I once saw a TV advertisement of a car, about ten years ago. I don't remember the specific model, but I do remember that I was shocked when it boasted that the car emitted “only” 300g of CO2 per kilometre. That number kept me thinking. In a 300km week-end trip (something usual for me at that time) you would have thrown 90kg of carbon dioxide in to the atmosphere. It was hard to digest, 90kg was quite more than what I weighted!!
In normal conditions a gas occupies 22.4 litres per mol, and in 90kg there are 2046 moles, which means 46000 litres (!!) of CO2released into the atmosphere every weekend. (Yes, I still was taking chemistry in high school at that time.)
At that time, all I had heard about environmental problems was the hole in the ozone layer, and the greenhouse effect. Both invisible problems caused by invisible gases... After the advertisement, CO2 stopped being an invisible thing that presumably was contaminating the atmosphere, to become a steamroller that could easily crush you and your car.
Time passed and I had the chance to look at things with a little more of formality. Actually almost no (new) cars emit that amount of CO2 today. But the situation is not a lot more hopeful.
In the full combustion of a litre of petrol or diesel, we obtain energy joining the carbon atoms present in the fuel with oxygen from the air, producing 2.3 and 2.6 kg of CO2 in each case. (with the price of fuel at 1.5€ per litre it's quite a lot cheaper to emit a kilogram of CO2 than to buy a kilogram of potatoes.)
The exact amount of CO2 emitted per kilometre would depend then on the consumption per kilometre, the combustion efficiency and so on. From next year the European Union will forbid new cars to be sold that emit more than 130g of CO2 per kilometre.The emissions of the Spanish fleet is hard to estimate, nevertheless, the current figure is above 150g per kilometre.
After that, I knew that mankind’s ecological footprint is nowadays around 1.4 Earths. This means that to keep the current level of
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| How many Earths can we screw? |
And I say waste because our ecological footprint would probably be less than one Earth if our system wasn't so spendthrift and inefficient at the same time.
The global performance of our system is around 3%. Yes, 3. Only 3 out of 100 units of energy that we transform are useful. Picture how traumatic it would be to make 100 euros and spend 97 in transportation to go to work, and then spend 2 on something you don't need. Well that's exactly what's happening. (Now if you live in Spain you can simply try to picture going to work. )
This number is hard to digest, but can be understood with some examples:
- A paradigmatic example of waste/inefficiency is a ski slope in the middle of the desert in Dubai. It didn't seem enough to ski in Dubai, there is some people that decide to take a coffee next to the slope, and for them not to be cold (!?) there are some gas burners. (update, it's two cafés: St. Moritz café and Avalanche Café.)
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| Forget about Switzerland. Dubai here we go. |
This example might seem bizarre, but is not far from behaviours that we consider normal:
- To extract oil, we need energy, so the net amount of energy that I can obtain from oil is lower, because I have to use account for a fraction of that energy for its extraction. (and processing, and transport...)
- From the 60W consumed by a traditional bulb, only 2W are transformed to light. The rest is wasted in the form of heat. Modern lights are more efficient. (It's hard to invent a less efficient way of producing light.)
- To take a 70kg person from home to work, one would transport a 700kg car, using a motor that is only able to exploit less than 30% of the energy contained in the oil.
- We are burning natural gas in power plants to produce heat that moves a turbine that produces electricity that is brought to our homes to produce heat for cooking.
For our ecological footprint to fit in our finite planet, we would have to reduce use of resources to the levels that we had in Spain in 1933. Someone might claim that we would lose our standard of welfare, but our “high” welfare level comes with three quarters of the world population having none. Besides, does someone really think that the increase in welfare level has been proportional to the increase in natural resources,that have been needed to sustain this ever since? That's the point.
So with this as the starting point, I decided to open this blog;to write about sustainability, and about how renewable energies aren't going to let us keep this level of waste, but are nevertheless the only choice if we want to have any chance for the future. This blog welcomes discussion, debate and has a big learning purpose for me.
Thanks for reading.
And now please feel free to comment.
(Click aquí para la versión original en castellano de este post.)
Special thanks to Phillip Old for helping with the translation.
