By Matt Owens October 5, 2013
First of all, hysteresis is an uncommon word. But it is important when we're thinking about climate change (and for that matter, many other things too). Basically, as far as systems go (like our climate), it refers to a change in a system that is difficult to reverse. More specifically, a system that exhibits hysteresis has “multiple stable states.” Each of these “stable states” is defined as a space of sorts within a set of limits - the system moves around within those specific limits, and when it gets near an edge, the internal stability of the system tends to pull it back into balance.
During Earth's history, the climate has mostly been in various stable states. These states have lasted from hundreds of thousands of years to many millions of years at a time. But every so often, accumulated pressure on the climate forces a change. Once a system that exhibits hysteresis is pushed outside the bounds of a stable state, it can then enter a new, different stable state, after a period of transition. This hysteresis behavior has significant implications for the impacts and trajectory of climate change - and you.
Our global climate is on the brink of - or already leaving - a stable state. As evidence of this, the atmospheric greenhouse gas levels have climbed above the limits of the past climate stable state, and global temperature is not surprisingly, very close to exceeding the limit of that same past stable state. Also, the rate of change of temperature is alarmingly fast, as evidenced by melting ice caps, and a host of other signs.
In theory we could return our climate to its previous stable state. But because of hysteresis, the path back would not just be a rewind process, so to speak. We would have to follow a different route. Think of it as our climate going up an escalator. We are leaving the first floor where there was a mix of warm and cold in the climate. It was generally good to us - it was habitable and we usually had enough water, but not too much water, and we usually had enough food. We're now rising towards the second floor - actually, as a society, we're running up the escalator like we're in a hurry. On the second floor is a climate that's a mix of very hot and warm. This second-floor climate as best we can tell, will be quite inhospitable. We presume that somewhere on the second floor is an escalator back down, but we don't know where. Things on the second floor look so unpleasant, we're not sure we'd last very long up there. But we're in a hurry - not to get there, we're just in a hurry - getting there is a consequence we suppose, but we haven't really thought about it...
The logical option is to turn around and run like mad - against the flow - running down the up escalator.
To return to recent a stable state climate would require a sustained removal of greenhouse gases from the atmosphere. That removal would in turn require a sustained investment and dedication to the process. As far as we know, this would be fairly energy intensive. At the same time, we've already triggered the beginning of some feedbacks that are venting more greenhouse gases into the air... We may be causing the escalator to speed up...
Plans for removing greenhouse gas from the air cheaply are variations of just one theme (to the best of my knowledge): fertilizing the oceans to produce lots of plankton that will grow calcium carbonate shells. This carbonate production would in theory pull CO2 from the air above the water through a chain of natural chemical balancing processes. However, in my best estimation, this “cheap alternative” method would not work. The rate of carbon removal that will be necessary, in part as a result of emerging carbon feedbacks from the warming and thawing permafrost, means that so much fertilization would be needed that the oceans would become choked with algae - living and dead, and would turn ghastly and then actually start venting greenhouse gases from the decaying algae, not absorbing them. We can see that the ocean is already dying in many places now because of excessive fertilization by human pollution. These areas are called “dead zones.” So there isn't much room for extra fertilization to begin with - at least not on the scale that will likely be needed.
The other method is expensive: the chemical extraction route - or possible a mechanized bio-system removal process. These are where I'd place my money (and I may have to). But if we consider the risk of a significant global systemic collapse (aka collapse of civilization) as real, then it could be difficult in the future to muster the resources to maintain such an ambitious project. Or, if we likewise consider as real a risk that agreement to engage in such a global project may not happen or may be significantly delayed by slow institutional processes, then ditto. These risks are all the more reason to hurry back down towards the bottom of the up escalator while we still have a decent chance to make it.
Successfully reversing course would not be significantly burdensome, at least once a “collective executive” decision has been made. However, this decision process is quirky on a global scale. If we look at polls of public attitudes, our prospects appear daunting. And doubly-so when we look at the track record of action to-date. And I dare say, we can all probably even look at ourselves and see plenty of room for worry that reversing course is a pipe-dream. However, public sentiment, is, if anything, prone to rapid reversal. So I wouldn't give up hope just yet.
Now, I would be negligent if I didn't mention that the transition period between stable states can be turbulent. So perhaps there are some dangling snakes along the mid and upper part of this escalator, possibly even a few where we are already. You probably already knew this however.
There are some critical questions that emerge from this train of thought: (1) To what extent is state-transition turbulence and/or the increasing risk for a decline of habitability already harming the world economy? (2) And, more to the point, to what extent is the ongoing US and European economic malaise harming and slowing progress towards making the collective executive decision? (3) Looking forward, will a worsening global economy make things even harder?
So what to make of all this? Hysteresis is actually playing a role in many complex systems - including the social and economic ones - and these multiple complex systems are nested within each other and overlapping and influenced by one another in a big crazy quilt way. And the outcome, which is ever-evolving, makes a big difference for us individually and collectively. The perception of our trajectory also matters too, and this is what shapes our decisions and plans for the future after all - again, both as individuals and collectively.
My gut instinct tells me that transitioning to renewable energy can happen much faster than projected by even the most optimistic estimates of academic researchers (such as Mark Jacobson). I think that a nearly complete global change in energy production for electricity and transport could happen in about 10 years. Or, I should say - I think that such a lightning-fast change might actually happen in our future!
Still, if we take this hysteresis principle in hand, we can evaluate our global situation, including climate, society, and economics, and reach some worrying conclusions about the multiple temporary and eventual stable states. In other circumstances, these are the kinds of conclusions one reaches right before they call the police. But there is no police for this, unless maybe we count a priest. Or, we can also reach the most obvious conclusion: that we as individuals are in fact subject to hysteresis ourselves and we can make our own personal executive decision to take climate action and stop letting this issue just drift around in front of us. This personal “change of state” can manifest itself in many ways, such as deciding that you're going to call, tweet, email, or otherwise contact your elected officials at their office, when they're on call-in shows on the radio, or wherever else that works - and ask them, “what are your plans to get us onto renewable energy ASAP?” Most will probably be shocked by the implicit assumption of the question, as much as they may try to hide it, but that's half the fun. This kind of behavior actually makes a real difference. It can in its own right force a change of state in the larger social system around you. So go for it! What do you have to lose that isn't already at threat from cascading climate consequences?