Intergovernmental Panel On Climate Change Report Research Articles

An assessment of the performance of scenarios against historical global emissions for IPCC reports

Long-term emissions scenarios have served as the primary basis for assessing future climate change and response strategies. Therefore, it is important to regularly reassess the relevance of emissions scenarios in light of changing global circumstances and compare them with long-term developments to determine if they are still plausible, considering the newest insights. Four scenario series, SA90, IS92, SRES, and RCP/SSP, were central in the scenario-based literature informing the five Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC) and the sixth assessment cycle. Here we analyze the historical trends of carbon dioxide (CO2) emissions from fossil fuel combustion and industry and emissions drivers between 1960 and 2017. We then compare the emission scenario series with historical trends for the period 1990–2017/2018. The results show that historical trends are quite consistent with medium scenarios in each series. As a result, they can be regarded as valid inputs for past and future analyses of climate change and impacts. Global CO2 emissions 1960–2018 (and 1990–2018) comprised six (and three) overall subperiods of emissions growth significantly higher and lower than average. Historically, CO2 emissions (in absolute numbers and growth rate) are tightly coupled with primary energy and indirectly with GDP. Global emissions generally followed a medium-high pathway, captured by “middle-of-the-road” scenario narratives in the earlier series, and by combinations of “global-sustainability” and “middle-of-the-road” narratives in the most recent series (SRES and SSP-baselines). Historical non-OECD trends were best captured by “rapid-growth” and “regional-competition” scenarios, while OECD trends were close to regional-sustainability and global-sustainability scenarios. Areas where the emissions scenarios captured the historical trends less well, are renewable and nuclear primary energy supply. The fact that the actual historical development is consistent with rapid-growth narratives in the non-OECD regions might have important implications for future greenhouse gas emissions and associated climatic change.

Is solar geoengineering ungovernable? A critical assessment of governance challenges identified by the Intergovernmental Panel on Climate Change

AbstractSolar radiation modification (SRM) could greatly reduce climate change and associated risks. Yet it has not been well‐received by the climate change expert community. This is evident in the authoritative reports of the Intergovernmental Panel on Climate Change (IPCC), which emphasize SRM's governance, political, social, and ethical challenges. I find seven such challenges identified in the IPCC reports: that SRM could lessen mitigation; that its termination would cause severe climatic impacts; that researching SRM would create a “slippery slope” to its inevitable and unwanted use; that decisions to use it could be contrary to democratic norms; that the public may not accept SRM; that it could be unethical; and that decisions to use SRM could be unilateral. After assessing the extent to which these challenges are supported by existing evidence, scholarly literature, and robust logic, I conclude that, for six of the seven, the IPCC's claims variously are speculative, fail to consider both advantages and disadvantages, implicitly make unreasonable negative assumptions, are contrary to existing evidence, and/or are meaninglessly vague. I suggest some reasons for the reports' failure to meet the IPCC's standards of balance, thoroughness, and accuracy, and recommend a dedicated Special Report on SRM.This article is categorized under: Integrated Assessment of Climate Change > Assessing Climate Change in the Context of Other Issues

The IPCC: A Primer for Archaeologists

The Intergovernmental Panel on Climate Change (IPCC) was founded in 1988 to provide governments with policy-relevant assessments of climate science as well as options for adaptation and mitigation. It is now recognized as providing the leading global compilation of climate science, adaptation, and mitigation research. The volunteer scientists who write these reports have carried out five complete assessment cycles, with the sixth cycle to be completed in 2022. Here, we review how information from and about archaeology and other forms of cultural heritage has been incorporated into these reports to date. Although this review shows that archaeology has not been wholly absent from work of the IPCC, we suggest that archaeology has more to offer the IPCC and global climate response. We propose five ways to more fully engage both archaeologists and knowledge from and about the human past in IPCC assessments and reports.

Drought indices for the Zagreb-Grič Observatory with an overview of drought damage in agriculture in Croatia

The Standardized Precipitation Index (SPI) for different time scales of n = 1, 2, 3, 6, 9, 12, and 24 months and the monthly Palmer Drought Severity Index (PDSI) were calculated for the Zagreb-Gric Observatory, located in North-Western Croatia, for the period 1862–2012. The PDSI exhibits a stronger long-term negative trend than the SPI due to the influence of the global warming, which corresponds with the global scale results published in the 4th IPCC (Intergovernmental Panel on Climate Change) report. The SPI for a 9-month scale was compared with the PDSI for a monthly scale because the correlation between them is the highest in comparison with other SPI time scales. The Chapman percentile classification regarding dryness/wetness severity was used instead of the “originally” proposed classes. Thirty-year moving averages indicate that long-term variation in dryness/wetness severity is more clearly emphasised for the PDSI than for the SPI, showing the last 30-year period to be the driest on record. Autoregressive function analysis indicates that the SPI for a 1-month scale has serialy independent values, while the SPI for the 9-month scale and the monthly PDSI are close to a Markov process. A significant correlation was established between the SPI and PDSI indices and crop damages in Croatia.

