One example of thresholds we use everyday is the fact that water goes through three states of matter easily and well within the boundaries of our everyday temperature/pressure experience. From frappuccino to cappuccino where would the Starbuckians be without it? Everyday we exploit another threshold changing reality when we turn on an electric light which works because, as we know from Quantum Physics, sub-atomic particles can only exist at certain discrete energy levels. When, either slowly or quickly, a particle absorbs enough energy to cross that level's threshold they instantly jump to the next higher level [valence] then by discharging a discrete quantity of energy [called a photon] they can return to their previous more stable energy level. Good ol' photons, how would we find the fridge without them?
Our small blue marble has been choked full of threshold crossing events during its billions of years long geologic and climatic history. Somehow the primordial soup crossed a threshold and voila, The Big Bang happened. Thresholds are everywhere [i tripped on one this morning]. Our biosphere too is subject to occult ecological thresholds most commonly defined as the non-linearity of the responses in ecological or biological systems to pressures caused by human activities or natural processes. The temperature and climate graph above of our earth's last 700,000,000 years shows that non-linear climate change has been the norm, not the exception, for awhile now.
Almost all opponents of the scientific consensus on anthropocentric global warming {AGW] theory refer to a graph like the one above and say that natural processes have been driving our climate over the thresholds since long before there were humans or human activities, which is true. What isn't true is the speed that those changes, those potential threshold crossings, could now be happening at. What once took place in a relatively short few thousand years now is taking place in a few decades. It seems only logical to infer that our species activities have had a hand in this recent rapid rate of change. It also seems logical then that the curve resulting from our current rate of change may or may not crest and stabilize at the levels the previous ones have.
Another confounding feature of the natural variability argument is that, though the degree of its influence on climate change is uncertain, natural variability has zero effect on so many of the other environmental disasters like the extinctions and the degraded soils and water caused by pesticide and other man-made chemicals or the deleterious effects of deforestation and mining or over fishing or over consumption of resources in general - it's a long list - so as to make it an unlikely candidate for a starring role in the global warming movie.
"Shit happens", as my old buddy Eddie used to say. Despite our emotional need to understand all this uncertain shit happening in some linear manner, sometimes it doesn't, sometimes a straw breaks the camel's back, sometimes the genetic roulette wheel produces a black swan, sometimes the climate is forced across an unknowable threshold and plunges or soars in a non-linear response for thousands of years causing myriad extinctions and planetary changes. It only seems logical to take precautions against crossing an ecological threshold.
Tomorrow we'll take a look at the precautions and plans the military and other security agencies along with the insurance industry and other businesses are taking not because they know where the ecological thresholds are, but because they don't.
