Explore the vast range of titles available.

Increasing evidence suggests that climate change impacts are already observed around the world. Global environmental assessments face challenges to appraise the growing literature. Here we use the language model BERT to identify and classify studies on observed climate impacts, producing a comprehensive machine-learning-assisted evidence map. We estimate that 102,160 (64,958–164,274) publications document a broad range of observed impacts. By combining our spatially resolved database with grid-cell-level human-attributable changes in temperature and precipitation, we infer that attributable anthropogenic impacts may be occurring across 80% of the world’s land area, where 85% of the population reside. Our results reveal a substantial ‘attribution gap’ as robust levels of evidence for potentially attributable impacts are twice as prevalent in high-income than in low-income countries. While gaps remain on confidently attributabing climate impacts at the regional and sectoral level, this database illustrates the potential current impact of anthropogenic climate change across the globe.Evidence is growing on the impacts of climate change on human and natural systems. A two-step attribution approach—machine-learning-assisted literature review coupled with grid-cell-level temperature and precipitation—allows comprehensive mapping of the evidence on impacts and tentative attribution to anthropogenic influence.

Constraints and limits to adaptation are critical to understanding the extent to which human and natural systems can successfully adapt to climate change. We conduct a systematic review of 1,682 academic studies on human adaptation responses to identify patterns in constraints and limits to adaptation for different regions, sectors, hazards, adaptation response types, and actors. Using definitions of constraints and limits provided by the Intergovernmental Panel on Climate Change (IPCC), we find that most literature identifies constraints to adaptation but that there is limited literature focused on limits to adaptation. Central and South America and Small Islands generally report greater constraints and both hard and soft limits to adaptation. Technological, infrastructural, and ecosystem-based adaptation suggest more evidence of constraints and hard limits than other types of responses. Individuals and households face economic and socio-cultural constraints which also inhibit behavioral adaptation responses and may lead to limits. Finance, governance, institutional, and policy constraints are most prevalent globally. These findings provide early signposts for boundaries of human adaptation and are of high relevance for guiding proactive adaptation financing and governance from local to global scales.

Climate change adaptation is paramount, but increasing evidence suggests that adaptation action is subject to a range of constraints. For a realistic assessment of future adaptation prospects, it is crucial to understand the timescales needed to overcome these constraints. Here, we combine data on documented adaptation from the Global Adaptation Mapping Initiative with national macro indicators and assess future changes in adaptation constraints alongside the Shared Socioeconomic Pathways, spanning a wide range of future socio-economic development scenarios. We find that even in the most optimistic scenario, it will take until well after 2050 to overcome key constraints, which will limit adaptation for decades to come particularly in vulnerable countries. The persistence of adaptation constraints calls for stringent mitigation, improved adaptation along with dedicated finance and increasing efforts to address loss and damage. Our approach allows to ground truth indicators that can be further used in climate modelling efforts, improving the representation of adaptation and its risk reduction potential.

Small island developing states are currently faced with two significant challenges that are more onerous due to limited financial resources: adapting to increasing climate change risk and recovering from the pandemic. Debt-for-climate swaps provide an avenue for SIDS to address these challenges.

Global emission reduction efforts continue to be insufficient to meet the temperature goal of the Paris Agreement 1 . This makes the systematic exploration of so-called overshoot pathways that temporarily exceed a targeted global warming limit before drawing temperatures back down to safer levels a priority for science and policy 2 – 5 . Here we show that global and regional climate change and associated risks after an overshoot are different from a world that avoids it. We find that achieving declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including for sea-level rise and cryosphere changes. However, the possibility that global warming could be reversed many decades into the future might be of limited relevance for adaptation planning today. Temperature reversal could be undercut by strong Earth-system feedbacks resulting in high near-term and continuous long-term warming 6 , 7 . To hedge and protect against high-risk outcomes, we identify the geophysical need for a preventive carbon dioxide removal capacity of several hundred gigatonnes. Yet, technical, economic and sustainability considerations may limit the realization of carbon dioxide removal deployment at such scales 8 , 9 . Therefore, we cannot be confident that temperature decline after overshoot is achievable within the timescales expected today. Only rapid near-term emission reductions are effective in reducing climate risks. Aiming for declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including sea-level rise and cryosphere changes.

Climate change adaptation needs, as well as the capacity to adapt, are unequally distributed around the world. Global models that assess the impacts of climate change and policy options to reduce them most often do not elaborately represent adaptation. When they do, they rarely account for heterogeneity in societies’ adaptive capacities and their temporal dynamics. Here we propose ways to quantify adaptive capacity within the framework of Shared Socioeconomic Pathways, a scenario set widely used by climate impact and integrated assessment models. A large set of indicators spanning different socioeconomic dimensions can be used to assess adaptive capacity and deliver adaptation-relevant, scenario-resolved information that is crucial for more realistic assessment of whether and how climate risks can be reduced by adaptation.Most models of global climate change impacts and policy do not consider adaptation or societies’ ability to adapt. Here the authors propose a way to better integrate adaptation in such models using the Shared Socioeconomic Pathway scenario framework to quantify adaptive capacity via a suite of socioeconomic indicators.

Does climate change influence if societies will be better or worse equipped to reduce climatic risks in the future? A society’s adaptive capacity determines whether the potential of adaptation to reduce risks will be realized. Assumptions about the level of adaptive capacity are inherently made when the potential for adaptation to reduce risks in the future and resultant levels of risk are estimated. In this review, we look at the literature on human impacts of climate change through the lens of adaptive capacity. Building on evidence of impacts on financial resources as presented in the Working Group 2 (WG2) report of the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), we here present the methodology behind this review and complement it with an analysis of climatic risks to human resources. Based on our review, we argue that climate change itself adds to adaptation constraints and limits. We show that for more realistic assessments of sectoral climate risks, assumed levels of future adaptive capacity should — and can — be usefully constrained in assessments that rely on expert judgment, and propose avenues for doing so.

Escalating 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 CO 2 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. Providing actionable climate information requires an end-user focused approach that links specific local climate risk thresholds with global emissions pathways.