Biodiversity loss is an ongoing challenge, but some of the language we use to describe it may be on shakier ground than we realize. Are we really living through a “sixth mass extinction”? What does that phrase technically imply, and how well is it supported by the data? And what about climate change: how much species-level extinction can credibly be attributed to warming so far, and how do you attribute causes when multiple threats interact?

To explore these questions, I spoke with John Wiens, an ecologist at the University of Arizona whose work focuses on extinction rates and climate-driven range losses. We discuss what the evidence suggests about acceleration (or the lack thereof) in extinction in recent decades, why documented extinctions have been concentrated on islands and in freshwater systems, and how climate change is expected to reshape extinction risk through mechanisms like heat extremes, shifting range limits, and disease dynamics. The thread running through it all is credibility and ambition: how to communicate urgency without overclaiming, and why a stronger conservation goal is not “avoiding a mass extinction,” but preventing extinctions wherever we still can.

Links to resources

• Future threats to biodiversity and pathways to their prevention - The 2017 Tilman et al. article that John referred to in our discussion
• Unpacking the extinction crisis: rates, patterns and causes of recent extinctions in plants and animals - A 2025 article by John and colleagues

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This episode does not argue against renewable energy—renewables are essential to decarbonization—but it does ask what the transition looks like when you account for materials, extraction, and infrastructure.

The clean energy transition is often framed as a straightforward swap: renewables replace fossil fuels, emissions fall, problem solved. But beneath that story sits a harder set of questions. How material-intensive is a renewables-led grid, really? What happens when you account for the steel, concrete, and critical minerals that make wind, solar, and battery storage possible? And if mining expands dramatically to enable decarbonization, what are the environmental and social trade-offs?

To explore these questions, I spoke with Saleem Ali, a systems scientist and industrial ecologist at the University of Delaware who studies the “materials–energy nexus”—the idea that energy systems are constrained not only by fuels and emissions, but by infrastructure, extraction, and supply chains. We talk about why wind and solar can be surprisingly material-heavy up front, how storage options like pumped hydro compare with large battery farms, why nuclear and biofuels remain part of the conversation, and what a more pragmatic approach looks like when every option carries trade-offs.

Links to Resources

• The fight over minerals for green energy — and a better way forward - Saleem's 2024 TED Talk

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The intersection of science, politics, and environmental discourse is full of puzzles: why has nuance gone missing from the conversation? Why are heterodox or balanced views often sidelined? And how do echo chambers, alarmist rhetoric, and the erosion of trust hinder lasting progress in conservation?

To explore these questions, I spoke with Roger Pielke Jr., a political scientist well-known for his work on contested science in contentious policy areas, from climate and extreme weather to COVID origins and sports governance.

Links to resources

• The Honest Broker - Roger's website and blog, with lots of free content and even more in the paid version.
• What Happened on Deliberation Day? 2007 paper mentioned by Roger in which the researchers found that like-minded deliberation led to stronger, more extreme post-discussion views, while mixed groups became more open and less certain.
• The Rightful Place of Science: Disasters and Climate Change - Book by Roger, emphasizing evidence-based nuance over alarmism.
• Messaging Should Reflect the Nuanced Relationship between Land Change and Zoonotic Disease Risk - BioScience paper that we discussed, on the links between land change and zoonotic spillover risk.

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The concept of rewilding has been applied in various ways, from the simple restoration of a single natural process like removing livestock to allow vegetation to recover, to ambitious proposals to reintroduce long-extinct megafauna. While some applications have obvious conservation benefits, rewilding also raises legitimate concerns, especially about how renewed interactions with reintroduced wildlife like large herbivores and carnivores, might affect human wellbeing, livelihoods, and land use. Rewilding has become a popular and sometimes controversial topic within conservation circles. It has also been gaining traction and growing public and governmental interest as societies search for more holistic approaches to restoring ecosystem processes and biodiversity.

Joining me to unpack what rewilding means, and to explore the potential conflicts and compromises that come with it, is Marine Drouilly. Marine is the Regional Coordinator for Wild Cat Surveys and Research in West and Central Africa with the NGO "Panthera".

