The Importance of Merging Humans and Nature with Dr. Liz Hadly – California China Climate Institute

Audio by: Megan Bergeron | Writing by: Marie Hogan, Amanda Neslund, Alexandra Jade Garcia  | Socials by: Wangyuxuan Xu

What is the Anthropocene?

The anthropocene is a term used to describe the magnitude of human caused changes to earth systems at every level. Proponents of the term argue that our impacts are so large, they are leaving a mark that will be observable in rock layers many years from now, distinguishing the anthropocene from prior geologic periods. While climate change and sea level rise are obvious features of the anthropocene, they are not the only ones. Modern humans have also introduced new chemicals into the environment, redirected 75% of global freshwater towards food production, and transformed landscapes via urbanization. Over the past several centuries, global trade and agriculture has resulted in the extinction of some species and the spread of others, like those used for food production. Some have even argued that the kickoff sign for the start of the anthropocene should be a chicken fossil. Although the anthropocene is not yet a formal geologic time unit, a scientific working group within the International Union of Geological Sciences convened is currently developing a proposal for its recognition as an epoch, and has chosen the mid-20th century as its beginning.

What effects have the Anthropocene had on biodiversity, and why does it matter?

Although biodiversity is often measured in terms of the number of species, that’s only part of the equation. Because of the complexity of many earth systems, human activity in one area can have far ranging impacts on the environment. This matters for conservation because it means that protecting species is not as simple as drawing lines on a map and designating the area inside as protected. 

Species evolve as part of complex ecosystems, each with its own structure and self-regulating mechanisms. When change is gradual, these systems have time to adapt to the new conditions. However, when change is comparatively sudden, as is the case of human induced impacts in the anthropocene, ecosystems can’t keep up and are destabilized. Biologists attribute current trends of high and accelerating rates of species extinction and declines in species richness to the impacts of human activity. In turn, that biodiversity loss can exacerbate threats like wildfires and jeopardize pollinators essential to agriculture, impacting humans in addition to the species themselves.

Who is Dr. Liz Hadly, and How Can Her Research Help Protect Biodiversity?

Dr. Liz Hadly is a biologist studying how human activity and human caused climate change affect global biodiversity and ecosystem function. At Stanford, she runs the Hadly lab, which researches both historical and contemporary patterns of biological diversity, species distribution, and ecosystem shifts, and is the faculty director of the Jasper Ridge Biological Preserve. Throughout her career, Dr. Hadly has used research to advocate for more effective and science based conservation policy, including as an author on the 2013 Scientific Consensus on Maintaining Humanity’s Life Support Systems in the 21st Century

The Hadly lab has developed new technology and research approaches to study network effects on biodiversity that can be used to inform conservation efforts. Ecosystems’ structure determines how they change when new forces are introduced, including human activity. For example, the loss of a single species could affect very little or trigger an extinction cascade across the entire ecosystem, depending on the role that species plays in food webs and its patterns of interactions with other species. As a result, many biologists believe that by studying these networks, we can protect biodiversity more effectively.

One policy Dr. Hadly’s research supports is the so-called 30×30 pledge to conserve 30 percent of both land and oceans by 2030. California promised to meet this target in an executive order by Governor Newsom in 2020, and the Biden administration also committed the US to 30×30 in 2021. Supporters of 30×30 hope that it will help set targets at this year’s upcoming COP15 Biodiversity Summit, hosted by the UN. 

Links to Learn More

The Hadly Lab

Scientific Consensus on Maintaining Humanity’s Life Support Systems in the 21st Century

The Anthropocene Curriculum

American Museum of Natural History: What is Biodiversity?

UN Report: Nature’s Dangerous Decline ‘Unprecedented’; Species Extinction Rates ‘Accelerating

American Nature Campaign: The 30×30 Goal

California Nature: 30×30 California


Dr. Hadley: Our present native vegetation is basically out of equilibrium with the climates of today. The more we think about engineering our way out of this, the more in trouble we’ll be and more rapidly. You can’t sacrifice biodiversity. 

Ethan: That’s Dr. Liz Hadley, professor in the Department of Biology at Stanford University. She discussed preserving native biodiversity as a way of building climate resilience, with former California Governor Jerry Brown at a recent California China Climate Institute discussion.

Dr. Hadley: How can we foster the new species of this place in the future, communities of interacting birds and insects and plants? We need to make considerations for nature and the city.

Ethan: Dr. Hadley supports the climate solution of setting land aside from development for biodiversity, such as the goal in California of 30% by 2030 or even 50%.

Dr. Hadley: Plants and animals and just life in general–you got to have a place for them to live out their lives. In California and a lot of places in the world, they’re doing 30 by 30 – that’s 30% by the year 2030. The more area you have, the more species can accumulate there. 

Ethan: To hear more from Dr. Hadley about biodiversity solutions, go to or wherever you get your podcasts. I’m Ethan Elkind and this was Climate Break.

The Importance of Merging Humans and Nature with Dr. Liz Hadly – California China Climate Institute