How we calculate carbon

Q: How do you calculate carbon emissions in the carbon calculator?

We want to  accurately represent the positive environmental impact you can have as a Trainhugger user. Below is all the information about where our data comes from and why attributing a specific amount of carbon to trees can be tricky.

Putting in Your Journey

  • When you input your destinations in the carbon calculator, we figure out how much CO2e per passenger KM is emitted from that train journey.
  • We use the latest official data from the UK’s Office of Rail and Road which is updated annually.
  • Currently, we’re using the measurement: 1 passenger KM of a train journey emits 36.6g of CO2e (on average). This is from the 2018 – 2019 Rail Emissions 2018-19 Annual Statistical Release. 


Tree CO2

  • When it comes to figuring out how much CO2 your tree will absorb, we use the generally accepted average measurement of one tonne of CO2 per broadleaf tree, over its lifetime (approx. 100 years, although we plan on having many of our trees growing well beyond 100 years – broadleaf trees can often grow for hundreds of years!) (Grantham Institute, Climate Change & The Environment, 2015). Although very tree is different and absorbs carbon at different rates.
  • Even though our growers are required to take very special care of their trees, we’ve also factored in a 10% buffer to account for any young trees that might not make it to full adulthood.
  • So, for our calculations, we equate one tree to absorbing 900kg (on average) over its lifetime.
  • Since trees absorb carbon at different rates depending on a number of factors (species, conifer vs broadleaf, local environment, how fast the tree grows, soil type, the age it is when the tree dies/is harvested, etc.), there is no comfortable universal number for the amount of CO2 absorbed by a tree. That is why we want to be conservative in our estimates and why we include the 10% buffer.


End Result

  • Once you’ve inputted your to/from destinations into the calculator on the Trainhugger website, it will show you how much CO2 your journey emits, how much CO2 your tree will likely absorb over its lifetime (900kg) and the CO2 you’ve helped save from the atmosphere by booking your train ticket with Trainhugger (tree CO2 absorbed – journey CO2 emitted). Yay!

Q: How do you calculate my Trainhugger impact in my account?

In your account you can see how many trees you’ve helped plant. To put this into helpful context , we’ve offered up some comparisons.

  • One tonne of CO2 absorbed is like stopping 3 sq metres of arctic sea ice melting (2016 Study)
  • One tonne of CO2 absorbed is like taking 0.22 cars off the road for a year (EPA Carbon Calculator)
  • One tonne of CO2 absorbed is like saving 0.12 homes’ energy use for a year (EPA Carbon Calculator)