The Science of Climate Change: Hockey Sticks
The gold standard for evidence-based arguments for tackling climate change remains the Stern Review, published by the UK Government in 2006. It’s an independent report that looks at the costs associated with tackling climate change, and the costs of not tackling climate change.
Chapter 1 is devoted to the science of climate change, and is a useful resource for rebutting popular climate change denier myths.
I particularly like this bit (p6):
Box 1.1 The “Hockey Stick” Debate.
Much discussion has focused on whether the current trend in rising global temperatures is unprecedented or within the range expected from natural variations. This is commonly referred to as the “Hockey Stick” debate as it discusses the validity of figures that show sustained temperatures for around 1000 years and then a sharp increase since around 1800 (for example, Mann et al. 1999, shown as a purple line in the figure below).
Some have interpreted the “Hockey Stick” as definitive proof of the human influence on climate. However, others have suggested that the data and methodologies used to produce this type of figure are questionable (e.g. von Storch et al. 2004), because widespread, accurate temperature records are only available for the past 150 years. Much of the temperature record is recreated from a range of ‘proxy’ sources such as tree rings, historical records, ice cores, lake sediments and corals.
Climate change arguments do not rest on “proving” that the warming trend is unprecedented over the past Millennium. Whether or not this debate is now settled, this is only one in a number of lines of evidence for human induced climate change. The key conclusion, that the build-up of greenhouse gases in the atmosphere will lead to several degrees of warming, rests on the laws of physics and chemistry and a broad range of evidence beyond one particular graph.