Chinese scientists, in a paper in the Journal of Earth Science, say there was a rapid rise in global mean surface air temperature after the late 1970s but this stalled and there was a even slight cooling that lasted for about 15 years (1998–2012). They add that even though the slowdown was acknowledged by the IPCC AR5 and termed as a hiatus (IPCC, 2013) there was a debate in the scientific community about whether there was a hiatus in global warming. The researchers believe that the debate about the global warming hiatus poses a substantial challenge to our understanding of the global climate response to anthropogenic greenhouse gas emissions and natural variability. They say that the disagreements about the recent global warming hiatus mainly arise from different sources, among which differences across observational SAT datasets may be a key contributor to the contradictory conclusions. So they use an alternative set of data. They use the ratio of two oxygen isotopes in precipitation, oxygen 16 and 18, which is a proxy for the temperature of precipitation and surface temperature. They are particularly interested in what they term a “robust correlation” between precipitation oxygen ratios and surface temperature over mid- and high-latitude regions. Twelve stations were selected of which ten are located in Europe, and the remaining two in Antarctica and North America, respectively. Using the data they constructed a composite isotope index spanning 1970–2016 by combining twelve precipitation oxygen isotope records collected over mid and high-latitude continents. With it they evaluate the recent global warming hiatus.

They found a cooling trend over the period 1998–2012 which was significantly different from that of the interval 1970–1997 which is characterised by a significant warming.