Paleoecology Perspectives for Planetary Health

Global environmental change, driven largely by human activities, is intensifying at an unprecedented rate. This so-called “great acceleration” has profoundly altered the structure and functioning of Earth's natural systems (Steffen et al. 2015). Humanity is leaving behind the relative stability of the Holocene epoch and entering into a new era of uncertainty. A growing body of scientific evidence suggests that the speed and scale of ecological transformations profoundly impact the health of humans and the health of ecosystems on which humans depend (Myers et al. 2013). The complexity and scope of these changes necessitate insights from a wide range of scientific disciplines. The field of planetary health has emerged as a focal point for leveraging interdisciplinary perspectives with a common goal of better understanding the intrinsic connections between the health of ecosystems and human populations on a changing planet (Whitmee et al. 2015).

A key feature of the planetary health framework is the concept of “planetary boundaries,” which represent a set of nine critical thresholds in Earth's biophysical systems, including climate change, biodiversity loss, and land-system change (Rockström et al. 2009). A “safe operating space” is delineated within each boundary, representing a range in which human activities may occur without significantly disrupting the critical planetary systems needed to ensure a sustainable future for humanity. Anthropogenic activities are pushing Earth's systems beyond these ecological thresholds, with a majority of boundaries having already been transgressed (Richardson et al. 2023). For instance, more than 10% of plant and animal genetic diversity has been lost over the past century, which significantly exceeds the boundary set for biosphere integrity (Exposito-Alonso et al. 2022).

Defining planetary boundaries, now and in the future, requires a comprehensive accounting of when (i.e., temporal scales) and where (i.e., spatial scales) environmental changes occur. In their recent paper in Global Change Biology, Gillson et al. (2025) address the need for high-quality data derived from a range of spatial and temporal scales. The authors propose integrating insights from the field of paleoecology to better assess the complexity of environmental changes at different timeframes and geographies. Paleoecology, the study of past ecosystems and environmental conditions, may be particularly useful for contributing data from long-term ecological trends. By examining Earth's historical records and collecting data on how ecosystems responded to past environmental changes, paleoecological perspectives may be particularly useful for refining the planetary boundaries framework.

Gillson et al. (2025) discuss the utility of integrating paleoecological methods with some of the core concepts of the planetary boundaries framework. To properly assess the impacts of ecosystem changes, relevant baseline ecological states must be established (Bayles et al. 2016). Paleoecology reveals how Earth's systems operated before human influence, offering baseline data for pre-industrial conditions. The authors consider integrating long-term historical data on Holocene-like conditions as a baseline reference for defining the parameters of “a safe operating space.” They also reference the need to reconstruct historical boundaries and identify natural thresholds with quantitative methods (e.g., change-point statistics, time-series analysis). For example, using ice core records to quantify historical CO₂ levels and climate stability to define climate change boundaries. Integrating long-term data and assessing temporal variation reveal events like past mass extinctions and serve to illustrate the Earth system consequences of crossing tipping point thresholds.

Social and ecological factors driving change operate as complex systems at different spatial (e.g., local, regional, and global) and temporal (e.g., seasons, decades, and millennia) scales. Gillson et al. (2025) discuss the important implications of scaling in the planetary boundaries framework. Local, regional, and global environmental processes often interact across time scales, resulting in nested feedback loops (Liu et al. 2015). The integration of long-term paleoecological data is needed to bridge these scales and reveal the impact of processes interacting across space and time. For example, utilizing climate data at different spatial and temporal scales may be used to quantify the varying impacts of climate change in different regions. This ensures interventions are appropriately scaled, equitable, and forward-looking, fostering resilience in Earth's systems while supporting sustainable development for current and future generations.

Gillson et al. (2025) further demonstrate the integration of paleoecological data and planetary boundaries across three socioeconomically and biophysically distinct areas. The Western Cape of South Africa, Taihu Lake, China, and the Murray–Darling Basin, Australia, all face changes associated with pollution, biodiversity loss, and climate change. Paleoecology distinguishes between historical variability and anthropogenic impacts on ecosystem processes, showing how human activities amplify risks compared to natural processes. Uncovering the drivers and consequences of environmental changes may also be useful for guiding adaptations designed to mitigate the potential impacts of uncertain future environmental conditions.

The planetary boundaries framework provides the ecological constraints for sustainable and equitable development, as outlined by the sustainable development goals (Randers et al. 2019). This highlights the importance of a “safe and just operating space” where humanity can thrive without further degrading the Earth's life-support systems. Paleoecology is a powerful tool for strengthening planetary boundary research, offering a long-term perspective on Earth's systems and their responses to change. By identifying past thresholds, consequences, and recovery processes, paleoecology helps to further refine planetary boundaries, predict future risks, and guide sustainable management strategies. Gillson et al. (2025) offer a compelling discussion centered on the premise that integrating high-quality historical knowledge strengthens our ability to maintain a “safe operating space” for humanity.

Brett R. Bayles: conceptualization, writing – original draft, writing – review and editing.

The author declares no conflicts of interest.

This article is a Commentary to the Review by Gillson et al., https://doi.org/10.1111/gcbb.70017.