The groundwork should be being laid for geoengineering projects in case there is not agreement fast enough on lowering GHG emissions or for if it is not agreed for emissions to come down fast enough. If the groundwork is done then if negotiations fail on the necessary cuts then the more radical solution of blocking out the sun can be implemented. If however no previous work had been done on the possibilities and projects we would be in a similar position as we are currently in with clean energy, lots of ideas but none of them yet showing themselves to be the most effective.

Beginning work on such a project when you don’t even know if it will be used is a waste of money and resources.

The costs of reducing greenhouse gases to the extent that will be needed to stop global warming will be immense. As such ways of geo engineering the planet are likely to be a significantly cheaper way of reducing climate change and its impact on the world. It could be 100 times cheaper to reduce the temperature of the world by putting aerosol particles into the atmosphere to reflect sunlight than it would be to reduce temperatures by reducing GHG emissions.

Geoengineering projects could act as a temporary solution to the problems of climate change that would allow technology to catch up with the problem. At the moment we do not have an magic bullet technologies that can provide our energy cleanly, or power our transport without emissions but it is likely that in the future technology will reach this point. Having such geoengineering projects could buy us the time to develop these technologies and then implement them globally.

Working on a stopgap could equally result in time being wasted when it comes to working on the real issues. If energy and time is poured into such projects then it is likely that the attempts to reduce CO2 emissions will be put on the back burner simply because the stopgap is the thing that it has been decided gets priority.

If we put particles in the air with the intention of blocking out sunlight then it may cause a dimming of the earth, with catastrophic consequences

Fiddling with the planet is dangerous. This should be very obvious from the problem of climate change in the first place. The GHGs that create climate change are being created because we have industrialised leading to better lives for (almost) all in those industrialised countries. Climate change is an unintended consequence of this generally good process of industrialisation that brings people out of poverty and improves living standards, life expectancy etc. Yet we are thinking of some grand scheme in response to these unintended consequences. Climate change was only noticed 200 years after the start of industrialisation so who knows how long it will take us to know all the consequences of such geoengineering, we could be setting ourselves up for greater problems. David Keith of the University of Calgary pointed out that "The idea of deliberately manipulating Earth's energy balance to offset human-driven climate change strikes many as dangerous hubris." This is likely to be even more the case among non scientists.

While agreement among nations should be encouraged it would not be necessary as many individual countries could act on their own. According to David Keith and his colleagues "It is plausible that, after exhausting other avenues to limit climate risks, such a nation [willing to go rogue, on its own] might decide to begin a gradual, well-monitored programme of deployment, even without any international agreement on its regulation." "In this case, one nation – which need not be a large and rich industrialised country – could seize the initiative on global climate, making it extremely difficult for other powers to restrain it."

Any large scale project to geoengineer the planet would preferably gain international agreement and be taken under the UN banner. However if there is no chance of a deal when it comes to reducing CO2 emissions, something we know a fair bit about, and there has been decades of research on then what are the chances we could get an agreement on some form of geoengineering that has barely been developed, certainly not comprehensively tested and has in the past been seen as something damaging. It is likely that many countries would see as many dangers in such a project as benefits. There is a good chance that some countries will be seen to benefit more than others – either because they are the ones who are developing technologies for it, or just naturally.

While geoengineering may well result in a reduction of global temperatures it will not mean getting to grips with the cause of the problem, the production of greenhouse gasses by industry. If this is not done then there is a good chance of the problem coming back at a later date. Providing such a miracle cure is likely to mean that politicians attention move away from getting any agreements on reducing GHG emissions. If there is not the motivation of consequences then politicians will not act. It would give countries such as China and India all the more excuse to emit more and bring themselves up to the level of emissions that the richest countries are already emitting, these developing nations claim that they should be allowed to emit the same amount per person, this would give the excuse.