Communicating Climate Change Risk: A Content Analysis of IPCC’s Summary for Policymakers

This study investigated the effectiveness of climate change risk communication in terms of its theoretical potential to stimulate recipients’ awareness and behavioral change. We selected the summary for policy makers (SPM) of the most recent Intergovernmental Panel on Climate Change (IPCC) report in order to conduct a content analysis; the extended parallel process model and construal level theory served as conceptual lenses to perform the analysis. Specifically, we evaluated to what extent the SPM included informational elements of threat, efficacy and psychological distance related to climate change. The results showed that threat information was prominently present, but efficacy information was less frequently included, and when it was, more often in the latter parts of the SPM. With respect to construal level it was found that in the IPCC report concrete representations were used only sparingly. Theoretical relevance and implications for climate change risk communication with key audiences are discussed.

The Effect of IPCC Reports and Regulatory Announcements on the Stock Market

This study explores U.S. public companies’ reactions to scientific announcements by the IPCC (Intergovernmental Panel on Climate Change) with respect to updated climate change knowledge and how it affects their stock valuations, given their carbon emission/environmental outlooks. Based on a sample of total daily returns collected for 10 industry indexes from the S&P 500 Index over the period 1990–2014, and using an event study approach, we analyze the connection between IPCC assessment report announcements and firms’ returns to evaluate panel data models. We found that various sectors, regardless of their carbon profiles, react abnormally to IPCC report announcements without remarkable long-run cumulative effects. The implications of these results are that there is no clear violation of the efficient markets hypothesis, yet short-term profits may be gained. Furthermore, the market still reacts to new scientific announcements, even though 24 years have passed since the first IPCC report. In addition, there is a negative relationship for low and medium carbon-intensive industries, especially in the short term.

Facilitating Climate-Smart Investments

The financial sector will play a key role in transitioning toward low-carbon and climate-resilient development, but financial decision makers need tailored information to guide climate-smart investment decisions. Here, we reflect upon the Sustainable Edge report and investor engagement to pilot a new approach to climate-risk assessment for companies.

Global Warming Potential of Biomass-to-Ethanol: Review and Sensitivity Analysis through a Case Study

In Europe, ethanol is blended with gasoline fuel in 5 or 10% volume (E5 or E10). In USA the blend is 15% in volume (E15) and there are also pumps that provide E85. In Brazil, the conventional gasoline is E27 and there are pumps that offer E100, due to the growing market of flex fuel vehicles. Bioethanol production is usually by means of biological conversion of several biomass feedstocks (first generation sugar cane in Brazil, corn in the USA, sugar beet in Europe, or second-generation bagasse of sugarcane or lignocellulosic materials from crop wastes). The environmental sustainability of the bioethanol is usually measured by the global warming potential metric (GWP in CO2eq), 100 years time horizon. Reviewed values could range from 0.31 to 5.55 gCO2eq/LETOH. A biomass-to-ethanol industrial scenario was used to evaluate the impact of methodological choices on CO2eq: conventional versus dynamic Life Cycle Assessment; different impact assessment methods (TRACI, IPCC, ILCD, IMPACT, EDIP, and CML); electricity mix of the geographical region/country for different factory locations; differences in CO2eq factor for CH4 and N2O due to updates in Intergovernmental Panel on Climate Change (IPCC) reports (5 reports so far), different factory operational lifetimes and future improved productivities. Results showed that the electricity mix (factory location) and land use are the factors that have the greatest effect (up to 800% deviation). The use of the CO2 equivalency factors stated in different IPCC reports has the least influence (less than 3%). The consideration of the biogenic emissions (uptake at agricultural stage and release at the fermentation stage) and different allocation methods is also influential, and each can make values vary by 250%.

