What Does CO2-Negative Footwear Actually Mean?

Quick answer: Carbon negative generally describes a situation in which more greenhouse gases are removed from the atmosphere than are emitted within a defined boundary. For a shoe to credibly be described as carbon negative, however, the carbon balance needs to consider much more than its main material. Raw materials, processing, manufacturing, transportation and other stages of the product's life cycle can all contribute emissions.

Hemp can help reduce the carbon footprint of a product because, like other plants, it absorbs CO2 from the atmosphere as it grows. But using hemp does not automatically make a finished shoe carbon negative.

Here's what the term actually means... and why the distinction matters.

The terms are related, but they don't mean exactly the same thing.

Carbon neutral generally means that the greenhouse gas emissions associated with a defined activity or product have been balanced by equivalent reductions or removals. Depending on the claim and methodology used, this can involve carbon credits or offsets.

Carbon negative goes further: it implies that the amount of greenhouse gases removed exceeds the amount emitted within the boundaries of the calculation.

That makes carbon negative a significant claim. To establish it for a physical product such as footwear, the entire relevant carbon balance needs to be measured rather than inferred from one material alone.

Every shoe starts with raw materials, and those materials contribute differently to its environmental footprint.

Conventional synthetic fibers and foams are commonly produced using fossil-fuel-derived feedstocks. Plant-based fibers have a different starting point: plants absorb atmospheric CO2 through photosynthesis while they grow.

That's one reason we chose hemp.

However, the carbon absorbed during cultivation is only one part of a product's carbon story. Turning a crop into textile fiber requires harvesting, processing, spinning, weaving or knitting, manufacturing and transportation — all of which can generate emissions.

So choosing a plant-based material can help reduce dependence on fossil-based materials, but it should not be treated as proof that the finished product is carbon negative.

Industrial hemp is a fast-growing annual crop that produces substantial biomass in a relatively short growing cycle. As that biomass develops, the plant takes CO2 from the atmosphere and stores carbon in its tissues through photosynthesis.

When hemp fibers are turned into durable products, some of that biogenic carbon remains stored in the material during the product's useful life.

There can also be environmental advantages beyond carbon. Depending on where and how it is grown, hemp can require relatively low levels of agricultural inputs compared with some conventional fiber crops.

But agricultural impacts vary considerably according to geography, farming practices, processing methods and yield. That's why broad claims about a universal amount of CO2 absorbed by "one acre of hemp" should be treated cautiously.

Not automatically.

This distinction is important.

Knowing how much carbon a hemp crop absorbs does not tell us the carbon footprint of the finished shoe.

A credible product-level calculation would also need to consider factors such as:

• hemp cultivation and harvesting

• fiber and textile processing

• other materials used in the shoe

• manufacturing

• energy consumption

• packaging

• transportation

• the methodology and life-cycle boundaries used in the assessment

The final result depends on the balance between these emissions and any carbon removals or storage that the chosen methodology legitimately attributes to the product.

Without a product-specific, independently verified life-cycle assessment showing a net-negative result, the safest conclusion is that hemp has characteristics that can contribute to lower-carbon footwear, not that every hemp shoe is inherently carbon negative.

Environmental claims should come with evidence. If a product is described as carbon negative, these are useful questions to ask:

• What exactly was measured?

• Which stages of the product's life cycle were included?

• How were emissions from manufacturing and transportation calculated?

• How was biogenic carbon treated?

• Were carbon offsets or credits included?

• Was the methodology or calculation independently reviewed?

• Is the claim about one material, one product, or the company's overall operations?

The more specific the claim, the easier it is for consumers to understand what it actually means.

At 8000Kicks, hemp is at the center of our material choices.

We use industrial hemp because it is a renewable, plant-based fiber with properties that make it particularly interesting for footwear: it is durable, breathable and versatile, while reducing our reliance on conventional synthetic textiles.

Hemp also absorbs atmospheric CO2 while growing, which makes its carbon cycle fundamentally different from that of materials made entirely from fossil-fuel feedstocks.

But material choice is only part of a shoe's environmental footprint.

That's why we believe environmental claims should be tied to measurable evidence rather than assuming that using a natural material automatically makes a finished product carbon negative.

Does hemp absorb CO2?
Yes. Like other plants, hemp absorbs atmospheric CO2 through photosynthesis as it grows. How much it absorbs depends on factors including yield, growing conditions, location and farming practices.

Does using hemp automatically make a shoe carbon negative?
No. The environmental footprint of the finished shoe also includes processing, other materials, manufacturing, transportation and other stages included within the chosen life-cycle boundaries.

Is carbon negative the same as sustainable?
No. Carbon impact is only one part of sustainability. Water use, land use, chemical inputs, durability, working conditions, material sourcing and end-of-life considerations can also matter.

Are synthetic materials automatically worse than natural materials?
Not necessarily in every environmental category. Environmental impacts depend on the specific material, production system and product life cycle. However, many conventional synthetic materials are derived from fossil fuels, whereas hemp is a renewable agricultural material that absorbs CO2 while growing.

How can the carbon footprint of footwear be measured?
A Life Cycle Assessment (LCA) can quantify environmental impacts across defined stages of a product's life cycle. The result depends on the scope, data and methodology used, which should be clearly stated when making product-level environmental claims.

• The Complete Guide to Hemp Footwear
• The Science Behind the Shifter's Airflow Hemp Knit
• Hemp Footwear and CO2: What You Need to Know

Learn more about the materials behind every pair. Explore 8000Kicks →