<story><title>Exponential Economist Meets Finite Physicist (2012)</title><url>https://dothemath.ucsd.edu/2012/04/economist-meets-physicist</url></story><parent_chain><item><author>philipkglass</author><text>I generally liked the Do The Math posts but I thought this was one of the weakest.&lt;p&gt;Physicist: &amp;quot;Right, if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span.&amp;quot;&lt;p&gt;It&amp;#x27;s not phenomenally faithful. There&amp;#x27;s an inflection point visible even in his large graph going back all the way to 1650. US primary energy consumption in 1977 was 78 quadrillion BTU (quads). At 2.9% annual growth it would have risen to 245 quads by 2017. Actual US primary energy consumption in 2017 was only 98 quads. The &lt;i&gt;per capita&lt;/i&gt; primary energy consumption in the US was actually higher in 1977.&lt;p&gt;Physicists don&amp;#x27;t need to imagine future limits to growth. The limits are already visible in the historical record. But, contra the fears of many scientists circa 1960, the limits to growth showed up on the demand side before the supply side. We ended up with a world where widespread obesity is a problem and predicted gigadeaths from starvation did not actually happen.&lt;p&gt;For any product you can imagine consuming, there are &amp;quot;obesity&amp;quot;-type limits to how much more of that same product you can consume before the marginal utility goes negative. For any service you might use, similar limits apply since there are only 24 hours in a day.&lt;p&gt;The physicist character gives the more correct answer but his supporting evidence is flawed. The economist has the much worse answers, but only (I suspect) because he&amp;#x27;s a strawman constructed for didactic purposes. Economists generally don&amp;#x27;t make 1400 year forecasts of any sort.</text></item></parent_chain><comment><author>hn_throwaway_99</author><text>Thank you thank you thank you. Honestly, this whole article had the veneer to me of &amp;quot;Ahh, poor silly economist...&amp;quot; I&amp;#x27;m not sure if there is a great word for it, but I call it the &amp;quot;humble-brag equivalent of obnoxiously condescending&amp;quot;</text></comment>
<story><title>Exponential Economist Meets Finite Physicist (2012)</title><url>https://dothemath.ucsd.edu/2012/04/economist-meets-physicist</url></story><parent_chain><item><author>philipkglass</author><text>I generally liked the Do The Math posts but I thought this was one of the weakest.&lt;p&gt;Physicist: &amp;quot;Right, if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span.&amp;quot;&lt;p&gt;It&amp;#x27;s not phenomenally faithful. There&amp;#x27;s an inflection point visible even in his large graph going back all the way to 1650. US primary energy consumption in 1977 was 78 quadrillion BTU (quads). At 2.9% annual growth it would have risen to 245 quads by 2017. Actual US primary energy consumption in 2017 was only 98 quads. The &lt;i&gt;per capita&lt;/i&gt; primary energy consumption in the US was actually higher in 1977.&lt;p&gt;Physicists don&amp;#x27;t need to imagine future limits to growth. The limits are already visible in the historical record. But, contra the fears of many scientists circa 1960, the limits to growth showed up on the demand side before the supply side. We ended up with a world where widespread obesity is a problem and predicted gigadeaths from starvation did not actually happen.&lt;p&gt;For any product you can imagine consuming, there are &amp;quot;obesity&amp;quot;-type limits to how much more of that same product you can consume before the marginal utility goes negative. For any service you might use, similar limits apply since there are only 24 hours in a day.&lt;p&gt;The physicist character gives the more correct answer but his supporting evidence is flawed. The economist has the much worse answers, but only (I suspect) because he&amp;#x27;s a strawman constructed for didactic purposes. Economists generally don&amp;#x27;t make 1400 year forecasts of any sort.</text></item></parent_chain><comment><author>msla</author><text>&amp;gt; But, contra the fears of many scientists circa 1960, the limits to growth showed up on the demand side before the supply side. We ended up with a world where widespread obesity is a problem and predicted gigadeaths from starvation did not actually happen.&lt;p&gt;And I think some people were... &amp;quot;disappointed&amp;quot;, for lack of a better word, that this happened. That their fantasies of global collapse &lt;i&gt;Soylent Green&lt;/i&gt;-style didn&amp;#x27;t pan out, that the lackadaisical masses who had the temerity to not give up all modern advances weren&amp;#x27;t punished by the Dread God Malthus. Call it Puritanical Luddism, call it Apocalyptic Deep Green, call it a dogmatic insistence that any system not under totalitarian control &lt;i&gt;must&lt;/i&gt; collapse.</text></comment>