Earlier in the week, the British prime minister, Gordon Brown, announced his aim of moving towards a reduction of 60-80% of carbon emissions by the year 2050.

Of course, there are various issues attached to this. For example, there are still people who are sceptical that human emissions of carbon dioxide are having any impact on the environment. To be honest, within reason, that isn’t something that bothers me. I think that from a Christian point of view, if we are to be good stewards of the resources that we have been given, then that ought to mean we use them as sustainably as we can.

Another issue that vaguely bugs me is the issue of baselines. We can save some percentage of CO₂ if we switch to energy saving lightbulbs. My question is – when? Most of the lights that would be suitable for energy saving bulbs have already been changed. Do I need to find more? Allied to this is the fact that the energy that is “wasted” by lightbulbs for a proportion of the year helps to heat the house up – so more energy saving bulbs means more gas burnt in heating systems. And so on.

Anyway, the challenge. How can we reduce our carbon footprint by half or more?

As an example of the sort of discussion that I have in mind, wikipedia has some detailed discussion of the concept of a space elevator.

This is a structure to transport material from the surface of a planet (classically, Earth) into space.  It would greatly reduce the cost of getting mass into orbit, in addition to drastically reducing the environmental impact.

The “big problem” that our use of fossil fuels has created is that large amounts of carbon deposited in the form of oil and coal a long way underground has been burnt as fuel, ending up in the atmosphere in the form of carbon dioxide.

One of the preferred strategies for dealing with this at the moment is by reforestation – planting new forests either to replace forests that have been removed or simply for growing trees to remove CO₂; and convert it to wood. Whether this will work is not clear – however, the carbon isn’t really removed from the ecosystem; it is just locked out of the atmosphere – at least until the tree dies and degrades.

The challenge: is there an alternative? For example, I wondered whether putting large amounts of plastic into deep landfill isn’t a bad idea – we are told, for example, that it takes hundreds of years to degrade, so won’t go anywhere fast. The UK government also recently failed to take advantage of a proposal to pump CO₂; into the space from where an oil company had just finished extracting gas. Does anybody else have any other ideas?

The Earth may be the only location in the solar system where life could appear – see “Rare Earth” by Ward and Brownlee for more detail. However, it is possible that, with some assistance, there are other places in the solar system where human life could be sustained.

This challenge relates to establishing a human colony elsewhere in the solar system. I’ve suggested Mars, as that is the place in the solar system which is perhaps most amenable to human life – it has an atmosphere, albeit a thin, unbreathable one – and a temperature that isn’t incomprehensibly extreme. However, if people think that somewhere else – the moon, Europa, Titan? – is more appropriate and they want to make a case for it, go ahead.

Getting a spacecraft like Galileo to Jupiter is itself a huge engineering challenge. How would it be possible to get a probe into at least the upper atmosphere, so that it could record images, sample the atmospheric contents, possibly move from place to place and so on?

This challenge involves multiple disciplines. There is the issue of how to get the craft to Jupiter – though this issue has largely been solved at least in principle. Then there is the issue of getting a probe into the atmosphere – at the bottom of a deep gravity well, it will have a lot of kinetic energy to lose if it isn’t to be destroyed! Then there is the issue of getting the probe to do something more than simply float downwards on a parachute, and somehow transmit significant amounts of data.

Arguably, the two most significant products – possibly the only two significant products – in years to come will be information and energy. It is already the case that countries with access to sources of energy can “punch above their weight” – they have a position on the world stage that they wouldn’t have were it not for those resources. 

There are some parts of the world which are rich in energy, but currently have little income. Have a look at the maps here, for example. Much of Africa has large amounts of solar energy potential which is untapped.

 The challenge is this: is there a way for this solar energy be harnessed large-scale in such a way as to provide income for those countries?