Gumtree’s carbon calculations prove the value of a circular economy

Business Area

Education, Operational

Key focus



Longer term


Buying new goods, like most things, creates a carbon footprint. So, to promote the true benefit of the circular economy, Gumtree worked with Leeds University to quantify the impact of buying something new, versus reusing something that already exists. To make this more tangible, they translated the cumulative carbon emissions of a group of people into an equivalent action, such as flying from London to Sydney. The intention? To show that if everyone makes a small change, it can make a big difference.

What are you aiming to achieve?

Gumtree enables millions across the UK to participate in a circular economy by making local trading safe, simple and enjoyable.

It’s generally understood that to tackle the unfolding climate crisis, we need to drive down the production of new goods by consuming less and reusing what already exists. And yet, the vast majority of people still default to buying new, often for convenience reasons. As a result, our research found the UK sent 3 million items to landfill between 2019-2021.

We created a carbon calculator to show consumers the environmental impact of their individual shopping habits via easy-to-understand comparisons. Our aim is to shock people into thinking ‘why’ before buying new.


A women standing on a ladder with a screwdriver in her hand.

Describe how the initiative works

Gumtree partnered with the University of Leeds to create a model that calculates the embodied Greenhouse Gas Emissions (GHG) associated with the production of all goods and services consumed in the UK. The data for Gumtree’s carbon emission saving’s calculator (or Carbon Calculator for short) is taken from the official UK Government analysis of the carbon footprint of UK residents and provides an average carbon footprint for individual products and services.

The model’s calculations give tangibility to our choices by showing how much CO2e is created when an item is produced new. The Gumtree team turns this amount into something relatable and easily understandable, such as the equivalent carbon footprint of daily hot showers or the number of long-haul flights. We make the amount of carbon emissions created when an item is bought new rather than second-hand obvious and unavoidable.

To tackle the climate crisis businesses must work together to create a sustainable future. Gumtree is therefore open to sharing its Carbon Calculator with other organisations to give visibility to the consumption choices we as a nation are making.


What was the first step you took to get the initiative off the ground?

We knew that for Gumtree to make a difference, we had to highlight the UK’s relationship with overconsumption and be brutally honest about the state of the ecommerce industry. We began by issuing freedom of information requests to all 33 local councils in England to understand the levels of waste generated each year.

The returned data clearly showed the UK is tackling a huge waste problem. We needed a way to communicate the issue and began to look for partners who could help explain the environmental impact of individual actions in a way that would make people take notice.


What budget/resource did you need to get started?

The project to produce a carbon calculator sat within Gumtree’s marketing team. We worked closely with our external communications agency, PLMR, to find a credible partner, which we did with John Barrett, Professor of Energy and Climate Policy in the School of Earth and Environment at the University of Leeds.


What positive impact has it had? 

The carbon calculator has enabled Gumtree to quantify overconsumption. To provoke and shock, we take the carbon footprint of an individual purchasing a single or small group of items new and multiply this figure across a larger community.

For example, the Carbon Calculator shows if every person swapped their homeware purchases from new to second-hand for the next three months alone, an estimated 10.9 billion kgs of carbon across the nation would be saved – enough carbon for every person in the UK to enjoy hot showers for six months.

Alternatively, if all new parents bought a new monitor, cot, pushchair and clothes for their baby, that’s the same carbon footprint as flying to the moon and back 57 times.


What have you learnt that could help others looking to do something similar? 

●  Reinventing the wheel is often a waste of time, but tweaking a great idea can be hugely productive. Gumtree’s Carbon Calculator isn’t the only carbon footprint calculator in existence, but none of the available models were right for what we needed. By analysing what already existed, we could work with the University of Leeds to create a bespoke carbon calculator that could talk directly to our customers and help emphasise the importance of embracing a circular economy.

●  Once you have invested in a tool, use it if it works. We’re always actively looking for ways to include our Carbon Calculator in our internal and external messaging and materials.


Can you sum the initiative up in one sentence?

Gumtree’s carbon calculator is an evergreen tool that quickly and simply demonstrates the impact of buying new versus embracing the circular economy.


Can you provide a quote from someone that works on the project?

Hannah Rouch, Chief Marketing Officer at Gumtree: “The climate crisis our world is facing is so huge that it can be difficult for people to understand how their individual actions can make a difference. Our carbon calculator brings to life the environmental impact of consumption choices, making it easier for people to grasp the consequences of their actions and, therefore, make better decisions. It is crucial we are all more aware of our carbon footprint and embrace a philosophy of reduce, reuse and recycle.

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