CLIMATE FEEDBACK LOOPS
Planet now at risk of heading toward ‘Hothouse Earth’ state
August 6, 2018, Stockholm Resilience Centre – SRC
Quote: “The authors of the study consider 10 natural (increasing) feedback processes, some of which are “tipping elements” that lead to abrupt change, if a critical threshold is crossed. These feedbacks could turn from being beneficial, by storing carbon, to a source of uncontrollable (CO2) emission in a warmer world.” (end)
Source study for this page: Trajectories of the Earth System in the Anthropocene, published at PNAS, Proceedings of the National Academy of Sciences (of the USA), referenced in this article by SRC:
Example of a Feedback Loop or Cascade:
Permafrost Melt and Methane Emission
Feedback / cascade: Many gigatons of carbon are trapped in permafrost. It can escape in bulk if the permafrost melts, causing accelerating warming and more rapid melting, and so on …
Cascading Climate Feedback Factors are –
1. (carbon held in) permafrost thaw,
2. loss of methane hydrate (uptake) from the ocean floor,
3. weakening land carbon sinks (forest cover) and
4. weakening ocean carbon sinks (plankton volume),
5. increasing bacterial respiration (decay) in the oceans,
6. Amazon rainforest dieback (from drought, heat, erosion),
7. boreal forest dieback (same),
8. reduction of northern hemisphere snow cover (and reflectivity),
9. loss of Arctic summer sea ice, and
10. reduction of Antarctic sea ice and polar ice sheets.
… Once one (of these dominoes) is pushed over, it pushes Earth toward another. It may be very difficult or impossible to stop the whole row of dominoes from tumbling over.” (Source: 10 Factors and Quote from ‘Hothouse Earth’ article)
Scorched Earth: The result of hitting cascading feedback is not a 4 – 8 deg F increase in temperature; it may be > 20 deg F, in northern places: – An Uninhabitable Planet.
Hothouse Earth is a polite term for Scorched Earth.
We are now experimenting with this risk and result.
Evidence of a tipping point in Greenland ice melt:
CNN article by Drew Kann, Dec 7-18: Melting of Greenland’s ice is ‘off the charts’. The news article introduces ground-breaking work from a recent study: Nonlinear rise in Greenland runoff in response to post-industrial Arctic warming, by Luke Trusel et al, published in Nature.com. A steep rise in core ice melting shows on the bottom right red line.
Sea Leavel Rise
“Business as Usual” (BaU) means 50% of cities may be under water by 2100. After reaching a tipping point, sea levels will rise more rapidly than the BaU projection.
Source: DOWNLOAD Climate Change in a Nutshell: The Gathering Storm, by James Hansen. Dec 6, 2018
WITHOUT TIPPING POINTS & CASCADING EFFECTS,
here’s how bad it is going to get anyway:
DOWNLOAD: Global Climate Change Impacts on the US, report by the US Government. “Business as usual” is the higher emissions scenario.
The higher emissions scenario takes earth back to the Eocene era, 50 million years ago, long before humans existed. The Last “Great Extinction Event, with palm trees in arctic swamps.
The lower emissions scenario requires significant reduction in fossil fuel usage and CO2, relative to present levels. A hot and inhospitable planet, with both raging storms and droughts.
THE GREATEST THREATS TO PLANET EARTH & HUMANITY:
(a) POPULATION GROWTH & (b) EXPANDING USE OF FOSSIL FUELS
Improvement in women’s education can be an ethical means to reduce the rate of world population growth.
Continued Expansion of Fossil Fuel Use to 2040
Massive Coal Reserves on Earth
- Coal reserves in 2006: _________________ 909,064 million tons.
- Coal now consumed per year: ___________ 9,000 million tons
- Years of coal reserves at current usage:____ 1,000 years
It’s time to push the panic button on fossil fuels. Climate deniers are like frogs in a boiling pot. “Everything seems fine?”
Diatoms, or ocean phytoplankton,
are responsible for 50% of the global oxygen released into the air by photosynthesis. There are trillions of diatoms, sometimes visible in a cluster, as algae. How tough are these little critters? How well will they adapt in a warming, more acidic ocean? Their adaptation is critical.
Specific Tipping Points:
Here are Hothouse Earth tipping points, from the source study:
Trajectories of the Earth System in the Anthropocene, published at PNAS, Proceedings of the National Academy of Sciences (of the USA)
Further Evidence of Irreversible Climate Changes:
90% loss of Aral Sea in Kazakstan & 90% loss of Lake Chad in Nigeria; both spawn terrorism: ISIS & Boko Haram.