Amplifying Feedback

The biggest risk of allowing the current warming of our planet to continue is that there are many ways in which warming can cause more warming, which causes more warming, and so on. Here are a few examples of these self-amplifying feedback loops.

But a warning first, these feedback loops are bleak news. It can be more energising to focus on an attractive future vision and the progress towards that vision.

Now here are the vicious feedback loops:


The Arctic warming feedback loop

More global warming———->More ice melt
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More open water & more sunlight absorbed <———-Less ice & less sunlight reflected

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 the sunlight reflected into space.
  • This increases the area of darker coloured exposed ocean and the sunlight that is absorbed by the ocean.
  • This tends to increase global warming, and the cycle repeats. 

(See The dwindling Arctic sea-ice on this website)

These causal links are tendencies

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

Tipping Points

A tipping point is reached when a feedback loop becomes dominant. When many factors influence a system, a feedback loop can become dominant for a while but then lose its ascendancy. For example, a “heating feedback” can be broken by a large volcanic eruption’s cooling impact.

See Tipping points and how they trigger amplifying feedback on this website.

Here are further examples of climate feedback cycles.


The permafrost methane feedback loop

More global warming———->More melting of ice containing methane
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More greenhouse heating <———-More methane release

See the methane feedback loop on this website


The phytoplankton feedback loop

More global heating———->More ocean surface warming
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More carbon dioxide in the atmosphereLess nutrient upwelling
^
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Less photosynthesis<———-Reduced phytoplankton population

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


The forest fire feedback loop

More climate change———->Higher temperatures & more drought
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*More forest fires
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More CO2 in the air<———-Release 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 heating———->More melting of the ice sheet surface
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Less reflection of sunlight <———-More 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 tend to increase the absorption of sunlight.
  • This tends to increase global heating.

Danger: The Amplification of Global Heating

The risk of allowing our planet’s current heating to continue is that feedback cycles that amplify the current heating could become dominant.  They could produce run-away heating, which 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 current climate system because global warming amplification threatens to destroy our current climate. Much of the planet could become too hot for humans. This poses a real risk for the global economy, political stability, human health, and the environment.

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


There may not be any climate dynamic that effectively resists  the current warming

James Lovelock (“The Revenge of Gaia”: 2006: page 35) is concerned by the observed rate of global warming.  It suggests that there is no global climate dynamic that will limit temperature increases, and retain a climate that is safe for life as we know it.

Lovelock notes that the current levels of methane and CO2 in the atmosphere are comparable to that 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. This is one area of scientific uncertainty.

Many amplifying feedbacks could cause runaway climate change. They pose a real risk for the global economy, political stability, human health and our environment.


Feedback is 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, and this kicks off a soft hum, which rapidly escalates into that ear-piercing shriek called feedback.

Louder microphone input———->*
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Louder loudspeaker output <———-More amplification

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.

Bigger pothole———->*
^
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* <———-More impact from car tyres

Something emerges,  like a new interest: something catches your interest, so you investigate it more, and become more interested, and turn it into a career.  Amplifying feedback can create new things.

Increased interest in a subject———->*
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* <———-More learning 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.


Feedback Reigns

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


Solution focussed pages

Here are two pages that focus on solutions rather than on the problem:


External Links


Updated: 18 Feb 2021

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