Hotter

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3 responses to “Hotter”

1. 

   Omar

   Jun 26, 2026 5:58 AM

   The Earth has been hotter before. I think it highly likely that as ocean tmperatures rise, increased water vapour in the atmosphere will increase atmospheric cloudiness and the planet’s reflectivity of incoming solar radiation. At least in that respect, Earth might become more like Venus, whose dense clouds permanently hide its surface; though the Venusian atmosphere is 96.5% CO2, making its surface hotter than that of Mercury, closest planet to the Sun.

   Geologists and paleontologists have found that in the last 100 million years, global temperatures have peaked twice. One spike was the Cretaceous Hot Greenhouse roughly 92 million years ago, about 25 million years before Earth’s last dinosaurs went extinct. A 2024 paleoclimate reconstruction named PhanDA (Phanerozoic Data Assimilation) found a strong correlation between temperature and carbon dioxide during the Paleozoic (from the start of the reconstruction at 485 million years ago through 250 million years ago) and the Cenozoic (the last 65 million years) but did not find a similarly strong link during the age of the dinosaurs. So, the precise cause of the Cretaceous Hot Greenhouse will need continued research, but the fossils indicate a very warm planet. Temperatures were so high that champsosaurs (crocodile-like reptiles) lived as far north as the Canadian Arctic, and warm-temperature forests thrived near the South Pole.

   Another hothouse period was the Paleocene-Eocene Thermal Maximum (PETM) about 56 million years ago. During much of the Paleocene and early Eocene, the poles were free of ice caps, and palm trees and crocodiles lived above the Arctic Circle.

   But please note, I could be wrong. The Earth’s lithosphere-hydrosphere-biosphere-cryosphere-atmosphere assemblage is the most complex system we know of in the entire Universe.

   See https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been
2. 

   iknklast

   Jun 26, 2026 11:28 AM

   Omar, I’m not sure why anyone would report this as news; we’ve known about those temperature spikes for a long time. I taught about them for 20 years before I retired.

   The thing is, water vapor is a greenhouse gas itself. Although clouds have a cooling effect, the heating usually overwhelms the cooling quickly, especially since CO2 and methane are both long lasting gases, while water vapor dissipates in a matter of days. So as CO2 and methane continue building up, water vapor might build, but much slower…and contribute some warming of its own.

   Not to mention, both of those spikes are known to have had substantial impact on flora and fauna, as have the ice ages. When temperature changes, the ecosystem changes. When the ecosystem changes, the organisms that can live there change. While humans have a relatively large range of tolerance, and we build air conditioners, a lot of other organisms don’t. We actually don’t have a high range of tolerance for famine or drought. We succumb just like most other creatures (I say most, because there are some that can survive extreme conditions).

   Every few months or so, I hear someone arguing that the warming of the earth will cause the cooling of the earth. Sure, that might happen. It might not. But the cooling process will be slower than the heating process, and as long as we continue adding greenhouse gases to the atmosphere, it is unlikely that we will see much cooling.

   The same thing was said about plants for a long time; they like CO2. This will be good for them. I, and many fellow botanists, were, at best, suspicious. We pointed to the many other things plants need, most of which hamper the movement of the plants to a new, further north system, and also the fact that most of the plants we eat are not limited by CO2 but by nutrients, water, or temperature.

   A recent study has confirmed what many of us already knew, because other studies had shown it…global warming is not good for plants. Speculations about cooling of the atmosphere are premature, at best. They are foolhardy at worst because they encourage people to ignore reality at their peril, especially when presented by someone as literate and erudite as yourself.
3. 

   Omar

   Jun 26, 2026 5:08 PM

   iknklast:

   A recent study has confirmed what many of us already knew, because other studies had shown it…global warming is not good for plants. Speculations about cooling of the atmosphere are premature, at best. They are foolhardy at worst because they encourage people to ignore reality at their peril, especially when presented by someone as literate and erudite as yourself.

   Thank you for that compliment. I find such to be increasingly welcome with every passing decade. But I have spent an awful lot of time arguing online and elsewhere against fossil-carbon shills and anthropogenic-global-warming (AGW) denialists, so I hope that I have not given you the wrong impression. The last thing we should be doing with our global fossil-carbon resources is burning up the large molecules they contain for power generation, etc, when renewable sources are available to do the same job. For a start, they are feedstock for synthetic rubber manufacture yielding us automobile tyres, and for the tarred roads we drive those vehicles on. As demand increasingly overtakes supply, prices will rise and availability will fall. So it could force us all back to horse-drawn vehicles with wooden wheels being driven over cobbled roads, and by drivers whose curses will be increasingly intemperate and obscene. And all in the damned cause of entropy increase and that fornicating Second Law of Thermodynamics.!