The world has breached seven of the nine planetary boundaries—“critical processes that regulate stability, resilience, and the conditions that support life on Earth”—states the third edition of “Planetary Health Check”. Authored by nearly 70 scientists, the report released in September 2026 says that four planetary boundaries—climate change; change in biosphere integrity; modification of biogeochemical flows; introduction of novel entities (such as plastic) stand “strongly transgressed”. Three boundaries—land system change, freshwater change and ocean acidification—have been “transgressed”. One boundary, atmospheric aerosol loading, is within the safe operating space globally, but with significant regional transgression. Another boundary, stratospheric ozone depletion, is within the safe operating space. Levke Caesar, a climate scientist at Germany’s Potsdam Institute for Climate Impact Research, who is co-leading the team that has published the annual report since 2024, tells Jayanta Basu about the key findings of the report.
Jayanta Basu (JB): Are there any nation-specific findings in the “Planetary Health Check” report?
Levke Caesar (LC): The report is based on studies linked to the planetary boundaries framework, which is fundamentally a global earth-system framework. Hence, we have to be careful not to simply translate each global boundary into a national number. At the same time, several of the underlying indicators and datasets are spatially explicit, which means that we can look at where pressures are particularly strong and how they vary regionally, including South Asia and India.
JB: Is there a specific area of concern for South Asia?
LC: Yes, one example that is especially relevant for India and South Asia is atmospheric aerosol loading. Aerosols can have particularly important effects on regional climate and the monsoon system.
The study shows that while “atmospheric aerosol loading” remains within the Safe Operating Space at the global level, it has transgressed the proposed regional boundary for South Asia. The new regional assessment shows that the Aerosol Optical Depth (AOD)—a measure of how much airborne particles like dust, smoke and pollution, prevent direct sunlight from reaching the earth’s surface by scattering or absorbing it—is approximately 0.32 in south Asia, exceeding the proposed regional boundary of 0.25. AOD values of 0.3 to 0.7 are indicative of moderate to high concentration, typical of hazy urban conditions or regional pollution.
JB: What about the other boundaries?
LC: There are several other boundaries that are clearly highly relevant in an Indian context, particularly freshwater change…
This interview was originally published in the October 16-31, 2026 print edition of Down To Earth
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