The consensus view of scientists is that volcanic activity at the end of the Permian period, associated with the Siberian Traps Large Igneous Province, emitted massive quantities of greenhouse gases into the atmosphere over a short time interval. This caused a spike in global temperatures and a cascade of other deleterious environmental effects.

An international team of researchers from the United States, Sweden, and Australia studied sedimentary deposits in eastern Australia, which span the extinction event and provide a record of changing conditions along a coastal margin that was located in the high latitudes of the southern hemisphere. Here, the extinction event is evident as the abrupt disappearance of Glossopteris forest-mire ecosystems that had flourished in the region for millions of years. Data collected from eight sites in New South Wales and Queensland, Australia were combined with the results of climate models to assess the nature and pace of climate change before, during, and after the extinction event.

Results show that Glossopteris forest-mire ecosystems thrived through the final stages of the Permian period, a time when the climate in the region was gradually warming and becoming increasingly seasonal. The collapse of these lush environments was abrupt, coinciding with a rapid spike in temperatures recorded throughout the region. The post-extinction climate was 10-14°C warmer, and landscapes were no longer persistently wet, but results point to overall higher but more seasonal precipitation consistent with an intensification of a monsoonal climate regime in the high southern latitudes.

Because many areas of the globe experienced abrupt aridification in the wake of the “great dying,” results suggest that high-southern latitudes may have served as important refugia for moisture-loving terrestrial groups.

The rate of present-day global warming rivals that experienced during the “great dying,” but its signature varies regionally, with some areas of the planet experiencing rapid change while other areas remain relatively unaffected. The future effects of climate change on ecosystems will likely be severe. Thus, understanding global patterns of environmental change at the end of the Paleozoic can provide important insights as we navigate rapid climate change today.

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A new study led by Dr. Corentin Bochaton and Professor Nicole Boivin of the Max Planck Institute for the Science of Human History in Jena, Germany, reveals far greater extinctions among the snakes and lizards of Guadeloupe following European colonization than previously believed. Partnering with colleagues from Centre National de la Recherche Scientifique (CNRS), Muséum National d’Histoire Naturelle (MNHN), Institut de Recherche pour le Développement (IRD) and the Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), the team studied an extraordinary 43,000 individual bone remains from fossil and archaeological assemblages on six islands, ultimately revealing that 50% to 70% of Guadeloupe’s squamate species went extinct after the arrival of European colonialists.

This enormous loss of biodiversity stands in stark contrast to the pre-colonial record, which shows that Indigenous populations co-existed with the islands’ snakes and lizards for thousands of years. In fact, the biodiversity of Guadeloupe’s snakes and lizards actually increased during the long history of Indigenous habitation, with no recorded extinctions and the introduction of two new lizard species.

“The long-term data from Guadeloupe are concerning,” notes Professor Boivin, Director of the Department of Archaeology at the MPI in Jena. “Snakes and lizards persisted through a broad range of climatic, environmental and human-induced changes on Guadeloupe over thousands of years. They do not appear to be sensitive animals. Yet in the last few hundred years, their diversity has plummeted.”

The new paper underscores the potential of archaeological and fossil records to provide information that is highly relevant in the modern world.

“Our research strongly advocates for the study of past biodiversity to address current conservation issues and for the study of less charismatic animals like reptiles, which are an essential part of tropical ecosystems,” says Bochaton.

The use of fossil data from Guadeloupe allowed the team to closely examine the dynamics of the extinctions, revealing links between species’ body size, habitat preference, and risk of extinction. Medium-sized, terrestrial species sustained the greatest losses, implicating recently introduced mammalian predators such as mongooses and cats as primary drivers in Guadeloupe’s reptile extinctions.

The extinction trends also highlight the impacts of a shift to intensive colonial agriculture. The destruction and fragmentation of habitats, combined with the degradation of soil and decimation of insect populations, placed enormous pressure on Guadeloupe’s snake and lizard species.

“In recent years, recognition of early human impacts has led to a kind of acceptance of humans as this inherently destructive species,” says Professor Boivin. “Yet the Guadeloupe data clearly show that Indigenous lifeways were supportive of snake and lizard biodiversity, whereas European ones were not. This provides us with important information for future management and sustainability initiatives, and calls into question some of the ways conservationists deal with Indigenous communities globally.”

The researchers hope that more of such studies will help managers and conservationists create realistic, data-driven strategies for mediating societal impacts on ecosystems.

“Archaeology budgets all around the world are under threat,” observes Professor Boivin. “But without our past, we move forward blindly. Study of the past, present and future must be intertwined.”

Printed carbon perovskite solar cells have been described as a likely front runner to the market because they are extremely efficient at converting light to electricity, cheap and easy to make.

A major barrier to the large-scale manufacture and commercialisation of these cells is the solvents used to control crystallisation of the perovskite during fabrication: this is because they are made from unsustainable materials and are banned in many countries due to their toxicity and psychoactive effects.

SPECIFIC’s researchers have discovered that a non-toxic biodegradable solvent called γ-Valerolactone (GVL) could replace these solvents without impacting cell performance.

GVL’s list of advantages could improve the commercial viability of carbon perovskite solar devices:

• It is made from sustainable feedstocks
• There are no legal issues in its use around the world
• It is suitable for use in large-scale manufacturing processes
• It is non-toxic and biodegradable

Carys Worsley, who led the research as part of her doctorate, said:

“To be truly environmentally sustainable, the way that solar cells are made must be as green as the energy they produce. As the next generation of solar technologies approaches commercial viability, research to reduce the environmental impact of large-scale production will become increasingly important.”

Professor Trystan Watson, research group leader, added:

“Many problems need to be resolved before these technologies become a commercial reality. This solvent problem was a major barrier, not only restricting large-scale manufacture but holding back research in countries where the solvents are banned.

We hope our discovery will enable countries that have previously been unable to participate in this research to become part of the community and accelerate the development of cleaner, greener energy.”

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