Intergovernmental Panel On Climate Change Assessment Research Articles

Learning about climate change solutions in the IPCC and beyond

There has been much debate about the assessment process of the Intergovernmental Panel on Climate Change (IPCC). Yet two of the most fundamental challenges that directly threaten the ability of the IPCC to fulfill its mandate have been largely neglected so far. Firstly, the magnitude and rapid expansion of the climate change literature makes it increasingly impossible for the IPCC to conduct comprehensive and transparent assessments without major innovations in assessment practices and tools. Secondly, the structure, organization and scientific practices across the social sciences and humanities prohibit systematic learning on climate change solutions and increasingly limit the policy-relevance of IPCC assessments. We highlight the need for responses along three avenues to prepare the IPCC for continued success in the future: 1) IPCC assessments must make better use of big-data methods and available computational power to assess the growing body of literature and ensure comprehensiveness; 2) systematic review practices need to be enshrined into IPCC procedures to ensure adequate focus and transparency in its assessments; 3) a synthetic research culture needs to be established in the social sciences and humanities in order to foster knowledge accumulation and learning on climate solutions in the future. As policymakers become more interested in understanding solutions, the future prospects of global environmental assessment enterprises will depend heavily on a successful transformation within the social sciences and humanities towards systematic knowledge generation. This article is part of a special issue on solution-oriented Global Environmental Assessments.

Assessment of the impacts of climate change on maize production in the Wami Ruvu basin of Tanzania

The IPCC (Intergovernmental Panel on Climate Change) assessment reports confirm that climate change will hit developing countries the hardest. Adaption is on the agenda of many countries around the world. However, before devising adaption strategies, it is crucial to assess and understand the impacts of climate change at regional and local scales. In this study, the impact of climate change on rain-fed maize (Zea mays) production in the Wami-Ruvu basin of Tanzania was evaluated using the Decision Support System for Agro-technological Transfer. The model was fed with daily minimum and maximum temperatures, rainfall and solar radiation for current climate conditions (1971–2000) as well as future climate projections (2010–2099) for two Representative Concentration Pathways: RCP 4.5 and RCP 8.5. These data were derived from three high-resolution regional climate models, used in the Coordinated Regional Climate Downscaling Experiment program. Results showed that due to climate change future maize yields over the Wami-Ruvu basin will slightly increase relative to the baseline during the current century under RCP 4.5 and RCP 8.5. However, maize yields will decline in the mid and end centuries. The spatial distribution showed that high decline in maize yields are projected over lower altitude regions due to projected increase in temperatures in those areas.

Reforming the IPCC's Assessment of Climate Change Economics

The Intergovernmental Panel on Climate Change (IPCC) is broadly viewed as the world’s most legitimate scientific assessment body that periodically assesses the economics of climate change (among many other topics) for policy audiences. However, growing procedural inefficiencies and limitations to substantive coverage have made the IPCC an increasingly unattractive forum for the most qualified climate economists. Drawing on our observations and personal experience working on the most recent IPCC report, published last year, we propose four reforms to the IPCC’s process that we believe will lower the cost for volunteering as an IPCC author: improving interactions between governments and academics, making IPCC operations more efficient, clarifying and strengthening conflict of interest rules, and expanding outreach. We also propose three reforms to the IPCC’s substantive coverage to clarify the IPCC’s role and to make participation as an author more intellectually rewarding: complementing the IPCC with other initiatives, improving the integration of economics with other disciplines, and providing complete data for policymakers to make decisions. Despite the distinct characteristics of the IPCC that create challenges for authors unlike those in any other review body, we continue to believe in the importance of the IPCC for providing the most visible line of public communication between the scholarly community and policymakers.

Implementing Local Climate Change Adaptation and Mitigation Actions: The Role of Various Policy Instruments in a Multi-Level Governance Context

Recently, considerable focus, e.g., in the fifth IPCC (Intergovernmental Panel on Climate Change) Assessment Report (2014) has been trained on why adaptation and mitigation have not been developed more than at present, with relatively few local government actions taken compared with, for example, more discursive policy agreement on the importance of the issue of climate change. Going beyond a focus on general limits and barriers, this comment suggests that one important issue is that climate change has not yet been sufficiently integrated into the state regulative structure of legislation and policy-making. A comparison between three cases suggests that local developments that are not supported in particular by binding regulation are unlikely to achieve the same general level of implementation as issues for which such regulative demands (and thereby also requirements for prioritization) exist. This constitutes an important consideration for the development of adaptation and mitigation as policy areas, including on the local level.

