IPCC Research Articles

A competence set for sustainable urban development: framing a research agenda

ABSTRACT The primary purpose of this paper is to call for more research on the competencies needed to promote sustainable urban development. Our premise is that sustainable urban development does not occur without transcending differing interests and identifying novel ways to collaborate across organisational and institutional boundaries. Relatedly, sustainable urban development calls for mobilisation and pooling of scattered assets. Therefore, sustainable urban development calls for enhanced competencies that significantly differ from the traditional capabilities valued in public administration. This premise leads us to determine what competencies are needed to support sustainable urban development and to ask how fragmented capabilities can be pooled to serve the common purpose. Sustainable urban development necessitates transformative system change, dependent on diverse stakeholders, relying on many actors’ knowledge and capabilities instead of a few selected actors’ expertise. To achieve a systemic perspective, we need to be able to group the capabilities and competencies; otherwise. We propose a conceptual framework drawing on insights from public administration, management studies, organisation studies, and the Intergovernmental Panel on Climate Change (IPCC) that might allow us to move from individual capabilities to shared competencies and collective learning processes, thus adding analytical leverage to our efforts to strengthen the competencies embedded in systems but held by individuals. For analytical purposes, we adopt the concept of the competence set. It is geared toward identifying how different capabilities of many actors could be integrated at a systemic level so that a set would serve both the entire urban system and the actors embedded in it.

Carbon utilization and storage through rehabilitation of groundwater wells

According to the Intergovernmental Panel on Climate Change (IPCC) of the United Nations (UN), rise in atmospheric concentration of carbon dioxide (CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document}) due to anthropogenic factors is considered as the primary driver for global climate change. With almost every major corporation around the world working towards their “net-zero goals”, it is becoming increasingly important to have more technologies that can help reduce carbon footprint. Achieving sequestration of CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document} in the subsurface through Carbon Capture Utilization and Storage (CCUS) technologies like CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document}-Enhanced Oil Recovery, CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document}-Enhanced Geothermal Systems, CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document}-Enhanced Coal Bed Methane, etc. is well accepted. We introduce yet another attractive CCUS opportunity through well rehabilitation. Aqua Freed® and Aqua Gard® are well-known well rehabilitation and preventive well maintenance technologies that utilize (inject underground) liquid CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document} for the purpose. The goal of this study was to quantify the storage capacity of Aqua Freed® and Aqua Gard®, and establish their CCUS credentials. Depending on the well being serviced, these technologies can inject up to 40 US tons of CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document} per well. Based on field data collection and statistical modeling, we estimated that 82–96% (median 90%) of the injected CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document} remains in the subsurface post injection. Overall, our results and analysis of the US market suggest that using CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document} for well rehabilitation and maintenance has a storage potential of several megatonnes of CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_2}$$\\end{document} annually in the US alone.

Decreasing Greenhouse Gas Emissions from the Municipal Solid Waste Sector in Chinese Cites.

Municipal solid waste (MSW) management systems play a crucial role in greenhouse gas (GHG) emissions in China. Although the government has implemented many policies to improve the MSW management system, the impact of these improvements on city-level GHG emission reduction remains largely unexplored. This study conducted a comprehensive analysis of both direct and downstream GHG emissions from the MSW sector, encompassing sanitary landfill, dump, incineration, and biological treatment, across 352 Chinese cities from 2001 to 2021 by adopting inventory methods recommended by the Intergovernmental Panel on Climate Change (IPCC). The results reveal that (1) GHG emissions from the MSW sector in China peaked at 70.6 Tg of CO2 equiv in 2018, followed by a significant decline to 47.6 Tg of CO2 equiv in 2021, (2) cities with the highest GHG emission reduction benefits in the MSW sector were historical emission hotspots over the past 2 decades, and (3) with the potential achievement of zero-landfilling policy by 2030, an additional reduction of 203.7 Tg of CO2 equiv is projected, with the emission reduction focus toward cities in South China (21.9%), Northeast China (17.8%), and Southwest China (17.3%). This study highlights that, even without explicit emission reduction targets for the MSW sector, the improvements of this sector have significantly reduced GHG emissions in China.

