Anointed modellers need further mechanisms to generate alarm and create heightened 'Climate Fear'.
They first use the concept of ‘sensitivity’ which is an alternative anthropocentric assertion.
They assert that increasing CO2 directly warms the surface of the Earth through the Greenhouse effect mechanism and this kicks into action a further mechanism of multiplication that nearly triples the theoretically alleged ‘direct’ warming.
This mechanism has not been well explained but is wrapped up in the idea that the Climate reaches a long-run equilibrium involving the enhanced effect of 'Direct' warming on water's Greenhouse and other effects.
Either CO2 increase causes humidity to increase and thereby increased Greenhouse absorption by water vapour or CO2 increase reduces cloud cover which enhances greater absorption of direct sun’s heat.
This IPCC endorse this sensitivity concept in their statement (AR6) “The likely range of equilibrium climate ‘sensitivity’ for CO2 doubling is 2.5⁰C to 4⁰C.
The concept of long-term equilibrium sensitivity is in direct conflict with two other concepts.
Developed by James Lovelock and Lynn Margulis in the 1970s the Gaia hypothesis views the Earth as a single, self-regulating system named Gaia. The hypothesis considers Earth as a complex system of interconnected components: the biosphere, atmosphere, hydrosphere, and pedosphere (the outermost layer of the Earth that is composed of soil and subject to soil formation processes).
The theory suggests that organisms collectively regulate global conditions through feedback loops, influencing factors like temperature, atmospheric composition, and ocean salinity to maintain a habitable environment. Recent extensions to this philosophy explain that a complex system is never in exact or permanent equilibrium. It is rather in a state of Dynamic Kinetic Stability’
The Earth has a vast array of individual chemical and physical system elements – each tending towards their chemical and physical equilibria. However, they overshoot or are disturbed by other elements in the vast array of systems. Exceptional events of vulcanisation, meteor impacts, tectonic movements and solar cycles constantly nudge elements of the system away from equilibrium. This is consistent with Natural Climate Variability.
Gaia thinking is concerned about biodiversity loss and changing land-use due to increasing human dominance. This may unsettle or even disrupt the complex interconnection of natural processes keeping the Earth in a state of Dynamic Kinetic Stability.
There is often talk of ‘Tipping Points’ being reached. Most famously the 2016 Paris accord set 1.5⁰C as a ‘tipping point’.
Once a ‘tipping point’ is reached, things worsen until other ‘tipping points’ are breached which in turn reinforce and accelerate the climate collapse process.
The anthropocentric argument is that this ‘domino effect’ leads climate toward collapse into a climate state that will lead to the end of human society as we know it.
The new climate mode threatened is argued to be a severe ‘hot-house’ mode following ‘runaway Global Warming’. The anticipated mode is not unlike the Earth during the PETM period 56 million years ago.
There have been, historically, quite abrupt changes to the Earth's climate and surface temperature.
The last abrupt warming came at the end of the cold snap known as the 'Younger Dryas' (approx. 12,900–11,700 years BP). This ended, with Greenland temperatures rising ~10°C in a decade. This transition from the last glacial period to the Holocene occurred roughly 11,600 years ago, driven by a resumption of ocean circulation after a cold, dry, 1,200-year spell. Orbital cycles may also have played a part.