Placing the Blame
The Intergovernmental Panel on Climate Change (IPCC) is a United Nations and World Meteorological Organisation group which has been studying the various possible causes, effects and repercussions of climate change. In 2007 the IPCC released its Fourth Assessment Report; a combination of reports from three groups analysing different aspects of climate change. Conclusions of Working Group 1 state that,
"From new estimates of the combined anthropogenic forcing due to greenhouse gases, aerosols and land surface changes, it is extremely likely that human activities have exerted a substantial net warming influence on climate since 1750."[1]
This means that the debate of whether humans are to blame for the warming climate is truly over. The issue now is to deal with the problem in the most effective way. The arguments of sceptics were built upon the previous uncertainty as to whether we are to blame, theorising that the current shift in climate is actually due to natural variation of various external influences (for example the energy output of the sun).
This would mean that there is no solution, and no change in human behaviour is required; there is nothing we would be able to do to prevent a natural shift in global temperatures. It is apparent that this is not the case, since we are responsible; we can no longer hope that the climate will recover on its own. As some of the possible repercussions of climate change include: rising sea levels; stronger and more frequent storms (such as hurricanes); more prolonged droughts and flash flooding, to name just a few, something needs to be done, and promptly.
The primary cause of climate change is due to greenhouse gas (GHG) emissions produced mostly by burning fossil fuels. The most sensible option appears to be to reduce the volume of fossil fuels which we burn, either by altering our lifestyles to adjust to the lower energy availability, or by switching our energy production to alternative, non GHG emitting sources. The IPCC anticipate a range of possible temperature rises, depending on how effectively we curb our emission of GHGs.
The most conservative estimate (B1 scenario) is that temperatures are to rise by 1.1 - 2.9oC, while the most pessimistic estimate (A1F1 scenario) shows a rise of between 2.4 - 6.4oC [2], meaning that the sooner we can reduce GHG emissions, the better our chances of reducing the impacts of climate change will be. Even if emissions were to drop to zero today, we are still committed to further warming.
Deviating from the Norm
The human race has a love of burning fossil fuels. The concept is so entrenched in the general (western) population that life seems impossible without them. For such widespread use of fossil fuels to stop, a truly viable alternative needs to be available to replace it. The question is, what could this alternative be?
Because of the scare surrounding the diminishing supplies of fossil fuels, anything that can be called 'renewable' is often perceived to be a clean and viable solution. Some renewables, like bio fuels (which are renewable because they can be regrown), are GHG emitters. Growing vast fields of sugar cane from which to make ethanol is rather similar to making our own fossil fuels, as burning them would still release GHGs into the atmosphere. Some cities, such as Reading, now run buses which are run on "environmentally friendly bio fuel" [3].
While bio fuels do significantly reduce CO2 emissions, it is the perception of what constitutes "environmentally friendly" which gives cause for concern. The layman might develop the misconception that these buses are a good idea because the fuel powering them is renewable, rather than because they reduce emissions. This fallacy leads to wondering why we shouldn't obtain all our energy from these sources. On the scale needed, bio fuels would need massive intensive farming and large amounts of land, which itself has been shown to have an effect on climate change. Growing that much biomass, at great speed, would require the use of chemical fertilisers which decompose into nitrous oxide - a gas which has a global warming potential (GWP) of 298 [4], i.e. over the space of 100 years, nitrous oxide has 298 times the effect on global warming as carbon dioxide.
So what about the others? There are unfortunately many problems with other forms of renewable energy which mean that it will take time and money to implement a system capable of replacing fossil fuels. For example, wind power is clean but it is inefficient, and it cannot be guaranteed to be available all the time [5]. This means that permanent power supplies need to run on in the background in the event of a calm day.
The same argument is true of most forms of clean renewable sources - the sun is often obscured by clouds, and obviously power generation wouldn't occur at night. The idea of switching entirely to energy from sustainable sources is a good one, but in the long term, and will take time. A future of carbon neutral, free and sustainable energy is realistic, but will take innovations in technology to increase efficiency and decrease cost. Another, existing, source of energy is required. Unfortunately that source of energy has a particularly bad reputation.