Carbon emission of municipal solid waste under different classification methods in the context of carbon neutrality: A case study of Yunnan Province, China

Carbon emissions from municipal solid waste (MSW) are one of the major sources of greenhouse gases. As the world’s largest emitter of carbon, China faces a critical challenge in reducing its carbon footprint. This study first employed the STIRPAT model to forecast the production of MSW in Yunnan Province, then followed the Intergovernmental Panel on Climate Change (IPCC) recommended methodologies to calculate and predict the carbon emissions from MSW under four scenarios based on different waste classification methods. The research found that per capita Gross Domestic Product (GDP) and urbanization rate positively influence the generation of MSW, while the proportion of the secondary industry had the opposite effect. Front-end sorting in MSW management is crucial, as enhancing the recycling rate of MSW was a determinative factor in reducing carbon emissions from MSW management. Scenario 1, based on the current situation, resulted in carbon emissions of 3.62 MtCO2-eq; whereas, adopting new classification methods in Scenario 4, carbon emissions were reduced to −1.42 MtCO2-eq. In Scenario 1, landfilling remained the primary source of carbon emissions in waste treatment, accounting for 70.69%. Achieving carbon neutrality in the MSW treatment process is possible when the recycling rate approaches 50%, and the landfill proportion does not exceed 6%. The study indicates that Scenario 4 offers the best carbon reduction outcome, and the results reveal that promoting waste classification to improve recycling rates is the most effective carbon reduction strategy in MSW management. This study proposed a practical MSW classification pathway to achieve negative carbon emission, which provides valuable guidance for the MSW management.

Investigating the impacts of climate change on hydroclimatic extremes in the Tar-Pamlico River basin, North Carolina

Evaluating the forthcoming impacts of climate change is important for formulating efficient and flexible approaches to water resource management. General Circulation Models (GCMs) are primary tools that enable scientists to study both past and potential future climate changes, as well as their impacts on policies and actions. In this work, we quantify the future projected impacts of hydroclimatic extremes on the coastal, risk-prone Tar-Pamlico River basin in North Carolina using GCMs from the Sixth International Coupled Model Intercomparison Project (CMIP6). These models incorporate projected future societal development scenarios (Shared Socioeconomic Pathways, SSPs) as defined in the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6). Specifically, we have utilized historical residential expansion data, the Soil and Water Assessment Tool Plus (SWAT+), the Standardized Precipitation Index (SPI), and the Interquartile Range (IQR) method for analyzing extremes from 2024 to 2100. Our findings include: (1) a trend toward wetter conditions is identified with an increase in flood events toward 2100; (2) projected increases in the severity of flood peaks are found, quantified by a rise of 21% compared to the 2000–2020 period; (3) downstream regions are forecast to experience severe droughts up to 2044; and (4) low-lying and coastal regions are found as particularly susceptible to higher flood peaks and more frequent drought events between 2045 and 2100. This work provides valuable insights into the anticipated shifts in natural disaster patterns and supports decision-makers and authorities in promoting adaptive strategies and sustainable policies to address challenges posed by future climate changes in the Tar-Pamlico region and throughout the state of North Carolina, United States.

Climate Change and Photochemical Ozone Creation Potential Impact Indicators of Cow Milk: A Comparison of Different Scenarios for a Diet Assessment

