The Royal Society has produced this overview of the current state of scientific understanding of climate change to help non-experts better understand some of the debates in this complex area of science.
This is not intended to provide exhaustive answers to every contentious argument that has been put forward by those who seek to distort and undermine the science of climate change and deny the seriousness of the potential consequences of global warming. Instead, the Society - as the UK's national academy of science - responds here to six key arguments that are currently in circulation by setting out in simple terms where the weight of scientific evidence lies.
Argument 1 : The Earth's climate is always changing and this is nothing to do with humans.
Argument 2 : Rises in the levels of carbon dioxide in the atmosphere are the result of increased temperatures, not the other way round.
Argument 3 : Computer models which predict the future climate are unreliable and based on a series of assumptions.
Argument 4 : It's all to do with the Sun - for example, there is a strong link between increased temperatures on Earth with the number of sunspots on the Sun.
Argument 5 : The climate is actually affected by cosmic rays.
Argument 6 : The scale of the negative effects of climate change is often overstated and there is no need for urgent action.
Our scientific understanding of climate change is sufficiently sound to make us highly confident that greenhouse gas emissions are causing global warming. Science moves forward by challenge and debate and this will continue. However, none of the current criticisms of climate science, nor the alternative explanations of global warming are well enough founded to make not taking any taking action the wise choice. If the more severe aspects of climate change are to be reduced, then the science clearly points to the need for nations to take urgent steps both to cut greenhouse gas emissions into the atmosphere as much and as fast as possible, and to adapt to the impacts of climate change, some of which are already inevitable.
This document was compiled with the help of the Royal Society Climate Change Advisory Group and other leading experts.
April 2007
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