Firstly, a bit about where the problem begins: the greenhouse effect.
Why go anywhere but Wikipedia for the defintion: The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without this atmosphere. Or if you are graphically minded, this is a nice illustration (thanks to these guys):
The greenhouse effect is critical to human life - without it the temperatures would plummet. However, there is now little doubt that global mean temperatures have been rising, and rising sharply:
Yes systems are complex, and it is impossible to know the impact of every human activity that leads to the warming or cooling of the planet, but almost all climate scientists - people whose job and passion it is to investigate this - agree that it is human addition to the number of greenhouse gases that is a key contributor to this.
So let’s look at the gases that cause it.
The biggest contributor is water vapour - yes steam! According to the International Panel for Climate Change (IPCC), steam accounts for up to 70% of the greenhouse effect. Fog, haze and clouds are all water vapor, and steam is the other main byproduct of the combustion of fossil fuels. Worse still, water vapour is involved in a vicious cycle - higher temperatures result in more water vapor, which results in higher temperatures, and so on. However see here for why it is less important to focus on water vapour than on the other gases that contribute to global warming.
The next biggest contributor is the most famous villain, Carbon-di-oxide or CO2. Plants take it in as part of the photosynthesis process, but many other processes release it including most animal’s breathing process. Much more on this both in this blog and beyond.
Next on the list of contributors is Methane or CH4. One of the reasons beef is terrible for the planet is because cows ruminate - they eat, they half-digest, they keep chewing, and they burp out Methane! And the worst part - Methane is 30 times more effective in trapping heat than CO2.
Nitrous Oxide (NO2) is 298 times more potent but luckily there isn’t a lot of ‘laughing gas’ in the atmosphere. Ozone (O3) and the gases that were the villians in the 90s - Chloroflouro carbons - are the next major contributors.
So while CO2 grabs all the headlines, the other gases can be more dangerous if they accumulate in the atmosphere. Hence when we talk about carbon emissions, really the best measure is CO2e where the ’e’ stands for equivalents - the weightier impact of all the greenhouse warming (and cooling) gases that are released from a process. However the reality is that this kind of granular and rigorous data is not always available but this blog will make every effort to keep its numbers accurate and up-to-date according to the best research out there.
By footprint, we mean the sum total of all the activities an individual might engage in, with the best known CO2e figures for each used to get an overall impact of a person’s lifestyle.
And since a large part of a person’s lifestyle entails the use of energy, a huge part of the calculations is down to the country you live in and the CO2e footprint of its energy generation.
The exact figures seem to differ, depend on the year and source, but in general, the average footprint per person in the developed world is between 5-15 CO2e tonnes and in the developing world is less than 4 CO2e tonnes per person.
Here’s a wonderful Guardian infographic to help the message sink home:
Now that you know the average footprint per person in your country, you can place the impact of a flight between say London and Tokyo (4 tonnes per person on average) in context.
Just do a quick Google to find out how far apart the the place you visited is and use the calculator below to compare the impact of your flight versus the average footprint of a person in X countries. Go calculate and get context!
So while the main source of footprint per country is based on the energy profile of a country (what % is from fossil fuels and what % is from renewable energy sources), the main part of many people’s footprint is down to the long haul flights they’ve taken. A single flight from Europe to Asia or the Western side of the US could be equal to half the average European’s annual footprint. Or in other terms, much much worse than the many other people who are slowly gaining the ability to fly just like you have done (more than once?).
If you’re reading this blog I suspect you care enough to not want to be one of the worst contributors - you don’t want to be one of the people that’s driving up your country’s average footprint. So go here to read about the various ways you can offset your CO2e footprint.
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