An estimate of the environmental impact of dairy farms in Northern Italy producing milk for hard cheese (protected designation of origin) has been obtained through a comprehensive life cycle assessment. The estimate focused on climate change (CC) and photochemical ozone creation potential (POCP) indicators, which were evaluated according to the Intergovernmental Panel on Climate Change (IPCC) guidelines and interpreted with the aid of the feeds’ composition evaluated using near-infrared reflectance spectroscopy (Foss NIR-System 5000) as well as with a diet evaluation according to the NRC (National Research Council) or the CNCPS (Cornell Net Carbohydrate and Protein System) nutrient requirement modeling. Herds were classified into high-, mid-, and low-performing based on the daily milk yield per cow. A lower impact on indicators was observed as herd performance increased. The high-performing herds had a lower contribution from enteric fermentation (6.30 × 10−1 kgCO2-eq), and the more milk that they produced allowed for a differentiation of CC from land use and transformation (2.39 × 10−1 kgCO2-eq), compared to low-performing herds (3.66 × 10−1 kgCO2-eq). Compared to the IPCC approach, the CC and POCP indicator estimates were reduced when addressing the feed’s quality, particularly in mid- and high-performing herds. The results could be helpful in the dairy sector as they provide an insight into how diet quality affects the environmental impact of milk.

A perspective on the next generation of Earth system model scenarios: towards representative emission pathways (REPs)

Abstract. In every Intergovernmental Panel on Climate Change (IPCC) Assessment cycle, a multitude of scenarios are assessed, with different scope and emphasis throughout the various Working Group reports and special reports, as well as their respective chapters. Within the reports, the ambition is to integrate knowledge on possible climate futures across the Working Groups and scientific research domains based on a small set of “framing pathways” such as the so-called representative concentration pathways (RCPs) in the Fifth IPCC Assessment Report (AR5) and the shared socioeconomic pathway (SSP) scenarios in the Sixth Assessment Report (AR6). This perspective, initiated by discussions at the IPCC Bangkok workshop in April 2023 on the “Use of Scenarios in AR6 and Subsequent Assessments”, is intended to serve as one of the community contributions to highlight the needs for the next generation of framing pathways that is being advanced under the Coupled Model Intercomparison Project (CMIP) umbrella, which will influence or even predicate the IPCC AR7 consideration of framing pathways. Here we suggest several policy research objectives that such a set of framing pathways should ideally fulfil, including mitigation needs for meeting the Paris Agreement objectives, the risks associated with carbon removal strategies, the consequences of delay in enacting that mitigation, guidance for adaptation needs, loss and damage, and for achieving mitigation in the wider context of societal development goals. Based on this context, we suggest that the next generation of climate scenarios for Earth system models should evolve towards representative emission pathways (REPs) and suggest key categories for such pathways. These framing pathways should address the most critical mitigation policy and adaptation plans that need to be implemented over the next 10 years. In our view, the most important categories are those relevant in the context of the Paris Agreement long-term goal, specifically an immediate action (low overshoot) 1.5 °C pathway and a delayed action (high overshoot) 1.5 °C pathway. Two other key categories are a pathway category approximately in line with current (as expressed by 2023) near- and long-term policy objectives, as well as a higher-emission category that is approximately in line with “current policies” (as expressed by 2023). We also argue for the scientific and policy relevance in exploring two “worlds that could have been”. One of these categories has high-emission trajectories well above what is implied by current policies and the other has very-low-emission trajectories which assume that global mitigation action in line with limiting warming to 1.5 °C without overshoot had begun in 2015. Finally, we note that the timely provision of new scientific information on pathways is critical to inform the development and implementation of climate policy. Under the Paris Agreement, for the second global stocktake, which will occur in 2028, and to inform subsequent development of nationally determined contributions (NDCs) up to 2040, scientific inputs are required by 2027. These needs should be carefully considered in the development timeline of community modelling activities, including those under CMIP7.

Indicators of Global Climate Change 2023: annual update of key indicators of the state of the climate system and human influence

