Posts Tagged ‘settled science’

No mask needed, just don’t breathe

August 25, 2020

There are some who believe that epidemiology is a science. Others believe it is an art and yet others that it is the study of social behaviour based on gut-feel and science.

Whatever it is, it is not settled science.

An enveloped virus such as the Wuhan virus can survive for up to 2 months in a refrigerated corpse.

In studies looking at how bird flu (avian influenza virus, an enveloped virus) survives in chicken carcasses, 90% of the virus was inactivated in around 15 days when the carcass was left at room temperature. But if the carcass was held at refrigerator temperatures (4C/40F), the virus lasted 4.5 times longer—that’s more than two months.


 

Low-salt pseudo science

August 19, 2014

For almost 100 years, some scientists have been warning about the harmful effects of salt in our diets. For the last 40 years or so that has also been the “consensus” view of the medical/regulatory establishment. It was “settled science” we were told. There was complete “consensus” within the medical world it was proclaimed.

Salt was evil.

But apparently the “settled” science was not quite so settled after all. The “consensus” was nothing more than “group think”. In the words of the Wall Street Journal:

Yet the latest USDA food pyramid, which was updated as recently as 2011, clings to simplistic low-salt pseudo-science. The FDA is pressuring food manufacturers and restaurants to remove salt from their recipes and menus, while the public health lobby is still urging the agency to go further and regulate NaCl as if it were a poison.

The larger point is that no scientific enterprise is static, and political claims that some line of inquiry is over and “settled” are usually good indications that real debate and uncertainty are aboil. In medicine in particular, the illusion that science can provide some objective answer that applies to everyone—how much salt to eat, how and how often to screen for cancer, even whom to treat with cholesterol-lowering drugs, and so on—is a special danger.

It is not so easy now to retrace exactly how the salt scare developed and became part of the establishment view. Certainly Lewis Dahl of the Brookhaven National Laboratory was one of the key actors who spread the alarm. He was well placed within US Government circles and soon rather dubious and alarmist conclusions became part of the “establishment view”. Pseudo science became “settled science”:

Scientific American:

In 1904 French doctors reported that six of their subjects who had high blood pressure—a known risk factor for heart disease—were salt fiends. Worries escalated in the 1970s when Brookhaven National Laboratory’s Lewis Dahl claimed that he had  “unequivocal” evidence that salt causes hypertension: he induced high blood pressure in rats by feeding them the human equivalent of 500 grams of sodium a day. (Today the average American consumes 3.4 grams of sodium, or 8.5 grams of salt, a day.)

Dahl also discovered population trends that continue to be cited as strong evidence of a link between salt intake and high blood pressure. People living in countries with a high salt consumption—such as Japan—also tend to have high blood pressure and more strokes. But as a paper pointed out several years later in the American Journal of Hypertension, scientists had little luck finding such associations when they compared sodium intakes within populations, which suggested that genetics or other cultural factors might be the culprit. Nevertheless, in 1977 the U.S. Senate’s Select Committee on Nutrition and Human Needs released a report recommending that Americans cut their salt intake by 50 to 85 percent, based largely on Dahl’s work.

Thereafter “group think” took over. Consensus opinion – and not objective science – ruled. Now we are finding out that there is no clear evidence that salt is harmful and there is some evidence that too little salt is dangerous and can increase the risk of heart disease.

Scientific American:

In April 2010 the Institute of Medicine urged the U.S. Food and Drug Administration to regulate the amount of salt that food manufacturers put into products; New York City Mayor Michael Bloomberg has already convinced 16 companies to do so voluntarily. But if the U.S. does conquer salt, what will we gain? Bland french fries, for sure. But a healthy nation? Not necessarily.

This week a meta-analysis of seven studies involving a total of 6,250 subjects in the American Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure. In May European researchers publishing in the Journal of the American Medical Association reported that the less sodium that study subjects excreted in their urine—an excellent measure of prior consumption—the greater their risk was of dying from heart disease. These findings call into question the common wisdom that excess salt is bad for you, but the evidence linking salt to heart disease has always been tenuous.

It has taken 40 years for this alarmist meme that salt is harmful to be brought down to earth. Group-think and “consensus science” has its own inertia which makes it difficult to overturn what becomes matters of faith rather than of evidence.

