The Newcastle University–led study, The true carbon costs of supplying potassium fertilizer to Brazilian agriculture, has produced the first comprehensive estimate of greenhouse‑gas (“GHG”) emissions from conventional potash (KCl) supplied to Brazilian farms, fully accounting for previously overlooked Scope 3 emissions from transport and distribution.

Publishing in the journal, Resources, Conservation and Recycling and using a new “cradle‑to‑hub” approach, Newcastle University researchers calculate a weighted average carbon footprint of 530.5 kg CO₂‑eq per tonne of KCl delivered to 5,563 agricultural distribution hubs across Brazil – almost double the 273.13 kg CO₂‑eq per tonne value widely used today in Brazilian agricultural and biofuel carbon‑accounting tools.

The study, based on 2022–2023 data and publicly reported emissions from major global producers, finds that:

• Manufacturing alone (“cradle‑to‑gate”) accounts for 200–353 kg CO₂‑eq per tonne of KCl, broadly in line with values used in international life‑cycle assessment (LCA) databases.
• Transport and distribution add, on average, a further 182 kg CO₂‑eq per tonne, increasing total emissions by more than 50% to 530.5 kg CO₂‑eq per tonne “cradle‑to‑”
• These previously uncounted emissions add roughly 4 million tonnes of CO₂‑eq per year to Brazil’s national emissions from KCl use alone.

“As a country that imports almost all of its potash, Brazil is a perfect case study to show how much ‘hidden’ carbon is embedded in fertilizer supply chains,” said Professor Oliver Heidrich, corresponding author of the study and Professor of Civil and Environmental Engineering at Newcastle University. “We’ve shown that fertilizer producers located close to farming regions tend to have a smaller overall carbon emission impact compared to those located in remote regions. Our hope is that this work will drive more rigorous Scope 3 accounting and accelerate the shift toward lower‑carbon potassium sources for Brazilian agriculture.”

Professor Heidrich is a leading researcher on climate‑change mitigation and adaptation, material flows and life‑cycle assessment, with a particular focus on building standardised, science‑based tools for decision‑makers in cities, industry and infrastructure.

“Our study tracks Scope 3 emissions from imported potassium fertilisers all the way to more than 5,000 distribution points serving over 5 million Brazilian farms,” commented Professor David Manning, co-author of the study and Professor of Soil Science at Newcastle University. “We show that the carbon footprint of potassium fertiliser use has been underestimated by about a factor of two—likely similar for nitrogen and phosphorus—in a country that is the world’s largest fertiliser importer and helps feed over 10% of the global population.”

Large differences between supply sources

The paper also reveals significant variation in emissions between supply origins. Canadian and Russian imports generally carry higher carbon footprints because of long rail and ocean journeys, while Chilean and Jordanian suppliers have much lower transport‑related emissions but currently provide far smaller volumes.

Overall, the authors conclude that transport‑related Scope 3 emissions are a “substantial and previously underappreciated component” of the carbon footprint of potash fertilizers and call for stronger, standardised Scope 3 disclosure requirements across jurisdictions so that companies, regulators and buyers can compare fertilizer options on a like‑for‑like basis.

Strategic importance of domestic potassium solutions

Brazil imports over 20% of global potassium production and relies on imports for about 97% of its KCl demand. While the Newcastle University study focuses on imported KCl, it notes that domestic potassium sources are beginning to emerge in Brazil, some of which may have substantially lower carbon footprints thanks to their proximity to major farming regions and different production routes.

Verde AgriTech Ltd. (“Verde”), a domestic specialty fertilizer producer focused on the Brazilian market, is a good example of how Brazil‑based production can help reduce fertilizer‑related emissions over time while also strengthening supply security. Verde’s low‑carbon strategy, which includes a well-positioned distribution network, is embedded in its business model through initiatives such as:

• A production process that avoids energy‑intensive chemical concentration steps typical of conventional KCl, thereby lowering energy use and associated emissions;
• Support of Brazil’s transition to lower-carbon fertilizer supply by reducing transport distances between fertilizer production and farms;
• Use of renewable energy sources, further reducing the carbon intensity of its fertilizers;
• Collaborations with academic partners to refine life‑cycle assessments of different potassium sources, including enhanced rock‑weathering pathways, such as its recently announced partnership with UK‑based UNDO Carbon Ltd.; and
• Providing data and field evidence to inform the broader scientific and policy debate on fertilizer decarbonisation.

Today, Verde’s strategy has been successful showing CO₂ emissions of 0.0655 kg CO₂‑e per kilogram (kg) of potassium oxide delivered versus 0.4552 kg CO₂‑e per kg potassium oxide for conventional potash delivered to the same region in Brazil.

“Brazilian agriculture feeds close to 10% of the world’s population, and KCl is one of the agricultural ecosystem’s largest embedded sources of emissions,” said Cristiano Veloso, Founder and CEO of Verde. “Studies like this help quantify the challenge and show where innovation and investment should focus. Verde intends to be part of the solution by advancing Brazilian‑made potassium specialty fertilizers which, according to our assessments, can cut carbon footprints by up to 89% compared with conventional fertilizer producers operating from remote, carbon‑intensive locations.”

Reference

Manning, D. a. C., Siqueira, T. R., Rajaeifar, M. A., & Heidrich, O. (2025). The true carbon costs of supplying potassium fertilizer to Brazilian agriculture. Resources Conservation and Recycling, 226, 108694. https://doi.org/10.1016/j.resconrec.2025.108694