Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”
Climate alarmism is like one of those pop-up Bozos. No matter how many times you bop it, up it springs. In fact, the only way to stop it, as most kids learn, is to deflate it. In this case, the air inside Bozo is your and my tax money.
Two scientific papers released last week combine for a powerful 1-2 haymaker, but, rest assured, Bozo springs eternal. The first says that human aerosol emissions are not that responsible for offsetting the warming influence of greenhouse gas emissions, while the second finds that the observed warming from human greenhouse gases is less than a lot of people think.
We aren’t at all surprised by the first result. The cooling effect of sulphate particulates, which go into the air along with carbon dioxide when fossil fuels (mainly coal) are combusted, was only invoked in the mid-1980s, when the lack of warming predicted by computer models was embarrassingly obvious.
This is the kind of thing that the iconic historian of science, Thomas Kuhn, predicted in his classic book, The Structure of Scientific Revolutions. When a scientific “paradigm” is assaulted by reality, increasingly ornate and bizarre explanations are put forth to keep it alive. Sulfates smelled like one of those to us back in the 1980s, and now it looks like the excuses are finally getting comeuppance.
The second result also comes as little news to us, as we have been saying for years that the human carbon dioxide emissions are not the only player in the climate change game.
The two new papers, in combination, mean that the human influence on the climate from the burning of fossil fuels is far less than what the IPCC’s ensemble of climate models says it is. This also goes for the U.S. Global Change Research Program, the EPA ,and the White House.
Rest assured, though, Bozo will rise again—despite a near-continuous barrage of blows supporting the idea that the climate’s sensitivity to human greenhouse gas emissions is far too low to justify any of the expensive and futile actions emanating from Washington and Brussels.
The aerosol paper describes research by a team of Israeli scientists led by Gerald Stanhill (from the ARO Volcani Center) who examined the causes of “solar dimming” and “solar brightening” that have taken place over the past half-century or so. Solar brightening (dimming) refers to multidecadal periods when more (less) solar radiation is reaching the surface of the earth. All else being equal (dangerous words in Science), the earth’s surface would warm during periods of brightening and cool during dimming. Solar dimming has been reported to have taken place from the 1950s through the 1980s and since then there has been a period of recovery (i.e., brightening). These patterns have been linked by many to human aerosol emissions caused by pernicious economic activity, with heavy emissions leading to global cooling from the 1950s (witness the opaque air of Pittsburgh and London) through the late 1970s and then, as air quality was cleaned up and aerosol emissions declined, an unmasking of the warming impact from greenhouse gas emissions.
This is an essential storyline that might as well have been written by Kuhn. Without invoking the previously undiscovered masking impact of human aerosols, climate models predict that far more global warming should have happened as a result of human greenhouse gas emissions than has been observed, even by the 1980s. Behaving more predictably than the climate, federal climatologists, led by Tom Wigley of the University Corporation for Atmospheric Research (hey, we couldn’t make up the name of that exclusively taxpayer-funded monster), relied on the aerosol “knob” to try to keep climate models from overheating.
Stanhill et al. have bad news for the feds. In their new paper, they examine the records of sunshine duration as recorded at five observation sites with long-term observations. When comparing these sunshine histories with fossil fuel use histories (a proxy for aerosol emissions) from nearby areas, they find very little correspondence. In other words, human aerosol emissions aren’t to blame for much of the solar dimming and brightening.
What may be the cause? Variations in cloud cover.
According to Stanhill and colleagues:
It is concluded that at the sites studied changes in cloud cover rather than anthropogenic aerosols emissions played the major role in determining solar dimming and brightening during the last half century and that there are reasons to suppose that these findings may have wider relevance.
Admittedly, there are only a small number of stations that were being analyzed, but Stanhill et al. have this to say:
This conclusion may be of wider significance than the very small number of sites examined in this study would suggest as the sites sampled Temperate - Maritime, Mediterranean, Continental and Tropical climates,… and covered a wide range of rates of anthropogenic aerosol emission.
The implications are that human aerosols have played a lot smaller role in the global temperature variability of the past 50 years than is generally taken to be the case. And if human aerosols are not responsible for muting the expected temperature rise from greenhouse gas emissions, then it seems that the expected rise is too much. That is, the earth’s temperature is less sensitive to rising greenhouse gas concentrations than forecasted by governmental climate models, and therefore we should expect less warming in the future.
The second paper, published last week in Science, is yet another study trying to explain the “pause” in the rise of global average surface temperatures. Using annual data from the University of East Anglia temperature history—the one that scientists consult the most, we are now in our 18th year without a warming trend.
(For a revealing exposé on how even this data is being jimmied to fit the paradigm, see what just showed up in the most recent Weekend Australian.)
University of Washington’s Xianyao Chen and Ka-Kit Tung found that a naturally occurring change in ocean circulation features in the Atlantic Ocean can act to enhance or suppress the magnitude of heat that is transferred from the surface into the ocean depths. The authors find that this natural cycling was responsible for burying additional heat since the late 1990s while maintaining surface heating during the previous three decades. Coupled with earlier research (Tung and Zhou, 2013), they figure that a substantial portion (~40%) of the rise in the global surface temperatures that has occurred since the mid-20th century was caused by natural variability in the circulation of the Atlantic Ocean.
The implication here is pretty clear—the role that human greenhouse gas emissions play in the observed warming isn’t what it was cracked up to be. And, with a little nudge from other variables—like the sun—the quaint myth that “all scientists agree that the majority of warming since 1950 has been caused by human activity” does look more and more like another pop-up Bozo.
Taken together, the two paper combination strikes a haymaker to the alarmist mantra—that dangerous climate change will result from greenhouse gas emissions. The Stanhill paper suggests that the projected warming wasn’t so masked by sulfate aerosols, and the Chen and Tung paper argues that less of the warming is due to a human influence anyway. This combination—greater warming pressure and less temperature change—means that the IPCC and federal climate models are just way off.
Going forward, we should expect much less human-induced global warming than government-fueled climate models project.
If this refrain sounds familiar, it is because we find ourselves frequently reporting on the subject of the earth’s climate sensitivity (how much warming results for a given input of carbon dioxide). This issue is the biggest key to understanding anthropogenic climate change, and, because evidence continues to mount that the climate sensitivity is much less than advertised, there will be much more where this came from.
But Bozo, inflated by public monies, will spring eternal.
Chen, X., and K-K Tung, 2014. Varying planetary heat sink led to global-warming slowdown and acceleration. Science, 345, 897-903.
Kuhn, T. S., 1962 (and reprints). The Structure of Scientific Revolutions. University of Chicago Press,, 174pp.
Stanhill, G., et al., 2014. The cause of solar dimming and brightening at the Earth’s surface during the last half century: evidence from measurements of sunshine duration. Journal of Geophysical Research, doi: 10.1002/2013JD021308
Tung, K-K., and J. Zhou, 2013. Using data to attribute episodes of warming and cooling in instrumental records. Proceedings of the National Academy of Sciences, 110, 2058-2063.