The annual “State of the Climate” report for the previous year which is included as a special supplement to the Bulletin of the American Meteorolgical Society was published recently. Responding to the various press releases issued about the report, written by NOAA, the news media said it was a clear example of accelerated global warming that showed no signs of levelling off. The media reports tied it to the “Climategate” scandal saying that despite all the fuss the science was never in doubt.
The NOAA report draws together the scientific data available that is pertinent to our ever-changing planet. The Independent said it was based on 50 climatic indicators. The Guardian said 11. The Met Office in its press release said it was based on 10 key climatic indicators. The NOAA report itself quotes 37. To be fair however, there are different ways of grouping environmental indicators.
As an aside, I note that the heading to their list of the datasets used in the report has the heading, “Datasets used in this chapter that are publically available for bona fide research purposes.” The italics are my emphasis.
Phillip Stott of the UK Met Office was widely quoted in the media saying that despite variations between individual years the evidence was unequivocal in that the world had warmed in the past 150 years.
This is a true statement that none could take issue with. No scientist of whatever viewpoint disputes the fact that we live in a warm decade or that the global temperature has risen since the Victorian age, and the Little Ice Age before that. The key point is what is natural and what is human influenced. The IPCC AR7 report says that all global temperature variation prior to 1960 was not influenced by mankind. So the fact that the past 50 years show a continuation of the warming trend evident since the commencement of the instrumental record 150 years ago means that many claims of mankind’s influence stand on dubious ground. What the pre-1960 data shows is the range of natural variability in the system. It shows that the global temperature increase between 1860 and 1960 was greater than between 1960 and 2010. It also took place at statistically identical rates. It is unscientific and misleading to use natural variability to bolster the range of human-influenced variability, and then to pass it off to the public as the same thing.
The NOAA report discusses whether 2009 was warmer than the previous years and, after a brief discussion about 0.1 deg C differences here and there, generally concludes that it probably was. However, at the end of that particular section it states the statistically obvious that should have been stated right at the start of that particular section, “the uncertainties in deriving the global mean surface temperature imply that 2009 is statistically indistinguishable from the other high ranking years shown in (their) Fig 2.2.”
Since the years 2001 -2009 are statistically indistinguishable, and some of Dr Stott’s colleagues maintain there has been no significant global warming since 1995, one wonders what are the individual yearly variations he is talking about?
One commentator said; “This confirms that while all of this [Climategate] was going on, the earth was continuing to warm. It shows that Climategate was a distraction, because it took the focus off what the science actually says.”
Considering that “the science says” that 2009 is no different from the previous decade in terms of temperature, and the fact that the past decade being the warmest on record has been known for years and is not a point of contention, this was a misleading statement. The science is not that simplistic.
But how is 2010 doing?
The possibility that 2010 might be a record year in terms of temperature was mentioned prominently alongside the NOAA report in the mainstream media. But one crucial factor was missing.
The warmest year on record is 1998 (according to the HadCrut data) and that was because of a very strong El Nino. The first half of 2010 has also seen a strong El Nino effect but in none of the 571 news reports mentioned in Google was El Nino mentioned as an explanation despite the fact that it increases the temperature by 2 degrees in the Central and Eastern Pacific. Neither was the Pacific Decadal Oscillation mentioned which went positive, thereby contributing to global warming, in the Autumn of 2009.
News reports are brief, intended to communicate the essentials of a story as well as providing a forum for critical reaction and, sometimes, analysis. News reporters sometimes have detailed scientific knowledge, sometimes do not, but are always pressed for time and deadlines. Press releases are useful sources of stories but, as the media coverage of the State of the Climate report shows, they often come with built in prejudices and limitations, as do commentators.
The science is usually more complicated, and uncertain, that a press release indicates. None of those issued about this report mentioned the dominant El Nino effect, and no journalist added it to the story in a way that actually appeared.