Pine beetle doom-sayers barking up the wrong treeRichard Treadgold | June 25, 2012
The turbulent science that blames humanity for climate change marks itself with smoke and mirrors. Opportunities to settle the truth are somehow sidelined. Tricks are employed to obscure the truth. When direct measurements show a negative temperature trend, indirect methods are sought to show the desired warming.
Then it is that we hear that polar ice is disappearing, polar bears are in peril, coral reefs are bleaching, there’s more rainfall, less rainfall, seasons are being disrupted, extinctions are occurring, glaciers are retreating, there’s more extreme weather, and on and on.
But these events, where true, and they often are simply untrue, are influenced by factors other than warming, so the believers also use slippery reasoning to pretend they’re caused by warming. We’re fed stories of disaster that could only be true if the temperature were going up, but it’s propaganda: when the science fails, the believers resort to misdirection. Even if it were warming, so what? What’s the cause? Believers never address the cause of warming – though that’s essential if we’re trying to stop the warming – because by now everyone thinks it’s themselves.
Rather than taking tales of alarm at face value, we try to investigate them. So to the humble North American Mountain pine beetle…
The Mountain Pine Beetle is tiny — about 5 mm long (same as the word “tiny”), but it packs a mighty punch: it can flatten forests.
The little beetles make interesting reading in the light of claims that the current outbreak in parts of the USA and Canada is caused by global warming.
Those claims are frivolous. Epidemics have been observed since Europeans arrived in America, long before the recent warming. In any case, the current epidemic is waning and could be over.
The epidemics are not unmitigated disasters. The beetle invasion creates opportunities that are exploited by other creatures and the forest itself is the better for it. The mountain pine beetle attacks only old or diseased trees, so their predation allows new growth to invigorate the forest.
The beetle is endemic to North America and never entirely vanishes from a region. A population can fluctuate greatly over several years and may diminish to almost undetectable levels, but numbers will bounce back at some point and eventually balloon into another “epidemic”. It’s possible that human activities have caused a reduction in forest fires, which could mean beetle populations are larger and survive for longer.
The mere fact that we’re interested in this little insect highlights the great commercial importance of timber.
A story on 15 June by Sophie Quinton in The Atlantic sparked this study. There’s been no “global warming” for a decade and a half, so it follows that any event ascribed to warming must have other causative factors. My curiosity was aroused.
The story begins “North America is witnessing the largest pine-beetle epidemic in recorded history. Temperature rises are more than likely to blame, but why is it so hard to admit that?”
Whether written by Quinton or a subeditor reaching for an eye-catching summary, the first sentence may be true. The “recorded history” of beetle epidemics is only about 100 years and records are unreliable. But the claim about higher temperatures being responsible is not self-evident.
Boring beetles are found throughout North America, though individual populations might plummet between epidemics. Each kind of beetle attacks a different kind of tree and has a different way of doing it. The mountain pine beetle tunnels beneath the bark to the moist, nutrient-rich phloem, where it lays eggs. The larvae feed on the phloem before emerging as winged adults to mate and subsequently lay eggs in other living trees. Much of the beetle’s life cycle is probably governed by temperature.
Thousands of tunnelling larvae under the bark disrupt sap flow, while a symbiotic fungus on the beetle infects the sapwood, curbing the tree’s defences against the beetle and further reducing the circulation of fluids. The dehydration can eventually kill the tree and many succumb. Numbers of pine beetles can climb into the gazillions during an outbreak, and millions of trees can die.
Sophie Quinton says “North America is witnessing the largest pine-beetle epidemic in recorded history.” So it’s the largest in a hundred years. Last April the Missoulian reported “Pine beetle infestation tapering off in Montana.”
A U.S. Forest Service official said that pine beetle activity in Montana was declining and the epidemic “may have reached its peak.”
Aerial surveys last year were reported in the 2011 Montana Forest Insect and Disease Conditions report prepared by the Forest Service and state Department of Natural Resources and Conservation.
There’s plenty of sound forest left: out of a total 20.5 million forested acres surveyed in Montana, beetle-killed trees were found on more than a million acres, down from 2 million in 2010 and 3.6 million in 2009. There are “emerging problems” with western spruce budworm and pine butterfly.
The pine beetle is not a new problem. There’s documentation dating to 1750 describing similar outbreaks. Settlers in the early 1900s apparently induced beetle infestations to help clear the land for pasture.
A report from Colorado titled “The Status of Our Scientific Understanding of Lodgepole Pine and Mountain Pine Beetles – A Focus on Forest Ecology and Fire Behavior” (undated, though it’s circa 2008) has important background, including this:
Some contend that the current epidemic with synchronous outbreaks at many locations is unprecedented and a clear warning of global climate change impacts on ecosystems around the world. Scientists and others point to other changes occurring in our region – Ips beetle-caused mortality of piñon pine in the Southern Rocky Mountains, aspen decline, and large fires in Front Range ponderosa pine forests and elsewhere. It is difficult to prove cause and effect, but all of these changes began during the last 10-15 years, coinciding with recent warm climatic conditions, increasing numbers of large trees, and advancing age of many forests. Whether or not the current epidemic is unprecedented is a question to which there is currently no clear answer because of the lack of precise information on extent and severity of beetle outbreaks prior to the early 1900s.
The report makes it clear that whether outbreaks occurred before the modern era (i.e., more than 100 years or so ago) is unknown. But it enumerates several factors that probably contributed to the current outbreak, such as “extensive forests of trees at the right age, size, and density to support large numbers of mountain pine beetles, and a climate warm enough over the last decade to favor beetle reproduction and survival.”
So it’s wrong to blame the single factor of warming even for this outbreak. Because the net warming in the period from 1993–2008, although it fluctuated a lot, according to the UAH record, was only about 0.1°C.
The NOAA Colorado temperature series is online and shows a warming trend of just 0.7°C from 1896 to 2012. That’s within the usual margin of error for temperature records of ±1°C–2°C.
On a Parks Canada web site page dated 2009 we’re told that pine beetle outbreaks in the mountain national parks are not new:
Two major outbreaks have occurred in Kootenay (1930-45 and 1981- present).
In Yoho there was a smaller infestation in the 1930′s, and current populations are quickly increasing.
Waterton had an extensive outbreak that occurred in the late 1970′s and early 1980′s.
Banff had a minor outbreak between 1940-43, a smaller outbreak in the 1970′s and early 1980′s in the Upper Spray Valley.
In 1999, mountain pine beetle was recorded for the first time in Jasper.
It seems unlikely the outbreak of pine beetle was caused by the minuscule amount of warming recorded there. In the absence of expert agreement, the claim is highly suspect.