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Energy for sustainable development requires replacing fossil fuel use by renewables. Such substitution is the kingpin of climate action. As per IPCC AR6 WG I latest report "limiting human-induced global warming requires limiting cumulative CO 2 emissions" and "every tonne of CO 2 emissions adds to global warming". In other words, climate action should focus on cumulative emissions and not on annual emissions. We need to shift the discourse from annual emissions to cumulated emissions. For example, in the Paris Agreement instead of the final level of emissions in 2030 as goals emphasis should have been on the cumulated emissions of the pathways till 2030. Responsibility for finance needs to be in that proportion. Moreover, an annual fee of even US$1 per ton from all countries big and small on their cumulated emissions from 1990 onwards incentivises them to reduce and postpone their emissions. Such a fee can currently raise annually at least US$ 733 billion for climate finance. Moreover, focusing on annual emissions can lead to a false sense of comfort that climate change is under control, whereas warming will continue even after net-zero is attained. • Cumulated emissions is a better scientific indicator to guide climate action and discourse than annual emissions. • It should be the measure for a country's mitigation responsibility and climate finance obligations. • A fee of one US$ per tCO2 from all countries for their cumulative emissions since 1990 can raise US$ 733 billion in 2020. • It would incentivize countries to postpone, reduce and increase negative emissions. • It can raise finance for domestic action, transfer resources to countries and purchase technology license for global goods. [ABSTRACT FROM AUTHOR]

• COVID-19 pandemic aside, climate change is the ultimate challenge of our time • There is lack of political thrust to facilitate appropriate climate action • Climate change-induced mortality and morbidity are expected to rise globally • Little time is left to develop and implement mitigation and adaptation strategies COVID-19 pandemic aside, climate change is the ultimate challenge of our time. However, to date, there has been insufficient political thrust to make that much-needed climate action a reality. Infectious diseases represent only one facet of the threats arising from climate change. Direct impacts from climate change include the more frequent occurrence and increased magnitude of extreme weather events, as well as changing temperatures and precipitation patterns. For climate-sensitive infectious diseases, these changes implicate a shift in geographical and temporal distribution, seasonality, and transmission intensity. Susceptibility to the deleterious effects of climate change is a net result of the interplay of not only environmental factors, but also human, societal, and economic factors, with social inequalities being a major determinant of vulnerability. The global South is already disproportionately affected by the climate crisis. The financial capacity to pursue adaptation options is also limited and unevenly distributed. Climate change-induced mortality and morbidity from both infectious and non-infectious diseases, among other adverse scenarios, are expected to rise globally in the future. The coming decade will be crucial for using all remaining opportunities to develop and implement adequate mitigation and adaptation strategies. [ABSTRACT FROM AUTHOR]

Abstract Global sustainability is intertwined with freshwater security. Emerging changes in global freshwater availability have been recently detected as a combined result of human interventions, natural variability and climate change. Expected future socio-economic and climatic changes will further impact freshwater resources. The quantification of the impacts is challenging due to the complexity of interdependencies between physical and socio-economic systems. This study demonstrates a vulnerability based assessment of global freshwater availability through a conceptual framework, considering transient hydro-climatic impacts of crossing specific warming levels (1.5 °C, 2 °C and 4 °C) and related socio-economic developments under high-end climate change (RCP8.5). We use high resolution climate scenarios and a global land surface model to develop indicators of exposure for 25,000 watersheds. We also exploit spatially explicit datasets to describe a range of adaptation options through sensitivity and adaptive capacity indicators according to the Shared Socioeconomic Pathways (SSPs). The combined dynamics of climate and socio-economic changes suggest that although there is important potential for adaptation to reduce freshwater vulnerability, climate change risks cannot be totally and uniformly eliminated. In many regions, socio-economic developments will have greater impact on water availability compared to climate induced changes. The number of people under increased freshwater vulnerability varies substantially depending on the level of global warming and the degree of socio-economic developments, from almost 1 billion people at 4 °C and SSP5 to almost 3 billion people at 4 °C and SSP3. Generally, it is concluded that larger adaptation efforts are required to address the risks associated with higher levels of warming of 4 °C compared to the lower levels of 1.5 °C or 2 °C. The watershed scale and country level aggregated results of this study can provide a valuable resource for decision makers to plan for climate change adaptation and mitigation actions. Highlights • Substantial impacts are avoided at 1.5 °C and 2 °C compared to 4 °C-SSP3. • New projections suggest reduced water stress for northern regions. • The opposite is foreseen for subtropical regions but with large range of responses. • Socioeconomic changes may have greater impact on water availability than climatic. • Larger adaptation efforts are required to address higher end climate change. [ABSTRACT FROM AUTHOR]

