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A Millennium of ENSO Influence on Jet Stream Driven Summer Climate Extremes
Get PDFSummertime spatially compound climate extremes in the Northern Hemisphere are associated with dominant jet stream Rossby wavenumber patterns, including wavenumber5 (wave5). However, our knowledge of wave5, including its response to anthropogenic warming, is limited by the short length of instrumental records of upper-level fields. To provide a longer-term perspective, we present a 1,000-year reconstruction of a wave5 pattern that modulates summertime compound extremes, constructed by targeting drought anomalies associated with this pattern in three regions. Our results show no major trends in the occurrence of this pattern over the past millennium. We further show that La Niña winters often precede a wave5 event the following summer, evident over centuries. This pattern was exemplified by the La Niña winter of 2022–2023, which was followed by wave5-driven compound heatwaves in July. The imprint of continued anthropogenic warming on ENSO may exacerbate wave5-driven extremes, especially if the tropical Pacific becomes more La Niña-like
Climate-induced redistribution of people is not inevitable
Get PDFAs climate change intensifies, scientific and policy discussions increasingly address questions of future habitability and potential population movements. In this perspective, we caution against premature or top-down characterizations of areas as uninhabitable, or portrayals of large-scale climate-induced displacement as inevitable—particularly when the perspectives and preferences of affected populations are excluded. While we recognize the importance of modelling and scenario-building to assess future risks, we argue that such efforts must be grounded in local realities and include diverse forms of knowledge.
Habitability is not determined by climate alone, but emerges from intersecting environmental, political, economic, and cultural dynamics—including governance, inequality, and historical injustice. Framings that do not consider this risk producing two problematic outcomes: first, by prematurely defining areas as uninhabitable, they may undermine the legitimacy of in-situ adaptation and the agency of affected communities; second, when modelling or the use of modelling results does not consider local context, it may inadvertently contribute to narratives portraying climate-induced mass displacement as inevitable, reinforcing deterministic understandings of migration and overlooking the complex drivers of mobility and immobility.
To counter these risks, we propose five guiding recommendations: (1) avoid declaring hard limits to habitability without inclusive, context-specific assessments; (2) treat model-based projections as possible, not predetermined futures; (3) reject simplistic global North/South assumptions in assessing vulnerability and mobility; (4) uphold people’s right to remain, alongside the right to move; and (5) prioritize investment in in-situ adaptation that addresses structural inequalities. These principles aim to inform more reflexive and justice-oriented approaches to climate mobility and habitability research—approaches that recognize lived experiences, engage diverse knowledge systems, and help secure equitable futures for those most exposed to environmental change
A method to identify positive tipping points to accelerate low-carbon transitions and actions to trigger them
Get PDFMeeting the Paris Agreement to limit global warming to “well below 2 °C” requires a radical acceleration of action, as the global economy is decarbonising at least five times too slowly. Tipping points, where low-carbon transitions become self-propelling, could be key to achieving the necessary acceleration. We deem these normatively ‘positive’, because they can limit considerable, inequitable harms from global warming and help achieve sustainability. Some positive tipping points, such as the UK’s elimination of coal power, have already been reached at national and sectoral scales. The challenge now is to credibly identify further potential positive tipping points, and the actions that can bring them forward, whilst avoiding wishful thinking about their existence, or oversimplification of their nature, drivers, and impacts. Hence, we propose a methodology for identifying potential positive tipping points, assessing their proximity, identifying the factors that can influence them, and the actions that can trigger them. Building on relevant research, this ‘identifying positive tipping points’ (IPTiP) methodology aims to establish a common framework that we invite fellow researchers to help refine, and practitioners to apply. To that end, we offer suggestions for further work to improve it and make it more applicable
How reference scenario selection affects technical mitigation potential at the sub-national level: Evidence from China's agricultural non-CO2 greenhouse gas emissions
