For the past few days I have been in Rome and a visit to the Colosseum is a must when one is there. That arena was constructed for 70.000 spectators and opened 80 years after Christ was born by the emperor Titus with an event lasting 100 days. However, it was Titus’ father, the emperor Vespasian, who began the construction of the Colosseum 8 years earlier. That this project took 8 years to build 2000 years ago must make it one of the world’s greatest ever building projects. China had about the same length of time to build its fantastic “Birdnest” stadium for the 2008 Olympic Games. Just think what emperor Vespasian’s architects might have accomplished if they had been given free rein in Beijing! For those who would like more information on the Colesseum you just need to look on the internet ( What I want to discuss now are the significant factors behind the rise and fall of the Roman Empire compared with today’s “Empire”.

A reconstruction of the Colosseum compared with the “Birdnest” in Beijing.

First we can state that powerful and wealthy leaders always have – and presumably always will – build monuments to their greatness. Building arenas to provide the populace with entertainment has always been high up on the agenda. These can be an opera house in Oslo, an Olympic stadium in Beijing, an enclosed arena for skiing in Dubai – and today’s edifices are being built higher and higher the world over. Today, the energy required to build these monuments is provided by fossil fuels but 2000 years ago it was provided by slaves and the food that allowed these slaves to do work. If one deciliter (100 ml) of oil contains 1 kilowatt-hour and one day of work by a man is almost 1 kilowatt-hour then that means that one can replace a barrel of oil, (159 litres), with about 2000 slaves. Today’s importation of oil can be compared with the Roman’s transportation of slaves from newly conquered lands to the capital in Rome. I have tried to find information on how many slaves were required to build the Colosseum but have not yet found any good estimates. A number of 30,000 to 50,000 slaves have been mentioned and that would correspond to work equal to 15-25 barrels of oil per day. At that time there were no sports drinks but every slave received a wine allowance of approximately two bottles per day. That corresponds to an energy intake of at least 1 kilowatt-hour per day. In the evening they ate a large dinner that represented the remainder of their energy intake, in total 2 kilowatt-hours. In oil equivalence they required 60 to 100 barrels per day. The interesting thing is that the Romans were apparently aware that the slaves needed to be properly fed in order to work.

In the year 217 AD the Colosseum was badly damaged by a large fire caused by a lightning strike. The fire destroyed the upper areas made of wood. Repairs were completed only by 240 AD and further repairs were done in 250 or 252 AD and in 320 AD. Repairs were also performed after an earthquake in 443 AD and then in 484 and 508 AD. The arena continued to be used until some time in the 6th century AD. The era when the Colosseum was used corresponded with the heyday of the Roman Empire. During this entire period slaves were the most important source of energy. As the empire expanded they needed more slaves and, ultimately, they reached the end of the road where they could not conquer additional nations to expand the number of slaves. In this way an energy shortage could have been the downfall of the Roman Empire. To buy slaves coins were pressed and trust was created in the value of these coins. The promised value was much greater than the value of the metal in the coin. There were many who wanted to own, in effect, worthless metal rather than real wealth such as farms and this gave the leadership in Rome the possibility to over-consume and live on Monopoly-money. (Wikipedia information on the Roman Empire.)

Today it is not slaves that are transported to the centres of power to do work but, rather, black oil. (However, as an example the labour force in Dubai is bordering on voluntary slavery. Many men come from Pakistan and are given a bunk in large barracks and food three times per day. There remains only $20 per day that they normally send home to their families.) They are no longer paid with stamped coins of precious metal but with worthless paper on which is printed a number and a quantity of zeros. On the paper there is also a “$” symbol. There are those that declare that the flow of oil will never end but will always increase. But there are others, e.g. Global Energy Systems at Uppsala University, who assert something quite different. The future value of those dollar bills that exist outside the USA remains to be seen.

We still have large flows of energy in the form of oil or manufactured products that enter the OECD nations but the question is if the nations outside the OECD plan to alter this flow. The number of potential customers outside OECD will increase dramatically. We now need leading people within the OECD to realize very quickly what is happening – the insight must come now. In 10 years it can be too late.

(You can make a comment on Aleklett’s Energy Mix:

The Colosseum after the fall of Rome.