Rapid Climate Change in the Past

"Rapid, or abrupt, climate change may be described as change that occurs when the climate system is forced across a threshold to a new state and where the rate of change is faster than the underlying cause; moreover, the amplitude of change within the climate system may often be much greater than that in the forcing..."

- Jonathan Holmes et.al.

Has there been rapid climate change in the past?

Significant changes in climate have occurred in the past, happening over decades to 1000s of years, but paced at millennial scales. Theory past rapid climate changes may have contributed to the collapse of some ‘ancient centres of human occupation’ (Holmes et.al. 2011), including drought clearing out Mayans in central America, Akkadian Civilisation in Mesopotamia or cooling leading to the abandonment of Norse settlements. LINK

Theorised thermohaline circulation (THC) could be cause of abrupt climate changes, studies found disruption of THC could be achieved with minor inputs of freshwater at specific zones in North Atlantic. https://www.sciencedirect.com/science/article/pii/S0921818110002298LINK

(Could there be something similiar in Pacific?)

Article on the ‘High consequence, low probability’ chance of the IPCC RCP8.5 Scenario estimates being to low. LINK

Further thoughts:

• Likely a change in circulation (atmospheric or ocean) most likely to produce rapid warming/cooling. If in right area could lead to mass melt and significant sea level rise. Methane release from permafrost another option.

• But need to look into possibilities for more global rapid change as well, going over tipping points and the chain reaction from that.