Our News

Photo by Jonas Weckschmied on Unsplash

Is the grass greener on the other side?

In an era dominated by concerns over climate change and environmental impact, our everyday choices hold greater significance than ever before. Continuing our ‘carbon cost’ series, we asked our audience what they wanted to know the carbon cost of next, and you answered: lawns!

Decisions about how we maintain our lawns are more significant than they might initially appear, because they extend beyond residential development to impact urban planning and corporate developments on a global scale. These decisions have various implications on climate resilience, water conservation, biodiversity, and community well-being, making them important not only for individual homeowners but also for entire communities, cities, and corporate entities worldwide.

The Carbon Footprint of Production

The journey of artificial grass and natural grass lawns begins with their production processes, which lay the foundation for their respective carbon footprint.

Producing artificial grass involves the manufacturing and transportation of fossil fuel-derived compounds, contributing to a notable carbon footprint. Artificial grass is made of synthetic fibres including polyethylene; the production of which emits approximately one ounce of carbon dioxide for each ounce of polyethylene (PET) produced.

The production of natural grass lawns entails traditional methods such as land preparation, soil treatment, and seeding. While not entirely devoid of carbon emissions, these practices are significantly less energy-intensive compared to the production of artificial grass. Natural grass lawns produced in-situ from seed have a lower carbon footprint than those from natural grass turf, which carries the increased carbon cost of transportation from where it was grown as it is heavier.

Carbon source vs carbon sink

As well as the carbon footprint associated with its production, artificial grass releases greenhouse gases as it degrades. When exposed to sunlight, the plastic compounds it is made from undergo a process known as ‘outgassing’ or ‘off-gassing’ – the releasing carbon dioxide, methane, and other harmful chemicals.

Natural grass, as a living plant, absorbs carbon dioxide from the atmosphere. This process allows grass to act as a carbon sink, helping mitigate the effects of greenhouse gas emissions. As natural grass grows, it stores carbon within its biomass and soil. This carbon sequestration ability can enable well-maintained grassy areas to contribute to local carbon balance.

However, when lawns are heavily maintained, the positive effects of carbon sequestration can be outweighed by the greenhouse gas emissions produced by routine maintenance practices, including mowing, irrigation and fertiliser application.

Maintenance Matters

While artificial grass is touted as a ‘low maintenance option’ since it doesn’t require watering or mowing, it still needs periodic cleaning. This requires the use of machinery, such as pressure washers and power sweepers, which carries an energy cost. The production and transportation of toxic chemicals used for cleaning also carries a carbon cost, while their application is harmful to local plants and animals, causing additional ecological damage.

Highly manicured natural grass lawns are often maintained with regular mowing, irrigation, and chemical use. While gas-powered mowers have largely been replaced by more efficient electric mowers (which emit 16 times less CO2 emissions per acre compared to gas mowers), mowing still has an energy cost.

Natural grass lawns typically require at least 1 to 1.5 inches of water per week, either by rain or irrigation. However, the grass species, soil, and weather conditions affect how much water lawns need. Water scarcity is a growing concern in many regions, amplifying the importance of water-efficient choices.

Chemical fertilisers, herbicides and pesticides are often used to maintain the aesthetics and vitality of manicured lawns. Manufacturing these products requires energy-consuming processes and the extraction of limited natural resources, thus adding to the carbon footprint. These chemicals also have an ecological cost; they harm local plant and animal species, reducing biodiversity, and can leach into groundwater, polluting waterways.

Natural grass lawns can be effectively maintained in less intensive ways. Mulching, a landscaping technique involving the application of organic materials like grass clippings or wood chips on the soil’s surface, serves to retain moisture, stabilise soil temperature, suppress weeds, conserve water and enhance soil quality. Adopting such practices can cultivate lush lawns, with a lower carbon footprint, that better harmonise with the local ecosystem.

Lifecycle considerations

Over time, artificial grass deteriorates and requires replacement, further contributing to greenhouse emissions through the disposal process. Due to its synthetic composition, artificial grass is not easily recyclable, resulting in its accumulation in landfills, where it releases methane; the greenhouse gas 21 times more potent than carbon dioxide.

On the other hand, when appropriately maintained, natural grass lawns can endure for extended periods without replacement; and even self-replace if allowed to go to seed.

The Heat Island Effect

Synthetic surfaces like artificial grass tend to absorb and retain heat, raising local temperatures in urban areas – contributing to the ‘heat island effect’. Concerns have been raised about artificial grass potentially causing third-degree burns, posing a particular risk to pets and children.

Unlike artificial grass, natural grass remains cooler due to the moisture content in the soil and the grass itself.

Flood management

The surface of artificial grass is non-porous and so does not absorb water. The infill material used in between the synthetic fibres, such as rubber pellets or sand, can further reduce absorbency. Poor drainage increases surface runoff and, in turn, flood risk. With heavy rainfall events happening more often due to climate change, the frequency and severity of flooding is a growing concern.

On the other hand, natural grass can absorb a significant amount of water into the soil, reducing the amount of surface water runoff that contributes to soil erosion and flooding.

Biodiversity

Artificial grass eradicates natural habitat for insects and birds, destroying the essential biodiversity of local ecosystems. But, as we’ve seen, highly manicured natural grass lawns heavily managed with chemical pesticides and herbicides also disrupt biodiversity.

Creating native grass lawns that align with local weather conditions and feature a diverse range of plants not only require less maintenance and have a lower carbon cost, but they also adapt better to the climate and foster biodiversity. The inclusion of flowering plants, like clovers, buttercups and daisies, attracts pollinators, supporting essential ecosystems. Furthermore, the absence of pesticides ensures the health of beneficial insects and other organisms, contributing to the overall resilience of the local environment.

Initiatives like ‘No Mow May’ have gained increasing popularity in recent years, marking a positive shift in landscaping practices that prioritise biodiversity. ‘No Mow May’ encourages homeowners and communities to refrain from mowing their lawns in May, when pollinators are actively foraging and in need of diverse and abundant food sources. This simple act has significant ecological benefits. Allowing wildflowers like daisies, clover, and other native plants to bloom provides nectar and pollen resources vital for the survival of various pollinator species. 35% of global crops plants rely on pollinators, so they are essential for our survival, too.

The winning solution?

As we strive for greener, low-carbon spaces, making an informed choice requires a holistic assessment that extends far beyond the surface. By critically evaluating the carbon cost of each option, we pave the way for landscapes that harmonise with nature and contribute to a more sustainable future.

And although lawns don’t need to conform to highly manicured standards, by reconsidering traditional landscaping approaches, individuals and communities can pursue options that not only have a lower carbon cost, but support ecosystem health.

What’s more, landscaping options go beyond the dichotomy of artificial grass versus natural grass; from embracing the untamed beauty of wildflower meadows to cultivating native plant gardens, there exists a spectrum of landscaping possibilities that challenge traditional norms and offer a harmonious blend of aesthetics and ecological responsibility.