Is all carbon the same??

I wrote two posts previously about why Carbon Dioxide was a greenhouse gas and why it was misleading to think of it as a 'trace gas' in the atmosphere.

In this post I thought I would have a look at the Carbon atom. Aren't all carbon atoms the same?? After all an atom is an atom isn't it?

Well no they aren't. In fact plants prefer some carbon atoms to others and fossil fuels have more of one type of Carbon atom to another. So what makes one Carbon atom different to another?

The difference occurs in the nucleus of the Carbon atom, which is made up of Protons and Neutrons. The most stable versions of Carbon (Isotopes) have similar numbers of Protons and Neutrons, when there are to few or to many Neutrons, the Carbon atom tends to be unstable and so doesn't hang around in the environment for long.

The two stable versions of Carbon are Carbon 12 (6 Protons and 6 Neutrons) and Carbon 13 (6 Protons and 7 Neutrons), these are what we find in our environment.

The atmosphere in current times is known to have a certain ratio of C13 to C12. Also we know that plants prefer C12 to C13 in the photosynthesis process. This is also reflected in the Carbon composition of fossil fuels that are made up of ancient plant materials. Compared with the atmosphere, fossil fuels have a lower C13/C12 ratio.

Hence by analysing changes to the Carbon Isotope composition of the atmosphere, it is possible to also determine where the increasing amounts of carbon are coming from. It turns out that the Isotope ratio is changing, showing that more Carbon from fossil fuels is remaining in the atmosphere.

But that isn't the only part of the environment where the Isotope ratio is changing. The same changes are happening in the surface of the Oceans, corals, sponges, and even our food.

So, we have another 'fingerprint' showing that we are changing our environment in many ways and altering the climate by burning fossil fuels.

More Climate Science