Towards a comprehensive characterization of evidence in synthesis assessments: the climate change impacts on the Brazilian water resources

The Intergovernmental Panel on Climate Change (IPCC) has put a lot of efforts to describe uncertainties and to judge the confidence level of its major conclusions. Despite a guidance to communicate uncertainty, the assignment of confidence is not sufficiently clear and, thus, hard to be reproduced by the extern community. By conducting a synthesis assessment about the impacts of climate change on the Brazilian water resources, we identified an opportunity to illustrate the characterization of evidence as adopted in IPCC reports. We propose a method to describe the evidence from model outputs wherein the quality and amount of studies, as well as the consistency among their conclusions, are subject of a transparent rating procedure. In summary, the more comprehensive the study in sampling uncertainties, the higher its quality. Likewise, the amount and consistency among conclusions is assigned in a systematic way. The method is applied for synthesizing a collection of 42 peer-reviewed articles. It reveals important aspects about the evidence of the potential impacts of climate change in the Brazilian water resources, such as changes into a drier hydrological regime. However, the use of multi-model ensemble, the evaluation of models, and the observational data is limited. The proposed method enables consistent communication of the degree of evidence in a transparent, traceable, and comprehensive fashion. The method can be used as a tool to support experts on their judgment. The approach is reproducible and can guide synthesis work not only in Brazil but anywhere else.

Towards a Blue Humanity

Towards A Blue Humanity Ian Buchanan (bio) and Celina Jeffery (bio) Although the ocean covers seventy percent of the planet and provides more than half of the oxygen vital to all life on earth it figures comparatively little in global cultural production. Most of us tend to treat the ocean as that which must be traversed rather than explored for itself—we lay beside it at the beach, we cruise on its surface, or more usually fly several thousand feet above it, but we don't enter it (except perhaps for brief dives), and we certainly don't dwell in it. Yet ocean-going, particularly of cargo from China to the U.S., underpins globalization, so much so that the ocean has been described as the "missing context" of postmodernity, and from an environmental point of view, the ocean is a repository for plastic pollution, waste and effluence and is rapidly dying as global temperatures rise. There is a certain kind of politics of invisibility at work here—we do not comprehend complex eco-systems of oceans or the interdependence of the seas, earth and atmosphere. Much less, do we acknowledge the effects of the depletion, erasure and expulsion of biological life from much of the world's oceans. The ocean is, as Allan Sekula acknowledged, the "forgotten space" in which the twin fissures of oceanic degradation and social injustice are converging and ramifying (Sekula 2010). The "Anthropocene" ocean then is characterized by a particular kind of "slow violence" described by Rob Nixon, which is perhaps less visible and spectacular than a catastrophe like Deepwater Horizon oil spill might suggest, and yet more profoundly unjust and enduring in its long-term ramifications (2011, 21-22). The Intergovernmental Panel on Climate Change (IPCC) 2018 Special Report on Global Warming of 1.5% highlighted the urgency of action needed to address global warming of oceans, resulting in acidification, the bleaching of coral reefs, rising tides, and the melting of the circumpolar regions (IPCC report 2018). Added to this heady mix are the impacts of over-fishing, industrial fishing, and ghost nets which have already resulted in extinction patterns, interruption of local food chains, and extensive plastic waste. Additionally, pollution in the form of oil, fertilizers, nuclear waste, and noise have further contributed to oceanic toxification. The cascading effects of these factors and their impact upon the Earth's life support system have yet to be fully understood, but the appearance of dead zones—often caused by algal blooms particularly by phosphorous run off from farms—in numerous areas of the world's oceans are a shocking sign of impending [End Page 11] collapse. It is interesting to note that at this time such algal blooms have caused the citizens of Toledo, USA to attempt to give Lake Erie legal rights to protect the lake, called the Lake Erie Bills of Rights. What are the cultural discourses of this hitherto unimaginable erasure and expulsion of biological life from much of the world's oceans? This special issue reflects upon a growing body of work known as the "blue humanities" which is historicizing the ocean and making it part of contemporary consciousness in a way—we hope—that will enable environmental activism's bid to "save" the ocean. A cornerstone of this issue is how we understand blue humanities in the context of an ecological catastrophe that is rarely seen by the human eye. As Nixon argues in his book Slow Violence, without the attention of writer-activists—and we might add, artists, film-makers, poets, and photographers—the environmental issues we face could go unnoticed, misapprehended and unchecked (2011, 14-15). This special section of symplokē explores how we can leverage transdisciplinary inquiry and begins to say why we need not only a blue humanities but also a blue humanity—a sense in which we restore our sense of connectedness and in the words of Rachel Carson, "return to the sea," in part, through a consideration of the contributions of creative artists and thinkers (2014, 247). This issue gathers texts that use critical theory, philosophy and visual art and culture, to demarcate how ocean-based economies have resulted in transnational environmental trends with...