Toward more realistic projections of soil carbon dynamics by Earth system models

AbstractSoil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other assessments. To achieve this goal, we suggest that (1) model structures should reflect real‐world processes, (2) parameters should be calibrated to match model outputs with observations, and (3) external forcing variables should accurately prescribe the environmental conditions that soils experience. First, most soil C cycle models simulate C input from litter production and C release through decomposition. The latter process has traditionally been represented by first‐order decay functions, regulated primarily by temperature, moisture, litter quality, and soil texture. While this formulation well captures macroscopic soil organic C (SOC) dynamics, better understanding is needed of their underlying mechanisms as related to microbial processes, depth‐dependent environmental controls, and other processes that strongly affect soil C dynamics. Second, incomplete use of observations in model parameterization is a major cause of bias in soil C projections from ESMs. Optimal parameter calibration with both pool‐ and flux‐based data sets through data assimilation is among the highest priorities for near‐term research to reduce biases among ESMs. Third, external variables are represented inconsistently among ESMs, leading to differences in modeled soil C dynamics. We recommend the implementation of traceability analyses to identify how external variables and model parameterizations influence SOC dynamics in different ESMs. Overall, projections of the terrestrial C sink can be substantially improved when reliable data sets are available to select the most representative model structure, constrain parameters, and prescribe forcing fields.

Global observed long-term changes in temperature and precipitation extremes: A review of progress and limitations in IPCC assessments and beyond

Abstract The Intergovernmental Panel on Climate Change (IPCC) first attempted a global assessment of long-term changes in temperature and precipitation extremes in its Third Assessment Report in 2001. While data quality and coverage were limited, the report still concluded that heavy precipitation events had increased and that there had been, very likely, a reduction in the frequency of extreme low temperatures and increases in the frequency of extreme high temperatures. That overall assessment had changed little by the time of the IPCC Special Report on Extremes (SREX) in 2012 and the IPCC Fifth Assessment Report (AR5) in 2013, but firmer statements could be added and more regional detail was possible. Despite some substantial progress throughout the IPCC Assessments in terms of temperature and precipitation extremes analyses, there remain major gaps particularly regarding data quality and availability, our ability to monitor these events consistently and our ability to apply the complex statistical methods required. Therefore this article focuses on the substantial progress that has taken place in the last decade, in addition to reviewing the new progress since IPCC AR5 while also addressing the challenges that still lie ahead.

“Peer Review is Melting Our Glaciers”: What Led the Intergovernmental Panel on Climate Change (IPCC) to Go Astray?

An error in the Fourth Assessment Report (2007) of the Intergovernmental Panel on Climate Change (IPCC), which wrongly predicted the disappearance of Himalayan glaciers by 2035, fueled doubts about the authority, honesty and rigor of the IPCC as a leading institution in climate science and, correspondingly, raised questions about whether global warming is anything more than a hoax put forward by environmentalists. The late and confusing reaction of the IPCC to these allegations only worsened the matter. By comparing assessment reports issued by the IPCC, this paper asks the question: ‘Why, despite extensive peer review, did the Himalayan glacier melting rate error get published?’ I chronicle exactly what happened (Sect. 3), consider why it happened as it did (Sect. 4), and show how these answers require us to rethink the concept of ‘peer review’ in scientific practice. I also identify several future directions for peer review (Sect. 5) if it wants to stay ahead of the game, bearing in mind the forthcoming IPCC Assessment Reports.

