Telegraph: A dangerous climate by Bob Carter, Marine Geophysical Laboratory at James Cook University in Australia
The latest IPCC report, published on Friday, is the most alarming yet: not for its claims of human-caused global warming, writes the leading environmental scientist Bob Carter, but for its lack of scientific rigour.
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For more than 90 per cent of recent geological time, the cores show that the earth has been colder than today. We modern humans are lucky to live towards the end of the most recent of the intermittent, and welcome, warm interludes. It is a 10,000 year-long period called the Holo-cene, during which our civilisations have evolved and flourished.
Backwards for hundreds of thousands of years, the core alternations march. Some, metronomic in their occurrence, are ruled by changes in the earth's orbit at periods of about 20,000, 41,000 and 100,000 years; others are paced by fluctuations in solar output on a scale of centuries or millennia; and others display irregular yet rapid oceanographic and climate shifts that are caused by\u2026 we know not what. Climate, it seems, changes ceaselessly in either direction: sometimes cooling, sometimes warming, often for reasons that we do not yet fully understand.
Similar cores through polar ice reveal, contrary to received wisdom, that past temperature changes were followed – not preceded, but followed – by changes in the atmospheric content of carbon dioxide. Yet the public now believes strongly that increasing human carbon dioxide emissions will cause runaway warming; it is surely a strange cause of climate change that naturally postdates its supposed effect?
Am I the first scientist to have observed these climate patterns? Of course not. That climate changes frequently, rapidly and sometimes unpredictably has been conventional knowledge among earth environmental scientists since the early days of ocean drilling in the 1970s.
Yet we do not read about natural climate change in the everyday news. Instead, newspapers, radio and television stations bludgeon us with a merciless stream of human-caused global-warming alarmism, egged on by a self-interested gaggle of journalists, environmental lobbyists, scientific and business groups, church leaders and politicians, all of whom preach that we must "stop climate change" by reducing human CO2 emissions.
The body from which most of these groups get their information is the Inter-govern-mental Panel on Climate Change (IPCC). It is also the organisation that advises national governments. The IPCC has issued three substantial statements, the First (1990), Second (1995) and Third (2001) Assessment Reports, each of which incorporates the research and opinions of many hundreds of qualified scientists. Its 20-chapter, 1,572-page Fourth Assessment Report was released on Friday. The full reports are detailed and compendious, and each is therefore accompanied by a short chapter termed a Summary for Policymakers (SPM) that is designed for political application.
Many distinguished scientists refuse to participate in the IPCC process, and others have resigned from it, because in the end the advice that the panel provides to governments is political and not scientific. Although at least -$50 billion has been spent on climate research, the science arguments for a dangerous human influence on global warming have, if anything, become weaker since the establishment of the IPCC in 1988.
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However, our most accurate depiction of atmospheric temperature over the past 25 years comes from satellite measurements (see graph below) rather than from the ground thermometer record. Once the effects of non-greenhouse warming (the El Niño phenomenon in the Pacific, for instance) and cooling (volcanic eruptions) events are discounted, these measurements indicate an absence of significant global warming since 1979 – that is, over the very period that human carbon dioxide emissions have been increasing rapidly. The satellite data signal not only the absence of substantial human-induced warming, by recording similar temperatures in 1980 and 2006, but also provide an empirical test of the greenhouse hypothesis as understood by the public – a test that the hypothesis fails.
An interjection here. This chart shows the temperature anomalies in the lower troposphere (2,500-26,000 feet above the Earth.) The surface-based measurements look something like this:
Clearly, there is a difference between the two readings. Carter calls the satellite readings the "most accurate." Clearly the placement of your surface measurement devices is critical. For instance, if they are overly concentrated near expanding cities, there will be distortion. (Just compare the temperature given on the evening news for a location from downtown versus temps from the fringes of the metro area.) Scientists believe they have accounted for these possible distortions, but it still does not entirely account for the difference. It seems to be a bit of a mystery as yet.
Whatever the case, Carter does not emphasize the key significance of the satellite temps. The current greenhouse warming models claim gasses build up in the higher atmosphere. Radiation hits the Earth. Heat comes off the Earth and gets trapped in the gasses. The increased heat in the atmosphere causes warming to happen at the surface. But the higher atmosphere isn't warming. The surface is warming. Barring further data, the conventional greenhouse warming scenario is contradicted by the data.
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Many different fields of study are involved and all are the subject of intensive ongoing research. From this research emerges one inescapable fact: that in no case yet has any climate-sensitive environmental parameter been shown to be changing at a rate that exceeds its historic natural rate of change, let alone in a way that can be unequivocally associated with human causation.
This generally happy news, does not mean that the planet has rendered a judgment of "not guilty" upon us, but that while the jury remains out a presumption of innocence applies. The scientific equiv-alent of this is Occam's Razor (the principle of simplicity), under which environmental change is assumed to be natural until cause can be demonstrated otherwise.
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However, GCMs [General Ciruclation Models constructed on computers] are not predictive tools, which is why even their proponents refer to their output as climate "scenarios" and not "predictions". For many parts of the climate system, such as the behaviour of turbulent fluids or the processes that occur within clouds, our knowledge of the physics is incomplete, which requires the extensive use of "parameterisation" (for which read "educated guesses") in the computer models.
Hendrik Tennekes, a former director of research at the Royal Dutch Meteor-ological Institute who pioneered methods of multi-modal forecasting, remarked recently: "A [GCM] prediction 50 or 100 years into the future is an idle gesture." That the IPCC relies so heavily upon complex GCM-generated scenarios as the basis for its climate alarmism is alarming in its own right; it also reflects the absence of any strong empirical evidence for human-caused climate change, as outlined earlier.
So the evidence for dangerous global warming forced by human carbon dioxide emissions is extremely weak. That the satellite temperature record shows no substantial warming since 1978, and that even the ground-based thermometer statistic records no warming since 1998, indicates that a key line of circumstantial evidence for human-caused change (the parallel rise in the late 20th century of both atmospheric carbon dioxide and surface temperature) is now negated.
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