Tipping Points - the Facts
When the temperature gets high enough to cause forests to give up their CO2 rather than sequest it, then every tonne of gas given up to the air increases the temperature and causes even more gas to be given up. This is a tipping point - an irreversible moment when the dreaded feedback loop begins.
This is now the central issue for the scientific community: have humans already have gone too far, and may we now be helpless to stop abrupt and runaway global warming.
These ten major tipping points are are right at this moment being triggered.
- Melting glaciers will raise sea levels so that less heat is reflected out to space
- Decline of the flow of fresh water from the Arctic will collapse the Gulf Stream
- Forests will no longer absorb carbon, but become a source.
- Methane clathrates held in the mud under the sea begin to burp
- Melting permafrost releases vast quantities of methane
- Drought kills the Amazon forest and its carbon sink is released
- The benefits of being shielded by global dimming ceases
- Bush fires increase the carbon load and reduce the storage capacity of forests
- As oceans warm the seas absorb less carbon
- All the above plus disastrous weather and coral bleaching and acidification of the oceans disrupt food production
Triggering any one of these ten carbon sinks would cause
runaway greenhouse warming.
The triggering of any one of them would start off the others.
The earth has over eons stored greenhouse gasses in forests, the soil and in the oceans. Recent scientific research has shown that small rises in temperature can trigger these sinks into becoming sources, and thus tip the scales against our survival.
Only now, in the past five years, has the scientific community begun to pat serious attention to them. We do not know if they will be triggered today or in decades, It seems there is a ten percent possibility that feedback loops from glacial-meltdown, permafrost methane burping and/or rainforest collapse will commence within the next few years.
Only intense and immediate action beyond anything the
world has ever done can stop this.
If all the good intentions from the Kyoto and Montreal meetings were to be executed in full and immediately, they would not alter the outcome. Like Munich, these agreements were set by politicians playing for time. This is discussed in Footprints #2.
The graph shows the range of temperatures possible by the end of the century from computer modeling. The latest ICCC meeting added 50% to these figures.
Taken together, concentrations of CO2 and methane have passed the threshold of 400ppm set as the upper limit of safety by the International Conference on Climate Change. This is of the most enormous significance.
It means we have actually entered the era of dangerous climate change.
We have already reached the point where our children
can no longer count on a safe environment.
The Earth is about to be trapped in a vicious cycle of positive feedback, which is why the issue is so serious and urgent. Any extra heat from any source (especially human activity) is amplified, and as it is added this sets off other processes so that heating is accelerating.
It is the self-regulating mechanism of Gaia itself that, perversely, will make it hard to master global warming - because the system contains feedback mechanisms that in the past have acted in concert to keep the Earth much cooler than it otherwise would be. Now, however, they could easily combine to amplify the warming being caused by our activities.
Tragically, there are no large negative feedbacks that would reverse the heating process – save the weathering of rocks and occasional fierce tropical storms. Neither can compete.
We are interfering with the natural regulating systems of the planet by increasing our own input while limiting the natural systems that would regulate it.
Global warming will submerge many low-lying island nations in an unstoppable process. Increased numbers of cyclones, droughts and floods are making life unviable for the people on the Carteret atolls in Papua New Guinea. Already 980 have had to be evacuated. Many were starving because rising salt water has destroyed their trees and stopped them growing greens and breadfruit. Next may be the small island nation of Kiribati of 33 small atolls, none of which is more than 2 meters above the Pacific. It is only a matter of time before the entire country is submerged by the rising sea. Also the Tuvalu people have had to arrange for the evacuation of the entire 10,000 population to New Zealand.
For these people, the tipping point has already occurred.To the top