The climate changes because it is forced to do so. That may sound a little strange, but “forcing” is a real technical term for any pressure that causes the “average weather” to shift. Positive forcings (e.g. increased solar activity, more greenhouse gases) induce global warming, whereas negative forcings (e.g. more low-level clouds, volcanic dimming) result in cooling. Climate system feedbacks (e.g. melting ice, more water vapour) act to enhance these processes. That’s the way it’s always been, throughout Earth’s long history. When the planet is thrown out of energy balance by a change in forcing, it must respond, by warming or cooling. It can’t be bargained with and it has no room to compromise. It will do what it must do. It’s the laws of physics.
So there’s no point in half-fixing climate change. If this is our strategy, whether implicit or explicit, people may as well enjoy the Platinum Age (as Ross Garnaut calls the last few decades) and be done. Cap-and-trade systems to reduce emissions by some percentage are a good example of a “half-fix” policy. Due to the long lifetime of carbon dioxide (CO2) in the atmosphere (about 20 per cent of CO2 released today will still be airborne in 1,000 years), it is only the total amount of CO2 released by humanity during the fossil-fuel age that really matters. We must limit total emissions.
In order to stop forcing the climate system towards further warming - to avoid the worst predicted impacts of climate change - we therefore have to stop using coal, oil and gas. We cannot afford to burn all of the available reserves of these, and other carbon sources, such as tar sands and oil shales. (Click below for entire article)