Earth's Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

AbstractEarth's equilibrium climate sensitivity (ECS) and forcing of Earth's climate system over the industrial era have been re‐examined in two new assessments: the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and a study by Otto et al. (2013). The ranges of these quantities given in these assessments and also in the Fourth (2007) IPCC Assessment are analyzed here within the framework of a planetary energy balance model, taking into account the observed increase in global mean surface temperature over the instrumental record together with best estimates of the rate of increase of planetary heat content. This analysis shows systematic differences among the several assessments and apparent inconsistencies within individual assessments. Importantly, the likely range of ECS to doubled CO2 given in AR5, 1.5–4.5 K/(3.7 W m−2) exceeds the range inferred from the assessed likely range of forcing, 1.2–2.9 K/(3.7 W m−2), where 3.7 W m−2 denotes the forcing for doubled CO2. Such differences underscore the need to identify their causes and reduce the underlying uncertainties. Explanations might involve underestimated negative aerosol forcing, overestimated total forcing, overestimated climate sensitivity, poorly constrained ocean heating, limitations of the energy balance model, or a combination of effects.

An evaluation of the treatment of risk and uncertainties in the IPCC reports on climate change.

Few global threats rival global climate change in scale and potential consequence. The principal international authority assessing climate risk is the Intergovernmental Panel on Climate Change (IPCC). Through repeated assessments the IPCC has devoted considerable effort and interdisciplinary competence to articulating a common characterization of climate risk and uncertainties. We have reviewed the assessment and its foundation for the Fifth Assessment Reports published in 2013 and 2014, in particular the guidance note for lead authors of the fifth IPCC assessment report on consistent treatment of uncertainties. Our analysis shows that the work carried out by the ICPP is short of providing a theoretically and conceptually convincing foundation on the treatment of risk and uncertainties. The main reasons for our assessment are: (i) the concept of risk is given a too narrow definition (a function of consequences and probability/likelihood); and (ii) the reports lack precision in delineating their concepts and methods. The goal of this article is to contribute to improving the handling of uncertainty and risk in future IPCC studies, thereby obtaining a more theoretically substantiated characterization as well as enhanced scientific quality for risk analysis in this area. Several suggestions for how to improve the risk and uncertainty treatment are provided.

Tony McMichael: a giant in the field of global environmental health.

Professor Emeritus Anthony J. (Tony) McMichael, MBBS, PhD, who passed away on September 26, 2014 was a hugely influential pioneer of global environmental health and a giant in the field of environmental epidemiology. He could be regarded along with other legendary names like Rene Dubos and Rachel Carson, who during their lives, challenged conventional assumptions and majorly advanced our understanding of the links between our environment and our health in the twentieth century; Tony Michael’s discoveries and teachings are foundational for the global challenges facing us today in the twenty-first century. McMichael’s exemplary and impactful career includes some of the most important advancements to date in the field of environmental and occupational health. For example, McMichael was the epidemiologist and co-author for the 15-year prospective study on children’s IQ and lead exposure: the Port Pirie study. Tony therefore was among the first health scientists to provide robust quantitative evidence of the link between lead and brain function. Tony McMichael’s next major discovery applied to occupational health. Hazardous exposures in the workplace were common in our industrializing era, with subsequent morbidity and mortality among workers. Eventually, guidelines were made establishing ‘‘safe’’ levels of exposures to workers. But why did workers continue to get sick? It was Professor McMichael who first described ‘‘The Healthy Worker Effect’’—whereby very sick individuals who were no longer in the workforce were left out of risk calculations. This discovery led to lowering the exposure thresholds across numerous occupational settings. I first met Tony at the World Health Organization in 1993. At that time, WHO had just been approached by the United Nations Intergovernmental Panel on Climate Change (IPCC) to contribute a health chapter for their 2nd Assessment Report—the subject of health was missing in IPCC’s first report. Naturally, it was Professor Tony McMichael who was invited to serve as ‘‘Convening Lead Author, a role for which he graciously undertook across many IPCC Assessment Reports. He also served as the lead on many other high-level international initiatives addressing global environmental health challenges. McMichael produced over 300 peer-reviewed papers and three major books, including his 1993 book Planetary Published online: November 19, 2014

Future Research Directions for Soil Carbon Modeling

Soil carbon is a recent but critical sub‐component of Earth system models that contributes significant uncertainty to carbon cycle simulations in the current Intergovernmental Panel on Climate Change (IPCC) assessment. Understanding and reducing this uncertainty is a high priority for the next round of IPCC assessments. To this end, experts in soil carbon dynamics gathered in Breckenridge, Colo., for 3 days to discuss next steps for global soil carbon modeling.