The Case against Carbon Prices

Professor Dr. Anthony Patt is head of the Climate Policy Group in the Department of Environmental Systems Science at ETH Zurich, Switzerland. His research focus is on technological pathways and public policies for climate change mitigation and adaptation. He is a Coordinating Lead Author in Working Group III of the Intergovernmental Panel on Climate Change. He obtained his PhD at Harvard University's Kennedy School of Government. He is the author of “Transforming Energy: Solving Climate Change with Technology Policy” (Cambridge University Press, 2015). Download : Download high-res image (204KB) Download : Download full-size image Professor Dr. Johan Lilliestam is head of the Renewable Energy Policy Group in the Department of Environmental Systems Science at ETH Zurich, Switzerland. His research focus is policies and strategies for a transition to a completely renewable energy system, including the effects of interactions between different energy policies. He obtained his PhD at the Central European University in Budapest, Hungary. Before joining the ETH, he worked at the Potsdam Institute for Climate Impact Research (PIK) in Potsdam, Germany, and the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria. He currently holds a grant from the European Research Council for his work on policy interactions. Download : Download high-res image (202KB) Download : Download full-size image

Impact of climate change on demands for heating and cooling energy in hospitals: An in-depth case study of six islands located in the Indian Ocean region

This research was conducted in order to assess the impact that climate change has on the demands for heating and cooling energy in hospitals in six cities located in six countries in the Indian Ocean region. Three scenarios (B1, A1B, and A2) of the Intergovernmental Panel on Climate Change (IPCC) were applied in the undertaking of this work. The hourly outdoor data relating to air temperature, wind speed, relative humidity, radiation, and atmospheric pressure recorded over the last 30 years were used as inputs by Meteonorm software to enable the forecasting. The averages obtained in all the 18 models used in the IPCC report 2007 were included in the Meteonorm software and applied for assessing the future climate. The Energy-Plus software was used for assessing the thermal performance of hospitals under natural ventilation, then the energy demand during five periods (past, current, 2030, 2060, and 2090). Thermal insulation was utilized as a passive strategy for reducing cooling and heating energy consumption in the hospitals. Results showed that the use of an envelope of thermal insulation in hospitals was one of the solutions that allowed a reduction in the energy consumption for cooling and heating while increasing the thermal comfort within the hospital. Moreover, by 2090, the ventilation system was recommended in all these hospitals for improving the quality of indoor air, since the heat rate was very high. In the cases of the six islands in the Indian Ocean, each of them represented by one city, the annual energy demand for cooling will increase between 17.1 and 25.4% by 2030; 34.6 and 50.2% by 2060; and 60.8 and 95.1% by 2090. With the use of passive design as a strategy, the annual mean thermal performance of hospitals is predicted to increase to 184% by 2060, while 40% of the cost of cooling energy will be saved. Despite this, the outdoor climate will be 5% harsher in Victoria than in other cities by the year 2090.

ESD Ideas: a simple proposal to improve the contribution of IPCC WGI to the assessment and communication of climate change risks

Abstract. The purpose of the Intergovernmental Panel on Climate Change (IPCC) is to provide policy-relevant assessments of the scientific evidence about climate change. Policymaking necessarily involves risk assessments, so it is important that IPCC reports are designed accordingly. This paper proposes a specific idea, illustrated with examples, to improve the contribution of IPCC Working Group I to informing climate risk assessments.

The growing importance of scope 3 greenhouse gas emissions from industry

Carbon reporting is increasingly focussing on indirect emissions that occur in the supply chain of establishments. The GHG protocol, a corporate standard, distinguishes scope 2 (emissions associated with electricity consumption) and scope 3 (emissions associated with other inputs), in addition to scope 1 emissions (occurring directly at the facility or company in question). However, the magnitude and growth trajectory of scopes 2 and 3 emissions at the economy-wide level is unknown. Here we conduct an input–output investigation of indirect carbon dioxide (CO2) emissions for the global economy organized in five sectors—energy supply, transport, industry, buildings, and agriculture and forestry—as defined by the Intergovernmental Panel on Climate Change (IPCC). In comparison to previous work that looks at indirect emissions of consumption, we present the first economy-wide analysis of indirect emissions of gross production. The goal of the work is thus to capture the potential agency different sectors have over supply chain emissions, rather allocating emissions between production and consumption. Between 1995 and 2015, global scopes 1, 2, and 3 emissions grew by 47%, 78%, and 84%, to 32, 10, and 45 Pg CO2, respectively. Globally, the industry sector was most important with scope 2 emissions of 5 Pg and scope 3 emissions of 32 Pg. For buildings, scope 3 emissions of 7 Pg were twice as high as direct emissions. Industry and buildings stood in marked contrast to energy and transport, where direct emissions accounted for >70% of total emissions responsibility. Most of the growth happened in developing countries. The proposed analysis scheme could improve the integration of sector chapters in future IPCC reports.

