From tap to tire: Industry strives to sustain hevea NR supply chain

Natural rubber, most commonly derived from the hevea brasiliensis tree, is a foundation of the global economy. After all, the world uses about 14 million metric tons of natural rubber in over 50,000 different products annually.

That's what Katrina Cornish, research director at Ohio State University, pointed out during last year's International Tire Exhibition & Conference—where she also noted that the global economy would cease to exist without the critical material.

"If you don't have natural rubber, you've got nothing," she said.

This is doubly so for the tire industry, which absorbs over 70 percent of the NR produced globally, according to the European Tyre & Rubber Association, as well as the Tire Industry Project.

And the U.S. Tire Manufacturers Association says NR makes up about 19 percent of the average passenger/light truck tire and 34 percent of the average truck tire.

While some companies are seeking commercial alternatives to hevea NR, such as the desert shrub guayule or the Taraxacum kok-saghyz (TKS) dandelion, as the industry stands today there is no complete, sustainable replacement to this monoclonal tree that dominates the rubber industry.

Even synthetics cannot meet all of hevea NR's current applications and performances.

"Natural rubber compounds are extremely flexible, a good form of electrical insulators, and are resistant to many corrosive substances," said Bonggeun Kim, ESG team manager at Hankook Tire & Technology Co. Ltd. "Synthetic (man-made) rubber can be produced through a chemical process, but industries haven't been able to develop a synthetic rubber with all of the properties of natural rubber."

So it makes sense that some of the top global tire makers have banded together to support the longevity of this material.

The Tire Industry Project, for example—formed in 2005 under the World Business Council for Sustainable Development—comprises 10 leading tire companies that represent more than 60 percent of the global tire manufacturing capacity, according to the association. These manufacturers include Bridgestone, Continental, Goodyear, Hankook, Kumho Tire, Michelin, Pirelli, Sumitomo Rubber Industries, Toyo Tires and Yokohama.

And in October 2018, TIP spearheaded the development of the Global Platform for Sustainable Natural Rubber, which is now the "primary channel" through which its members work toward a sustainable NR supply chain.

The platform includes more than 200 members representing over 55 percent of the global NR supply chain. This includes tire makers and other natural rubber makers or buyers; end users; producers, processors and traders; civil society; and affiliate members, such as academic institutions, associations, governments and government organizations, and service providers.

"The commitment of our members to sustainable natural rubber is integral to the (tire) industry's overall efforts toward sustainability," Gavin Whitmore, senior manager of TIP communications, told Rubber News in an email.

"Natural rubber is a crucial element of tire production, and one reason Tire Industry Project members want to ensure the sustainable production and supply of natural rubber," he said. "This, of course, means looking after the people, communities and natural resources touched by natural rubber production and supply—which all stand to benefit from the creation and adoption of sustainable practices and businesses."

To do this, TIP identified seven "impact opportunities" when it launched its sustainability roadmap in 2021—based off the United Nation's 17 Sustainable Development Goals launched in 2015.

These goals "lay out a global agenda to tackle the world's most pressing social, environmental and economic challenges by 2030," according to TIP's "Sustainability Driven: Accelerating Impact with the Tire Sector SDG Roadmap."

Of TIP's seven "impact opportunities," it dedicates the first two to the sustainability of the NR supply chain:

• "Accelerate and scale activities to achieve a fair, equitable and environmentally sound natural rubber value chain—including ensuring decent work and upholding human rights"; and
• "Implement sustainable procurement practices and establish environmental, social and governance (ESG) responsibilities throughout the supply chain, including the promotion of transparency and traceability."

GPSNR members have taken TIP's impact opportunities and the U.N.'s SDGs in stride, dedicating time and resources to developing partnerships and programs that support smallholders, encourage biodiversity and work to mitigate the effects of climate change on hevea NR.

For Michelin, this includes doubling down on support for the production and sustainability of hevea. The company understands that while alternatives are critical to the sustainability of the overall NR supply chain, hevea cannot fall by the wayside.

And supporting the NR supply chain means supporting its producers—85 percent of which include about 6 million smallholder farmers who maintain an average of 2-3 hectares each, according to Michelin.

"Michelin supports a responsible and resilient management of the natural rubber value chain," the company states on its website. "It is essential that rubber is produced in a responsible manner to contribute to the sustainable mobility of tomorrow.

"There is no mobility without tires … and no high-performance tires without natural rubber," Michelin added, noting the material's unique properties contribute to a tire's durability, heat resistance, noise and vibration reduction, and tear reduction.

With about 2 million NR farmers supporting Michelin's needs, the French tire maker holds activities in Brazil, Africa, Thailand, Singapore and Indonesia.

"In Indonesia and Thailand, it is common for natural rubber processing factories to source raw material through different levels of intermediary dealers," Michelin said. "This results in a very complex supply chain, with a single natural rubber processing factory having thousands of smallholder farmers within their supply, having little or no interaction with them."

