Mammut and Protect Our Winters Switzerland are helping to make mountain sports even more sustainable. With the project “Close the Loop” they give climbing ropes a new life.

Ropes are firmly anchored in Mammut’s DNA – and account for 13% of Mammut’s global carbon footprint. A climbing rope is usually used for about five years and then thrown away. This realization triggered a fundamental rethink within the company and the project “Close the Loop” was born. The goal was clear – to find out how the polyamide that makes up the ropes could be reused again and again.

In June 2020, Mammut began collecting used ropes, in collaboration with the climate NGO Protect Our Winters (POW) Switzerland. Climbers had the option to donate their used ropes at nine collection points around Switzerland, as well as the option to use a free shipping service. “Close the Loop” was well received by the climbing community. What began as nine collection points at the start of the project, grew to a total of fifty.

Regenerated nylon from waste

In three months, 748 kilograms of rope were collected. They were then delivered to Aquafil, a company which produces man-made fibers and is specialized in sustainable production models. Aquafil developed a system to convert nylon waste, from items such as ropes, fishing nets and fabric scraps into their Econyl® regenerated nylon. Through a chemical process, the nylon contained in the waste is processed into recycled nylon – with identical properties as the yarn made from fossil fuels.

Mammut’s designers then developed a T-shirt made of 100 percent regenerated nylon. To minimize CO2 emissions during the production process, Mammut put emphasis on establishing a European supply chain. Aquafil regenerates the ropes, together with other nylon waste, in Slovenia. Then, in Lithuania, the textile company Utenos Trikotažas, processes the Econyl® regenerated nylon into a functional T-shirt.

The route is completed in Switzerland using HeiQ Pure technology, which prevents the build-up of odor. Thanks to this technology, the consumer can wash the T-shirt less often and save water.

“Together with Mammut, we were able to show that concepts for a circular economy can also be implemented in the outdoor industry. This is urgently needed to strive for a net zero society,” says Nicholas Bornstein, Head of POW Switzerland.

Photo: Stefan Weiser

Evaluated all the way

The non-profit foundation Myclimate conducted a comprehensive life cycle assessment to determine if and how CO2 emissions are reduced through the “Close the Loop” project. It evaluated the entire production process, from the collection point of the ropes in Switzerland, to T-shirts at the hands of the end consumer. The analysis included water and energy consumption, as well as land use. The study was carried out according to current scientific standards and was checked by an independent third-party company.

The result: during the whole production Mammut was able to save 67 percent of CO2 emissions per T-Shirt, compared to the traditional production with raw materials from oil. The 748 kg of collected ropes were mixed with other nylon waste to create the regenerated nylon yarn.

“By disposing our collected ropes with Aquafil and producing 1’000 T-shirts the pilot project saved a total of 5.41 tons of CO2 emissions compared to traditional production. For comparison: this is equivalent to the average CO2 emissions of a car in one year,” says Alice Martin, Corporate Responsibility Manager and Project Lead of ”Close the Loop,” and continues:

“This project is an important step on our path to become carbon neutral by 2050.

” With the upcoming global roll-out of “Close the loop,” Mammut is committed to pioneering far-reaching changes within the outdoor industry.


Main Photo: Thomas Senf

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