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Towards net-zero electricity sector in emerging economies – Brazil, India, Indonesia and South Africa
No full textEmerging middle-income countries have indicated a strong commitment towards mitigating their greenhouse gas (GHG) emissions not only through their Nationally Determined Contributions (NDCs) but also by raising their climate ambition and committing to net-zero emissions at COP 26 in Glasgow, as well as to tripling renewables at COP 28. The electric power generation sector plays a crucial role in supporting the sustainable social and economic development of a nation but is also currently one of the largest and growing sources of energy related GHG emissions in major emerging economies. In this study, we analyse current policy and deep decarbonization scenarios of the power sector in four developing middle-income economies (Brazil, India, Indonesia and South Africa). Through retirement of old, inefficient fossil-based power plants and a transformative shift towards non-fossil-based variable and firm primary energy sources the results demonstrate a reduction in carbon intensity to 104 grams CO2//kWh (Indonesia), 96 grams CO2//kWh (India) and 43 grams CO2//kWh (South Africa). To achieve power sector decarbonization a step change increase in policy stringency is required, combined with substantial international financial support through mechanisms like Just Energy Transition Partnerships. This must be combined with necessary market reforms to make these markets self-sustaining for needed investments to meet development, energy security and climate goals
Land use modelling needs to better account for multiple cropping to inform pathways for sustainable agriculture
Get PDFMultiple cropping, the simultaneous cultivation of several crops in space or time, is a global practice essential for intensifying and diversifying agriculture. Despite its substantial impact on environmental and socioeconomic outcomes of farming, multiple cropping is hardly accounted for in assessments of global food production, sustainability, and climate impacts. Such studies, often relying on modelling of cropping systems, land use change, and eventually the Earth system, are of growing importance in decision-making and policymaking. However, they primarily assume monocropping, neglecting carryover effects between crops and their implications for land use. This limitation compromises the representativeness of these studies and the conclusions they draw, essentially overlooking a substantial option space for sustainable intensification, nature-based solutions, and resulting land-atmosphere feedback. Herein, we outline the relevance of multiple cropping, reflect on its consideration in land-use models, and identify development requirements to enhance their inclusion in informing policymaking for sustainable food systems
The Legal Power of Highest Possible Ambition: Setting Legal and Scientific Indicators to Assess Highest Possible Ambition under Article 4(3) of the Paris Agreement
Get PDFThe Paris Agreement requires each state party to submit a nationally determined contribution ( ndc ) every five years. Current ndc s fall short of limiting global warming to 1.5°C, making the 2025 submissions crucial. Against commonly held belief, the level of climate change mitigation ambition in ndc s does not entirely lie within the discretion of Parties. Article 4(3) of the Paris Agreement requires that each party’s successive ndc will reflect its ‘highest possible ambition’ ( hpa ); an important normative requirement crucial for raising mitigation ambition. This article examines hpa and provides legal and scientific indicators for assessing whether parties’ 2025 ndc s and subsequent submissions align with the hpa requirement in Article 4(3). In doing so, a comprehensive framework essential for ensuring that ndc s are ambitious, credible, and effective in reducing emissions and mitigating climate impacts is offered. The success of the global effort against climate change depends on parties reflecting their hpa in ndc s and implementing effective mitigation measures, highlighting the urgency of hpa in each party’s climate efforts
The utility of the Living Planet Index as a policy tool and for measuring nature recovery
Get PDFThe Living Planet Index (LPI) is a leading global biodiversity indicator based on vertebrate population time series. Since it was first developed over 25 years ago, the LPI has been widely used to indicate trends in biodiversity globally, primarily reported every two years in the Living Planet Report. Based on relative abundance, a sensitive metric of biodiversity change, the LPI has also been applied as a tool for informing policy and used in assessments for several multilateral conventions and agreements, including the Convention on Biological Diversity 2010 Biodiversity Target and Aichi targets. Here, we outline all current and some potential uses of the LPI as a policy tool and explore the use of the LPI in policy documents to assess the reach of the LPI geographically and over time. We present limitations to the use of this indicator in policy, primarily relating to the development of the index at the national level, and suggest clear pathways to broaden the utility of the LPI and the underlying database for temporal and spatial predictions of biodiversity change. We also provide evidence that the LPI can detect recoveries in biodiversity and suggest its suitability for measuring progress towards the goal of biodiversity recovery by 2050.This article is part of the discussion meeting issue 'Bending the curve towards nature recovery: building on Georgina Mace's legacy for a biodiverse future'
Entry points for assessing ‘fair shares’ in national mitigation contributions
Get PDFFairness considerations have long been central to the international climate change mitigation discourse, generating numerous scientific and philosophical debates. Yet, there remains a pressing need for practical guidance on developing assertions of fairness in national mitigation contributions. The Paris Agreement mandates that subsequent nationally determined contributions (NDCs) submitted under Article 4 represent a progression compared to previous NDCs. Further decisions under the Paris Agreement mandate that NDCs include clear and transparent considerations of fairness, as recalled in the first Global Stocktake. We propose a practical approach to this, comprising a set of 'entry points' that represent key stages where decisions are taken in 'fair share' quantifications, from interpreting foundational principles to selecting indicators and presenting results. By bridging the gap between scholarly debates and practical application, this work supports the integration of clear and transparent fairness considerations into climate policy commitments. We demonstrate the use of our approach through a case study
Can spatial self-organization inhibit evolutionary adaptation?
