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I find it surprising that the 1896 answer of warming estimates closely match modern estimates. Back then: - They didn't have electronics, radio was barely bei

by GuB-42 3y ago

I find it surprising that the 1896 answer of warming estimates closely match modern estimates. Back then: - They didn't have electronics, radio was barely being discovered - They didn't have airplanes, they just discovered the upper atmosphere, with the very first weather balloons - They knew about atoms, the periodic table was 30 years old, but nucleus wasn't discovered yet Climate science is a notoriously difficult topic, with countless feedbacks, positive and negative. Nowadays, we run simulations on supercomputers based on satellite data, decades of precise historical data, geological data, etc... They didn't have that at the time. Maybe he got the precise value by chance. Sometimes it happens. For example it is said that Eratosthenes (240 BC) calculated the Earth circumference with great accuracy (<1%) and no one managed to get a better estimate until modern times. In fact, many later estimates were off by more than 10%. The technology available at the time wasn't capable of such accuracy, but by chance, it turned out to be spot on (but they didn't know it was).

Cheer2171 3y ago
The 1896 warming estimates that were accurate were not estimating future CO2 emissions. They were of the form: if we emit X tons of CO2 a year, the greenhouse effect will be Y. The greenhouse effect of CO2 can be studied in a literal greenhouse, and the effect can be extrapolated to the earth with methods we teach in high school today. They didn't predict at what year we would be at a tipping point, but at what the effects would be with a given level of CO2.
- GuB-42 3y ago
  The greenhouse effect and how CO2 affects it is actually quite complicated and not what happens in an actual greenhouse, and most of what happens that is relevant to climate change actually happens in the upper atmosphere (which cools!). And there are other effects, like how CO2 get absorbed in the oceans, clouds, water vapor, etc... That CO2 has an effect on temperature is "easy" to realize, quantifying it is much, much harder. And I am just talking about short term effects, long term effects (including a potential tipping point) is yet another layer of complexity.
tim333 3y ago
I read somewhere that if you take a simple model based simply on the extra heat trapped by CO2 in the atmosphere and the black body emission from earth to space as a function of temperature it comes as close to reality as all the elaborate models. Or probably closer as the elaborate models can easily produce extreme results if you assume a lot of positive feedback and so far the real world results have been closer to feedback free results.

by GuB-42 3y ago

Cheer2171 3y ago

The 1896 warming estimates that were accurate were not estimating future CO2 emissions. They were of the form: if we emit X tons of CO2 a year, the greenhouse effect will be Y. The greenhouse effect of CO2 can be studied in a literal greenhouse, and the effect can be extrapolated to the earth with methods we teach in high school today. They didn't predict at what year we would be at a tipping point, but at what the effects would be with a given level of CO2.

GuB-42 3y ago
The greenhouse effect and how CO2 affects it is actually quite complicated and not what happens in an actual greenhouse, and most of what happens that is relevant to climate change actually happens in the upper atmosphere (which cools!). And there are other effects, like how CO2 get absorbed in the oceans, clouds, water vapor, etc... That CO2 has an effect on temperature is "easy" to realize, quantifying it is much, much harder. And I am just talking about short term effects, long term effects (including a potential tipping point) is yet another layer of complexity.

tim333 3y ago

I read somewhere that if you take a simple model based simply on the extra heat trapped by CO2 in the atmosphere and the black body emission from earth to space as a function of temperature it comes as close to reality as all the elaborate models. Or probably closer as the elaborate models can easily produce extreme results if you assume a lot of positive feedback and so far the real world results have been closer to feedback free results.