Two Decades of International Climate Negotiations - Carbon Budget Allocation Approach to Re-shaping Developing Country Strategies

(ProQuest: ... denotes formulae omitted.)I. IntroductionBy the year 1992 the world has accepted the fact that the global emissions of greenhouse gases are alarming and immediate actions are warranted in order to avoid the catastrophes of climate change. Rio earth summit testimonies this global agreement. This global agreement has resulted in the institutionalization of United Nations Environment Program (UNEP), United Nations Framework Convention of Climate change (UNFCCC), and Inter Governmental Panel on Climate Change (IPCC) and thus the year 1992 is purposefully a decisive year for the mitigation of Greenhouse Gases (GHG). Accordingly 1990 was considered as base line for all the Climate Change Mitigation efforts, which is institutionalized in the first commitment period of the Kyoto Protocol (UN, 1997). Ever since, the climate negotiations are on with as much success as the failures. As the time progressed we have come across more academic evidences in terms of IPCC Assessment reports as well as natural ones such as increasing incidence of natural catastrophic events that re-emphasized the impending danger of climate change and its intensity. Recent report of average CO2 concentration touching 400 ppm on 9th of May 2013 (The Guardian, 2013) makes it almost an evidence of where we are heading. In this context, Nicholas Stern, the author of Economics of climate change has recently confessed that the impacts of climate change have been underestimated in their original work and it needs sooner and firmer action to fight the impending danger (The Independent, 2014; Stern, 2006). The need for early reaching of the peak for GHG emissions by 2050 is re-emphasized and so is the need to meet the intermediate target of achieving 50% cut from their 1990 level emissions in the next fifteen years (Stern, 2006).Therefore, it is an important time for us to take stock of what is achieved so far with CO2 emissions and what is in stock for us as we plan for the future course of actions on a global scale. As argued from time to time, such global actions have to be based on the principles of equity and differentiated responsibility. Thus, the present paper analyzes how the global action on CO2 mitigation progressed post 1990 till 2009, what is the degree of inequity in the historical and the present use of the development among the industrialized and developing countries and the way forward in planning for the future allocations of such a space on equity grounds.II. Global Climate Negotiations and the Trend of CO2 EmissionsThe Kyoto Protocol is the main framework of CO2 emission control on global scale. However, all the pledges from various countries, by and large, remain voluntary and also very marginal when compared to the magnitude of the problem. Thus, CO2 emission by various countries and regions retained their upward sloping trend line. Figure 1 presents the trends of CO2 emissions in the world during the period of 1991-2009, capturing post-Rio trends of CO2 emissions. For the data analysis and structured presentation of CO2 emission patterns in the world, CO2 contributing countries in the world are categorized into different clusters such as Asia, OECD, Annex 1, Non-Annex 1, BRICS, Sub-Saharan Africa. Emissions by each cluster under consideration are calculated by aggregating the annual CO2 emissions of all countries.All the developing countries and OECD countries, individually and as clusters, showed an upward trend over the entire time period with steeper slopes after 2002. It is a surprising trend as the emissions are actually expected to reduce from the year 2002 with the beginning of the first commitment period of the Kyoto Protocol. It is interesting to note that the total CO2 emissions of BRICS, Annex I and OECD countries as clusters converge towards a common factor over the year 2009 leaving the Sub-Saharan Africa far behind. Though OECD and Annex I countries did increase their CO2 emissions post 1991, their total emissions have shown a declining trend after 2007 but almost at the same level of 1990. …