How Well Do COP22 Attendees Understand Graphs on Climate Change Health Impacts from the Fifth IPCC Assessment Report?

Graphs are prevalent in the reports of the Intergovernmental Panel on Climate Change (IPCC), often depicting key points and major results. However, the popularity of graphs in the IPCC reports contrasts with a neglect of empirical tests of their understandability. Here we put the understandability of three graphs taken from the Health chapter of the Fifth Assessment Report to an empirical test. We present a pilot study where we evaluate objective understanding (mean accuracy in multiple-choice questions) and subjective understanding (self-assessed confidence in accuracy) in a sample of attendees of the United Nations Climate Change Conference in Marrakesh, 2016 (COP22), and a student sample. Results show a mean objective understanding of M = 0.33 for the COP sample, and M = 0.38 for the student sample. Subjective and objective understanding were unrelated for the COP22 sample, but associated for the student sample. These results suggest that (i) understandability of the IPCC health chapter graphs is insufficient, and that (ii) particularly COP22 attendees lacked insight into which graphs they did, and which they did not understand. Implications for the construction of graphs to communicate health impacts of climate change to decision-makers are discussed.

Lateral Boundary of Cirrus Cloud from CALIPSO Observations

AbsractDue to the thinness and small scale of cirrus clouds, its lateral boundary may be missed by conventional passive remote-sensing techniques and climate models. Here, using satellite observations in June–August from 2006 to 2011, a global dataset for the cirrus cloud lateral boundary (CCLB) was established. The results indicate that the optical properties, such as the lidar backscatter, the depolarization ratio and the optical depth, sharply decrease from cloudy regions to clear-sky regions. There are significant regional differences in optical properties and height and thickness of the CCLB. Based on a quantitative estimation, the strongest longwave warming effects (>0.3 W m−2) are found near the Equator and over tropical continents. The global average longwave warming effect of the CCLB is at least 0.07 W m−2, which is much larger than some of the radiative forcings considered in the Intergovernmental Panel on Climate Change (IPCC) reports. Specifically, the CCLB in traditional “clear-sky” region may be totally missed by current models and IPCC reports, which contributes 28.25% (~0.02 W m−2) of the whole CCLB radiative effect, twice greater than contrail effect. It is recommended that the CCLB effect should be taken account in future climate models and the next IPCC reports.

Modelling the dynamics of total precipitation and aboveground net primary production of fescue-feather grass steppe at Askania Nova according to global climate change scenariosModelling the dynamics of total precipitation and aboveground net primary production of fescue-feather grass steppe at Askania Nova according to global climate change scenarios