So how do you ensure the rubber you are receiving is fair trade with such a complex structure?

For Michelin, this takes shape in engaging "all players in the value chain" through a digital solution called RubberWay, a "risk-mapping solution developed to identify sustainability risks throughout the whole natural rubber upstream supply chain."

It can flag risks for mitigation at each level of the supply chain, "using responses to an environmental and social questionnaire carried out through a mobile app," according to RubberWay's website.

With this app, Michelin says it ensures sustainability along the supply chain, including the livelihoods of farmers and local communities as well as supporting farmers with responsible land use.

"Farmers often face livelihood challenges, such as limited access to agricultural training, income diversification options, and other soft skills," according to Michelin. "The RubberWay tool helps the group to understand better farmers and the specific guidance they need."

With its subsidiaries and joint ventures in West Africa, Brazil and Indonesia, Michelin provides about 100,000 smallholders training in agricultural practices. And at the end of 2020, the group said it used RubberWay findings to launch a project in Sumatra, Indonesia, "to empower farmers with tailored training and digital tools."

At Nokian Tyres—also a member of GPSNR—Vice President of Quality and Sustainability Teppo Huovila noted, like Michelin, that the NR supply chain's layers of smallholders, dealers, processors, traders and manufacturers make it difficult to fully map NR to its source.

To ensure the rubber it receives is ethical, Nokian traces its NR to the processor level.

"All the processors are sustainability risk evaluated, and the suppliers with highest risk rating are on-site sustainability audited," Huovila told Rubber News.

"The assessment has four different categories: quality, sustainability, business/strategic criticality and safety at work," he said. "Nokian Tyres' Sustainability Self-assessment is also used as one tool. If non-compliances are identified, the suppliers are required to create a corrective action plan and Nokian Tyres monitors the development of the actions. Re-audit is arranged typically after three years."

Hankook's Kim said that while tire makers face "many challenges with the procurement and availability of natural rubber," climate change is the biggest threat to the NR supply chain, noting that the latex trees are highly sensitive and dependent on their surrounding climate as monoclonal crops, requiring specific soil conditions and amounts of rain and sunlight.

And unmet conditions—combined with improper tapping—puts the trees at risk for leaf disease, which historically has had significant impacts on hevea NR supply.

As Cornish said in her ITEC presentation last year, 10 percent of global production was lost in 2020 following the spread of leaf blight to "500,000 hectares in seven countries in less than six months."

To help prevent leaf disease, Hankook implemented a project in Indonesia in 2022 to provide formic acid to farmers "to improve the environment of rubber tree plantations," Kim said.

"Acid is used as a coagulant to solidify latex collected from rubber trees. Since formic acid is less harmful than sulfuric acid, we have attempted to protect the growth of rubber trees through this support program," he said.

He added, however, that one of the most significant causes of leaf disease is indiscriminate tapping.

"If latex is collected continuously without giving enough time for the rubber trees to recover, the resilience of the rubber tree will inevitably decrease," he said. "Therefore, we continue to require NR processors to guide NR plantation farmers on collecting latex while keeping rubber trees resilient."

Like Michelin, Pirelli recognizes the value in seeking an alternative to hevea NR, but not moreso than supporting hevea NR production itself.

While the company made its first guayule-based UHP tire in 2016, it said it "does not currently feel these alternative materials are scalable due to volume issues."

The Italian tire maker also echoed Hankook's sentiment that while synthetics are useful in tires, they simply do not match their bio-based counterpart.

"Natural rubber is a key component of tires and other goods, and generally cannot be substituted with synthetic alternatives," Maureen Kline, Pirelli North America's vice president of Sustainability and Public Affairs, told Rubber News in an email.

"The industry needs to be sure of the supply of natural rubber, be prepared for price fluctuations, and ensure that we are good stewards, responsible for the impacts of our product," she added. "All of these things point to the need to map and understand supply chains and to engage with the value chain to promote a system that is fair, thriving and sustainable over the long term."

Pirelli has several programs to support these initiatives, including its own natural rubber policy, implementation manual and roadmaps, involving all natural rubber suppliers.

The company also has several partnerships with producers and communities, such as its Kirana Megatara project, which enhances training of smallholders, and the Hutan Harapan project, which raises awareness to protect forest biodiversity and improve the lives of the local people.

"In general, Pirelli is committed to improving our environmental and social impacts," Kline said. "Today, we have the leverage to change the way we source natural rubber, especially if we engage with the whole value chain and the entire industry."

Most recently, Pirelli acquired Brazil's largest independent NR producer, Hevea-Tec, which gives the tire maker "direct control" over its Brazilian NR supply chain, "and thus a greater ability to map the supply chain and implement engagement with smallholders and environmental and social protections."

"We must ensure that natural rubber is not contributing to deforestation, which is a key factor in climate change and biodiversity loss," Kline said. "And we must contribute to the sustainability of natural rubber business in the long term, considering that the global demand of rubber is expected to grow in the future."