Abstract. Intergovernmental Panel on Climate Change (IPCC) assessments are the trusted source of scientific evidence for climate negotiations taking place under the United Nations Framework Convention on Climate Change (UNFCCC). Evidence-based decision-making needs to be informed by up-to-date and timely information on key indicators of the state of the climate system and of the human influence on the global climate system. However, successive IPCC reports are published at intervals of 5–10 years, creating potential for an information gap between report cycles. We follow methods as close as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One (WGI) report. We compile monitoring datasets to produce estimates for key climate indicators related to forcing of the climate system: emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radiative forcing, the Earth's energy imbalance, surface temperature changes, warming attributed to human activities, the remaining carbon budget, and estimates of global temperature extremes. The purpose of this effort, grounded in an open-data, open-science approach, is to make annually updated reliable global climate indicators available in the public domain (https://doi.org/10.5281/zenodo.11388387, Smith et al., 2024a). As they are traceable to IPCC report methods, they can be trusted by all parties involved in UNFCCC negotiations and help convey wider understanding of the latest knowledge of the climate system and its direction of travel. The indicators show that, for the 2014–2023 decade average, observed warming was 1.19 [1.06 to 1.30] °C, of which 1.19 [1.0 to 1.4] °C was human-induced. For the single-year average, human-induced warming reached 1.31 [1.1 to 1.7] °C in 2023 relative to 1850–1900. The best estimate is below the 2023-observed warming record of 1.43 [1.32 to 1.53] °C, indicating a substantial contribution of internal variability in the 2023 record. Human-induced warming has been increasing at a rate that is unprecedented in the instrumental record, reaching 0.26 [0.2–0.4] °C per decade over 2014–2023. This high rate of warming is caused by a combination of net greenhouse gas emissions being at a persistent high of 53±5.4 Gt CO2e yr−1 over the last decade, as well as reductions in the strength of aerosol cooling. Despite this, there is evidence that the rate of increase in CO2 emissions over the last decade has slowed compared to the 2000s, and depending on societal choices, a continued series of these annual updates over the critical 2020s decade could track a change of direction for some of the indicators presented here.

Reflecting on the Science of Climate Tipping Points to Inform and Assist Policy Making and Address the Risks they Pose to Society

AbstractThere is a diverging perception of climate tipping points, abrupt changes and surprises in the scientific community and the public. While such dynamics have been observed in the past, e.g., frequent reductions of the Atlantic meridional overturning circulation during the last ice age, or ice sheet collapses, tipping points might also be a possibility in an anthropogenically perturbed climate. In this context, high impact—low likelihood events, both in the physical realm as well as in ecosystems, will be potentially dangerous. Here we argue that a formalized assessment of the state of science is needed in order to establish a consensus on this issue and to reconcile diverging views. This has been the approach taken by the Intergovernmental Panel on Climate Change (IPCC). Since 1990, the IPCC has consistently generated robust consensus on several complex issues, ranging from the detection and attribution of climate change, the global carbon budget and climate sensitivity, to the projection of extreme events and their impact. Here, we suggest that a scientific assessment on tipping points, conducted collaboratively by the IPCC and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, would represent an ambitious yet necessary goal to be accomplished within the next decade.

Harmonizing existing climate change mitigation policy datasets with a hybrid machine learning approach

With the rapid proliferation of climate policies in both number and scope, there is an increasing demand for a global-level dataset that provides multi-indicator information on policy elements and their implementation contexts. To address this need, we developed the Global Climate Change Mitigation Policy Dataset (GCCMPD) using a semisupervised hybrid machine learning approach, drawing upon policy information from global, regional, and sector-specific sources. Differing from existing climate policy datasets, the GCCMPD covers a large range of policies, amounting to 73,625 policies of 216 entities. Through the integration of expert knowledge-based dictionary mapping, probability statistics methods, and advanced natural language processing technology, the GCCMPD offers detailed classification of multiple indicators and consistent information on sectoral policy instruments. This includes insights into objectives, target sectors, instruments, legal compulsion, administrative entities, etc. By aligning with the sector classification of the Intergovernmental Panel on Climate Change (IPCC) emission datasets, the GCCMPD serves to help policy-makers, researchers, and social organizations gain a deeper understanding of the similarities and distinctions among climate activities across countries, sectors, and entities.

