Warmest regards
The Northern hemisphere summer is around the corner, and, as usual, incantations about heatwaves and deadly warming could be hearkened to.
It might be refreshing to discover that runaway greenhouse effect on Earth due to carbon dioxide levels alone, whencesoever produced it may be, is exceedingly unlikely, because the loop is self-correcting, so to say.
Even the (imaginary) total burning of all hydrocarbons available for extraction shan’t suffice. We would need to import oil and gas from, say, Titan, and even then the “success” is far from guaranteed.
For example, higher carbon dioxide levels in the atmosphere shall result in a less hot Earth than expected, due to enhanced Rayleigh scattering. There are, of course, uncertainties in the currently available models, but it’s generally assumed that the Simpson-Nakajima limit is unattainable in this way.
Global warming could be expected to reduce cold related deaths more than it increases the rarer heat related deaths, and statistics on populations in different climates suggest that we will adjust to global warming with little change in heat mortality.
Currently annual number of deaths from natural disasters, including climate events, is among the lowest in modern history.
Yes, but what about Venus, where the global warming runs amok?
During the evolution of Venus, the following three main factors brought the crucial striking difference: 1) its proximity to the brightening Sun, 2) stagnant lid convection, and 3) the almost total lack of magnetospheric protection against photodissociation of water.
It seems that outer core convection on Venus is being suppressed by a warm mantle or some other features of the core that prevent emergence of the magnetic dynamo. Without magnetosphere strong enough, Earth would, too, have lost almost all of its water into space, hence triggering the runaway greenhouse.
Mars presents, although, another edge case, the so-called runaway freezer: some unknown, non-CO2 greenhouse forcing agent had been present in its atmosphere long ago, but since has been lost, turning Mars into uninhabitable cold dry planet.
Clark Ashton Smith seems to be the first science fiction (or science fantasy) writer who made a try to integrate more plausible picture of Mars into his works, among which I wholeheartedly recommend The Vaults of Yoh Vombis from 1932, an one obvious source of inspiration for the creators of Alien universe.
Better try Smith’s classics than observe what may disfigure Isabela Merced’s buttocks in Alien: Romulus. (We, after all, already saw the end result flushing down the toilet in Dreamcatcher, didn’t we? I wasn’t positively impressed, to put it mildly. Not for nothing Alien’s young is called Chestburster instead of Assburster or Black Destroyer, while both possible pathways of escape are quite far from masterpieces of science fiction world building.)
You see that too low levels of CO2 are no less forbidding to life as we know it than elevated levels. Take this into mind when you list to war drums of ecoalarmists.
Moreover, the continental glaciers were present on the surface of the Earth only during 1/5 of the last 500 million years.
So the current icehouse climate is strictly an exception, not the norm.
Sending warmest regards.
