A tipping point is where, once you go past it, there is no possibility of recovery or repair. There is no going back, at least not in the short term. Of course, natural cycles being what they are and because things are forever changing on this dynamic planet, over (geologic) time things might change yet again. But this is looking at the short term, at our lifetimes and the lifetimes of our children, grandchildren and great grandchildren.
Very short-term of course, when looking at the lifetime of a planet. But for us humans, entirely natural and of extreme importance. After all, this is our habitat that's changing. We are adaptable but question is if we can adapt en masse fast enough and effectively enough, to survive as a species. It is from that point of view that I'm looking at these issues. Selfishly, I want survival of the human species and more specifically, my family.
Science has identified a number of tipping points in our world's climate. Over the next months I'll be looking at each of these in detail, examining what the current situation is, what it used to be, where it's heading to, and what the expected effects will be of crossing that point of no return.
So far, on my list, are:
1. Loss of Arctic summer sea ice
2. Melting of Greenland ice sheet
3. (Partial) collapse of the Gulf Stream
4. Collapse of the West Antarctic ice sheet
5. Severity and frequency of El Niño
6. Amazon rain forest - permanent change into Savannah-type landscape
7. Monsoons - West African, Indian
8. Loss of Boreal forests
Other urgent issues that will severely affect human society and resources (local and global):
• Worldwide loss of coral reefs, destroying much of world fisheries
• Global sea level rise
• Increasing severity of weather
• Permafrost disappearance and the resultant release of huge quantities of Methane into the atmosphere
• Desertification
• The ozone hole (no, that problem is not "fixed")
• Changes in ocean salinity and pH
Like a thread running through it all is the Carbon Dioxide level, whether it will exceed 450 ppm.