Denying the Catastrophe: The Science of the Climate Skeptic’s Position
Oct. 15 2010 - 12:19 am | 19,771 views | 1 recommendation | 64 comments
Warren Myer
In last week’s column, I lamented the devolution of the climate debate into dueling ad hominem attacks, which has led in almost a straight line to the incredible totalitarian vision of the 10:10 climate group’s recent film showing school kids getting blown up for not adhering to the global warming alarmists’ position.
In writing that column, it struck me that it was not surprising that many average folks may be unfamiliar with the science behind the climate skeptic’s position, since it almost never appears anywhere in the press. This week I want to give a necessarily brief summary of the skeptic’s case. There is not space here to include all the charts and numbers; for those interested, this video and slide presentation provides much of the analytical backup.
It is important to begin by emphasizing that few skeptics doubt or deny that carbon dioxide (CO2) is a greenhouse gas or that it and other greenhouse gasses (water vapor being the most important) help to warm the surface of the Earth. Further, few skeptics deny that man is probably contributing to higher CO2 levels through his burning of fossil fuels, though remember we are talking about a maximum total change in atmospheric CO2 concentration due to man of about 0.01% over the last 100 years.
What skeptics deny is the catastrophe, the notion that man’s incremental contributions to CO2 levels will create catastrophic warming and wildly adverse climate changes. To understand the skeptic’s position requires understanding something about the alarmists’ case that is seldom discussed in the press: the theory of catastrophic man-made global warming is actually comprised of two separate, linked theories, of which only the first is frequently discussed in the media.
The first theory is that a doubling of atmospheric CO2 levels (approximately what we might see under the more extreme emission assumptions for the next century) will lead to about a degree Celsius of warming. Though some quibble over the number – it might be a half degree, it might be a degree and a half – most skeptics, alarmists and even the UN’s IPCC are roughly in agreement on this fact.
But one degree due to the all the CO2 emissions we might see over the next century is hardly a catastrophe. The catastrophe, then, comes from the second theory, that the climate is dominated by positive feedbacks (basically acceleration factors) that multiply the warming from CO2 many fold. Thus one degree of warming from the greenhouse gas effect of CO2 might be multiplied to five or eight or even more degrees.
This second theory is the source of most of the predicted warming – not greenhouse gas theory per se but the notion that the Earth’s climate (unlike nearly every other natural system) is dominated by positive feedbacks. This is the main proposition that skeptics doubt, and it is by far the weakest part of the alarmist case. One can argue whether the one degree of warming from CO2 is “settled science” (I think that is a crazy term to apply to any science this young), but the three, five, eight degrees from feedback are not at all settled. In fact, they are not even very well supported.
Of course, in the scientific method, even an incorrect hypothesis is useful, as it gives the scientific community a starting point in organizing observational data to confirm or disprove the hypothesis. This, however, turns out to be wickedly difficult in climate science, given the outrageously complex nature of the Earth’s weather systems.
Our global temperature measurements over the last one hundred years show about 0.7C of warming since the early 1900s, though this increase has been anything but linear. Skeptics argue that, like a police department that locks on a single suspect early in a crime investigation and fails to adequately investigate any other suspects, many climate scientists locked in early on to CO2 as the primary culprit for this warming, to the exclusion of many other possible causes.
When the UN IPCC published its fourth climate report several years ago, it focused its main attention on the Earth’s warming after 1950 and in particular on the 20-year period between 1978 and 1998. The UN IPCC concluded that the warming in this 20-year period was too rapid to be due to natural causes, and almost certainly had to be due to man’s CO2. They reached this conclusion by running computer models that seemed to show that the warming in this period would have been far less without increased CO2 levels.
Skeptics, however, point out that the computer models were built by scientists who have only a fragmented, immature understanding of complex climate systems. Moreover, these scientists approached the models with the pre-conceived notion that CO2 is the main driver of temperatures, and so it is unsurprising that their models would show CO2 as the dominant factor.
In fact, the period 1978 to 1998 featured a number of other suspects that should have been considered as potentially contributing to warming. For example, the warm phase of several critical ocean cycles that have a big effect on surface temperatures, including the Pacific Decadal Oscillation, coincided with this period. Further, the second half of the 20th century saw far greater solar activity, as measured by sunspot numbers, than the first half of the century. Neither ocean cycles nor solar effects, nor a myriad of other factors we probably don’t even know enough to name, were built into the models. Even man’s changing land use has an effect on measured temperatures, as survey efforts have shown urban areas, which have higher temperatures than surrounding rural locations, expanding around our temperature measurement points and biasing measured temperatures upwards.
If CO2 is but one of several causes of warming over the past decades, then current climate models almost certainly have to be exaggerating future warming. Only by attributing all of the past warming to CO2 can catastrophic future warming forecasts be justified. In fact, even the 0.7C of measured historic warming is well under what the climate models should have predicted for warming based on past CO2 increases and their assumed high sensitivity of temperature to CO2 levels. In other words, to believe a forecast of, say, 5C of warming over the next 100 years, we should have seen 2C or more of warming over the past century.