Links to resources:

• Guidelines for evaluating the success of large carnivore reintroductions - A relevant paper in Biological Conservation co-authored by Marine
• Panthera - Website of the organization Marine works for

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Multilateral environmental agreements (MEAs) are negotiated by national governments, but they also include input from various societal groups. One of these groups is youth, and their role in negotiations has grown more visible and coordinated over time. But are these contributions helping to enrich discussions and inspire ambition, or simply adding another layer to already complex processes? And why have separate groups if governments are meant to represent all of their citizens? In this episode, we take a closer look at the place of youth in forums like these — and what constructive and meaningful participation looks like.

My guest is Mika Tan, advisor to the Southeast Asia chapter of the Global Youth Biodiversity Network (among other roles) and a passionate advocate for youth voices in global decision-making.

Links to resources:

• Youth in international nature conservation: The example of youth participation in the Convention on Biological Diversity (CBD) - Analysis of the extent and quality of youth participation within the CBD (German article, English abstract).
• The contradictions of youth participation for intergenerational justice in urban environmental planning - An article that critiques the politicization of the application of intergenerational justice.
• Global Youth Biodiversity Network - Website of the organization that Mika mentions in our discussion.

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One of the most popular terms in conservation these days is “nature-based solutions” (NbS). The concept is centered around the various ways in which conservation (including restoration and sustainable use) can benefit society, economy and environment. NbS are alternatives to engineered solutions to these problems, which benefit people as well as nature. Sounds straightforward, and the concept has been taken up in government policy and largely embraced by conservation science. And yet it has been somewhat divisive, for very different reasons.

Joy Ommer is scientific lead at KAJO, a Slovakia-based geoservices consultancy focused on disaster risk reduction and management. In a recent paper she and some project partners write about the importance of understanding the impacts of nature-based solutions before they are actually implemented. We discussed this and other issues around the NbS concept.

Links to Resources

• Quantifying co-benefits and disbenefits of Nature-based Solutions targeting Disaster Risk Reduction - 2022 article in the International Journal of Disaster Risk Reduction by Joy and co-authors, which we refer to in our discussion
• Nature-based solutions: using the power of nature - Some examples of NbS on an IUCN webpage

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The term "precision agriculture" has high-tech and “big ag.” connotations, and is usually not associated with biodiversity. But there is a strong argument to be made that it is one of the best things that has happened to conservation in recent decades. Agriculture remains the biggest driver of biodiversity loss in most parts of the world, so anything that reduces its impact might be worth taking note of.

Mark McConnell, an assistant professor at Mississippi State University, joins us on this episode to explain why precision agriculture is a boon for conservation. We also talk about the accompanying concept of precision conservation, which he has been promoting, as well as the old “land sharing versus land sparing” debate. For listeners unfamiliar with that debate, check the podcast notes for a couple of key references, as well as some of Mark’s work.

Links to resources:

• What conservationists need to know about farming - early (2012) paper by Balmford and co-authors on the land sharing versus land sparing debate
• Precision Conservation to Enhance Wildlife Benefits in Agricultural Landscapes - 2017 book chapter by Mark and a co-author
• Gamebird University - Mark's podcast

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The concept of biodiversity loss is absolutely integral to conservation, and I have never met anyone who has seriously challenged the idea that too many species are going extinct, nor that their extinction is a result of human pressures. So, what do we make of multiple studies telling us that we shouldn’t be focusing so much on biodiversity loss? These studies say that, on average in samples across the world, roughly equal numbers of sites are increasing in species richness and decreasing.

Maria Dornelas is the ecologist, from the University of Lisbon and the University of St Andrews, at the centre of this research and she joins me to elaborate. It should be mentioned right at the start that Maria is not suggesting that biodiversity loss is not a problem, but she explains why she thinks we are doing conservation a disservice by focusing on it the way we do. Maria emphasized the importance of nuance in conversations about conservation, and this discussion is an illustration of the importance of avoiding too much generalization and simplification.

Links to resources:

• Looking back on biodiversity change: lessons for the road ahead - 2023 article by Maria and colleagues.
• Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss - Maria's 2014 paper in Science, which announced the surprising results of her research.
• BioTIME - Global database of assemblage time series for quantifying and understanding biodiversity change.
• Inside Biodiversity - Related IDIV podcast that is referenced in the intro to this episode.

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