Part One - Epilogue
As we have seen, the global ecosystem has been dramatically damaged by human activities. The time of the “Great Acceleration” has been an especially consequential period during which GHG emissions have rapidly increased, the oceans have been acidified and over-fished, the quality of land used for farming has been degraded by mono-cropping and the heavy use of synthetic fertilizers, pesticides, and herbicides, the poles have begun melting, and biodiversity loss threatens a million species; there is no part of the earth’s biosphere that has not been adulterated. Each of these systems is being forced to or has already surpassed a tipping point beyond which it will be unable to provide its process as part of the greater system.
This begs the question: are we approaching a planetary-scale critical transition because of human activities?
A Planetary Tipping Point
Although science can provide some guidance about how we can expect natural systems to change, depending on recent trends is woefully inadequate for predicting the future of something so complex as the earth’s ecosystem. The IPCC reports essentially avoid the topic of state changes and fail to take into account the probability that we are dealing with a system of changes that are non-linear. This in spite of the fact that “critical transitions caused by threshold effects are likely.”1
The earth has already experienced five mass extinctions and numerous shifts from glacial to inter-glacial periods. These events occurred over thousands, if not millions, of years. What humans have done to the planet during the 12 thousand years of the Holocene and, more significantly, during the last few human lifetimes is unprecedented. The Holocene could have lasted another 50,000 years, but human activity has destroyed that possibility, forcing the world into an unknown future and a climate unknown to humans.
The previous global scale transitions have been characterized by changes to the atmosphere, oceans, and climate. That these changes are now occurring because of human activity is reason to deliberate on the scale of that forcing. Although climate change is only one among a number of threats to the ecosystem, it could be the catalyst, provoking crises of food and water deprivation in parts of the world. In the wake of such events, mass migration within just three areas, Sub-Saharan Africa, Southern Asia, and Latin America could lead to migration within countries of 140 million people by 2050.2
We cannot know when tipping points will occur but, when they do, a return to the previous state is unlikely. Prudent risk-management would dictate a precautionary approach to maintaining earth systems and minimizing the possibility of reaching tipping points. This would entail not a transition (Green New Deal), but a transformation in humanity’s relationship with nature.