Climate Change: An Obvious Phenomenon or Myth, in the African Context

Climate change is a global phenomenon of unprecedented consequence, engendering substantial scientific, political, and societal discourse. This literature review article offers an exploration of climate change perceptions and realities in the African context. It begins by establishing the unmistakable scientific consensus, with the Intergovernmental Panel on Climate Change (IPCC) serving as a primary authority. The review highlights robust evidence, including temperature trends, extreme weather events, and ecological impacts across the African continent, affirming climate change as an undeniable scientific phenomenon. However, the discourse surrounding climate change in Africa is not homogeneous. Dissenting arguments challenging climate change as a myth emphasize the variability in public perception, data limitations, and the complexities of attribution. These counterarguments reflect diverse perspectives, economic interests, and political inclinations, contributing to the multifaceted character of the climate change discussion. The implications of these findings are substantial, especially for a region highly susceptible to climate change impacts. Proactive measures for climate mitigation and adaptation are imperative to address the vulnerabilities experienced by communities, ecosystems, and economies. A multidisciplinary approach is underscored, recognizing climate change as an intricate challenge interwoven with economics, politics, and human behaviour. The diversity of voices in this discourse emphasizes the need for ongoing research, collaborative efforts, and an inclusive approach to policy formulation. In navigating the complex terrain of climate change, unwavering commitment to scientific rigor, transparency, and sustainable solutions is paramount. This literature review contributes to the ongoing dialogue, providing a basis for further inquiry and informed decision-making. It has the potential to guide future investigations, shape public policy, and elevate awareness regarding the critical significance of addressing climate change in the African context and, by extension, the entire world. The findings presented here are a testament to the indispensable role of rigorous scholarship in comprehending and confronting one of the most pressing challenges of our time

Comprehensive analysis of the impacts of climate and land use changes on flood damage (Case study: AqQala, Iran)

ABSTRACT Population growth, community development, and waste generation impact climate, land use, water resources, and urban heat island effect. This research assesses the impacts of climate and land use changes on flood damage for different return periods (RPs) in AqQala area, Iran. Climate change anticipation is conducted using the CMCC-ESM2 model under shared socioeconomic pathways (SSPs) 126, 370, and 585 of the Intergovernmental Panel on Climate Change (IPCC) sixth assessment report (Coupled Model Intercomparison Project Phase 6 – CMIP6). The LARS-WG model is used to downscale climatic information, and land use mapping is processed through Landsat satellite images in ENVI 5.3. The Markov chain method is implemented for 2050 and 2080 via TerrSet. Hydrographs and inundation maps are generated by the Autodesk Storm and Sanitary Analysis (SSA) and Hydrologic Engineering Center's River Analysis System (HEC-RAS) models. Results show an increase in average annual precipitation (up to 46%) and temperatures (up to 3.39 °C) under different SSP scenarios until 2080. The result indicates that land use changes are more significant than climate change. Peak flood discharge and damages could escalate by 38 and 29%, respectively, in the worst-case scenario. Eco-friendly design and implementation are crucial for improving the situation.

Vested Interest Theory as a Framework for Understanding Anthropogenic Climate Change Risk Perceptions

ABSTRACT Climate change due to anthropogenic activities is contributing to the systematic warming of Earth. A warming planet represents an existential threat to humanity, contributing to the increased frequency and magnitude of multiple natural hazards. The UN’s Intergovernmental Panel on Climate Change (IPCC) notes that time is running out to create meaningful change to avert climate-related consequences. This research posits Vested Interest Theory (VIT) as a potentially useful framework for assessing attitudes and risk perceptions associated with anthropogenic climate change (ACC). Vested Interest Theory mediates the attitude-behavior relationship where highly vested individuals are more likely to behave in attitudinally-consistent ways. Vestedness is conceptualized as five distinct and observable variables: salience, certainty, immediacy, self-efficacy, and response-efficacy. To test VIT’s efficacy in this context, a survey was conducted with participants crowdsourced from Amazon’s Mechanical Turk platform (N = 1053). Participants responded to items designed to measure their individual vestedness in ACC consequences, risk perceptions, and behavioral intentions. This initial investigation shows that VIT’s constituent variables predict consequential amounts of observed variance in critical variables including risk perception, perceived event severity, and behavioral intentions related to ACC hazard mitigation. The results support the use of VIT as a framework for understanding attitude-behavior relationships associated with ACC mitigation. Based on these findings, we argue that VIT can also serve as a valuable message design framework to motivate ACC-related mitigation actions.

