related to more highly aggregated global scenario studies using IAMs?]

The rapidly growing interest of governments in determining strategic plans for emissions within their jurisdiction, and the many studies already being undertaken for regional initiatives that would reduce carbon intensity or increase energy efficiency, signal a clear need to keep such developments in mind when considering future emissions scenarios. Regional considerations can have significant implications for investment strategies (in relation to both adaptation and mitigation), the nature and scale of new infrastructure, the rate at which new technologies penetrate markets, and the governance structure that affects the balance between individual and communal decisions. One technique for ensuring consistency between the regional and global levels is through use of storylines that carry sufficient contextual detail to allow the matching of compatible changes across different regions and ultimately with a world view of each scenario considered.

[] New institutional interactions may be needed to ensure that regional policy options are promptly and effectively considered in relation to emissions scenarios used for research purposes. Several international organizations are already involved in such work and could contribute their perspectives and knowledge base. However, it may be necessary to demonstrate more clearly to such organizations that their interests can be advanced through analyses of climate change impacts and vulnerability, or of regional- to global-scale economic interactions, by the international research communities.

[] This is an area in which experts from DC/EIT countries should clearly play major roles. Such local experts provide the best means of linking their government strategies to international research, and provide the local credibility that one would expect international funding agencies to be looking for when considering new research initiatives.

[::6. How can the proposed scenario process be strengthened to evaluate key dimensions of uncertainty (e.g., in our understanding of key natural processes or socioeconomic futures)?]

Scenario analyses are themselves a primary tool for exploring uncertainties in future climate change. The parallel process envisaged here, through its early agreement on RCPs followed by its development of new scenarios, will extend the work undertaken for the SRES scenarios and provide new insights into the factors in socioeconomic development that are most influential in determining future climate change, its impacts, and human and natural vulnerabilities.

[] The growing regional disaggregation of factors that underlie scenarios and the increasing sophistication and spatial resolution of ESMs should be used to provide additional information on those uncertainties that are common to all regions and those that are of more importance within particular areas or sectors. The strategy of covering the full range of plausible scenarios should also allow identification of the widest possible range of thresholds in the physical climate system as well as consideration of the key aspects and timing of socioeconomic and technological change that may act as bifurcation points in determining world futures. The introduction of an overshoot scenario for the low RCP will raise, for the first time, important issues of recovery of physical and biological systems.

[] The focus on two or four RCPs that are well spaced in terms of radiative forcing, and the generation of large ensembles of simulations for these cases, should provide a better focus for future IAV studies in terms of reducing uncertainties in determining the impacts of extremes. It will also support new intercomparisons and assessments of the methodological and sectoral modeling uncertainties in IAV analyses. This focus on fewer and more clearly separated future climate scenarios should also enable better estimates of avoided impacts.

[] The summary above indicates many areas in which future research is clearly needed to ensure that the parallel process is effective in bringing together a truly cross-disciplinary synthesis of research on climate change. By its nature, research can uncover new sources of uncertainty, however, through accelerating the transfer of information between disciplines, the parallel process described in this report should address currently known uncertainties more rapidly and comprehensively than would be possible otherwise.

[] [...]},
  isbn = {978-92-9169-125-8},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-14172769,climate-change,climate-projections,ipcc,ipcc-scenarios,rcp26,rcp45,rcp60,rcp85},
  options = {useprefix=true}
}
Downloads: 0
About
Documentation
Keywords
Search
Users
Terms and Conditions of Use
Privacy Policy
Sitemap
© BibBase.org 2021