At http://math.ucr.edu/home/baez/balsillie/ John Baez has slides from his recent talks on the characterization of climate change and what we will do about it. They are clearly thought out and presented, as always. Climate change is just one aspect of the anthropocene: the new era created by human activity. One of the todo actions is to leave fossil fuels in the ground.
The elephant in the room of this story is that our best chance to leave fossil fuels in the ground is to find cheaper energy and the only realistic chance of that lies in developing nuclear power. The trouble is that the anthropocene has arisen from cheap energy. It lets us destroy habitats, destroy fish stocks, and much more. Cheaper energy will make this worse, even if it fixes the CO2 problem. The answer will lie in extending the 19th/20th century idea of a national park, to create an international park which is a substantial subset of the biosphere. The other side of the coin is the human conquest of space. There are many lifeless worlds out there, just waiting for us to make them more interesting.
Saturday, October 26, 2013
Friday, October 25, 2013
scientific errors in medicine
The obesity-health saga is an interesting example of scientific error. There is a clear correlation between being overweight and having various health problems, particularly Type 2 diabetes. So nobody looked more closely at that. Everyone is advised to lose weight.
But then they did look more closely and low and behold we find: For most people, carrying extra weight is actually protective. At any given level of fitness it is better to have more weight.
So why is carrying weight associated with disease? The answer is that most people who are fit are relatively slim because it is hard to keep the weight on if you get fit. So being overweight is correlated with lack of fitness, and that is the problem. If you can be fit and keep the weight, with a high proportion of muscle, then that is ideal.
Medical science seems particularly prone to jump to conclusions based on correlation alone, but it is an easy mistake in many disciplines. Medical science is pretty good at other sorts of errors, including pure guesswork, like "eating fat makes you fat" (most people lose weight on a high fat low carb diet); or eating cholesterol will increase your cholesterol levels leading to heart disease.
But then they did look more closely and low and behold we find: For most people, carrying extra weight is actually protective. At any given level of fitness it is better to have more weight.
So why is carrying weight associated with disease? The answer is that most people who are fit are relatively slim because it is hard to keep the weight on if you get fit. So being overweight is correlated with lack of fitness, and that is the problem. If you can be fit and keep the weight, with a high proportion of muscle, then that is ideal.
Medical science seems particularly prone to jump to conclusions based on correlation alone, but it is an easy mistake in many disciplines. Medical science is pretty good at other sorts of errors, including pure guesswork, like "eating fat makes you fat" (most people lose weight on a high fat low carb diet); or eating cholesterol will increase your cholesterol levels leading to heart disease.
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