New Zealand's planted forests–Carbon stocks and yield in fast growing exotic tree plantations of the Southern Hemisphere

Every year New Zealand measures 1/5th of the permanent sample plots of the National Planted Forest Inventory administered by the Ministry for the Environment (MFE). This means that all plots are measured once during a five-year cycle to provide the full inventory, while each measurement year in its own right provides a random nationally-representative sample of New Zealand's plantation forests.Land-use change and planted forest area are highly dynamic in New Zealand compared to forests in many northern hemisphere countries and every year new plots are added to the inventory due to new afforestation areas. Over time, old plot data representing stands that have been recently harvested will be replaced with measurements of the new forests growing on these sites or will drop out altogether due to improvements in mapping or deforestation. This means that estimates from a single year's plot measurements can give different results from the previous year due to the changes that the plantation forest estate experiences from year to year.In this paper we analyse results for the latest measurement cycle (Panels 2016 - 2020) and identify any issues or trends in carbon stocks. We use all panel data plus data from previous periodic forest inventories to generate a fully representative yield table for all plantation forests in the sub-categories of Kyoto Protocol-compliant afforestation and other planted forests (“non-Kyoto”). Furthermore, we use an imputation approach to provide a statistically accurate representation of stock changes over time. The yield tables generated are used in MFE's Land Use Carbon Analysis System (LUCAS) to generate estimates of carbon stocks and stock changes for international reporting.The estimated mean carbon sequestration rate over the typical rotation for New Zealand's dominant plantation species is higher than the default range provided by the IPCC (Intergovernmental Panel on Climate Change). Predicted carbon sequestration in non-Kyoto planted forests (10.5 tC ha−1 yr−1) exceeds the estimated carbon sequestration in Kyoto-compliant planted forests (9.8 tC ha−1 yr−1) with both at the upper range of estimates for temperate plantation forests (IPCC). Current mean carbon stocks are significantly larger in Kyoto-compliant plantation forests (169 tC ha−1) than in non-Kyoto planted forests (108 tC ha−1) across New Zealand, largely because they are on average five years older. Estimated Mean annual increment, m3 ha−1 yr−1 expressed as a comparable index (“300Index”) indicates that Kyoto-compliant forest land has slightly higher productivity than non-Kyoto planted forests, but because the latter are composed of younger stands, greater carbon sequestration rates but lower current stocks are estimated. Plots with slower growing tree species such as Douglas-fir, cypresses and coastal redwood are now an increasing part of the Kyoto-compliant estate, reducing the overall sequestration rates for this forest type.

A snapshot of fundamental geological knowledge to deal with climate change

The 28th meeting of the Conference of the Parties (COP 28) to the United Nations Framework Convention on Climate Change (UNFCCC) in Dubai, United Arab Emirates, concluded in December 2023. The meeting discussed the overarching goal of the legally binding Paris Agreement to limit “global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels”. The COP 28 recognised recent findings of Intergovernmental Panel on Climate Change (IPCC) that “limiting global warming to 1.5 °C with no or limited overshoot requires deep, rapid and sustained reductions in global greenhouse gas emissions of 43% by 2030 and 60% by 2035 relative to the 2019 level, and reaching net zero carbon dioxide emissions by 2050”.

