In about a month’s time we will be told, with much hoo-haa, that the IPCC’s ‘thousands of scientists’ are 95 per cent certain that humans have caused the earth to warm. This will be a key message in the IPCC’s Fifth Assessment Report, which will probably be abbreviated to AR5. All the forces of orthodoxy will be wheeled out to tell us that it is still not too late to undertake decisive global action to ‘combat climate change’.
Quite a lot has been leaked from the report by somebody or other, including the 95 per cent figure I just mentioned. The problem is that, as I wrote a little time ago, Nature persists on taking no notice of the IPCC. For this reason, those who really know about this chaotic field will be looking really hard at how the authors of the report have been able to deal with this lamentable failure.
The IPCC no longer has much control over the data, because there are five major sources, and all their data are in the public domain. Anyone who wants to can use simple software to download the data and produce his or her own accounts of what has been happening, employing other software which again is publicly available, at sites like <woodfortrees.com>. People have been doing this for some years now, and there is no doubt that the warming of the 1980s and early 1990s has paused. Here is one of many diagrams:
On the vertical axis you can see the global temperature anomaly, while the horizontal axis displays time, from 1996 to the present. The faint grey line that goes from the bottom left to the top right is the trend of the increase in carbon dioxide emissions measured at the Mauna Loa Observatory in Hawaii, centred on the actual emissions. (The sine-wave shape of the actual emissions reflects the seasonal nature of carbon dioxide, which growing plants love in spring and summer, when they absorb more of their food in the atmosphere.)
The blue plot measures the average global temperature anomaly of all five of the recording organisations, while the solid blue line displays the trend. You can see the great el Nino spike of 1998, plus a couple of other relatively warm years in 2007 and 2010. But the trend over the 16 and a half years from December 1996 to June 2013 is pretty flat. It plainly bears little relationship to the increase in carbon dioxide emissions.
Some of the orthodox complain that this is cherry-picking — that is, choosing dates that give one impression while ignoring other possibilities. But this diagram includes the year of the el Nino spike. If we were to start the analysis in 1999 the trend would show a cooling. As it is, the warming trend shown is very small. Were it to continue for a century there would be no warming that anyone would notice (a bit over half a degree C), even less, in fact, than occurred in the 20th century (about 0.7 of a degree C).
I wouldn’t suggest for a moment that this trend must continue. I haven’t the faintest idea whether or not it will, and nor does anyone else. There are those who think we are in for a couple of decades of cooling because of the current solar cycle, and others who think that the ‘missing heat’ has gone into the oceans, or been masked by aerosols. Every year we learn something new about climate. The notion that the science of global warming is somehow ‘settled’ is, to me me anyway, ludicrous.
But what the diagram above shows is first, that there has been a notable pause in the warming that was thought to be caused by carbon dioxide emissions, and second, that these emissions have gone on increasing as they have done since they were first measured. at Mauna Loa. In short, something is wrong with the models*. Maybe the IPCC will come up with a persuasive explanation. It will have to be extraordinarily persuasive to overcome these data.
If anyone would like to see more of this sort of analysis, this diagram came from Anthony Watts’s website, here. A second can be seen at another good website for data, that of Ole Humlum in Norway, here. Humlum points out that when temperatures began to level out the orthodox stopped taking about ‘global warming’, and started on the new phrase ‘climate change’. There may be something in it.
* And having published this post, I went to the morning’s email and found a new paper discussed at Judith Curry’s Climate etc, which says exactly that!