By David L. Brown
Val Germann asks (in the previous post) the question, How high can carbon dioxide go? Good question, and he outlines the problem very well. However, there is an upper limit on this problem, and we may reach that limit sooner rather than later.
The limit is simply this: When there are no people left to burn fossil fuels and contribute greenhouse gas (GHG) to the atmosphere; or when (less dramatically but nevertheless catastrophic) the world economy is so devastated by the effects of climate change that the same result is realized — then the amount of carbon entering the atmosphere will ipso facto drop back to its normal levels.
Well, sort of. The problem with that simplistic assessment is that it doesn’t take into account all the feedback and tipping point factors that come into play as a result of global warming. For example, the Arctic is in a state of rapid meltdown and this is releasing a growing flow of GHG as the muskeg and permafrost turns to soup. Warming oceans are in danger of releasing vast quantities of methane long sequestered in frigid clathrates. Tropical rainforests once acting as the “lungs” of the planet are being destroyed, and even if humans do not cut down all the trees they may soon fall prey to desertification as climate change kicks in.
Unfortunately, even if we were somehow able to reduce our carbon emissions to zero right now, tomorrow at the very latest, the amount of carbon in the atmosphere would continue to rise.
Climate change nay-sayers would like us to think that change is linear. Would that it were so. Linear change is easy to visualize — all one has to do is look back to history, then draw a straight line through the present and extend the trend straight into the future. If you accept this method as valid it is easy to see that change is not something that can happen in a rapid, accelerating way.
But the way the world (and practically everything else in the universe) works is not, never has, and never will be in a linear fashion. From the macrocosmic to the microscopic, the rule is for exponential effects that can cause change to take place with alarming rapidity.
On the mega-scale, contemplate an aging star larger than our Sun. If it contains a certain threshold amount of mass, it will burn quite happily for millions of years — but suddenly a tipping point is reached and that star becomes a supernova, blowing itself to bits in a matter of seconds.
On the microscopic scale, imagine a strain of bacteria that lives in balance with its environment most of the time, e. coli for example, but that suddenly bursts into runaway growth due to some change in the conditions in which it lives (for example, perhaps the potato salad having been left out at room temperature). Suddenly, that normally harmless e. coli can become a deadly threat.
These are examples of exponential change, the kind that are found almost everywhere you look. And there is another thing to notice about exponential change, and that is the fact that it often leads to sudden “tipping points” in which conditions might change from apparent stability quite dramatically, even in a brief instant.
Could the environment of the Earth have something in common with those stars that are destined to go nova in an instant of time? Those common bacteria that can suddenly become serial killers? Hard to imagine, isn’t it? And yet, we should seriously consider that question because exponential change and tipping points are more the norm than the exception in the natural world. Our propensity to think in linear terms — to visualize the future by reference to the past — is based on false observations and is actually contrary to fact. Buying into a model that predicts natural forces will operate in a linear fashion is a serious handicap when trying to envision the possibilities of how climate change can affect our future.
Here is an analogy that may help to bring things into focus. Imagine that you have placed a pan of cold water on a stove and turned up the heat. Failing to heed the old wives tale about watched pots failing to boil, you stand there and watch the water as the stove continues to warm it. Hmm, not much going on is there? Those old wives may have had something, eh? There is the pot, its contents of water just sitting there, just continuing to behave as plain old water always does. Nothing much seems to be happening.
This provides a good analogy for what the linear, rear-looking view of our climate conditions on Planet Earth may lead us to believe. Just as with the slowly warming pot of water, not much seems to be going on. And yet, as we well know, as the stove continues to heat the pot the temperature of the water is rising steadily. This you know; this you understand from your direct experience.
As you continue to watch, at last there is a subtle change in the water. Small bubbles begin to appear on the surface of the pot. Something is about to happen. In our analogy of the climate, those little bubbles are the first signs of impending change. We are seeing those signs in the melting of the Arctic ice, in the disappearance of plant and animal species, in the climbing amount of GHG in the atmosphere, and in the inexorable rise of the ocean.
So, what happens next? You know the answer — the pot quickly advances beyond the first signs of change and comes to a rolling boil, releasing a cloud of steam and causing the water to bubble frantically and perhaps even spill over onto the stovetop — unless you turn down the heat soon enough. This is how a tipping point works, with sudden and dramatic change that could only be anticipated by the foreknowledge of how nature works.
Well, there we are, with (in our analogy) the world climate showing the first signs of coming to a boil. Are we turning down the heat? No. Stuck in our linear thinking, we cannot conceive that the entire planet could suddenly and catastrophically “come to a boil” with all that could imply for the future of our civilization. That boiling pot is an excellent analogy for what might be about to happen to the climate, as slow and steady heating reaches a tipping point. And most of us are acting like individuals who have never seen a pot come to a boil, for whom that event will be a great and unanticipated surprise.
Scientists have been warning of this danger for quite some time, several decades in some cases. Few others have listened or paid heed. And yet, all that time the heat has been rising, the feedback effects have been slowly coming on-line, and the tipping points are approaching at alarming speed.
The time to turn down the heat on global warming may already be past, for when the pot has already come to a boil it is too late. Clearly, tipping points have been passed in the Arctic where the ice cover is melting like a Fudgesickle on a sidewalk in July. Ocean levels have not risen very much — yet — but the trend is gathering speed. Average temperatures around the world are climbing, and in some places are already at alarming levels. With each increment of warming, more feedbacks kick in, more tipping points will be reached. There is growing danger that the pot will boil over.
Do you get what I am saying here, people — that the environmental “pot” of climate change is about to come to a boil? What will happen when it does, when that environmental pot boils over and scalding water (or something much worse) figuratively splatters around all over the landscape?
When are we going to turn down the heat? When?