Millions of trees need to be planted to offset carbon generated by COP25 international participants.

I have been able to make a reasonably accurate, yet ultimately conservative calculation of the amount of trees the 20,000 - 30,000 international visitors to the upcoming COP25 summit in Santiago would have to plant in order to offset the carbon they produced to fly there, thanks to the United States Environmental Protection Agency (EPA) and my personal experience planting trees here in Chile. The numbers are shocking and are a very sobering reminder as to just how far we have to go to mitigate climate change. I hope you will take the time to read what I have written below to understand why I now believe that over forty three million trees would have to be planted to absorb the air flight carbon by those visitors to Santiago within one year.

There are numerous calculators to check the carbon your air flight will create. They appear to be fairly accurate, but calculators that estimate how many trees you would have to plant to absorb that carbon vary greatly and almost all base their calculations on the amount of carbon a mature tree can absorb. A well quoted estimate is around 44 pounds per year. While it is very nice to know what a fifty year old tree, that you can't plant unless you are the Incredible Hulk,can absorb in a year, it is useless information when estimating the carbon absorption capacity of a very young tree. In fact it is very misleading.

It has taken me a while, but finally I have found accurate information from the United States Environmental Protection Agency (EPA) and I find not surprisingly, that a young tree absorbs a whole lot less than forty pounds!

Using the figures provided in this table (see photo) by the EPA and the knowledge of having planted 1200 trees provided by the Chilean Forestry Service CONAF I have been able to make a very conservative calculation knowing that the average tree planted here in Chile would be much smaller than what is considered a year '0' tree in the United States. However, I will use the EPA statistics in the table for a year '0' tree for convenience and use their 'moderate hardwood' recommendation (1.9 pounds = 0.86 kilos) to find an average of carbon absorbed by softwoods and hardwoods in that first year of planting.

Here is the mathematics for carbon created, flying economy - using this carbon calculator and the figures provided in the EPA table. 

https://calculator.carbonfootprint.com/calculator.aspx?tab=3

London - Santiago Return = 1.85 Metric Tons Carbon Produced ÷ .86 kilos carbon absorbed by a freshly planted tree = 2151 trees needing to be planted to absorb the carbon of that return flight within one year.

Tokyo Santiago Return = 2930 trees need to be planted per person

New York Santiago = 1406 trees need to be planted per person

Sydney Santiago = 1937 trees need to be planted per person

Most visitors to the COP25 will come from Europe, Asia, North America and Australasia. As an average amount of kilometers flown I have chosen a flight from London to Santiago. I am also choosing the lower figure of 20,000 visitors to calculate how many trees should be planted here in Chile to absorb the carbon created by those visitors within one year.

Visitors 20,000 x 2151 trees = 43,020000!!!! This is astonishing and by my calculations, which have been very conservative, the number of trees needing to be planted could be much higher, especially when you consider that flying first class and business class creates way more carbon than economy. A person flying business class on that same trip would have to plant 6230 trees. Let's hope that everyone flies economy.