#### Calculating Carbon Footprints

###### Dr Cooke's Yearly Carbon Emissions

Using Dr Cooke's self assessment of her lifetime's yearly contributions towards carbon emissions in the form of average, below average, above average, well below average, and well above average, these figures have been generated to reflect her yearly emissons, with the total metric tonnes shown at the bottom.

###### Brief

In order to calculate Dr Cooke's lifetime carbon footprint, various calculations and methods were needed to attempt as much accuracy as possible. Using a combination of data from the World Bank website, comparisons with calculations generated using Carbonfootprint.com, and estimations of specific years and future predictions, Esther Tun developed a system for calculating one's lifetime carbon output.

###### The Method - Carbon Emissions

Below is a downloadable link to a PDF of an excel spreadsheet. This provides data, generated initially from The World Bank website, of the average yearly carbon output of someone living in the UK from the year 1960 until 2018.

Every ten years since 1960, the UK carbon emissions per capita has increased initially by 0.581 tonnes, then decreased by 1.445, 0.563, 0.723, 1.325 and 2.277 (8 years between 2010-2018 due to available data) until currently at 5.399 metric tonnes. If the exponential reductions of carbon emissions continues until the UK-pledged goal of carbon neutral 0 tonnes by 2050, it has been estimated that the year 2030 will be approximately 4.0 and the year 2040 approximately 2.0, with the 10 years in between to average these estimates. This is the basis upon which the estimates of carbon emissions per capita after 2018 have been calculated.

Further columns have been created to provide 4 alternative options than the average amount of carbon produced, in metric tonnes. These are 'well below average' which is a half value, 'well above average' which is one plus half value, 'below average' which is three quaters value and 'above average' which is one and a quarter value.

Dr Cooke then estimated the years of her life and how she beleived her yearly carbon emissions would compare to the national average. Anyone wanting to calculate their lifetime's emissions should do the same. From here you can use the PDF above to add together all of your years, along with estimates of your future yearly carbon output.

###### The Method - Trees and Carbon Offsetting

Once you know how many tonnes of carbon you would like to offset through tree planting, you need to calculate the number of trees that would be needed. There are no exact figures for how much CO2 a tree will sequester in it's lifetime and there are many factors that affect CO2 absorbtion, such as soil quality, tree species, weather etc. However, upon talking to a Woodland Trust representative, we are to understand that '25m2 of native planting will sequester 1 tonne of carbon over the first 100 years of its life (400 tonnes per hectare), assuming all the trees are the same age when planted, are a mix of native species and are managed to industry standards'.

From this information we can calculate that, if 25m2 = 1 tonne over first 100 years, then an acre would sequester 162 tonnes over the first 100 years. As we need to offset 695.8 tonnes for Dr Cooke's lifetime, and rounding up to 700, then 700/162 is 4.3 acres. Which is equivilant to 1.7 hectares. This is the amount of land that CO20 needs to acquire as the location for planting enough trees to offset Dr Alison Cooke's lifetime carbon emissions.