This was a month late at WUWT but better late than never I suppose. WUWT's current leading blog writer, Eric Worrall, has written about
a paper published last month in Nature Climate Change (archived
here). The authors, Mark Richardson, Kevin Cowtan, Ed Hawkins and Martin B. Stolpe, had a look at how temperature records are sampled. They found that
slower warming regions are preferentially sampled, which means that observations are biased low.
The authors reported that after adjusting for biases, and
using observations, the transient climate response (TCR) is
1.66 °C with a 5% to 95% range of 1.0 to 3.3 °C. This is consistent with that derived from climate models considered in the AR5 IPCC report.