Amplifying Feedback

the self-amplifying feedback loop linking global heating and the melting of ice

The biggest climate risk

The current global heating has set in motion the Earth’s own heating mechanisms. The heating is causing more heating which is then causing even more heating – and these self-amplifying feedback processes are destroying our nurturing climate. Note that some of these feedback processes are reversible and could help us cool the planet.

The Arctic warming feedback loop

More global warmingMore ice melt
Less sunlight reflected & more absorbed. Less ice cover & more dark water.

In the Arctic, warming is causing further warming. In this cycle:

  • Global warming tends to increase temperatures in the Arctic and melt more ice.
  • This tends to decrease the area covered by sea-ice and increase the area of open ocean.
  • This tends to decrease the sunlight reflected and increase the sunlight absorbed.
  • This tends to increase global warming, and the cycle repeats. 

See The dwindling Arctic sea-ice on this website.

These linkages are tendencies

The linkages in these feedback loops are tendencies or likely outcomes. For example, when the area of reflective ice in the Arctic drops, this only tends to increase global heating; global temperatures could fall due to a volcanic eruption with volcanic ash reducing the amount of sunlight reaching the earth.

Feedback loops that could limit global heating

Feedback loops amplifying global cooling

The above Arctic warming feedback loop is reversible.

More global coolingMore sea-ice formation
Less open water & less sunlight absorbed. More ice & more sunlight reflected.

The current exceptionally high level of greenhouse gases in our atmosphere means that we are unlikely to see any global cooling soon, so we are unlikely to see any amplification of global cooling. However, if we do get cooling, this dynamic could help us cool the planet.

Some other global heating feedbacks are also reversible, and I will identify these below.

The amplification of climate action

Here is one feedback loop that could amplify climate action in Australia.

More popularity for the superpower vision
More benefits More progress towards the vision

Rather than focusing on the many feedback loops that amplify global heating, it can be more energising to focus on (1) an attractive future vision, (2) the progress towards that vision and (3) the resulting benefits.

Now, here are other examples of feedback cycles that amplify global heating.

Other global heating feedback loops

The permafrost methane feedback loop

More global heating More melting of ice containing methane
More greenhouse gassesMore methane release

This feedback is not reversible as global cooling will not remove methane from the air and trap it in permafrost.

See the methane feedback loop on this website.

The water vapour feedback loop

More global heatingAir temperatures increase
More greenhouse gasesMore water vapour in the atmosphere

Warming increases water vapour in the atmosphere, and water vapour is a potent greenhouse gas.

(Climate Change: Now or Never: New Scientist: 24 April 2021: page 37).

This loop is reversible as global cooling would reduce water vapour in the atmosphere.

The phytoplankton feedback loop

More global heatingMore ocean surface warming
More carbon dioxide in the atmosphereLess nutrient upwelling
Less photosynthesisReduced phytoplankton population

See the warming of the ocean surface and the phytoplankton feedback loop on this website.

The forest fire feedback loop

More climate changeHigher temperatures & more drought
More forest fires
More CO2 in the airRelease of CO2 and Less use of CO2 in photosynthesis

See fires intensifying climate change on this website

The ice surface darkening feedback loop

More global heatingMore melting of the ice sheet surface
Less reflection of sunlightMore dark dust in the ice surface
  • Global heating tends to increase the melting at the surface of an ice sheet, e.g. the Greenland ice sheet.
  • This tends to increase the amount of exposed dust on the ice’s surface, dust that originally fell onto the glacier and was buried by snow before becoming part of the ice sheet.
  • This exposed dust will be less reflective than the ice and will increase sunlight absorption.
  • This tends to increase global heating.

Glacier melt feedback loop

More melting of the glacierA drop in the altitude of the glacier surface
.A rise in average temperature at the glacier surface

See glaciers in retreat on this website.

Migration, Populism & Climate inaction feedback loop

More global heatingMore extreme weather
Less climate actionMore social & political instability
More right-wing populismMore deprivation & migration

See migration, right-wing populism, climate inaction feedback on this website.

The danger of global heating amplification

The risk of allowing our planet’s current heating to continue is that feedback cycles that amplify the current heating could produce run-away heating that would continue even if humans stopped burning all fossil fuels.

We have co-evolved with our climate, so our current climate system suits human beings and the rich diversity of life on our planet.  We need to protect our climate system because global warming amplification threatens our current climate, the global economy, political stability, human health, and the environment.

When a loudspeaker goes into “feedback”, you can quickly turn it off.  Unfortunately, the earth’s climate does not have an easily-flicked off-switch.

No effective resistance to the current heating

James Lovelock (“The Revenge of Gaia”: 2006: page 35) writes that the observed rate of global warming is a grave concern.  This rate suggests that no global climate dynamic will effectively resist the current warming, limit temperature increases, and retain an environment safe for life as we know it.

Lovelock (published in 2006) noted that the levels of methane and CO2 in the atmosphere were comparable to those caused by natural releases of these gases fifty-five million years ago. At this time, temperatures rose between 5 and 8 degrees C, with consequences lasting 200,000 years.

We do not know whether a climate dynamic will emerge to limit temperature increases to a safe level. We do know of many amplifying feedback loops that could feed runaway climate change. They pose a real risk for the global economy, political stability, human health and our environment.

Feedback Loops

Feedback: A well-established concept

Feedback is a long-established concept that is a central part of “Systems Theory”. You may know about amplifying feedback under other names, like:

Non-climate examples of amplifying feedback

A person speaks into a loudspeaker, which kicks off a soft hum, rapidly escalating into that ear-piercing shriek called feedback.

Louder microphone inputLouder microphone output

Something develops a fault, like a pothole in a road: the bigger the hole, the greater the pounding from car tyres, so the hole gets bigger. Amplifying feedback can destroy things.

The bigger a pot-hole in a roadThe more violent the impact from car tyres

Something emerges,  like a new interest or fascination, so you study it, build up your knowledge about it, and you might even turn it into a career.  Amplifying feedback can create new things.

A growing fascination with a subjectGrowing knowledge about the subject

Amplifying feedback can start with a change so small that you cannot notice it.  A repeating sequence of events can amplify this small initial change. Amplifying feedback is happening when:

  • a change,
  • leads to more of that change,
  • which leads to more of that change …

Negative Feedback

While amplifying feedback loops tend to change systems, negative feedback tends to prevent change.  See the above Maruyama article or Wikipedia.

Site name: Feedback Reigns

The importance of “amplifying feedback cycles” led to this website’s name: “Feedback Reigns”.

Updated: 18 September 2021

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