You know what they say about the guy with the big feet...?

...He has a big footprint.

A footprint consisting of 8.33 metric tonnes of CO2, to be precise. That’s roughly the size of the carbon footprint I’ll be leaving when I jet off around Asia, and that figure doesn’t even take into account any internal travel. To put that into perspective the average car emits around 5.2 tonnes of CO2 per year, and the average British household around 6 tonnes.

So what was my airline willing to do to help me slip into a smaller sized loafer, other than cut off my toes?

One concept which you may have come across, particularly when booking flights, is the notion of carbon offsetting. This can come in three general forms;

1. Investing in greener energy sources. This usually means investing in the development of wind farms. It’s debatable whether you’re actually offsetting anything here because the net effect is still negative, that is, your flight will still pump x amount of CO2 into the atmosphere while the wind farms don’t remove any CO2, only reduce our reliance on fossil fuels (by a negligible amount).

2. Investing in carbon capture projects. This involves preventing emissions, usually from cows (they emit an incredible 300bn litres of methane into the atmosphere every day) and land fill sites, from entering the atmosphere. This methane can be turned into liquefied natural gas which burns much cleaner than fossil fuels, but the energy required to transform the gas to liquid might undermine the benefits.

3. Planting Trees. This is perhaps the most popular scheme. The idea here is that your airliner will plant x amount of trees in order to offset the proportion of the flights total CO2 emissions which are directly attributable to you. There seems to be a lot of confusion about the actual benefits of this method, but a little science lesson can teach us how this process works, and draw attention to some of the common misconceptions.

The process of photosynthesis uses the energy from light to convert CO2 (plus water and nutrients from the soil) into oxygen, water and organic carbon compounds such as carbohydrates (i.e. glucose), which are then stored within the cells of the tree. Cellular respiration is the process of converting this stored glucose and oxygen back into energy (which the plant uses to grow), water and CO2.

This means that it takes at least a few years to realise any net benefit from planting trees as the by-products of photosynthesis and cellular respiration initially cancel each other out. However, as the tree grows it begins to store increased amounts of glucose which are surplus to the current energy requirements (much like how humans store fat). The critical thing to remember is that excess CO2 is stored in an organic compound which can only be maintained in living cells. The stored glucose will revert back to CO2 as soon as the tree dies and begins to rot. Therefore, the net effect on CO2 levels of planting a tree is zero.

At a basic level we should think of CO2 as being redistributed rather than permanently transformed, and this seems to be a common misunderstanding. In order to benefit from this method it is vital to manage forests effectively to ensure that the number of new trees being planted is greater than the number which are dying or being deforested.

The second misconception regards the immediacy and scale of the effects. There is an interesting interview with Andy Harrison, CEO of EasyJet, in which the interviewer, George Monbiot, raises an important point - 1 ton of CO2 saved today is the equivalent of 10 tonnes of CO2 in the future. Over a 40 year life span the average sub-tropical tree will absorb around 650kg more carbon dioxide than it will emit. So that 1 tonne of CO2 you emit on a single flight will affect the planet for 40 years before the two trees you plant finally offset it, and by this time the damage is already done.

So in my case, for example, I would probably have to plant around 123 trees to offset the effects of the CO2 emissions (rather than simply offsetting the numbers). Now consider the number of flights which an airline makes in one day and you’re talking about a biblical amount of trees! Armed with this information it becomes apparent that offers to plant 5 or 10 trees to offset our carbon footprint are simply insignificant token gestures. It’s so important not to be taken in by the spin of the corporation because they’re essentially green washing their activities to ensure that you feel satisfied you’ve done your part for the planet. It prevents any type of consumer activism which gives them a license to further avoid regulation and continue to maximise their profits at the expense of the planet.

It also fuels the misconception that by simply planting 10 trees we can offset the carbon footprint of our cars or houses and by doing so we are doing everything we can in the battle against climate change. Somehow, by planting a tree we are morally absolved for our wasteful actions and disrespect for the environment. Unfortunately, it just isn’t the case.

What I’m driving at is that we shouldn’t consider planting a tree as the silver bullet for climate change. We should, however, utilise carbon offsetting in tandem with reducing emissions and regulating the emissions of big business, while continuing to encourage the development and use of greener technology.

So what am I going to do to rectify my carbon footprint? Well none of the options are exactly toe-severingly drastic. Maybe a swift pedicure is in order, I'll have to run a hot bath and think about it... or go and sit in the car with the engine running, I'm easy.