Get PDFPlants often respond to drier climates by slow evolutionary adaptations from fast-growing to stress-tolerant species. These evolutionary adaptations increase the plants' resilience to droughts but involve productivity losses that bear on agriculture and food security. Plants also respond by spatial self-organization, through fast vegetation patterning involving differential plant mortality and increased water availability to the surviving plants. The manners in which these two response forms intermingle and affect productivity and resilience have not been studied. Here we ask: can spatial patterning inhibit undesired evolutionary adaptation without compromising ecosystem resilience? To address this question, we integrate adaptive dynamics and vegetation pattern-formation theories and show that vegetation patterning can inhibit evolutionary adaptations to less productive, more stress-tolerant species over a wide precipitation range while increasing their resilience to water stress. This evolutionary homeostasis results from the high spatial plasticity of vegetation patterns, associated with patch thinning and patch dilution, which maintains steady local water availability despite decreasing precipitation. Spatial heterogeneity expedites the onset of vegetation patterning and induces evolutionary homeostasis at an earlier stage of evolutionary adaptation, thereby mitigating the productivity loss that occurs while the vegetation remains spatially uniform. We conclude by discussing our results in a broader context of evolutionary retardation
Demand-side strategies enable rapid and deep cuts in buildings and transport emissions to 2050
Get PDFDecarbonization of energy-using sectors is essential for tackling climate change. We use an ensemble of global integrated assessment models to assess CO2 emissions reduction potentials in buildings and transport, accounting for system interactions. We focus on three intervention strategies with distinct emphases: reducing or changing activity, improving technological efficiency and electrifying energy end use. We find that these strategies can reduce emissions by 51–85% in buildings and 37–91% in transport by 2050 relative to a current policies scenario (ranges indicate model variability). Electrification has the largest potential for direct emissions reductions in both sectors. Interactions between the policies and measures that comprise the three strategies have a modest overall effect on mitigation potentials. However, combining different strategies is strongly beneficial from an energy system perspective as lower electricity demand reduces the need for costly supply-side investments and infrastructure
Adaptive Mitigation of Warming-Induced Food Crisis and Nitrogen Pollution
No full textFeeding the world's population in the face of global warming is a challenging task. Warming poses a dual threat to both global food security and nitrogen pollution in croplands. However, a consensus remains elusive regarding the precise impact of warming on the nitrogen cycle in global croplands. Our study revealed that warming alone could reduce grain yields by 21% (with a 95% confidence interval of 15-27%) while increasing nitrogen losses to the environment by 54-169%. Under the 2050 warming scenario, the annual global nitrogen harvest is projected to decrease by 16 million tonnes (Tg), accompanied by an increase in nitrogen surplus (nitrogen lost to the environment) of 29 Tg relative to the baseline. Implementation of timely and robust adaptive mitigation strategies, including optimization of planting dates, cultivars, irrigation, and fertilization practices, could mitigate the warming-induced food crisis and nitrogen pollution, averting potential losses of US 73 billion
Stakeholder engagement for inclusive climate impact attribution studies
Get PDFSince its emergence in the 1990s, the science of attributing observed phenomena to human-induced and natural climate drivers has made remarkable progress. To ensure the relevance and uptake of climate impact attribution studies, scientists must effectively engage with stakeholders. This engagement allows stakeholders to pose key questions, which scientists can then substantiate with evidence evaluating the existence of causal links. Although significant advancements have been made in climate impact attribution science, much work remains to understand the varied requirements of different stakeholders for impact attribution findings. This perspective explores the usefulness of stakeholder engagement in climate impact attribution, the challenges it presents, and how it can be made more relevant for addressing societal questions. It advocates for prioritizing stakeholder involvement to achieve greater transparency, legitimacy, and practical application of findings. Such involvement can enhance the societal impact of attribution studies and support informed decision-making in the face of climate change
Closing the global sand circularity gap needs a systems approach
No full textSand is the most-mined mineral globally and yet demand is set to increase. With significant environmental and societal consequences driven by sand extraction, facilitating sand circularity to maximize the reuse and recycling of aggregates, particularly from waste from construction and demolition, where sand is primarily used, becomes imperative. However, a systemic understanding of such reuse and recycling potential toward achieving circularity remains underexplored. In this review, we investigate this potential by examining the existing literature to evaluate the difference between the inflow (demand) and the outflow (end-of-life for reuse and recycling) of concrete aggregates. Although end-of-life aggregates are projected to increase nearly five-fold by 2060, they continue to fall short of demand by 11.4 Gt. This disparity, coupled with low rates of secondary aggregate use, will likely perpetuate the sand circularity gap for decades, especially in lower-income regions. Bridging this gap demands a comprehensive systems approach with significant coordination among stakeholders