No full textReference scenarios serve as a foundational benchmark for evaluating the mitigation potential of technological options and policy proposals, and their specifications play a critical role in ensuring accurate and policy-relevant assessments. Leveraging the Agricultural non-CO2 Greenhouse gAs InveNtory (AGAIN) model, this study assessed the mitigation potential of agricultural non-CO2 greenhouse gas (GHG) emissions under technical potential (TP) scenarios relative to four reference scenarios: China-specific business-as-usual (CBAU), Shared Socioeconomic Pathway 2 (SSP2), and two current policy scenarios (CP-CBAU and CP-SSP2). The results indicated that both socioeconomic assumptions and current policy inclusion substantially influenced emission trajectories and mitigation estimates. Under the CBAU scenario, emissions were projected to rise continuously, reaching 1161 MtCO2eq by 2060. In contrast, emissions under the SSP2, CP-CBAU, and CP-SSP2 scenarios were expected to peak between 2042 and 2050 at levels ranging from 1017 to 1109 MtCO2eq. Excluding current mitigation policies led to an overestimation of mitigation potential by 42–52 %, while differences in socioeconomic assumptions contributed to a smaller uncertainty of approximately 7 %. Although the choice of reference scenario had a limited impact on the regional prioritization of mitigation efforts, it significantly affected the prioritization of mitigation subsectors. Furthermore, the influence of reference scenario selection on mitigation potential assessments varied spatiotemporally, with greater effects observed in the long term and in provinces that had not yet peaked in emissions by 2023. These findings underscore the need to enhance the diversity, timeliness, and transparency of reference scenario design to support robust mitigation strategy development and policy evaluation
Opinion dynamics meet agent-based climate economics: An integrated analysis of carbon taxation
Get PDFWe introduce an integrated approach, blending Opinion Dynamics with a Macroeconomic Agent-Based Model (OD-MABM) to explore the co-evolution of climate change mitigation policy and public support. The OD-MABM links a novel opinion dynamics model that is calibrated for European countries using survey data to the Dystopian Schumpeter meeting Keynes model (DSK). Opinion dynamics regarding climate policy arise from complex interactions among social, political, economic and climate systems where a household's opinion is affected by individual economic conditions, perception of climate change, industry-led (dis-)information and social influence. We examine 133 policy pathways in the EU, integrating various carbon tax schemes and revenue recycling mechanisms. Our findings reveal that effective carbon tax policies initially lead to a decline in public support due to substantial macroeconomic transition costs, threatening political feasibility. However, they also pave the way for a positive social tipping point in the future. This shift stems from the evolving economic and political influence associated with the fossil fuel-based industry, which gradually diminishes as the transition unfolds. Second, hybrid revenue recycling strategies that combine green subsidies with climate dividends successfully address this intertemporal trade-off in our model by accelerating the transition and mitigating its economic fallout, thus broadening public support
A dual-focus analysis of wikipedia traffic and linguistic patterns in public risk awareness Post-Charlie Hebdo
Get PDFThis study investigates the dynamics of public risk awareness in the aftermath of the Charlie Hebdo terrorist attack on January 7, 2015, through a dual-focus analysis of Wikipedia traffic and Google Trends data. Analyzing the temporal patterns of Wikipedia page views in both English and French, sheds light on how significant media events, anniversaries, and related incidents influence public engagement with terrorism-related content over time. The study highlights the critical role of linguistic and cultural factors in shaping these patterns, revealing that Francophone regions, particularly France and its former colonies, exhibit a more sustained and consistent interest in the Charlie Hebdo event compared to Anglophone regions. The heightened engagement in French-speaking areas suggests that cultural and historical ties influence public risk perception and awareness. Complementing this analysis with geographic insights from Google Trends, the study provides a more comprehensive understanding of how people in different regions perceive and respond to terrorism. The findings underscore the importance of digital platforms in gauging public awareness and suggest practical implications for designing targeted risk communication strategies. These strategies could be timed to coincide with moments of heightened public interest, such as anniversaries, to enhance public resilience and preparedness in the face of terrorism. This study contributes to the broader understanding of digital media's role in shaping and sustaining public risk awareness in a global context
Reversal of the impact chain for actionable climate information
No full textEscalating impacts of climate change underscore the risks posed by crossing potentially irreversible Earth and socioecological system thresholds and adaptation limits. However, limitations in the provision of actionable climate information may hinder an anticipatory response. Here we suggest a reversal of the traditional impact chain methodology as an end-user focused approach linking specific climate risk thresholds, including at the local level, to emissions pathways. We outline the socioeconomic and value judgement dimensions that can inform the identification of such risk thresholds. The applicability of the approach is highlighted by three examples that estimate the required CO2 emissions constraints to avoid critical levels of health-related heat risks in Berlin, fire weather in Portugal and glacier mass loss in High Mountain Asia. We argue that linking risk threshold exceedance directly to global emissions benchmarks can aid the understanding of the benefits of stringent emissions reductions for societies and local decision-makers
