HADCRUT and GISS (the two primary land-based metrics) and UAH and RSS (the satellite-based metrics) are combined into a single metric by the very useful website Wood For Trees. Here is the combined index:
There have been various attempts to redefine global warming through various other indicia, ocean heat content, etc. I'm not going to go into all of those, especially some of them are merely attempts to move the goalposts. The HADCRUT data is the one upon which the IPCC based its forecasts. Those forecasts of rapidly increasing temperatures as CO2 increased are abject failures.
As I always want to stress, I do believe that (netting out the pluses and minuses of warmer temperatures) global warming is a small problem. It is not "no" problem. I also believe we need to take a serious look at two other related threats:
- Oceans becoming more acidic due to adding CO2 to the atmosphere.
- The threat of global cooling as a result of the sun producing far fewer sunspots. Here is a balanced story from NASA.
As stated many times on this blog, we urgently need to ramp up research into the relation between the sun and our climate. We also need to conduct open-minded research into the acidification issue. It may be the most serious issue of all.