“We are not droids”– IPCC participants’ senses of responsibility and affective experiences across the production, assessment, communication and enactment of climate science

The growing understanding of how and why the climate is changing has led to mounting calls on climate scientists to take on more responsibility in the context of climate science. While an increasing responsibilisation takes place in the academic literature, asking scientists to “do more”, there is limited engagement with the responsibilities that scientists already assume in practice. Drawing on novel empirical insights from 77 semi-structured interviews with participants of the Intergovernmental Panel on Climate Change (IPCC), I take the increasing ‘peer-to-peer responsibilisation’ as a point of departure to contextualise such calls, asking what scientists themselves already feel and assume responsibility for at both the personal and professional level. I find that climate experts participating in the IPCC not only assume increasing responsibility across different stages of the IPCC process but also beyond. As my data analysis demonstrates, IPCC participants increasingly feel and take on responsibility not only for producing and assessing climate science but also for communicating and/or enacting it (PACE). The contribution of the article is threefold. Firstly, it makes sense of the mounting peer-to-peer responsibilisation by surfacing and contextualising how, why and with what consequences particular climate knowledge holders already assume responsibility for climate science at four key moments (PACE). Secondly, conceiving of the IPCC as a community of practice, the article provides novel insights into the work of IPCC participants and their individual experiences with the institution and its processes. Thirdly, the article adds evidence to a growing body of literature on practices of responsibility and climate emotions by focussing on participants' individual affective experiences. As the 7th Assessment Cycle gathers pace, I propose some measures the IPCC may undertake to support participants in assuming their responsibilities in the context of climate science.

Waste-Heat Renewable Gasifier Design through Taguchi's Method and MANFIS

Ensuring a global average temperature increase of no more than 1.5°C is crucial for aligning with the objectives of the Paris Agreement. The Intergovernmental Panel on Climate Change (IPCC) estimates that a 45% reduction in carbon dioxide emissions by 2030 or a 25% reduction by the same year is necessary to cap the temperature rise at 2°C. Failure to achieve this target by 2030 would necessitate substantial subsequent reductions to compensate for the delayed progress toward net zero emissions, potentially incurring higher costs. Elevating the focus on enhancing energy efficiency has emerged as a key strategy in expediting progress toward these climate goals. Hydrogen, renowned for its high efficiency and emission-free combustion, is anticipated to play a pivotal role in this endeavor. Traditionally, gasifiers have served as the conduit for transforming inexpensive fuels like coal or biomass into hydrogen. However, their energy-intensive nature poses a challenge.Addressing this inherent issue, an innovative approach known as the external-heating gasifier has been proposed and designed. The design of the external-heating gasifier represents a quintessential nonlinear and multiple-input multiple-output (MIMO) problem. To achieve optimal performance, the integration of Taguchi's method and inverse-model technology has been employed, with a simulation platform developed using the COMSOL Multiphysics software.Initially, Taguchi's method was utilized to determine the minimum number of experiments required for a full-factorial design and identify the most critical factors influencing product performance. Subsequently, an adaptive neuro-fuzzy inference system (ANFIS) was developed with a MIMO–ANFIS architecture. This system was employed to train an inverse model, facilitating the mapping of relationships between each input and output set. In essence, this approach enables the identification of manufacturing parameters that result in optimal performance. To illustrate the efficacy of the proposed method, a simulation study on an existing gasifier is presented.

Effect of urbanization on surface runoff and performance of green roofs and permeable pavement for mitigating urban floods

Floods are increasingly becoming a significant concern due to climate change, global warming, and excessive urbanization. The Intergovernmental Panel on Climate Change (IPCC) has projected that global warming will continue to contribute to more frequent and severe floods and hydrological extremes. In response to these challenges, nature-based solutions (NBSs) have gained recognition as effective approaches to mitigate the adverse impacts of floods by focusing on ecosystem conservation, restoration, and sustainable utilization of natural resources. This study examines a flood that occurred in the Erkilet District of Kayseri, Türkiye on September 22, 2022, as a result of intense rainfall. It involves a thorough on-site investigation to assess the hydraulic, hydrologic, and geotechnical attributes of the study area. The findings from the field study indicate that the primary cause of the flood is attributed to excessive urbanization. To further analyze the impact of urbanization, a hydraulic model is developed considering both the physical and topographical conditions of the study area for both the year 2006 and 2022. The simulation results reveal that the extent of inundation area and water depth has increased significantly due to the excessive urbanization that occurred within a 16-year period. Additionally, the effectiveness of green roofs and permeable pavements as NBSs to mitigate urban flooding is explored. The implementation of green roofs and permeable pavements shows promising results, reducing the adverse effects of urban floods by 3% to 8%, depending on their specific locations and configurations. However, the results suggest that NBSs alone cannot fully prevent floods so they should complement gray infrastructure. The novelty of the study lies in its ability to demonstrate the impact of urbanization and the effectiveness of nature-based solutions in mitigating flood extent based.

