Previous research had demonstrated a link between some droughts and peculiar patterns of sea surface temperatures in different parts of the world. (scientificamerican.com)
The temperature changes are relative to the global average surface temperature of 1961 - 1990. (royalsociety.org)
A third set of simulations used modern greenhouse gases but removed the unusual pattern of sea surface temperatures in 2014 - 15. (sciencedaily.com)