The International Energy Agency (IEA) has estimated that the governments of the world will need to spend $45 trillion (i.e. $45,000 billion) by 2050 to develop a low-carbon economy. They are calling for an "energy revolution" in order to curb CO2 emissions, which it predicts will otherwise "more than double" if present energy practices are maintained. The IEA also stressed that demand for oil will rise by 70% during this period. However, demand can do as it will it is supply that will provide the limit to whatever actions might by then be sustained. As the old saying goes: "If wishes were horses, beggars might ride." I very much doubt that another 70% per year can be found, which would add-up to a total of just over 50 billion barrels a year from 30 billion barrels used annually now.
It is not just a simple matter of dividing the total reserve volume by current annual use, which would suggest 1,200/(50-30) = 24-40 years worth, since the output of oil from a well roughly follows the Hubbert curve and production reaches a maximum and thenceforth declines until it is no longer economic or possible to get more oil out. Hence the world oil production must begin to fall, and some think within a few years. Therefore, such future enhanced demand figures make no real sense. We won't be able to maintain the present output within a few years and it would make more sense to plan for that eventuality rather than promulgate some fantasy of unlimited growth.
The IEA proposals do in fact address this, albeit in a less explicit way. In addition to various schemes for carbon-capture and sequestration - which the UK government has not agreed to, and indeed granted a permit for a new coal-fired power station in Kent, recently, with no CCS equipment, on the grounds it was an untried and untested technology (true!) - the agency calls for new nuclear plants, and retrofitting 35 coal-fired and 20 gas-fired power plants with CCS technology at a cost of $11.5 billion per unit. It also recommends building 35 new nuclear power plants and 17,500 wind turbines every year until 2050 (i.e. for the next 40 years).
Other recommendations are a massive development of solar-energy and the implementation of so-called second-generation biodiesel (made by converting lignocellulose into a mixture of CO and H2 which is then turned into diesel via Fischer-Tropsch catalysis). The latter has the advantage that the whole plant is converted to fuel rather than just the sugar components. I wonder though, in an age when fossil fertilizers must become more scarce and expensive, that might be the time to return as much of the organic chaff from plants to the soil to maintain its fertility and health. It is already a problem now, that overproduction using synthetic fertilizers has in some regions all but removed the organic component of soil, leaving just a mineral (inorganic) matrix on which to grow anything.
I am doubtful that fractious and generally world-divided political will is likely to be brought to bear in a concerted, potentially altruistic fashion, but at least the IAE has emphasised the scale of the problem. $45 trillion accounts for around 1.1% of the world's GDP which is not much to spare humanity and the ecology of the planet, but it may prove a bridge too far, and once again even these draconian proposals do not solve the problem of scarce and relentlessly expensive liquid fuel without which air transport will all but disappear, destroying the global village, and the lack of cheap, road-fuel which will tend to restore us to more familiar actual villages.
"IEA calls for $45 trillion global energy technology revolution." By Nick Clark. The Independent, Saturday, 7-6-08. http://www.independent.co.uk/news/business/news/