Thursday, March 27, 2014

The Danger of a Single Climate Change Threshold

Climate change is frequently associated with some threshold that scientists refer to. For instance, a common threshold is a 2 degree Celsius rise in temperature over the pre-industrial level, which is cited as the threshold for dangerous changes in the climate. I have always had problems with these thresholds because they give the impression that the danger is way down the road and isn't anything we need to worry about today. That is a completely false impression to give. The changes are already happening and just because there are stages that won't occur until after the threshold doesn't mean we can't suffer from some changes right now.

An analogy would be declaring bankruptcy. You don't just wake up one morning and find your finances have so completely fallen apart you need to seek protection with the court. No, things were falling apart for quite some time, getting progressively worse. At first, things weren't bad. Maybe you noticed that you had less and less spare money after paying the bills, but you were still OK. Then, more and more things happened. Maybe you were turned down for credit when you applied for it. Maybe your credit card was turned down at the restaurant. At first, it was once a month. Then, it was every week. Finally, it was every day. Then, you found out you didn't have enough money in your paycheck to pay the bills, not to mention buy groceries. How were you going to feed the kids? That is when you sit down and wonder, "How did I get in this mess?"

That is the situation with climate change. Things have started out slowly. A little warming, maybe a few more severe storms than we use to have. Over time, more and more things happen. Mountain snow gets less and less leading to drier months in the summer. More and more crops fail due to heat or are destroyed in more frequent severe storms. You go to the grocery store and are stunned to see the price of food. Droughts occur more often and last longer. Reservoirs that use to be full of water are now full of weeds. When it does rain it comes down so fast that the area is flooded, washing everything away. You notice your electric bill in the summer is going through the roof because you have to run the air conditioner so much. The list goes on, but it is still manageable. We haven't reached the crisis point yet.

But, some day, we will reach that crisis point. When we do, we will realize that we saw it coming for years and didn't do anything about it. We will all sit down and wonder, "How did we get in this mess?"

That is the danger with the thresholds. We need to educate the public that it isn't some switch that will be flipped some day. Instead, it is a gradual ratcheting up of the consequences of our actions and the ratchet will continue to get tighter until we take responsibility for our actions and do something about it.

This is something I have fought with for years now. So many deniers just want to say that we don't need to do anything because even the scientists say it is years down the road. So, it was with interest that I read a paper today about that very issue. "The difficult, the dangerous, and the catastrophic: Managing the spectrum of climate risks," by Amy L Leurs and Leonard S Sklar addresses this very issue and they discuss many of the same issues I just did.

But, they propose an alternative approach. 

In their scenario they use two individuals with different viewpoints concerning a number of events that occur as a result of global warming. The plot of the two individuals' viewpoints is presented below.

Climate risk space. Conceptual map of climate risk perceptions held by multiple stakeholders. Risks vary across a spectrum of severity and time scale over which impacts may be realized with increasing global temperature. Two hypothetical stakeholders (red and blue) may value impacts differently (vertical position) and perceive impact likelihood differently (box-line thickness). Four possible combinations are illustrated.

Once we have the changes, there are three things we can do: mitigate, adapt or suffer. That leads to this plot:

Risk management quadrants. Conceptual map of options for managing climate risks. Four distinct quadrants are defined by inherent limits to mitigation (vertical, solid line) and adaptation (horizontal, dashed line). Grey bands represent uncertainty. The size of the suffering quadrant will depend on the extent (arrows) to which the full potential of mitigation and adaptation are realized by climate policies.

Events will plot a certain way, illustrating the current risk. Then, those events will be replotted over time, reflecting the changing situation. They conclude by stating, 

We argue that the notion of a single, global threshold of dangerous climate change, has outlived its usefulness as a focus for the climate discourse. In its place, we propose a new climate risk management framework that incorporates the inherent limits to mitigation and adaptation, and links scientific risk assessment with social values and risk perceptions. This risk management quadrants framework overcomes the problems with the dangerous threshold by restructuring the climate challenge around minimizing collective suffering, rather than averting a distant catastrophe.

I agree with their argument completely. We need to change the way we do business on this issue to make it clear to the public that we are not discussing changes that won't happen in our life times. These are things that are going on right now and are affecting everyone on the planet. I don't know if their proposal is the right way to do it, but it sounds interesting and is certainly a good start.

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