Guest post by Jos Hagelaars. Dutch version is here.
Discussions on the Internet regarding climate change are sometimes about scientific details, sometimes about the climate sensitivity regarding the equilibrium situation hundreds of years from now, but the most prevalent discussion topic is probably: the global average temperature. Will it get warmer or colder, is there a temporary slowdown or acceleration in the rise in temperature, are the models correct or not, will the eventual warming of our earth in the future be large or small? New numbers are released on a monthly basis and every month megabytes of text are generated about them. My forecast is that 2015 again will lead to a discussion-spike.
The graph above shows the evolution of the global surface temperature anomaly for three datasets, where the average of the period 1981-2010 is defined as 0. For the year 2015 only data are presented up to and including June. So far 2015 exceeds all other years and the evolving El Niño makes it likely that 2015 will set a new world record.