The Land Burns: Heat, Acid Rain, and Atmospheric Collapse

By Cliff Potts, CSO, and Editor-in-Chief of WPS News

Baybay City, Leyte, Philippines — May 26, 2026

When the Permian–Triassic extinction event reached the continents, the outcome was already constrained by what had happened in the seas. With oceans warming, oxygen-poor, and in places toxic, Earth’s atmosphere had become unstable. What followed on land was not a mirror of oceanic collapse, but its consequence.

Life on land did not simply die. It was stripped of the conditions that made survival possible.

A Rapid Rise in Heat

Volcanic gases released during the Siberian Traps eruptions accumulated over long periods. Carbon dioxide drove sustained warming that reshaped continental climates. Temperature increases of several degrees were enough to push many regions beyond the tolerance limits of plants and animals adapted to earlier conditions.

Heat stress affected physiology directly. Large-bodied animals struggled to regulate temperature. Plants lost moisture faster than they could replace it. Seasonal cycles became erratic, undermining reproduction and food availability.

Unlike oceans, land offered some refuges—but far fewer than expected.

Acid Rain and Soil Failure

Sulfur dioxide released during prolonged volcanism combined with atmospheric moisture to form acid rain. This precipitation did not simply damage leaves or bark. It altered soils at a chemical level.

Nutrients leached away. Root systems weakened. Forests that had stabilized ecosystems for millions of years began to thin and then collapse. As plant cover disappeared, erosion increased, further degrading habitats.

Once soils failed, recovery became unlikely even if temperatures stabilized. Land ecosystems depend on soil chemistry as much as climate.

Atmospheric Instability

The atmosphere itself became hostile. In addition to carbon dioxide and sulfur compounds, volcanic activity released halogens and other trace gases. These likely contributed to ozone depletion, increasing ultraviolet radiation at the surface.

Higher UV exposure stresses plants, damages DNA, and reduces photosynthetic efficiency. For animals already weakened by heat and food shortages, this additional pressure proved lethal.

The land was not facing a single threat. It was facing many at once.

Why Distance Did Not Save Anyone

One of the defining features of the Great Dying is that even regions far from volcanic activity experienced collapse. Continents on the opposite side of Pangaea show evidence of forest loss and vertebrate extinction.

This was not because lava reached them. It was because the atmosphere connects the planet. Heat, gases, and precipitation patterns do not respect geography. Once the atmospheric system shifted, no landmass remained isolated.

This explains why extinction on land was nearly global despite localized eruptions.

Survivors in the Margins

As on the oceans, survival favored organisms that were small, adaptable, and tolerant of harsh conditions. Burrowing animals found shelter from heat and radiation. Opportunistic feeders survived where specialists starved.

Large herbivores and apex predators disappeared in disproportionate numbers. Complex food webs collapsed into simpler, temporary systems dominated by generalists.

The land did not empty completely—but it lost its structure.

The End of an Old World

By the height of the extinction, forests had vanished from many regions. River systems changed as vegetation loss altered runoff patterns. What remained was a hotter, harsher planet with limited capacity to support complex life.

The Great Dying on land was not a sudden apocalypse. It was a drawn-out failure of climate, soil, and atmosphere acting together.

The next essay will examine why extinction extended even into regions untouched by lava—and how planetary feedback loops ensured that nowhere remained safe.

For more social commentary, please see Occupy 2.5 at https://Occupy25.com

This essay will be archived as part of the ongoing WPS News Monthly Brief Series available through Amazon.

References

Beerling, D. J., & Berner, R. A. (2002). Biogeochemical constraints on the end-Permian mass extinction. Proceedings of the National Academy of Sciences, 99(7), 4172–4177.
Retallack, G. J. (1995). Permian–Triassic life crisis on land. Science, 267(5194), 77–80.
Self, S., Thordarson, T., & Widdowson, M. (2005). Gas fluxes from flood basalt eruptions. Earth and Planetary Science Letters, 235(1–2), 17–30.

