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Species respond to climate change with range and abundance dynamics. To better explain and predict them, we need a mechanistic understanding of how the underlying demographic processes are shaped by climatic conditions. Here, we aim to infer demography–climate relationships from distribution and abundance data. For this, we developed spatially explicit, process-based models for eight Swiss breeding bird populations. These jointly consider dispersal, population dynamics and the climate-dependence of three demographic processes—juvenile survival, adult survival and fecundity. The models were calibrated to 267 nationwide abundance time series in a Bayesian framework. The fitted models showed moderate to excellent goodness-of-fit and discriminatory power. The most influential climatic predictors for population performance were the mean breeding-season temperature and the total winter precipitation. Contemporary climate change benefitted the population trends of typical mountain birds leading to lower population losses or even slight increases, whereas lowland birds were adversely affected. Our results emphasize that generic process-based models embedded in a robust statistical framework can improve our predictions of range dynamics and may allow disentangling of the underlying processes. For future research, we advocate a stronger integration of experimental and empirical studies in order to gain more precise insights into the mechanisms by which climate affects populations. This article is part of the theme issue 'Detecting and attributing the causes of biodiversity change: needs, gaps and solutions'. [ABSTRACT FROM AUTHOR]

Populations around the world have already experienced the increasing severity of extreme weather causing disaster displacement. Anthropogenic climate change can intensify these impacts. Extreme event attribution studies center around the question of whether impactful extreme events could have occurred in a pre-industrial climate. Here, we argue that the next step for attribution science is to focus on those most vulnerable populations to future extremes and impacts from climate change. Up until now, the vulnerability dimension has not been systematically addressed in attribution studies, yet it would add urgently needed context, given the vast differences in adaptive capacity. We propose three integrative points to cascade disaster displacement linked to anthropogenic climate change. [ABSTRACT FROM AUTHOR]

The phenomenon of ‘climate change litigation’ has come to the fore in recent years as campaigners and activists have become increasingly frustrated at a perceived lack of action on the part of the international community and individual states in terms of getting to grips with the climate change problem. Existing legal mechanisms available to private parties and other bodies, such as non-governmental organizations (NGOs) have been used as a means of endeavouring to hold governments and polluters to account for the effects of climate change. The physical impact of climate change on life and property has been thrown into sharp relief by floods and wildfires in all parts of the globe. One aspect of climate change litigation focuses on the role that tort might play in attempting to secure compensation for at least part of such losses. No one would pretend that actions of this nature can actually solve the problem, but they may serve to shame polluters and so forth by establishing an actual link between their activities and the tangible consequences of climate change. However, such actions raise formidable causation difficulties which have, until recently, rendered such claims outlandish and highly speculative. Nevertheless, developments in extreme weather event attribution may be about to reduce the conceptual and theoretical barriers to bringing such claims. In this article it is argued that, from a UK perspective, existing causality tests may be capable of accommodating such evidence, although, one must be aware of countervailing policy considerations which may inhibit the courts from adopting such an approach.

The question whether a single extreme climate event, such as a hurricane or heatwave, can be attributed to human induced climate change has become a vibrant field of research and discussion in recent years. Proponents of the most common approach (probabilistic event attribution) argue for using single event attribution for advancing climate policy, not least in the context of loss and damages, while critics are raising concerns about inductive risks which may result in misguided policies. Here, we present six ethical predicaments, rooted in epistemic choices of single event attribution for policy making, with a focus on problems related to loss and damage. Our results show that probabilistic event attribution is particularly sensitive to these predicaments, rendering the choice of method value laden and hence political. Our review shows how the putatively apolitical approach becomes political and deeply problematic from a climate justice perspective. We also suggest that extreme event attribution (EEA) is becoming more and more irrelevant for projecting loss and damages as socio‐ecological systems are increasingly destabilized by climate change. We conclude by suggesting a more causality driven approach for understanding loss and damage, that is, less prone to the ethical predicaments of EEA. Plain Language Summary: When climate change induced extremes hit society, there is often a call for responsibility—who is to blame, or even liability—who should pay for the loss and damage. Loss and damage is the most controversial part of the global climate change policy regime, and particularly so questions about liability. Extreme event attribution (EEA) using frequentist statistics, that is, determining what (and ultimately perhaps even who) was the cause of the damage from an extreme event, has received much attention lately as a putatively objective scientific approach. We argue however, that methodological choices can render EEA highly value laden and political. We describe six such situation where frequentist statistics may cause ethical predicaments. Instead we propose a more causality driven approach (Comparative Risk Assessment) for advancing our understanding of causality between climate change and loss and damage. Key Points: Methodological choices for extreme event attribution (EEA), particularly frequentist statistics, render climate science political and value ladenIncreasing instability of socio‐ecological systems is rendering EEA less relevant for understanding loss and damageWe propose a causality driven approach for assessing loss and damage, less prone to ethical predicaments than statistics driven approaches [ABSTRACT FROM AUTHOR]

Abstract The question whether a single extreme climate event, such as a hurricane or heatwave, can be attributed to human induced climate change has become a vibrant field of research and discussion in recent years. Proponents of the most common approach (probabilistic event attribution) argue for using single event attribution for advancing climate policy, not least in the context of loss and damages, while critics are raising concerns about inductive risks which may result in misguided policies. Here, we present six ethical predicaments, rooted in epistemic choices of single event attribution for policy making, with a focus on problems related to loss and damage. Our results show that probabilistic event attribution is particularly sensitive to these predicaments, rendering the choice of method value laden and hence political. Our review shows how the putatively apolitical approach becomes political and deeply problematic from a climate justice perspective. We also suggest that extreme event attribution (EEA) is becoming more and more irrelevant for projecting loss and damages as socio‐ecological systems are increasingly destabilized by climate change. We conclude by suggesting a more causality driven approach for understanding loss and damage, that is, less prone to the ethical predicaments of EEA.

