3 ms·

So, half a degree centigrade in twenty years - 0.25C per decade. That’s higher than the actual warning of the global troposphere observed over the most recent

• scythe 3y ago
  Von Neumann may have meant the cumulative delta-T as of 1955; he may have also been referring to the expected equilibrium delta-T given the total emissions as of 1955. I don't think he meant the change over a generation; he was saying that CO2 emissions over the preceding generation were as large as all of the emissions before it. If we take the simple, cumulative change interpretation, he was off by about a factor of 2 using the usual start date of 1880; the equilibrium is harder to reckon. To make things more confusing, the years 1883-1920 were actually much colder than the preindustrial norm due to the eruption of Krakatoa, which he also mentions; using these as the baseline, one degree Fahrenheit is quite close to accurate (but no longer solely human-forced). The Krakatoa anomaly is why pre-1880 is usually chosen as baseline.