Is the climate changing?

The last few weeks have seen substantial questioning of the quality of the analysis of the global climate record. This presentation, made to the top year at a local secondary school, looks at the Oxford climate series and shows how the way the data is presented may significantly affect judgments on how fast warming is occurring at one particular point on the earth's surface. Apparently innocuous changes, such as varying the number of years in a moving average, can make substantial changes to the appearance of a temperature series. The notes to this presentation can be seen by downloading the PowerPoint file and clicking Notes Page in the View tab; or alternatively by downloading the PDF. Anybody wanting the raw data and the accompanying charts is very welcome to email Chris Goodall at

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No difference in the nutritional value of organic and conventionally produced food

A study commissioned by the UK Food Standards Agency concluded that: 'there is little, if any, nutritional difference between organic and conventionally produced food and that there is no evidence of additional health benefits from eating organic food.'

Yes and no. What the study actually shows is that organic food typically does have higher levels of important nutrients but the high degree of variability in the measured levels means that we cannot be 95% sure that these higher levels are not the outcome of chance. The Food Standards Agency and the report’s authors have misled people interested in this topic and should revise the summaries of their work.

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