Climate change is an issue that has targeted, and continues to target, the tolerance limits of many organisms. Efforts by international institutions in the form of conventions primarily serve as a serious warning against destructive human activities and, secondly, as an attempt to address their consequences, including the Paris Agreement and recent decisions under the Convention on Biological Diversity (CBD), which place particular emphasis on marine ecosystem protection, ocean resilience, and the expansion of marine protected areas. In this context, a substantial part of these strategies depends not on policy alone, but on advances in fundamental scientific knowledge. Understanding the structure of biodiversity, evolutionary processes, and ecological dynamics is essential for designing conservation strategies that are both effective and sustainable in the long term.

The expertise of an evolutionary biologist is mainly defined at the level of individuals and species. By examining species origins, genetic structure, and the capacity of organisms to respond to environmental stimuli, evolutionary biologists can provide key baseline information for species conservation. However, an effective framework for species protection requires identifying safe and reliable environments that can support survival and persistence. Such information emerges from an ecological perspective at a broader scale and can move conservation strategies one step closer to practical implementation. Identifying threatened environments or suitable habitats is a crucial component of conservation, yet it has often been addressed at local scales.

For long-term and effective planning, conservation efforts must acknowledge that ecosystems, although seemingly discrete, are interconnected through complex ecological networks. The stability of biodiversity depends on this connectivity and overall ecological integrity. Consequently, large-scale ecological studies are essential for making conservation strategies more realistic, integrative, and actionable.

A study recently published in Nature Communications provides a strong example of this approach. In this study, Zhuang et al. identified and mapped climate refugia for marine organisms by considering the high-emission scenarios (SSP5-8.5) by 2100. They integrated marine species distribution, phylogenetic information, and climate projections to locate future marine climate refugia for biodiversity.

Figure 1 shows a global ocean map with 36% shaded red as ‘sensitive zones‘ which are the areas facing extreme changes in temperature, pH, oxygen, and currents by 2100 (per CMIP6 models). Equatorial upwelling zones and polar shelves light up brightest, flagging high risk for coral reefs and kelp forests. In contrast, 34% stays blue as ‘stability zones‘ with minimal shifts, often in deeper waters.

Fig2 (fig3a in the paper) maps marine climate refugia (MCR) as green zones where stable areas overlap ‘conservation consensus areas’ (CCAs), spots prioritized by global plans for biodiversity hotspots, fish migration routes, and vital habitats. These green MCR total 17.6 million km², with 96% inside exclusive economic zones (EEZs) of 105 countries. Of the 340 identified refugial patches, 20 large clusters account for 85% of the total area, primarily near Indonesia, French Polynesia, Hawaii, and the Philippines.

Fig3 (fig4 in the paper) overlays existing marine protected areas (MPAs) and other effective area-based conservation measures (OECMs) onto the mapped MCRs, revealing substantial protection gaps. Only 14–29% of MPAs and OECMs currently overlap with climate refugia, leaving nearly 70% of the critical areas unprotected under high-emission climate projections. At present, 99 EEZs exhibit conservation gaps exceeding 160,000 km².
These findings underscore the importance of integrating large-scale ecological perspectives into marine conservation planning. In particular, they highlight how the identification of climate refugia can inform the spatial prioritization of marine protected areas, including those that extend across national boundaries, in support of long-term biodiversity conservation goals.

Reference
Zhuang, H., Zhao, L., Wang, Z. et al. Identifying global marine climate refugia through a conservative approach to ocean biodiversity preservation. Nat Commun 16, 10752 (2025). https://doi.org/10.1038/s41467-025-65791-z