How Many Species Are There on Earth?

What does it actually take to combat desertification? From satellites and sustainable land management to international negotiations, the world has a growing toolkit to address land degradation and drought. But putting those solutions into practice is another story. In Part 2 of our coverage of the UN Convention to Combat Desertification (UNCCD) COP17 in Ulaanbaatar, Mongolia, we're moving from the problem to the solutions. Host Clark Marchese speaks with Dr. Tatenda Lemann of the Centre for Development and Environment (CDE) at the University of Bern and WOCAT about the science of sustainable land management, the importance of local knowledge, and what makes restoration projects successful. Then, Dr. Pamela Chasek, Executive Editor of the Earth Negotiations Bulletin, helps us unpack the politics of COP17, from international cooperation and financing to the negotiations that left countries divided over drought. Along the way, we hear directly from delegates and officials at COP17 to explore how science, policy, and people come together to protect the land we depend on. Because knowing what works is only half the battle. The other half is making it happen.

What is desertification, why is land degrading around the world, and what can Mongolia teach us about the causes? In Part 1 of Green Frequency’s coverage of UNCCD COP17 in Ulaanbaatar, host Clark Marchese explores the science and politics of land degradation, from the origins of the UN Convention to Combat Desertification and Land Degradation Neutrality to the pressures facing Mongolia’s vast grasslands. Featuring audio from inside COP17 and reporting from Mongolian journalist Turmunkh Gongorjav, the episode examines climate change, drought, overgrazing, mining, urbanization, coal and the growing demand for critical minerals. It also asks a deeper question: whose knowledge counts when governments decide why land is degrading? From Fiji’s coastal farmland to Mongolia’s rangelands, this episode explores how land degradation looks different around the world, why local and Indigenous knowledge matters, and how the way we diagnose environmental problems shapes the solutions we pursue. Part 2 turns to sustainable land management, science and technology, finance, and the political outcomes of COP17.

Ocean technology cannot operate alone. Nicolas Pade, executive director of the European Marine Biological Resource Centre, joins Green Frequency to unpack five policy recommendations emerging from Blue Tech Europe 2026. We explore technological sovereignty, strategic procurement, collaboration between academia and industry, usable ocean data, market demand and the skills needed to sustain ocean-observation systems. Although developed for Europe, many of these questions apply wherever science must become lasting public infrastructure. And we ask what happens when what markets consider viable is not necessarily what society considers valuable.

What happens behind the exhibits at a natural history museum? At Te Papa Tongarewa, the Museum of New Zealand, millions of specimens form a scientific record stretching across species, ecosystems, and generations. In this episode of Green Frequency, Clark is joined by deep-sea researcher and curator of fishes Dr. Thom Linley to explore what those collections are actually for. We find out why researchers sometimes need to borrow a shark, how curators decide what to preserve for scientists a hundred years from now, and how technologies like micro-CT scanning, hyperspectral imaging, and machine learning are changing what we can learn from specimens collected decades ago. Along the way, we encounter snailfish, bioluminescence, colossal squid, the world's friendliest "meat library," and a much bigger question: what does it mean for a museum to preserve the memory of a changing natural world?

What would happen to coffee and cocoa if humans deliberately tried to cool the planet? Atmospheric scientist Dr. Nina Grant joins Green Frequency to explain stratospheric aerosol injection, or SAI, a proposed form of solar geoengineering that would introduce reflective particles into the upper atmosphere.