Heatwaves have significant adverse effects on human health. The frequency, duration, and intensity of heatwaves are projected to increase dramatically, in the context of global warming. However, there are few comprehensive assessments of the health impact of heatwaves considering different definitions, and their characteristics under climate change scenarios. We aimed to compare future excess mortality related to heatwaves among different definitions under climate change, population, and adaptation scenarios in China and further explore the mortality burden associated with heatwave characteristics. Daily data during 2010–2019 were collected in Guangzhou, China. We adopted nine common heatwave definitions and applied quasi-Poisson models to estimate the effects of heatwaves and their characteristics' impact on mortality. We then projected the excess mortality associated with heatwaves and their characteristics concerning climate change, population, and adaptation scenarios. The relative risks of the nine common heatwave definitions ranged from 1.05 (95% CI: 1.01, 1.10) to 1.24 (95% CI: 1.13, 1.35). Heatwave-related excess mortality will consistently increase in the future decades considering multiple heatwave definitions, with more rapidly increasing rates under the Shared Socioeconomic Path5-8.5 and non-adaptability scenarios. Regarding heatwave characteristics, the intensity is the main factor involved in the threat of heatwaves. The increasing trend of characteristic-related mortality burden is similar to that of heatwaves, and the mortality burden caused by the duration of the heatwaves was the largest among all characteristics. This study provides a comprehensive picture of the impact of heatwaves and their characteristics on public health under various climate change scenarios, population changes, and adaptive assumptions. The results may provide important public health implications for policymakers in planning climate change adaptation and mitigation policies, and implementing specific plans. [ABSTRACT FROM AUTHOR]

Studies of global environmental change make extensive use of scenarios to explore how the future can evolve under a consistent set of assumptions. The recently developed Shared Socioeconomic Pathways (SSPs) create a framework for the study of climate-related scenario outcomes. Their five narratives span a wide range of worlds that vary in their challenges for climate change mitigation and adaptation. Here we provide background on the quantification that has been selected to serve as the reference, or ‘marker’, implementation for SSP2. The SSP2 narrative describes a middle-of-the-road development in the mitigation and adaptation challenges space. We explain how the narrative has been translated into quantitative assumptions in the IIASA Integrated Assessment Modelling Framework . We show that our SSP2 marker implementation occupies a central position for key metrics along the mitigation and adaptation challenge dimensions. For many dimensions the SSP2 marker implementation also reflects an extension of the historical experience, particularly in terms of carbon and energy intensity improvements in its baseline. This leads to a steady emissions increase over the 21st century, with projected end-of-century warming nearing 4 °C relative to preindustrial levels. On the other hand, SSP2 also shows that global-mean temperature increase can be limited to below 2 °C, pending stringent climate policies throughout the world. The added value of the SSP2 marker implementation for the wider scientific community is that it can serve as a starting point to further explore integrated solutions for achieving multiple societal objectives in light of the climate adaptation and mitigation challenges that society could face over the 21st century. [ABSTRACT FROM AUTHOR]

Policy makers and citizens must choose from among a growing variety of strategic options as they try to cope optimally with climate change. As a means of more accurately predicting different types of climate change engagement, we empirically distinguish individuals’ felt responsibility for mitigation (FRm) from felt responsibility for adaptation (FRa), and assess support for different climate action strategies (mitigation and adaptation). We surveyed two U.S. samples two months apart, and the replication study confirmed Study 1′s findings of differing predictive powers for FRm vs. FRa. Each type of felt responsibility, controlling for the other, served as a mediator between belief in global warming (as well as belief in anthropogenic cause of climate change) and its corresponding climate action strategy (mitigation vs. adaptation). FRa predicted adaptation measures but not mitigation measures, while FRm predicted mitigation measures more strongly than it predicted adaptation but did predict both action strategies. We also found important individual differences: people’s disposition toward behaving proactively correlated positively with all types of climate engagement, and political orientation (liberal/conservative ideology) interacted with climate action strategy (mitigation vs. adaptation) in predicting all engagement variables. Comparing levels of support across the political spectrum, the mitigation measures were highly polarizing, while the adaptation measures were less divisive. [ABSTRACT FROM AUTHOR]

• A new definition of 'climate change transformation' and an accompanying typology is presented. • Climate change transformation is defined to include: 1) the explicit coordination of adaptation and mitigation actions. • 2) a new regime of 1.5 degrees Celsius (only) of warming by 2100. • 3) sufficient actions to be well adapted to this new regime. • The definition and typology aim to guide climate change decision making in the built environment. Climate change presents a threat to the sustainability of cities and their societies, and must be adequately addressed. Urban environments (cities) are responsible for the creation of a significant amount of greenhouse gas emissions which are the source of climate change. Cities have been increasingly the focus of action to address climate change, yet emissions are not significantly reducing. Additionally, there a lack of integration between adaptation and mitigation. This prevents responses adequate to limit global warming to 1.5OC, and to be well adapted to anticipated changes. This paper critically analyses existing definitions and typologies of climate change actions. A definition of 'climate change transformation' is proposed which includes the integration of adaptation and mitigation goals to enable a new regime in which global warming is limited to 1.5OC. A new three-part typology: 'coping, malaction and transformation,' is presented for categorising climate change actions by the extent to which they integrate adaptation and mitigation, and define a new regime. The typology is accompanied by illustrations to demonstrate the relationship between adaptation and mitigation. The definition, typology and illustration serve to guide effective climate change decision making, and provides principles to guide application in urban environments. [ABSTRACT FROM AUTHOR]