A major analysis of cutting edge studies has been published in Nature Geoscience this week by an international team of over 70 scientists. Although the authors rightly qualify that their report is not designed in the terms of ‘attribution studies’ which is the most reliable approach to distinguishing causes, their ‘region-up’ analysis of global temperature variance over the last 2,000 years found exactly what would be expected if the current consensus on anthropogenic climate change (ACC) was correct.
Global temperatures were warmer between 1970 and 2000 -the period with the greatest greenhouse gas emissions- than in any other period in the last 1,400 years. This is despite the fact that we should still be experiencing a long period of global cooling which began c.1580 AD, because, as the study indicates, rises and falls in global temperature take place very gradually over long periods. Recent warming, with its rapid arrival in the late 19th century is: 1) by contrast, too sudden to fit the pattern for natural shifts in global temperature, and 2) also perfectly correlated with where we would expect to find warming if it were caused by the explosion of polluting industrial activity, and 3) inexplicable by natural causes such as volcanic eruptions and changes in solar irradiance. Such natural causes do, however, predict earlier periods of significant change which were often short lasting but in such cases were always restricted to small regions, unlike the current global change.
The report therefore adds ‘the Earth has warmed up like this in the past’ to the ever growing list of arguments favoured by the ideological (i.e. bribed) opponents of ACC science    to have been refuted empirically. If you are at all interested in the other items on this list and how they relate to the evidence for ACC, why this climate change is such a catastrophic threat to human civilisation, and what actions we can be taking to ameliorate it, I wholeheartedly recommend The No-Nonsense Guide To Climate Change (2nd Edition) by Danny Chivers as an extremely succinct introduction.