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Wednesday, March 23, 2011

Scientific consensus on climate change: 97% of active climate science researchers agree that climate is changing and humans are causing it (Thomas Stemler, Skeptical Science)

Why we have a scientific consensus on climate change

by Thomas Stemler, Skeptical Science, March 23, 2011

(listen to the original audio podcast)

Recently a research group analysed the current literature on climate science. Their aim was to find out how many of the active researchers in the field agree on man-made climate change. The answer is, 97 out of 100 agree that the climate is changing and that we are causing it.
From my own experience, such a high proportion is quite unusual. As scientists we are trained to be professional sceptics, who doubt everything and who moreover love a good debate. Therefore putting 3 scientists together in a room sometimes results in an argument with 5 different opinions.
While this is the more enjoyable side of science, the more important one is that being sceptic lets us identify errors and improve our understanding of nature.
Climate science is a very special science. It includes experts who study the dynamics and data from the atmosphere, the oceans, glaciers, and so on. Some of us specialise in building models, others use them to make predictions.
So how come that 97% of the experts agree that the current warming is not natural but a consequence of burning fossil fuels?
First, it is because all our data show that the global mean temperature is increasing, that the glaciers and the arctic ice are melting and therefore sea levels are rising.
Second, we know that burning fossil fuel releases CO2 into the atmosphere. The properties of CO2 were first studied by John Tyndall in the late 1850s. Tyndall was an experimental physicist interested in how different gases absorb heat. John Tyndall's observations were remarkable. His pioneering work eventually inspired physicists to develop the theory of quantum mechanics, but his results about CO2 also led Arrhenius in 1896 to the conclusion that burning fossil fuel will result in global warming. So climate science is a very old science indeed; we have known about CO2 for more than 150 years.
Nowadays we know how much CO2 we put into the atmosphere by using it as our global garbage bin for fossil fuel. All our climate observations show a global increase in temperature. This increase is consistent with the well established properties of CO2.
Taking this into account it is no longer surprising that 97% of the professional sceptics working in the area of climate science agree that we are currently witnessing man-made climate change. The only question remaining is, what do we do? Ignore the facts or generate energy from other sources?
Dr Thomas Stemler is a physicist who is currently an Assistant Professor of Mathematics at the University of Western Australia. He is an expert in forecasting of complex nonlinear dynamical systems.


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