This article is a follow up to my article from 12-days ago, “Dramatic Confirmation of Temperature Change for 1980-2010”, which presented a global map that showed using the AgMERRA dataset temperature trends between 1980 and 2010 that were statistically significant, in some sense showing climate change, or at least the areas that have experienced climate change over the last 30 years.
Jawoo Koo from the International Food Policy Research Institute (IFPRI) suggested that I examine another global dataset, the CRU Time Series, by Phil Jones and Ian Harris, from the University of East Anglia’s Climate Research Unit. This dataset spans the period 1901 to 2012, much longer than that of AgMERRA, which was only 1980 to 2010. CRU has wider geographic coverage, as well, reaching to the northern- and southern-most parts of the earth. Like the AgMERRA dataset, the CRU dataset has a half-degree resolution. However, unlike the AgMERRA dataset, the CRU only has monthly statistics rather than daily weather.
The map above shows the results. They are very similar to those of AgMERRA from the earlier article. This almost had to be the case, since they were using similar reference data to build the datasets. What is perhaps noteworthy is how AgMERRA’s use of satellite data produced differences. One might note, for example, cooling in southern India that was in AgMERRA but not in CRU.
The table shows the results of analysis for every 30-year period covered in the CRU dataset. The dataset has 67,420 land-based gridcells with data. We see that the 1980 to 2010 period had the highest number of gridcells that had statistically significant changes in temperature. We also see that of those with at least 10% statistical significance, almost 92% were positive changes (increases in temperature). This was second highest to the 1970 to 2000 period.