This talk looks at some recent climate controversies from a statistical standpoint. The issues are motivated via changepoints and their detection. Changepoints are ubiquitous features in climatic time series, occurring whenever stations relocate or gauges are changed. Ignoring changepoints can produce spurious trend conclusions. Changepoint tests involving cumulative sums, likelihood ratio, and maximums of
\(F\) statistics are introduced; the asymptotic distributions of these statistics are quantified under the changepoint-free null hypothesis. The case of multiple changepoints is considered. The methods are used to study several controversies, including extreme temperature trends in the United States and Atlantic Basin tropical cyclone counts and strengths.
Welcome to everyone.