This is why the IPCC actually had to make the assumption that global temperatures would have fallen naturally and due to other manmade pollutants over the past several decades. By arguing that without man’s CO2 the climate would have cooled by, for example, 0.5C, then they can claim past warming from CO2 as 1.2C (the measured 0.7C plus the imaginary 0.5C). Anyone familiar with how the Obama administration has claimed large stimulus-related jobs creation despite falling employment levels will recognize this approach immediately.
Despite these heroic efforts to try to find observational validation for their catastrophic warming forecasts, the evidence continues to accumulate that these forecasts are wildly overstated. The most famous forecast of all is perhaps NASA’s James Hansen’s forecast to Congress in 1988, a landmark in the history of global warming alarmism in this country. Despite the fact that 2010 may well turn out to be one of the couple warmest years in the past century (along with 1998, both of which are strong El Nino years), the overall trend in global temperatures has been generally flat for the last 10-15 years, and have remained well below Hansen’s forecasts. In fact, Hansen’s forecasts continue to diverge from reality more and more with each passing year.
Of course, as we all know, global warming has been rebranded by alarmist groups as “climate change” and then more recently as “climate disruption.” This is in some sense inherently disingenuous, implying to lay people that somehow climate change can result directly from CO2. In fact, no mechanism has ever been suggested wherein CO2 can cause climate change in any way except through the intermediate step of warming. CO2 causes warming, and then warming causes climate changes. So the question of warming and its degree still matters, no matter what branding is applied.
In fact, it is in the area of the knock-on effects of warming, from sea level increases to hurricanes, that some of the worst science is being pursued. Nowhere can we better see the effect of money on science than in climate change studies, as academics studying whatever natural phenomenon that interests them increasingly have the incentive to link that phenomenon to climate change to improve their chances at getting funding.
The craziness of climate scare stories is too broad and deep to deal with adequately here, as nearly every 3-sigma weather anomaly suddenly gets attributed to climate change. But let’s look at a couple of the more well-worn examples. In an Inconvenient Truth, Al Gore warned of the world being battered by more and more Katrina style category 5 storms; in fact, 2009 and 2010 have seen record low levels of global cyclonic activity, despite relatively elevated temperatures. Or take the melting ice cap: on the same exact day in 2007 when newspapers screamed that the Arctic had hit a 30-year low in sea ice extent, the Antarctic hit a 30-year high. The truth of the matter is that ice is indeed melting and sea levels are rising today – as they were in 1950, and 1900, and even 1850 (long before much man-made CO2). The world has warmed continuously since the end of the little ice age around 1820 (a worldwide cold spell generally linked to a very inactive period in the sun) and sea levels can be seen to follow an almost unbroken linear trend since that time.
Alarmists like to call climate skeptics “deniers,” usually in an attempt to equate climate skeptics with holocaust deniers. But skeptics do not deny that temperatures have warmed over the last century, or even that man (through CO2 as well as land use and other factors) has played some part in that warming. What skeptics deny, though, is the catastrophe. And even more, what skeptics deny is the need to drastically reduce fossil fuel use – a step that will likely be an expensive exercise in the developed west but an unmitigated disaster for the poor of Asia and Africa. These developing nations, who are just recently emerging from millennia of poverty, need to burn every hydrocarbon they can find to develop their economies.
Postscript: You will notice that I wrote this entire article without once mentioning either the words “hockey stick” or “Climategate.” I have never thought Michael Mann’s hockey stick to be a particularly compelling piece of evidence, even if it were correct. The analysis purports to show a rapid increase in world temperatures after centuries of stability, implying that man is likely the cause of current warming because, on Mann’s chart, recent temperature trends look so unusual. In the world of scientific proof, this is the weakest of circumstantial evidence.
As it turns out, however, there are a myriad of problems great and small with the hockey stick, from cherry-picking data to highly questionable statistical methods, which probably make the results incorrect. Studies that have avoided Mann’s mistakes have all tended to find the same thing – whether looking over a scale of a century, or millennia, or millions of years, climate changes absolutely naturally. Nothing about our current temperatures or CO2 levels is either unusual or unprecedented.
The best evidence that the problems identified with Mann’s analysis are probably real is how hard Mann and a small climate community fought to avoid releasing data and computer code that would allow outsiders to check and replicate their work. The “Climategate” emails include no smoking gun about the science, but do show how far the climate community has strayed from what is considered normal and open scientific process. No science should have to rely on an in-group saying “just trust us,” particularly one with trillions of dollars of public policy decisions on the line.
http://blogs.forbes.com/warrenmeyer/2010/10/15/denying-the-catstrophe-the-science-of-the-climate-skeptics-position/?boxes=opinionschannellatest