The IPCC and treatment of uncertainties: topics and sources of dissensus

Characterizing uncertainty in the assessment of evidence is common practice when communicating science to users, a prominent example being the Intergovernmental Panel on Climate Change (IPCC) Assessment Reports (ARs). The IPCC guidance note is designed to assist authors in the assessment process by assuring consistent treatment of uncertainties across working groups (WGs). However, debate on this approach has surfaced among scholars on whether applying the guidance note indeed yields the desired consistent treatment of uncertainties thus facilitating effective communication of findings to users. The IPCC guidance note is therefore a paradigmatic case for reviewing concerns regarding treatment of uncertainties for policy. We reviewed published literature that outline disagreement or dissensus on the guidance note in the IPCC assessment process, structured as three distinct topics. First, whether the procedure is reliable and leads to robust results. Second, whether the broad scope of diverse problems, epistemic approaches, and user perspectives allow for consistent and appropriate application. Third, whether the guidance note is adequate for the purpose of communicating clear and relevant information to users. Overall, we find greater emphasis placed on problems arising from the procedure and purpose of the assessment, rather than the scope of application. Since a procedure needs to be appropriate for its purpose and scope, a way forward entails not only making deliberative processes more transparent to control biases. It also entails developing differentiated instruments to account for diversity and complexity of problems, approaches, and perspectives, treating sources of uncertainty as relevant information to users. WIREs Clim Change 2014, 5:663–676. doi: 10.1002/wcc.297This article is categorized under: Integrated Assessment of Climate Change > Integrated Assessment by Expert Panels Social Status of Climate Change Knowledge > Climate Science and Decision Making

Geoengineering and the politics of science

The latest reports from the Intergovernmental Panel on Climate Change (IPCC) include an assessment of geoengineering—methods for removing carbon dioxide from the atmosphere, or cooling the Earth by reflecting more of the sun’s radiation back into space. The IPCC assessment signals the arrival of geoengineering into the mainstream of climate science, and may normalize climate engineering as a policy response to global warming. Already, conservative forces in the United States are promoting it as a substitute for emissions reductions. Climate scientists are sharply divided over geoengineering, in much the same way that Manhattan Project scientists were divided over nuclear weapons after World War II. Testing a geoengineering scheme, such as sulfate aerosol spraying, is inherently difficult. Deployment would make political decision makers highly dependent on a technocratic elite. In a geoengineered world, experts would control the conditions of daily life, and it is unlikely that such a regime would be a just one. A disproportionate number of scientists currently working on geoengineering have either worked at, or collaborated with, the Lawrence Livermore National Laboratory. The history of US nuclear weapons laboratories during the Cold War reveals a belief in humankind’s right to exercise total mastery over nature. With geoengineering, this kind of thinking is staging a powerful comeback in the face of climate crisis.

Lost in translation? Interpretations of the probability phrases used by the Intergovernmental Panel on Climate Change in China and the UK

Tackling climate change is a global challenge and the Intergovernmental Panel on Climate Change (IPCC) is the organisation charged with communicating the risks, dangers and mechanisms underlying climate change to both policy makers and the general public. The IPCC has traditionally used words (e.g., ‘likely’) in place of numbers (‘70 % chance’) to communicate risk and uncertainty information. The IPCC assessment reports have been published in six languages, but the consistency of the interpretation of these words cross-culturally has yet to be investigated. In two studies, we find considerable variation in the interpretation of the IPCC’s probability expressions between the Chinese and British public. Whilst British interpretations differ somewhat from the IPCC’s prescriptions, Chinese interpretations differ to a much greater degree and show more variation. These results add weight to continuing calls for the IPCC to make greater use of numbers in its forecasts.

Key themes in the Working Group II contribution to the Intergovernmental Panel on Climate Change 5th assessment report

Assessments conducted by the Intergovernmental Panel on Climate Change (IPCC) are significant undertakings that require input from experts and practitioners in multiple scientific disciplines, integrating local to international information across spatial and temporal scales. An IPCC report is a unique collaboration between the scientific community and policymakers, with governments (through their Focal Points) providing guidance and input to the scientists conducting an assessment at several stages during the process. This commentary reviews the IPCC mandate and process; summarizes key themes to be addressed in the Working Group II contribution to the 5th assessment report; discusses challenges for the WGII report when assessing qualitative literature, incorporating local knowledge, and identifying particularly vulnerable groups; and touches on the expertise and commitment of the WGII authors. Active engagement of the wider scientific community in IPCC assessments through publication and review will enhance their relevance to decision- and policy-makers.