This article discusses the implications of recent developments in climate science for the efforts of Pacific Island States to avert, minimize and address loss and damage from climate change through international law. It discusses these implications in connection with three areas of international law pertaining to loss and damage: averting the threat of existential losses; minimizing loss and damage through adaptation and climate resilience; and addressing loss and damage through reparations for victims. As the article demonstrates, evolving climate science highlights the need for urgent action in each of these areas while providing fresh insight into the specific requirements for compliance with States’ international obligations related to such action. It examines how these obligations can be met through the established mechanisms of the international climate regime, including the Warsaw International Mechanism on Loss and Damage associated with Climate Change Impacts. Further, it explores how, and to what extent, evolving climate science may bolster the evidentiary basis of climate cases seeking to hold States to account for failing to meet these obligations. [ABSTRACT FROM AUTHOR]

• Development of the nonstationary stochastic paired watershed approach. • Detecting, attributing, and quantifying forest harvest effects on floods. • Forest harvesting affects small and large flood events at large watershed scales. • Probabilistic physics reveals high sensitivity of floods to forest disturbance. • Using probabilistic physics to evaluate the environmental controls on floods. Drawing on advances in nonstationary frequency analysis and the science of causation and attribution, this study employs a newly developed nonstationary stochastic paired watershed approach to determine the effect of forest harvesting on snowmelt-generated floods. Moreover, this study furthers the application of stochastic physics to evaluate the environmental controls and drivers of flood response. Physically-based climate and time-varying harvesting data are used as covariates to drive the nonstationary flood frequency distribution parameters to detect, attribute, and quantify the effect of harvesting on floods in the snow-dominated Deadman River (878 km2) and nested Joe Ross Creek (99 km2) watersheds. Harvesting only 21% of the watershed caused a 38% and 84% increase in the mean but no increase in variability around the mean of the frequency distribution in the Deadman River and Joe Ross Creek, respectively. Consequently, the 7-year, 20-year, 50-year, and 100-year flood events became approximately two, four, six, and ten times more frequent in both watersheds. An increase in the mean is posited to occur from an increase in moisture availability following harvest from suppressed snow interception and increased net radiation reaching the snowpack. Variability was not increased because snowmelt synchronization was inhibited by the buffering capacity of abundant lakes, evenly distributed aspects, and widespread spatial distribution of cutblocks in the watersheds, preventing any potential for harvesting to increase the efficiency of runoff delivery to the outlet. Consistent with similar recent studies, the effect of logging on floods is controlled not only by the harvest rate but most importantly the physiographic characteristics of the watershed and the spatial distribution of the cutblocks. Imposed by the probabilistic framework to understanding and predicting the relation between extremes and their environmental controls, commonly used in the general sciences but not forest hydrology, it is the inherent nature of snowmelt-driven flood regimes which cause even modest increases in magnitude, especially in the upper tail of the distribution, to translate into surprisingly large changes in frequency. Contrary to conventional wisdom, harvesting influenced small, medium, and very large flood events, and the sensitivity to harvest increased with increasing flood event size and watershed area. [ABSTRACT FROM AUTHOR]

Anthropogenic forcing of the climate is estimated to have increased the likelihood of the 2015–2017 Western Cape drought, also called ‘Day Zero’ drought, by a factor of three, with a projected additional threefold increase of risk in a world with 2 °C warming. Here, we assess the potential for geoengineering using stratospheric aerosols injection (SAI) to offset the risk of ‘Day Zero’ level droughts in a high emission future climate using climate model simulations from the Stratospheric Aerosol Geoengineering Large Ensemble Project. Our findings suggest that keeping the global mean temperature at 2020 levels through SAI would offset the projected end century risk of ‘Day Zero’ level droughts by approximately 90%, keeping the risk of such droughts similar to today’s level. Precipitation is maintained at present-day levels in the simulations analysed here, because SAI (i) keeps westerlies near the South Western Cape in the future, as in the present-day, and (ii) induces the reduction or reversal of the upward trend in southern annular mode. These results are, however, specific to the SAI design considered here because using different model, different SAI deployment experiments, or analysing a different location might lead to different conclusions.

The 2017 North Atlantic hurricane season caused the highest disaster-related losses ever seen in the United States, with many people asking questions about the causes and liabilities for the impacts of these kinds of events. As climate-related loss and damage mount, there is growing interest in the role of law in dealing with the complex and multi-scalar problem of climate change. This article builds on a shorter piece entitled ‘Acts of God, human influence and litigation’ published by the authors in Nature Geoscience in August 2017. It is an interdisciplinary and cross-jurisdictional analysis of the emerging science of extreme weather event attribution (which analyses the human impact on extreme weather events), and the implications this new science may have for the law, litigation and the scope of the duty of care of a range of actors. We suggest that the science of event attribution may become a driver of litigation, as it shifts understanding of what weather is expected and, relevantly for law, foreseeable. This may have an impact on the duties of government actors as well as private parties. We explain the discipline of event attribution science to lawyers, discuss some technical issues related to the use of this evidence in court and make some suggestions regarding the types of ‘climate change’ cases it may influence. We conclude that the first kind of litigation to emerge is most likely to arise from failures to adapt to, or to prepare for, our changing climate. [ABSTRACT FROM AUTHOR]