James Reinhart, CEO of ThredUp, one of the largest online resale platforms for secondhand clothing. James co-founded the company while he was a Masters’ student at Harvard and has spent the last 15 years scaling a national logistics and digital infrastructure platform for resale. 

In this episode James describes why the company decided to handle physical goods rather than act as a pure marketplace, how ThredUp helps brands run their own resale channels, and how AI and automation are reshaping their operations. James also describes related public policies like extended producer responsibility (EPR) and provides advice for those pursuing careers in circular economy innovation. 

In the latest episode of Climate Rising from Harvard Business School, Karen Pflug, Chief Sustainability Officer of Ingka Group (IKEA), shares how IKEA is embedding circularity throughout its business model. 

She discusses how IKEA is redesigning iconic products like the Billy bookcase to make them easier to disassemble and repair, how secondhand retail pilot programs at IKEA stores are reaching new customers, and how investments like RetourMatras are developing circular solutions for end-of-life mattresses. Karen also describes how policy, design, and customer nudges can accelerate circularity at global scale—and offers advice for those seeking careers in circular economy innovation. 

Lauren Rodriguez, who leads partnerships at Circular Services, a Closed Loop Partners company, joins host Mike Toffel to discuss building the infrastructure and investment models needed to scale the circular economy.

Lauren explains how Closed Loop Partners supports the transition from a linear to a circular economy through capital management, innovation initiatives, and operating companies like Circular Services. She shares how their private equity, venture capital, and catalytic credit strategies are helping scale recycling, reuse, and circular supply chains.Lauren also explores the critical role of policy—especially extended producer responsibility(EPR) laws—in driving investment and highlights emerging technologies like AI-powered waste stream analysis and autonomous electronics disassembly that are accelerating progress. She closes with advice and resources for students and professionals interested in careers at the intersection of circular economy, investing, and innovation.

Fabian Barthel, Co-Founder of Vytal, a circular economy packaging-as-a-service startup, joins host Mike Toffel to explore the innovation, behavioral science, and regulations shaping the market for reusable containers for take-out food and beverages. 

Fabian shares how Vytal is tackling packaging waste by building a reusable container system for restaurants, canteens, and major events. He explains why deposit-based systems often fail, how Vytal’s “borrow and return” model changes consumer behavior, and how data, technology and behavioral science underpin their service design. Fabian also discusses the evolving regulatory landscape, including Germany’s reuse mandates and emerging municipal single-use taxes. He closes by offering advice to circular economy entrepreneurs about how to align impact with profit. 

In this bonus episode of Climate Rising, we share an episode from Harvard Business School’s Cold Call podcast, featuring HBS professor Mike Toffel and Duncan van Bergen, Co-Founder of Calyx Global. The discussion focuses on Mike’s recent HBS case study, Calyx Global: Rating Carbon Credits, which explores how the company is helping improve transparency and credibility in the voluntary carbon market. Mike and Duncan join host Brian Kenny to unpack how Calyx Global evaluates carbon credit quality, how the company maintains independence in a space vulnerable to conflicts of interest, and how data and technology—from satellite sensing to AI—are transforming how carbon credits are verified and rated. The conversation also highlights key themes in the voluntary carbon market, including the tension between financial models and credibility, the challenges of measuring impact, and the broader implications for corporate climate action.

Luke Leslie, Co-Founder and CEO of Key Carbon, joins Climate Rising as part of our series on voluntary carbon markets. Luke has spent over 20 years in carbon markets and finance, working in investment banking, private equity, and structured finance. 

Luke explains how Key Carbon is financing high-integrity carbon projects and how new overlaps between the voluntary and compliance carbon markets are at the center of their investment strategy. He provides a “climate finance 101” introduction and discusses the role of investors in the carbon credit space, how structured finance can scale climate solutions. Luke also describes how investors source and evaluate carbon projects, the risks of over-crediting, and the future role of biodiversity markets. Finally, he offers career advice for those interested in climate finance. 

Alexia Kelly, Managing Director of the Carbon Policy and Markets Initiative (CPMI) at theHigh Tide Foundation, joins host Mike Toffel for the fifth episode in our series on voluntarycarbon markets. Alexia has worked for nearly two decades atthe intersection of carbonmarkets, policy, and finance, with roles spanning government, private industry, andnonprofits.

In this episode, Alexia discusses how voluntary carbon markets are evolving, the criticalrole of policy in shaping carbon finance,and how standards and governance can improvemarket integrity. She also explores how advances in digital technology, data transparency,and AI-driven monitoring are transforming carbon credit verification and marketconfidence. Additionally, she shares herperspective on the integration of voluntary andcompliance markets, including recent developments in Article 6 of the Paris Agreement.Alexia also offers career advice for those looking to enter the field and shares resources forstaying informed on carbon markets and climate finance.

Amy Merrill, CEO of the Integrity Council for the Voluntary Carbon Market (ICVCM) joins host Mike Toffel in this fourth episode of the Climate Rising series on voluntary carbon markets. Amy has extensive experience in carbon markets, including leading negotiations on Article 6 of the Paris Agreement and advising on global carbon finance. 

Amy explains how ICVCM uses a multi-stakeholder approach to enhance the integrity of carbon credits, including by developing ten Core Carbon Principles (CCPs) and using them to evaluate and strengthen carbon credit programs and methodologies. She discusses the challenges in ensuring credit quality and how the boundary is evolving between voluntary and compliance markets. Amy also shares her insights into the latest trends in carbon markets and offers advice for those interested in learning more about these topics. 

This episode, the third in our series on Voluntary Carbon Markets, features Mark Kenber, Executive Director of the Voluntary Carbon Markets Integrity Initiative (VCMI). Mark has worked in carbon markets and climate finance for nearly three decades, with experience at organizations like WWF, The Climate Group, and Fundación Natura in Ecuador. 

Mark describes VCMI’s mission to provide guidance for companies and other non-state actors on how to credibly use carbon credits as part of their climate commitments. He discusses the current challenges and opportunities in voluntary carbon markets, the role of businesses and governments in ensuring integrity, and how emerging trends—such as the blurring lines between voluntary and compliance markets—will shape the future. Mark also shares career advice for those interested in working in carbon markets and climate finance. 

Our second episode on the voluntary carbon market is a bonus episode of a panel discussion recorded at Harvard Climate Action Week in 2024. Harvard Kennedy School Professor Joe Aldy

moderates this discussion with Nat Keohane from the Center for Climate and Energy Solutions, Donna Lee from Calyx Global, UC San Diego Professor David Victor, and Carolyn Weinberg, formerly of Blackrock. Together, they bring perspectives from policy, business, and academia. The conversation explores the role of voluntary carbon markets in mobilizing finance for decarbonization, ensuring the integrity of carbon credits, and scaling high-quality projects. They also discuss emerging standards, innovative financial products, and how companies can leverage VCMs to achieve net-zero goals while addressing climate risks.