Leveraging climate and remote sensing metrics for predicting forest carbon stock using Bayesian geostatistical modelling under a projected climate warming in Zimbabwe

Climate change, driven by escalating carbon dioxide (CO2) emissions, poses a significant threat to forest ecosystems and the livelihoods of communities reliant on them, especially for the global south countries and regions like the eastern highlands of Zimbabwe. The 2000 land redistribution programme reduced buffer zones between ecologically sensitive forests and land reform beneficiaries near major carbon reservoirs. In light of these challenges, this study aimed to assess the potential effects of climate change on a strategically important plantation forest ecosystem in Zimbabwe's eastern highlands. Using data from the Coupled Model Inter-comparison Project Phase 6 (CMIP6) of the Intergovernmental Panel on Climate Change (IPCC), we modelled and predicted changes in forest carbon (C) stock density under different climate scenarios: current (1970–2000), SSP5–4.5, and SSP5–8.5. Employing a hierarchical Bayesian geostatistical approach, we compared the baseline scenario (1970–2000) with projected scenarios (RCP4.5 and RCP8.5) for 2075 to estimate changes in forest carbon stock distribution. Our results indicated a decline in carbon stock concentration under future climate scenarios, reflecting the adverse impact of greenhouse gas emissions on forest growth. We found that the projected range of forest carbon stock under the RCP8.5 scenario for 2075 is notably lower (2≤MgCha−1≤44.9) than that of the baseline period (1970–2000) (1≤MgCha−1≤97), suggesting a substantial reduction in carbon storage. As the difference in posterior mean C stock (μ̅1−μ̅2), 52.1 MgCha-1 is well above zero, we deduce that the posterior mean C stock distribution of the projected future RCP8.5 2075 climate projection is indeed credibly different from the current (1970–2000) climate scenario. Additionally, there is a high probability (>90%) that forest plantations will be adversely affected by the business-as-usual climate warming projection. Overall, our findings highlight the urgent need for climate change mitigation strategies, such as reforestation programs and careful selection of tree species for plantations, to safeguard forest ecosystems and the communities dependent on them. These insights are crucial for informing effective adaptation measures in the face of future climate uncertainties.

Impacts of New Town developments on carbon sinks: Implications from the Case of Seoul Metropolitan Area, Korea

The Intergovernmental Panel on Climate Change (IPCC) ambitious goal of achieving carbon neutrality by 2050 has been embraced by a variety of countries including South Korea. In South Korea, an increasingly vital neutrality strategy is enhancing carbon absorption through land use planning. A key consideration in these strategies is the comprehensive evaluation of carbon sinks present in various land cover categories. These carbon sinks—most notably forests, grasslands, and wetlands—play a critical role in mitigating the effects of climate change by locking carbon dioxide out of the atmosphere. However, forests and grasslands have long been prime avenues for new exurban development. This study analyzes the effects of large-scale development across several key carbon sinks for the Seoul Metropolitan Area of South Korea. Our findings indicate that the key carbon sinks increased from 2007 to 2021. Regardless, urban development has flourished where greenbelts were released, leading to significant depletion of forests, grasslands, and wetlands. However, converting farmland to New Town developments with massive park systems has contributed to an increase in carbon sinks in some parts of the region. In the perspective of South Korea’s goals for carbon neutrality, absorption is insufficient. Therefore, it is necessary to reflect the loss of sinks as a cost of sprawl and frame policies to expand storage through afforestation or reassessment of idle, undeveloped land.