Thursday 14 November 2013

Humanities Great Carbon Binge

The Intergovernmental Panel on Climate Change (IPCC) this week made minor revisions to the amount of CO2 it believes humans are responsible for emitting since the industrial revolution.

The main changes revise the total amount of carbon emitted since the mid 19th Century down
from 531 billion to 515 billion tonnes and revising up the total cumulative amount emitted since the mid 18th Century to 555 billion tonnes, an increase of 10 billion tonnes since their latest report was published in September.

Whilst these changes don't tell us anything new, they highlight the sheer contribution humanity has had on transferring carbon into the atmosphere.

The standout figure is the amount of carbon emitted globally each year - now about 10 billion tonnes. That's a very, very large number and nigh-on impossible to get your head around. The average car in the UK emits about 166 grams of CO2 for every kilometre it drives. Of that, approximately 45 grams is carbon and the rest is oxygen. For that car to annually emit 10 billion tonnes carbon it would have to drive more than 222 trillion kilometres. Ignoring the time it would take, you'd easily get to Pluto, at a mere 5.9 billion kilometres. In fact you'd be able to drive to our closest star Alpha Centauri, 4.4 light years away from Earth, a staggering 5 and a half times.

Now imagine that all of that carbon is all emitted into the confines of our thin envelope of atmosphere each year. Of course, a great deal of that carbon is removed by our oceans and forests, but there's a limit to how much and how quickly they can do this. We're now over half way to the trillion tonne ceiling that the IPCC believes could cause 2°C in warming, which many believe is the cut off for really frightening and irreversible consequences, including sea level rise on the order of metres that will completely transform our coastlines.

What it all means

Trillionth Tonne is an eye-opening site showing how much we've emitted and how much we need to reduce our emissions to keep within 'safe' boundaries. At the moment we're on course for hitting the trillionth tonne mark in 2040 and to avoid that happening we're going to have to start cutting back emissions by nearly 2.5% each year. Realistically, we know that's unlikely to happen in the near future. The world has seen an insatiable rise in our appetite for dirty fuels and the amount we emit is controlled primarily by economic climate, and not, unfortunately, by effective green policies carried through with good intent. Between 2008 and 2009, we did manage to cut back our emissions by 0.35%. But consider that between 2007 and 2008 emissions grew at a rapid 2.3% and it soon becomes obvious that the fall in demand has much more to do with the onset of global recession rather than an abrupt turnaround in attitude.

Emissions of carbon each year between 1750 - 2009. Source 

What Trillionth Tonne really tells us is just how great and rapid a change in attitude there has to be. The truth is that to get to where we are today humanity has needed to burn over 500 billion tonnes of carbon. That's how much energy it takes for the world to go from horse and cart to personal cars and cheap flights. That's how much energy we have to consume in order to develop technology to the point where we can work out, among many other things, how much carbon we've burnt and what the effects of that will be.

Without doubt, humanities greatest achievement is  reaching the advanced technological state that it has. We must remember that it is fossil fuels that has fuelled such enlightenment. But the next great achievement is long overdue; an international collaboration on how we can finally move on from our heavy addiction to all things carbon.