Is there a four year cycle in global temperatures? The short answer to that question is probably not. But the last three well defined peaks in the 12 monthly average in 2016, 2020 and 2024, do fit very nicely with the idea of four year cycle. Before that you have to twist the theory quite a bit to find another vague, but much less well defined series, with the years 1998, 2002, 2006 & 2010.