Cooling Down the World Oceans and the Earth
No full textThe world is going through intensive changes due to global warming. It is well known that the reduction in ice cover in the Arctic Ocean further contributes to increasing the atmospheric Arctic temperature due to the reduction of the albedo effect and increase in heat absorbed by the ocean's surface. The Arctic ice cover also works like an insulation sheet, keeping the heat in the ocean from dissipating into the cold Arctic atmosphere. Increasing the salinity of the Arctic Ocean surface would allow the warmer and less salty North Atlantic Ocean current to flow on the surface of the Arctic Ocean, considerably increasing the temperature of the Arctic atmosphere and releasing the ocean heat trapped under the ice. This chapter argues that if the North Atlantic Ocean current could keep the Arctic Ocean ice-free during the winter, the longwave radiation heat loss into space would be larger than the increase in heat absorption due to the albedo effect. It presents details of the fundamentals of the Arctic Ocean circulation and presents three possible approaches for increasing the salinity of the surface water of the Arctic Ocean. It then discusses how increasing the salinity of the Arctic Ocean would warm the atmosphere of the Arctic region, but cool down the oceans and possibly the Earth. However, it might take thousands of years for the effects of cooling the oceans to cool the global average atmospheric temperature
A comprehensive provincial-level VOCs emission inventory and scenario analysis for China: Enhanced sectoral resolution through GAINS-China model
Get PDFVolatile organic compounds (VOCs) are key precursors to secondary organic aerosol (SOA) and ground-level ozone, posing significant challenges to air quality and public health in China. Although previous studies have established VOCs inventories and projected emission trends, many lack the granularity needed to capture sectoral and regional emission variations, especially within the highly contributive solvent use sector. To address this gap, this study aims to develop a detailed VOCs emission inventory for China at the provincial level for 2020, utilizing the GAINS-China model and covering 5 major sectors, 20 subsectors, and 80 distinct emission sources. Uniquely, this inventory subdivides the solvent use sector into 5 subsectors and 22 specific sources, enabling a more precise analysis of VOCs emission sources. Future emission trends and reduction potentials were projected for the period 2020–2050 under two scenarios: reference (REF) and current legislation (CLE). The results revealed that the total anthropogenic VOCs emissions in China were estimated to be 23,114.8 kt in 2020, with solvent use contributing 56.0%, followed by the residential (17.0%), others (11.0%), transportation (10.0%), and industry and power (6.0%) sectors. Under the REF scenario, VOCs emissions are expected to decline to 19,162.2 kt by 2040 but remain stable thereafter. This reduction is driven mainly by the replacement of household solid fuels with clean fuels in the residential sector, especially in Sichuan Province. Compared with those in the REF scenario, the total VOCs emissions in the CLE scenario continuously decreased throughout 2020–2050, with the solvent use sector contributing the most to the reductions (46.1%–81.7%), followed by transport (16.8%–41.3%). A provincial analysis highlights that high-emission regions such as Guangdong, Jiangsu, and Shandong offer the greatest reduction potential. To effectively and precisely reduce VOCs emissions, key subsectors contributing to emissions, including paint use, non-road machinery, industrial processes, and agriculture, should be prioritized for further control measures. This study provides essential insights into sectoral and regional VOCs emissions, offering a robust foundation for formulating targeted emission control policies
Planting 10 Million Trees with Lukenya University in Kenya: Methodology and Preliminary Observations and Forecasts
Get PDFLukenya University has recently begun implementing a Ten Million Tree Growing Initiative, as part a larger national multi-institutional country-wide tree growing program. In this paper we describe the methods used as far as tree selection and the planting itself. Note that most of the trees are not planted directly by the institution by given to farmers to plant on their land, with instruction as to how to choose a location and how to technically perform the planting and maintenance to ensure greater success for the tree and the environment surrounding it. This knowledge arises out of years of experience as far as both the biology of planting and the social interaction with smallholder farmer communities. We kept track of the survival and growth of a subsample of a number of different tree species. After about two years of operation, we performed a statistical analysis on preliminary data. We observe statistically significant advantages to survival and relative growth volume to indigenous trees and the aforementioned comprehensive instruction before plotting, among other observations we relate from the hypothesis tests performed. Finally, we present estimates of the carbon sequestration and economic value of the trees to the community. Summarizing, the paper presents a comprehensive transparent display of a tree growing initiative, a common endeavor motivated to maximize social welfare and climate change resilience, and in so doing can develop the knowledge of best practices for these purposes