And just a few days ago another establishment paper created headlines when it stated that salt “causes 1.65 million deaths every year across the globe. A published study in New England Journal of Medicine on Thursday, found that an average consumed salt (sodium) per day is twice the amount recommended by the World Health Organization. A 3.95 gm consumption per day beyond the recommended amount of 2 gm”. But all they actually did was measure/estimate salt consumption and then multiplied that by an assumed death rate.  By the time the headlines were written a simple measurement of salt consumption became evidence of the dangers of salt! That’s consensus science!

The 1970s and 80s saw many such alarmist memes – based on little and dubious science – become the “consensus view” and the “politically correct” faith to be followed. It was the time when the nonsensical “Limits to Growth” became the bible of the day. It was the time of the DDT scare where the disadvantages were blown out of all proportion and the subsequent ban has been a case of “throwing the baby out with the bath water. Natural variations of the ozone hole were taken to be due to the human use of fluorocarbons. Acid rain was going to kill all the forests.

Whenever I now hear that some science is “settled” or that there is a consensus around some “belief” – as with climate science today – I am inclined to view the claims with a very large bushel of salt.

Chaos of climate models only shows that “we don’t know what we don’t know”

April 17, 2013

I spent a large part of my early career in mathematical modelling (of combustion systems and of heat flow) and have a very clear idea of what models can do and what they can’t. Models after all are used primarily to simplify complex systems which are otherwise intractable. They are – always – severely limited by the assumptions and simplifying approximations that have to be introduced. Models are a powerful tool for investigation but are only as good as their most inaccurate assumption. But they are a tool primarily for investigation — and can be dangerous when used for decision making based on their imperfect predictions. The spectacular failures of mathematical models of the global economy are a case in point. It is worth noting that in spite of the great strides made in weather forecasting  for example – much of which is empirical – the simple statement that “tomorrows weather will be like today’s”  is as correct – statistically – as the most complex model running on some super-computer somewhere.

It has therefore always amazed me that so-called “scientists” would be so certain about their approximate models of climate systems – which are perhaps as complex, chaotic and “unknown” systems as any one could study. It has been a boon for politicians looking for new ways of raising revenue. It has been exploited by the alarmists since the alarmist predictions cannot be tested. The wide spread of results from climate models is rarely mentioned.

When reality does not match model forecasts it is time to back off and rethink the models and hopefully they will be better next time. And it is time to back track from all the political decisions made on the basis of patently incomplete and inaccurate models.

The simple reality about climate is that rather than being a “settled science”

  • we don’t know the impact of solar effects on climate
  • we don’t know the impact of clouds or even if they are net “warmers” or net “coolers”
  • we don’t know how much of the earth’s radiative energy balance is dependent upon carbon dioxide
  • we don’t know how much carbon dioxide is absorbed  by the oceans and living things
  • we don’t know the impact of aerosols and particles in the atmosphere
  • we don’t know the role of the oceans in transporting heat around the globe
  • we don’t know how much heat is stored in the oceans and how it varies
  • we don’t know the impact of solar effects on cloud formation
  • we don’t know what triggers ice ages, and
  • we don’t know what we don’t know.

This from Dr. Roy Spencer and the ridiculously wide spread of the model results and the obvious deviation of reality from model results are particularly striking:

Global Warming Slowdown: The View from Space

Since the slowdown in surface warming over the last 15 years has been a popular topic recently, I thought I would show results for the lower tropospheric temperature (LT) compared to climate models calculated over the same atmospheric layers the satellites sense.

Courtesy of John Christy, and based upon data from the KNMI Climate Explorer, below is a comparison of 44 climate models versus the UAH and RSS satellite observations for global lower tropospheric temperature variations, for the period 1979-2012 from the satellites, and for 1975 – 2025 for the models:

CMIP5-global-LT-vs-UAH-and-RSS

CMIP5-global-LT-vs-UAH-and-RSS

Clearly, there is increasing divergence over the years between the satellite observations (UAH, RSS) and the models. The reasons for the disagreement are not obvious, since there are at least a few possibilities:

……… 

The dark line in the above plot is the 44-model average, and it approximately represents what the IPCC uses for its official best estimate of projected warming. Obviously, there is a substantial disconnect between the models and observations for this statistic.

I find it disingenuous for those who claim that, because not ALL of individual the models disagree with the observations, the models are somehow vindicated. What those pundits fail to mention is that the few models which support weaker warming through 2012 are usually those with lower climate sensitivity.

So, if you are going to claim that the observations support some of the models, and least be honest and admit they support the models that are NOT consistent with the IPCC best estimates of warming.


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