Handling uncertainty in science

In his biography of the great twentieth century theoretical physicist Richard Feynman, James Gleick writes [[1][1]]: ‘He [Feynman] believed in the primacy of doubt, not as a blemish on our ability to know, but as the essence of knowing.’ That is to say, Feynman recognized that doubt, or

Treatment of uncertainties in IPCC Assessment Reports: past approaches and considerations for the Fifth Assessment Report

The assessments of the Intergovernmental Panel on Climate Change (IPCC), since the First Assessment Report, have involved calibrated uncertainty language and other methods aimed towards clear communication of the degree of certainty in findings of the assessment process. There has been a continuing tradition of iterative improvement of the treatment of uncertainties in these assessments. Here we consider the motivations for the most recent revision of the uncertainties guidance provided to author teams of the Fifth Assessment Report (AR5).WefirstreviewthehistoryofusageofcalibratedlanguageinIPCCAssessmentReports, along with the frameworks for treatment of uncertainties that have been provided to IPCC author teams. Our primary focus is the interpretation and application of the guidance provided to author teams in the Fourth Assessment Report, with analysis of the successes and challenges in the application of this guidance and approaches taken in usage of its calibrated uncertainty language. We discuss the ways in which the AR5 Guidance Note attempts to refine the calibrated uncertainty metrics and formalize their interrelationships to improve the consistency of treatment of uncertainties across the Working Group contributions.

Climate uncertainties and their discontents: increasing the impact of assessments on public understanding of climate risks and choices

US public awareness of the reality and risks of human-caused climate change remains limited, despite strong evidence presented in the IPCC and other major climate assessments. One contributing factor may be that the immense collective effort to produce periodic climate assessments is typically not well matched with public communication and outreach efforts for these reports, leaving a vacuum to be filled by less authoritative sources. Print and online media coverage provides one metric of the US public reach of selected climate assessments between 2000 and 2010. The number of Lexis-Nexis articles for the search terms “climate change” or “global warming” within 14 days of each report’s release varied significantly over time with a peak occurring in 2007. When compared to background “chatter” relating to climate change, each assessment had widely diverse penetration in the US media (~4% for US National Climate Assessment in 2000; ~17% for Arctic Climate Impacts Assessment in 2004; ~19% and ~10% for Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report Working Group I and Working Group II respectively in 2007; ~4% for the US Global Change Research Program (USGCRP) assessment report in 2009; and ~5% for US National Research Council’s America’s Climate Choices reports in 2010). We propose ways to improve the public reach of climate assessments, focusing in particular on approaches to more effectively characterize and communicate the role of uncertainty in human actions as distinct from other sources of uncertainty across the range of possible climate futures.

Emulating coupled atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 – Part 1: Model description and calibration

Abstract. Current scientific knowledge on the future response of the climate system to human-induced perturbations is comprehensively captured by various model intercomparison efforts. In the preparation of the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), intercomparisons were organized for atmosphere-ocean general circulation models (AOGCMs) and carbon cycle models, named "CMIP3" and "C4MIP", respectively. Despite their tremendous value for the scientific community and policy makers alike, there are some difficulties in interpreting the results. For example, radiative forcings were not standardized across the various AOGCM integrations and carbon cycle runs, and, in some models, key forcings were omitted. Furthermore, the AOGCM analysis of plausible emissions pathways was restricted to only three SRES scenarios. This study attempts to address these issues. We present an updated version of MAGICC, the simple carbon cycle-climate model used in past IPCC Assessment Reports with enhanced representation of time-varying climate sensitivities, carbon cycle feedbacks, aerosol forcings and ocean heat uptake characteristics. This new version, MAGICC6, is successfully calibrated against the higher complexity AOGCMs and carbon cycle models. Parameterizations of MAGICC6 are provided. The mean of the emulations presented here using MAGICC6 deviates from the mean AOGCM responses by only 2.2% on average for the SRES scenarios. This enhanced emulation skill in comparison to previous calibrations is primarily due to: making a "like-with-like comparison" using AOGCM-specific subsets of forcings; employing a new calibration procedure; as well as the fact that the updated simple climate model can now successfully emulate some of the climate-state dependent effective climate sensitivities of AOGCMs. The diagnosed effective climate sensitivity at the time of CO2 doubling for the AOGCMs is on average 2.88 °C, about 0.33 °C cooler than the mean of the reported slab ocean climate sensitivities. In the companion paper (Part 2) of this study, we examine the combined climate system and carbon cycle emulations for the complete range of IPCC SRES emissions scenarios and the new RCP pathways.