The greenhouse gas emissions produced by humans are the result of individual people doing things [5] like taking the train, or buying a burger. Each activity or product releases emissions either directly or did so when it was being made and transported [5].

This can be summarised very neatly in an equation [6]…Don’t be scared! It’s a friendly equation and we’ll go through it step-by-step:

Total emissions = P x C x E

P = Population (the number of people on the planet)

C = Consumption (everything each person “consumes” in a year: buying a phone, driving a car etc. – anything you do!)

E = Greenhouse gas emissions per service (the amount of emissions caused before, during or after you use each service, which could be an activity or a physical product). The greenhouse gas that contributes the most to climate change is carbon dioxide (CO2) [2].

Total emissions = Global greenhouse gas emissions in a year

Of course, everyone consumes different things, so we can expand this to show the emissions from each individual service. Swipe to see an example!

Both population (P) and consumption per person (C) have increased [3,4,7,8] (swipe!) so unsurprisingly total emissions have also increased a lot over the past decades [1].

If we are to stop climate change then we need the total of global emissions to be zero [9]! If we could bring one or more of P, C, or E down to zero, then we would have no emissions – you can see in the next image (swipe!) that it’s basic maths: multiply anything by zero and you’ll get zero [10].


[1] Within report see: Global trends in total greenhouse gas emissions

[2] See: SPM.3 Trends in stocks and flows of greenhouse gases and their drivers

[3] Within report see: section 2.1. Increase from 26.7b tonnes to 75.6b tonnes 1970 to 2010, so a 2.8-fold increase

[4] Within article see: How much energy does the world consume? Calculation: 64052.6 TWh in 1970 to 153595.66 TWh in 2017, so an increase by 2.4x (153595.66/64052.6 = 2.40)

[5] Within paper see: abstract.

[6] Innovating to zero! Bill Gates Ted Talk 2010. The equation explained in this talk inspired Eric Steinberger’s “climate equation”

[7] Within article see: World population from 10,000 BC to today, accompanying graph

[8] Decrease from 0.61kg/$ in 1970 to 0.35 kg/$ in 2014 ((0.61-0.35)/0.61 x100 = 42.62% decrease). GDP per person is standardized using Purchasing Power Parity and the international-$ in 2011.

[9] Within report see: section 3.2.3

[10] Within article see: Any number multiplied by 0 is 0

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