Saturday, April 16, 2011

When Scientists Confuse Cause and Effect

excerpt from Matt Ridley in the Wall Street Journal 4/16/11:

Even climate science has encountered cause-effect confusion. When in 1999 Antarctic ice cores revealed carbon-dioxide concentrations and temperature marching in lockstep over 400,000 years, many—including me— found this a convincing argument for attributing past climate change to carbon dioxide. (About 95% of carbon dioxide in the atmosphere is natural, coming from the exhalations of living things. In the past, carbon-dioxide levels rose as the earth warmed at the end of ice ages and fell as it cooled at the end of interglacial periods.)

Then four years later came clear evidence from finer-grained analysis of ice cores that temperature changes preceded carbon-dioxide changes by at least 800 years. Effects cannot precede their causes by eight centuries, so temperatures must drive carbon dioxide, chiefly by warming the sea and causing carbon dioxide dissolved in water to "out-gas" into the air.

Climate scientists fell back on a "feedback" hypothesis, arguing that an initial change, probably caused by variations in the earth's orbit that affect the warmth of the sun, was then amplified by changes in carbon-dioxide levels. But this made the attribution argument circular and left the reversal of the trend after a period of warming (when amplification should be at its strongest) still harder to explain. If carbon dioxide is still driving the temperature upward but it falls instead, then other factors must be stronger than expected.

Some climate scientists see cause-effect confusion at the heart of climate modeling. Roy Spencer of the National Aeronautics and Space Administration argues from satellite data that the conventional view has one thing backward. Changes in cloud cover are often seen as consequences of changes in temperature. But what if the amount of cloud cover changes spontaneously, for reasons still unclear, and then alters the temperature of the world by reflecting or absorbing sunlight? That is to say, the clouds would be more cause than consequence. Not many agree with Mr. Spencer, but it is an intriguing idea.


  1. Louis HooffstetterApril 19, 2011 at 7:31 AM

    I'm continually amazed at how easily scientists (and especially liberals) confuse 'Cause and Effect'. Here are my two favorite examples:

    1) The incidence of snake bites and shark attacks strongly correlates with ice cream sales. (Ice cream apparently makes us much tastier to snakes and sharks.) Banning the sale of ice cream would significantly reduce snake bites and shark attacks.

    2) There is a remarkable correlation between the IQ's of preschoolers and shoe size: the bigger the feet, the smarter the kid. So Bigfoot's love child would be smarter than your kid! Not necessarily. Preschoolers with big feet are simply the oldest kids who therefore score better on IQ tests.

  2. hockeyschtick

    I have had a rather disturbing exchange of posts with Joel Shore over at WUWT near the end of the topic below.

    I had quoted correct physics from the ninth edition (1995) in which the Greenhouse Effect did not appear
    But Joel had the 13th edition which as you will find now contains hyper alarmist rubbish which even Skeptical Science would find embarrassing.
    Why did a standard physics text feel compelled to include a couple of paragraphs of unsubstantiated pseudo science.
    Its very worrying that the thought police are hard at work corrupting normal science textbooks.
    See what you think - it might even be worth a feature.
    Joel says of
    University Physics by Young and Freedman

    ….”Speaking of which, would you care to enlighten us about what that textbook has to say on the subject of the greenhouse effect and global warming? I have a copy of the latest edition back in my office, so I can tell you tomorrow if your edition is too old to mention it or if you would rather not tell us here.”…..

    My reply
    My edition is the ninth in which they say;

    Energy transfer that takes place soley because of a temperature difference is called heat flow or heat flow transfer and energy transferred in this way is called heat .
    page 470

    Heat always flows from a hot body to a cooler body never the reverse. page 559

    This statement is impossible to reconcile with the conclusion reached in your “comment” paper page 15

    ….”the surface is now HEATED not only by the sun but also by the downward emission of terrestrial radiation from the atmosphere”…..

    The colder atmosphere HEATING a warmer Earth surface!
    I dont think so!
    Joel perhaps to you the actual direction of heat flow is as you say “nitpicking”, however if you read your textbook carefully you will find that this is a very isolated viewpoint and one that would fail an examination question in physics.

    Joel Shore says:

    Well, my edition is the 13th and they have about a page on the greenhouse effect and climate change right in the part of the chapter that discusses radiation. Here is some of what they says:

    Molecules of CO2 in the atmosphere have the property that they absorb some of the infrared radiation coming upward from the surface. They then re-radiate the absorbed energy, but some of the re-radiated energy is direct back down toward the surface instead of escaping into space. In order to maintain thermal equilibrium, the earth’s surface must compensate for this by increasing its temperature T and hence its total rate of radiating energy (which is proportional to T^4). This phenomenon, called the greenhouse effect, makes our planet’s surface temperature about 33 C higher than it would be if there were no atmospheric CO2. If CO2 were absent, the earth’s average surface temperature would be below the freezing point of water, and life as we know it would be impossible.

    It then goes on to talk about the burning of fossil fuels, the increase in CO2, and the increase in temperatures, ending with these two sentences:

    The resulting temperature increase will have dramatic effects on climate around the world. In the polar regions massive quantities of ice will melt and run from solid land to the sea, thus raising ocean levels worldwide and threatening the homes and lives of hundreds of millions of people who live near the cost. Coping with these threats is one of the greatest challenges facing 21st-century civilization.

  3. Bryan,

    That is disturbing and Clausius must be rolling over in his grave. Sadly, most physicists seem unwilling to question the so-called "consensus" in this age of post-normal science.