Trees & CO2 : What's your tree score?

Forest absorbing CO2

Trees are the most efficient carbon capture machines on the planet.

Through photosynthesis, they absorb carbon dioxide, the greenhouse gas that traps heat in the environment, and turn it into energy. That energy creates new leaves, longer stems and more mass – locking away carbon.

It's estimated that the World produces about 50 Billion Tonnes of CO2 each year. This adds to the unprecedented levels of CO2 already in our atmosphere, which at 412 parts per million (ppm) is the highest it's been for a million years.

It would take something like 3 trillion trees to absorb just the amount of CO2 we produce each year, yet alone the extra already in our atmosphere.

Planting billions of trees is one of the most impactful things we can do to combat climate change but there is simply not the space to plant enough trees to solve our climate crisis. We have to also cut emissions.

"How many trees" is about cutting output

At Homesmart, we have been inspired by the campaign to plant trees to absorb CO2 but we realise that this is only part of the answer. We could never plant enough trees to totally combat our Carbon deficit. So, cutting our output of CO2 is critical.

However, the image of a tree fighting climate change is so powerful that we thought why not use it to show how many trees would be needed to absorb the CO2 from a particular activity? Sort of like a "tree currency"!

Cutting CO2 output is the fundamental basis for reducing carbon emissions and stopping climate change.

Cutting carbon emissions is something we all can do. It's the things we all do in our day-to-day lives that are going to have the biggest and long-lasting impact.

We know that smart heating control can cut your CO2 output dramatically but we thought it'd be interesting to look at some other areas as well.

So, we've thought about various things that we do every day and converted them to a "tree score".

We hope that this might inspire you to take some simple actions.

If you like these or have any other ideas to add to our list - let us know and we'll add them!

The Homesmart Tree Score

1 Tree absorbs 21.7kg CO2 per year

Quite simply we've calculated the number of mature trees that are needed to absorb CO2 from a given activity.  Each mature tree absorbs 21.7kg of CO2 / year over its life.


Your Tree Score

We're all different but the actions that each of us take count.

We've given some ideas which we hope will help you think about your CO2 emissions.

If a lot of people only did some of these things the impact could be quite amazing.

Below we've calculated an example for one of our typical customers. She is not average. A busy executive working for an international company, she travels quite a lot, fuelled by coffee and high protein food. We have installed an Evohome multi-zone system and through our service plan switched her energy bills to a green tariff (actually cheaper than the one she was on). The rest she does herself.

By making the changes below she will be saving a massive 7.2 tonnes of CO2 a year! That's equivalent to planting a small forest of 333 trees.

Here's a summary of what changes she is making:

7.2 Tonnes needs 332 trees to absorb it

If you'd like to calculate your personal carbon footprint we can recommend the following calculator from Carbon Footprint:

Homesmart sell and install smart heating control like Honeywell Evohome multi-zone and Nest Thermostats. We also provide an inclusive energy tariff auto-switching service to all our customers.


Annual Global CO2 Emissions 50billion

Planting Trees to Absorb CO2

Planting billions of trees across the world is one of the biggest and cheapest ways of taking CO2 out of the atmosphere to tackle the climate crisis, according to scientists.

New research estimates that a worldwide planting programme could remove two-thirds of all the emissions from human activities that remain in the atmosphere today, a figure the scientists describe as “mind-blowing”.

The analysis found there are 1.7bn hectares of treeless land on which 1.2 trillion native tree saplings would naturally grow. That area is about 11% of all land and equivalent to the size of the US and China combined. Tropical areas could have 100% tree cover, while others would be more sparsely covered, meaning that on average about half the area would be under tree canopy.

“This new quantitative evaluation shows [forest] restoration isn’t just one of our climate change solutions, it is overwhelmingly the top one,” said Prof Tom Crowther at the Swiss university ETH Zürich, who led the research. “What blows my mind is the scale. I thought restoration would be in the top 10, but it is overwhelmingly more powerful than all of the other climate change solutions proposed.”

Crowther emphasised that it remains vital to reverse the current trends of rising greenhouse gas emissions from fossil fuel burning and forest destruction, and bring them down to zero. He said this is needed to stop the climate crisis becoming even worse and because the forest restoration envisaged would take 50-100 years to have its full effect of removing 200bn tonnes of carbon already in the atmosphere.

20 trees

Trillion Trees Campaign

In 2007, Wangari Maathai launched the Billion Tree Campaign.

So far, 15 billion trees have been planted in 193 countries under the guidance of the UNEP and Plant-for-the-Planet.

The Trillion Tree Campaign was launched as the next step to that.

It's estimated that 3 trillion trees currently exist globally. The trillion tree campaign believes that the world has space for up to 600 billion more mature trees without competing with agricultural lands. To restore these trees, we need to plant at least 1 trillion trees, since some will not survive.

A Trillion Trees could capture 25% of all human-made CO2 emissions and thereby help to keep global temperature rise below the crucial 2°C limit. The Trillion Trees do not replace the need to avoid carbon emissions, as agreed in Paris, but are a necessary addition.

If you want to get involved follow this link:

Greta Thrunberg

Planting trees is only part of the answer

Greta Thunberg, said planting trees is good but no solution to global warming. Thunberg and others emphasise that countries and industries must also stop emitting carbon and switch to solar, wind and other clean energy. Most environmentalists, including those involved in reforestation, would agree with that sentiment.