[Illustrations, footnotes and references available in PDF version]
The scare: In late January 2009, Time magazine blamed the bird-strike that brought down an Airbus passenger aircraft in the Hudson River, New York, on “global warming”. This was the latest in a long series of articles in scientifically-unaware mainstream news media, blaming real or imagined climate events on “global warming”. Such alarmism defies Occam’s razor, the philosophical principle by which the simplest explanation of an event is nearly always the true explanation. The Time article said that “Wildlife mitigation” was the official term for avoiding bird strikes. A report published in June 2008 by the Federal Aviation Administration had found that since 1990 the number of bird strikes had quadrupled, from 1,759 in 1990 to a record 7,666 in 2007. According to Time, “Officials cite a number of possible causes for the increase”, including “habitat destruction and climate change”, which “have disrupted migratory patterns”. Time adds, “Al Gore should be very proud of himself.”
The truth: As the article also points out (though not in the headline), most commercial airlines are replacing three-engine and four-engine aircraft with twin-engine aircraft. The newer engines are quieter, so birds are less likely to detect and avoid them. Also, aircraft with fewer engines are less able to survive bird-strikes.
The article fails to mention the chief reason why there are more bird-strikes: increased economic activity. Each hour at the time of the accident, there were more than 1100 commercial passenger flights taking off in US airspace; and, in the day of the accident there were 2.5 million aircraft flights of all kinds. More than 3 million people worldwide now fly on commercial flights in any one day.
Bird strikes have been responsible for numerous accidents all over the world, of which the following caused the worst fatalities –
The geographical spread of the bird strikes shows that there is no basis whatever for the suggestion that “global warming” has aggravated the problem. Bird strikes have occurred in all parts of the globe, from the tropics to the Arctic, and they have involved birds of all kinds. Birds, like most species on earth, are necessarily tolerant of different climates. This tolerance of varying temperatures is essential to survival, since the temperature difference between a summer’s day and a winter’s night, in the same location, can be at least 100 times greater than the 0.74 °C (1.3 °F) difference between mean global surface temperature 100 years ago and today.
Birds, which are by their nature highly mobile, can adapt to climate changes more easily than most species: all they need to do to find an optimal temperature in a warming world is to fly a few dozen miles further north. Time offers no evidence that the species that caused the Airbus crash in New York was at a new northerly limit for its habitat: indeed, remarkably, the magazine did not even identify the species.
Al Gore, mentioned with approval in Time’s article, complains in the entertaining fiction book that accompanies his inaccurate movie An Inconvenient Truth, that pied flycatchers can no longer hatch at the right time to feed their young on the customary species of caterpillar, which “hatch two weeks earlier after 20 years of ‘global warming’”. He is careful not to point out that “global warming” has been happening not for 20 years but for 300. He is also careful not to point out that, even if the caterpillars were indeed becoming available a couple of weeks later in the year than previously, the birds would merely have to fly a few miles further north to find caterpillars that hatched at a more convenient moment.
Gore illustrates his scare story about the supposed threat from “global warming” to the pied flycatchers by showing what purports to be a tiny photograph of a flycatcher feeding a caterpillar to her chick. However, enlargement of the photograph reveals that the bird is not a pied flycatcher but a black tern, and the “caterpillar” is in fact a fish.
(Figure1) A black tern, not a “pied flycatcher”, feeds her chick a fish, not a “caterpillar”.
Finally, there are two logical fallacies inherent in all stories attributing recent minor climatic changes to “global warming”.
First, there is the assumption that the warming (to the extent that it has actually occurred) is of anthropogenic rather than natural origin. The mere fact of warming tells us nothing of the cause. For 70 years between 1645 and 1715, the Sun was less active than at any time during the previous 10,000 years. For 70 years centered on the 1960s, the Sun was more active than at almost any time during the previous 11,400 years (Solanki et al., 2005). Seen in this perspective, the “global warming” that occurred during the 300 years that separated these two events is unsurprising. Indeed, Scafetta & West (2008) say that 69% of the warming of the past half-century is not anthropogenic (as the IPCC imagines it to be) but solar in origin.
Secondly, there is the assumption that “global warming” is continuing to occur. One cannot legitimately attribute events to “global warming” when “global warming” is not actually happening. For the entire eight years of the presidency of George Bush, the trend in global mean surface temperatures has been firmly downward, at a rate exceeding 1 °C per century –
The cooling Bush years: During the entire presidency of George Bush, the SPPI composite global-temperature index shows a cooling trend (the thick red line) equivalent to 1.1 °C per century. The IPCC predicts warming (pink region, with the paler pink representing 1 standard deviation either side of the IPCC’s central estimate) at a rate equivalent to between 2.4 and 5.3 °C over the 21st century. Not one of the models relied upon by the IPCC predicted so long a period of cooling, though solar physicists, noticing the decline in solar activity after the solar Grand Maximum that ended with the 2oth century, had predicted the cooling that is now occurring.
How have temperatures fared since 2005, since Al Gore launched his movie? The downtrend is considerably steeper than since 2001. In fact, ever since Gore went public with his alarming message about the damage to be expected from “global warming”, the planet has been cooling at a rate equivalent to 6 degrees Celsius (11 °F) per century. In the unlikely event that the cooling were to persist at that rate until 2100, the Earth would once again be in an Ice Age.
The current interglacial warm period has already endured for approximately twice as long at today’s temperatures as any of the previous four interglacials over the past half million years. Arguably, therefore, an Ice Age is long overdue.
The Gore effect: For fully four years, since Al Gore’s movie about the climate was first released, global temperatures have been falling at a rate equivalent to 6 degrees Celsius (11 degrees Fahrenheit) per century. Yet throughout that time carbon dioxide concentration has been steadily increasing.
While it would be irresponsible to spread alarm by predicting that the current interglacial will suddenly give place to a new Ice Age in the very near future – for the timing of such events is beyond our current ability to predict – it is noteworthy that, in the mainstream media there has been almost no mention of the global cooling that has occurred in the 21st century. If the trend had been towards warming rather than cooling at a rate as great is 6 degrees C/century for as long as four years, there would have been worldwide headlines. Instead, after this sharp cooling, we are told that “global warming” caused the bird-strike that downed the Airbus in the Hudson River. As the Duke of Wellington used to say, “If you will believe that, Sir, you will believe anything.” End of scare.