This article discusses modelling of Aboveground Net Primary Production (ANPP) of steppe (arid grassland ecosystems) plant species in relation to changes in total precipitation over the previous year at the “Stara” study site, Biosphere Reserve “Askania-Nova”, Khersonregion (Ukraine). To investigate linkages between precipitation and Aboveground Net Primary Production, correlation analysis was chosen and a time series regression analysis was based on the data set for the period 1988–2012. The NPP dependence on quantity of precipitation was found to be more significant for the previous autumn-winter-spring period (AWSP) than for the previous 12 month period. A regression model of ANPP’s dependence on AWSP is proposed. This model was further validated by the authors’ samples of ANPP, collected at the “Stara” study site in 2013–2016. The regression model showed a non-linear (quadratic) dependence of net primary production of zonal and intrazonal plant coenoses and total precipitation for the autumn-winter-spring period for arid grasslands with a coefficient of determination equal to 0.54 and significance level less than 0.05. The non-linear equation for these relations, visualized by a parabola curve, was calculated using the Nonlinear Least-Squares Regression Method. The data set, based on calculated predicted values, using the calculated equation, had a similar dynamic to the historical data on ANPP, but the model could not predict critical values. For this reason, additional studies are required for critical precipitation events. Non-linear response, investigated according to regression analysis, reveals optimal zones of plant growth, depending on the total precipitation level before the vegetation peak. For research areas where the dominant species are the turf grasses Stipa ucrainica P. Smirn., S. capillata L., S. lessingiana Trin. & Rupr., Festuca valesiaca Gaudin, Koeleria cristata (L.) Pers.) the optimal precipitation rates were found to be 350–400 mm during AWSP with ANPP at 350 g/m 2 . On the basis of the regression model and current forecasts of changes in precipitation rates we made a forecast of net primary production of plant communities for four climate change scenarios (RCP2.6, RCP4.5, RCP6, and RCP8.5) described in the Fifth Assessment of Intergovernmental Panel on Climate Change (IPCC). For this purpose, bioclimate projections of 10 major climate models (The Community Climate System Model Version 4 (CCSM4), GISS-E2-R, HadGEM2-AO, HadGEM2-ES, IPSL-CM5A-LR, MIROC-ESM-CHEM, MIROC-ESM, MIROC5, MRI-CGCM3, NorESM1-M), used for preparation of the IPCC report, were analyzed and imported to the geographical information system package QGIS. QGIS modelling software was used for geoanalysis and calculation of GIS-layers for Askania-Nova and adjacent arid grasslands. The results of modelling with the 10 climate models were compared and analyzed for each of the four IPCC scenarios, depending on predicted CO 2 levels. The presented modelling results showed a trend to growth in AWSP precipitation and NPP for all scenarios up to 2040–2060. The scenarios RCP2.6, RCP4.5, RCP6 predicted the optimum precipitation zone for current plant diversity for the period of 2040–2060 and scenario RCP8.5 predicted an optimum zone peak after 2080. The study confirmed the importance of monitoring the productivity of herbaceous communities in dry steppe ecosystems ofUkraine.

Current trends in solar photovoltaic and zero emission vehicle growth and its impact in Climate Change Mitigation

Recently concluded Paris Conference 2015 notes that, even after complying by pollution reduction commitments by variousnations, estimated greenhouse gas (GHG) emissions in 2025 and 2030 will reach 55 Giga tons of carbon emissions, and will notreduce the global average temperature rise to below 2 ̊C above pre-industrial levels. The Intergovernmental Panel on ClimateChange (IPCC) predicts that if greenhouse gas (GHG) emission levels continue to rise, future changes are likely to be even moreextreme, with millions of people displaced by rising sea levels and global food supplies under threat. The only possible recoveryfrom this imminent danger appears to be in the form of global cooperation in mitigating climate change at a pace unprecedented in modern history. Adoption of Paris Agreement 2015 will not be beneficial, unless, reduction in energy demands in the form offossil fuel as well as resources consumption by people around the world and other mitigating measures are employed at massscale, the most important being one switching to cleaner energy. According to IPCC report (2014) electricity generation andtransportation together contributes 39% of global greenhouse gas emission. A very promising way to achieve this daunting task of reduction in GHG emission is by switching to cleaner sources of energy such as solar photovoltaic and fuel cells away from fossil fuel based electricity production and transportation. Recent data suggest that contribution of solar energy has already crossed 1.5% of global electricity demand and it is the fastest growing energy market in China which is the second largest GHG emitter in the world. Whereas, fuel cells possess the capacity of becoming the future power house. The present paper intends to illustrate and discuss current as well as future prospects of these sources of clean energy, their contribution in mitigation of climate change and imminent danger of unchecked climate change.

Integrating and differentiating meanings in tweeting about the fifth Intergovernmental Panel on Climate Change (IPCC) report

The publication of the fifth Intergovernmental Panel on Climate Change (IPCC) Working Group 1 report in September 2013 was highly debated on Twitter. In this paper we focused on tweets that mention “IPCC”, and in particular the content and sentiment of the tweets sent by tweeters that were identified as unconvinced or as convinced towards the scientific basis of global warming. Our results indicate that the content and sentiment of those convinced reflect mainly information sharing activities instead of expressing opinions or participation in the debate. Climate change science is, however, challenged by some unconvinced tweeters who tend to use more negative words in their tweets. Our theoretical contribution is on the processes of meaning making around the IPCC report in relation to different groups of tweeters. We identify how certain words may be given different meanings by different groups, and how certain words have a differentiating function between the groups and integrating function within the groups. Our results increase our knowledge about the content of climate change debate in social media and on Twitter in particularly and contribute to research interested in how words function as differentiating and integrating meanings between and within social groups.

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.