Climate change, while a global phenomenon, manifests differently across regions and impacts biophysical and sociocultural systems based on local conditions. Modeling suggests varied temperature increases and rainfall patterns globally, disproportionately affecting nature-dependent communities. Furthermore, diverse cultural frameworks influence how climate change is perceived and experienced. Current research faces challenges in providing a global picture. Instrument-based measurements, crucial for understanding global climate change impacts, lack the detail of local experiences, especially in areas with sparse data like those inhabited by Indigenous Peoples and local communities. Models often focus on a few variables, neglecting locally significant crops or phenomena. Conversely, existing research using Indigenous and local knowledge emphasizes unique impacts but lacks global comparability, hindering the identification of general trends. This study addresses these limitations by using a place-specific but cross-culturally comparable protocol to gather data from 48 Indigenous Peoples and local communities across all inhabited continents, encompassing diverse climate zones and livelihoods. The goal is to provide globally comparable information on climate change impacts as experienced by these communities, informing adaptation strategies and identifying loss and damage.

The existing literature highlights the challenges in comprehensively understanding the global impacts of climate change. While instrumental measurements provide crucial data on global climate patterns, they often lack the resolution and context to capture the nuances of local experiences, particularly in areas with sparse data. Studies focusing on Indigenous and local knowledge offer valuable insights into locally specific impacts, but often lack the standardization and comparability necessary for global-scale analysis. The IPCC's call for integrating local knowledge into climate change research has led to an increase in studies examining Indigenous and local knowledge systems. However, these studies often lack a common methodological framework, making it difficult to identify broader trends and patterns. This study builds upon this existing literature by employing a standardized protocol to collect and analyze data from a large, globally distributed sample, thereby bridging the gap between local knowledge and global climate change research.

This research utilized a place-specific yet cross-culturally comparable protocol to document climate change indicators and impacts as perceived by Indigenous Peoples and local communities. Data were collected in 48 sites across all inhabited continents between 2019 and 2022, selected to maximize variability in climate zones and livelihood types (agropastoralism, agriculture, fishing, pastoralism, and other nature-dependent livelihoods). Semi-structured interviews were conducted with 15-25 key informants in each site to document changes observed over decades, focusing on elements of the atmospheric system (indicators) and their impacts on the physical and life systems. Interviews explored perceived drivers of change. Focus groups were used to resolve discrepancies or unclear information. Observations were classified into locally agreed-upon indicators of climate change and impacts (LICCIs), organized hierarchically by system (atmospheric, physical, life), subsystem, impacted element, and indicator. Only indicators agreed upon in focus groups were included in the analysis. Sites were categorized by Köppen-Geiger climate classification and decadal temperature change using IPCC data. Statistical analyses, including Poisson general linear models and non-parametric multivariate analysis of variance (NPMANOVA), were used to assess differences in the distribution of LICCIs across climate zones, temperature changes, and livelihood activities. The Bray-Curtis dissimilarity index was used to analyze LICCI composition. Ethical considerations included obtaining permits from local authorities and Free Prior Informed Consent from all participants, with approval from relevant ethics committees.

The study documented 1,661 site-agreed observations of climate change and its impacts, categorized into 369 LICCIs (94 indicators of climate change, 275 indicators of climate change impacts). Changes in atmospheric elements were most frequently cited (46.4%), particularly precipitation (20.4%) and temperature (13%). Impacts on the physical system were least frequent (19.6%), with changes in freshwater being most common. Impacts on the life system comprised 33.9%, with changes in plant cultivation and terrestrial flora most prominent. The most frequently reported indicators of climate change included changes in mean temperature and seasonal temperature. The most common indicators of climate change impacts included changes in crop productivity and changes in abundance of wild plants and fungi. While the classification masks nuanced observations, it allows for global-scale analysis. The number of LICCIs per site varied significantly. Analysis revealed that the average number of LICCIs related to freshwater was significantly higher in tropical climates compared to snow/polar climates. In arid and snow/polar climates, the average number of LICCIs related to impacts on pastures and grasslands was higher than in tropical climates, while plant cultivation impacts were lower than in temperate climates. Impacts on ice and snow were higher in snow/polar and temperate climates. Analyses comparing LICCI distribution across livelihood activities showed that precipitation changes and freshwater impacts were more frequent in agriculture-dominant sites, while air mass changes and marine ecosystem impacts were more common in fishing-dominant sites. Pastoralist sites reported more impacts on pastures and grasslands. Finally, multivariate analysis demonstrated a significant association between LICCI composition and climate zone and livelihood activity, but not decadal temperature change.

The findings strongly support the observation that Indigenous Peoples and local communities are experiencing tangible and widespread climate change impacts. The detailed and nuanced nature of the reported changes highlights the value of locally grounded research in capturing the complexity of climate change effects on social-ecological systems. The study reveals that the distribution of reported changes is heavily influenced by both the climate zone and the predominant livelihood activity of the community. These findings underscore the importance of considering both biophysical and sociocultural factors when developing climate adaptation strategies. The diverse range of observed impacts also emphasizes the need to move beyond a narrow focus on a few key variables and to incorporate a broader understanding of the complex interrelationships between climate change and social-ecological systems. The research acknowledges limitations such as the challenge of definitively attributing all observed impacts to climate change due to the interplay of multiple environmental drivers and the potential for biases in translating local knowledge into scientific categories.

This global study provides compelling evidence of ongoing, widespread, and tangible climate change impacts on Indigenous Peoples and local communities. The findings highlight the crucial role of local knowledge in understanding the diverse manifestations of climate change and its effects on social-ecological systems. The observed patterns in the distribution of reported changes, influenced by both climate zone and livelihood activity, underscore the need for locally tailored adaptation strategies. This research offers a methodology for identifying and comparing climate change impacts across cultures, potentially informing discussions on loss and damage and contributing to more just and equitable climate action. Future research could explore the economic and non-economic valuations of these impacts, further strengthening the link between local observations and global climate policy.

The study acknowledges several limitations. First, it is difficult to definitively attribute all observed impacts solely to climate change, as other factors like land-use change may play a role. Second, the sample of sites, while large for this type of study, is geographically biased and may not fully represent the global diversity of Indigenous and local communities. Third, the classification of observations into LICCIs, while aiming for cross-cultural comparability, may involve some loss of nuance in the translation of local knowledge into a standardized framework. Despite these limitations, the study provides valuable insights into the widespread impacts of climate change on Indigenous Peoples and local communities and offers a robust methodology for future research.