Poisoned Waters: When Earth’s Oceans Turned Toxic

By Cliff Potts, CSO, and Editor-in-Chief of WPS News

Baybay City, Leyte, Philippines — April 28, 2026

By the time the Permian–Triassic extinction event reached its peak, oxygen loss alone no longer explains the scale of destruction. Evidence suggests Earth’s oceans did something worse than suffocate life. In many regions, they became chemically hostile.

The seas did not simply run out of oxygen. They turned toxic.

From Anoxia to Euxinia

As described in the previous essay, warming oceans lost oxygen and circulation slowed. In many basins, this progressed from anoxia (low oxygen) to euxinia—a condition where waters are oxygen-free and saturated with hydrogen sulfide.

Hydrogen sulfide (H₂S) is not a minor pollutant. It is a potent toxin. In modern oceans, it appears only in small, isolated pockets. During the end-Permian, it likely spread across vast areas of the seafloor and, at times, into shallower waters.

This shift marked a qualitative change. The oceans were no longer just uninhabitable. They were lethal.

The Role of Sulfur Bacteria

Euxinic conditions favor sulfur-reducing bacteria. These organisms thrive where oxygen is absent and organic matter is abundant. As they multiply, they produce hydrogen sulfide as a metabolic byproduct.

Once established, this process becomes self-reinforcing:

• Oxygen loss allows sulfur bacteria to expand
• Sulfur bacteria produce toxic gases
• Toxicity prevents the return of oxygen-dependent life

The normal biological checks that keep these microbes in balance collapse. What follows is a microbial takeover of the marine environment.

Evidence in the Geological Record

Geologists identify these toxic conditions through multiple independent signals:

• Black shale layers, formed under oxygen-free conditions
• Sulfur isotope anomalies consistent with widespread sulfide production
• Trace metal concentrations that indicate stagnant, poisoned waters

These markers appear across multiple continents, showing that toxic seas were not localized accidents. They were a global state.

When the Sea Poisoned the Sky

One of the more disturbing hypotheses is that hydrogen sulfide did not remain confined to the oceans. In extreme cases, it may have escaped into the atmosphere.

Hydrogen sulfide is heavier than air, but large releases can overwhelm atmospheric mixing. Even small concentrations are deadly to animals. Larger releases could also damage the ozone layer, increasing ultraviolet radiation at the surface.

While the extent of atmospheric release remains debated, even episodic events would have placed immense additional stress on land ecosystems already weakened by heat and acid rain.

Why Recovery Became So Difficult

Toxic oceans create a trap. Even after volcanic activity wanes and temperatures stabilize, the chemistry of the seas can remain hostile for long periods. Oxygen does not return easily once circulation patterns collapse and sulfur cycles dominate.

This helps explain why recovery after the Great Dying was so slow. Life did not simply need time to evolve. It needed the planet’s chemistry to become survivable again.

A Planet Out of Balance

The Great Dying was not caused by a single factor. It was the convergence of heat, oxygen loss, and chemical poisoning. Euxinic oceans represent the point at which Earth’s life-support system crossed from stress into failure.

Understanding this stage is critical. It shows how environmental change can accelerate beyond gradual decline into conditions that actively resist recovery.

The next essay will turn to the land—where heat, acid rain, and atmospheric instability finished what the oceans began.

For more social commentary, please see Occupy 2.5 at https://Occupy25.com

This essay will be archived as part of the ongoing WPS News Monthly Brief Series available through Amazon.

References

Algeo, T. J., & Twitchett, R. J. (2010). Anomalous oceanic conditions associated with the end-Permian mass extinction. Annual Review of Earth and Planetary Sciences, 38, 525–553.
Kump, L. R., Pavlov, A., & Arthur, M. A. (2005). Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia. Geology, 33(5), 397–400.
Wignall, P. B. (2001). Large igneous provinces and mass extinctions. Earth-Science Reviews, 53(1–2), 1–33.