The IWTO Green Book: Building the Scientific Foundation for Wool’s Environmental Story
When we launched the IWTO Green Book Project in July 2024, we set out to address a fundamental challenge facing the wool industry: how can we accurately communicate wool’s true environmental performance when current measurement systems were designed for factories, not biological systems?
As we close out 2025, we can look back with pride at what we have achieved. Most importantly, we’ve built a scientific foundation that will fundamentally change how natural fibres are assessed and valued in the marketplace. In this post, we share what the Green Book is all about, what it means for brands/retailers, producers, and industry partners, and highlight the progress we’ve made toward our 2026 launch.
What is the IWTO Green Book?
The Green Book is a comprehensive source for wool’s eco-credentials. At its heart is a new biogenic carbon accounting methodology that accurately reflects what actually happens in wool production systems – the natural carbon cycles that current Life Cycle Assessment (LCA) methodologies ignore.
This matters because conventional LCA treats all carbon emissions identically but only counts permanent carbon removals – ignoring the short-term carbon cycle, where carbon is re-cycled through photosynthesis and biodegradation. It doesn’t matter to conventional LCA whether the emissions come from burning fossil fuels, or from the natural respiration of a sheep eating grass that captured CO₂ from the atmosphere just weeks earlier.
The Science Behind the Breakthrough
Our biogenic carbon accounting approach was developed in alignment with ISO 14067. It recognizes what the science has always shown: wool production operates within natural carbon cycles.
More than 50% of the carbon sheep ingest is returned as manure, supporting soil health and carbon sequestration. Only about 5% is released as enteric emissions.
This methodology has been reviewed and verified by leading certification body TÜV SÜD. And, just before the end of 2025, a paper applying the method to six case study wool farms was published in one of the world’s top agricultural science journals, Agricultural Systems. Find that paper, A biogenic life cycle approach towards estimating the carbon intensity of wool production, at sciencedirect.com.
From Theory to Reality: Case Studies in Action
Additionally, three comprehensive case studies have already been completed, using the methodology in real-world farm conditions.
One particularly enlightening study examined a farm that spent over one million dollars on supplementary feed during drought years. Our model predicted the farm would be sequestering carbon in the soil even during drought. The farm’s detailed soil testing records over many years validated this prediction.
Fifteen more case studies are currently planned. We are open to more!
Looking Ahead: 2026
Additionally, three comprehensive case studies have already been completed, using the methodology in real-world farm conditions.
The Green Book manuscript is being readied for release at the 2026 IWTO Congress. For the first time, wool businesses will have access to comprehensive sustainability standards backed by independent third-party verification, demonstration real-world application, and alignment with internationally recognized ISO standards.
👉 Are you a brand or retailer? The Green Book will provide you with credible environmental data to support product claims and marketing communications, a defensible position against misleading narratives, and competitive advantage in differentiating wool products based on accurate environmental assessment.
👉 If you are a wool producer: Opportunities exist to participate in the expanding case study programme, demonstrating on-farm carbon dynamics and validating sustainable production practices.
👉 Seeking industry partners: We’re actively seeking collaboration on cross-sectoral initiatives and standards development, particularly with other agricultural sectors facing similar LCA challenges. Get in touch with us to express your interest!
The IWTO Green Book Project is generously funded by the Italian wool trade, Confindustria Moda.
For a comprehensive overview of the Green Book Project, including details on the biogenic carbon methodology, TÜV SÜD verification, and 2025 achievements, download our IWTO Green Book Briefing (PDF).
Based in Brussels, she enjoys the challenge of coordinating communications across time zones and cultures, whether she's working with sheep farmers in Australia or fashion brands in Europe. When not immersed in wool industry trends, you might find her on a yoga mat or exploring Belgium's excellent coffee scene.
Have a question about wool or the wool industry? Contact Jeannette through IWTO at iwto@iwto.org.
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