Climate Change Feedbacks and Tipping Points
March 2024
What is a feedback?
In Climate Change a Feedback is something which, once started, accelerates the overall warming.
In biology, there are many natural feedbacks which are stabilizing (aka negative feedback), but in Climate Change the feedbacks are almost all accelerating ones, which is BAD NEWS.
In this context, POSITIVE means BAD.
What is a Tipping Point?
A tipping point occurs when a feedback goes so far as to be irreversible during several human lifetimes.
Science does not yet have precise enough models to adequately predict the timing and long-term effects, but there are many serious concerns.
When does a feedback become a tipping point?
Only time will tell!
Scientists are concerned about ALL of these
Ice Albedo Reflection Feedback
Ice or snow reflect lots of the sun’s energy back. But once ice melts, the darker earth or water absorb more sunlight which ACCELERATES the melting and the overall warming.
This effect is of special concern in the arctic.
Arctic Sea Ice
Tipping Point
For the Arctic a Tipping Point will happen when the Arctic Ocean is ice
free in the summer.
It will then get rapidly warmer which will have huge effects on single weather events and the overall climate.
Antarctic Ice Shelves and Glaciers
Video link. 7min
Includes science and tipping points
Ice shelves in light blue around the coast of Antarctica hold back the glaciers.
Permafrost
(permanently frozen ground)
Rising temperatures are starting to melt arctic permafrost which releases METHANE (CH4), causing further warming - an accelerating feedback.
Methane is highly flammable
Wildfires on the Siberian tundra release loads of CO2 and
CH4 - increasing warming even more.
Past AMOC Shutdown
Scientific data indicate that the AMOC has shut down before. The clearest example began about 12,800 years ago. Glaciers that once had covered much of North America and Europe had retreated considerably, and the world was almost out of the deep freeze. But then, in just a few decades, Greenland and Western Europe plunged back into cold.
Past Amoc Continued
In parts of Greenland, temperatures fell by around 10 degrees Celsius, or 18 degrees Fahrenheit,.
Arctic-like conditions returned to parts of Europe.
The cold period lasted perhaps 1,300 years — before reversing even more abruptly than it began. Scientists have observed the sudden changes in the pollen deposited at the bottom of European lakes and in changes in ocean sediments near Bermuda.
A “Day After Tomorrow” Scenario is highly unlikely but concerns, especially for Europe are real.
Boreal Forests
Boreal (i.e.northerly) forests currently absorb huge amounts of CO2 during the brief summer.
They are threatened by logging, insect infestation and wildfires.
Protecting them is important.
Coral Reefs
Healthy coral reefs are beautiful and host a wonderful diversity of life - but warmer, more acidic oceans are killing them. They turn white - coral bleaching. The tipping point of too much warming and too much acidity of the water may be reached in ten years or less.
Droughts and Wildfires
Amazon Problems
Deforestation of the Amazon for cattle production and logging is accelerating drought.
This causes wildfires releasing more CO2 and soot and other gases.
LESS MEAT consumption would help slow this!
For eons the Amazon has been absorbing CO2, but scientists worry that it could change to releasing CO2, a huge tipping point, which would then become a huge feedback for the world’s climate.
Droughts have a major impact in various parts of Africa and Central America, as well as other places.
If it gets too much, this is likely to cause people to migrate to other places, including the US!
We could call it a socio- economic feedback.
Atmospheric Water Vapor
This also causes greater water vapor content in the upper troposphere, which traps MORE heat. This is an accelerating feedback.
Warmer temperatures produce more evaporation, causing heavier rain and flooding.
Conclusion
We need to do everything possible - as soon as possible - to minimize the potential for feedbacks and tipping points