As I promised last week I commented on what I believed climate sceptics believe. I got a comment on that from Richard, and I think this post will also answer some of that comment. In the end, I think there are three major points: 1) Uncertainty of science is a given; 2) the “precautionary principle” needs to drive our actions in any environmental case; 3) recognition of trade-off between environmental loss against welfare gain.
It is interesting that I just read an article (Marshall and Toffel, 2004) on definitions of sustainability that highlighted that sustainability really needs to be tested on three hierarchical levels (in my words):
1) Will it kill us (us being humans in general)?
2) Will it make us sick or worse off?
3) Will it kill other parts of the ecosystem?
So, in terms of our current lifestyle and related increasing global CO2 levels we also would need to answer these three questions. I think, most people (even some of the sceptics!) will agree that our current lifestyle easily fails on level 3. A majority of people (at the moment) would say it fails also on level 2 and people described by the sceptics as “alarmists” (the IPCC) argue it will fail at level 1. Personally I am not sure whether we will reach level 1, but I am definitely worried about how easily we are reaching level 2. Sure, all life styles are sustainable when there are only 100 million people left on the planet. The problem is we don’t know if we will be part of those 100 million, will you be?
So here are my views
1) Nature has a limited adsorption capacity. Note that this is strongly in contrast to what I interpret that most climate sceptics seem to believe. There is ample evidence in Science that ecosystems are able to adsorb a certain level of pressure, but that in the end there is always a straw that can break the camel’s back. We only have to point at nutrient runoff, eutrophication, erosion, falling groundwater pressure in the Great Artesian Basin, coral bleaching etc. Some of these pressures can be taken away and we can resolve local and regional problems (luckily we humans are an inventive lot). Many pressures were unknown at the time we first applied them (such as overgrazing, ploughing, fertiliser applications and water extraction), but with the advance of science more and more detrimental effects became obvious. DDT was perfectly safe when they started of, nobody knew about the slow build-up of residues. In the end, it does point at the limited adsorption capacity of ecosystems.
2) All our actions have an impact on Nature: we have to decide what we want to lose for our gains. I have hammered on this point many times in this blog, so I am not going to spend too much time on it. Basically, given the above in point 1, we need to recognise that our actions have impacts (although not all impacts are yet known or can yet be known). Sometimes we might choose to live with the impact as we believe the gains are greater than the losses.
3) Science cannot understand all problems, but we are learning. Science will always be uncertain, certainty is a myth, particular in complex natural systems. If you don’t believe this you are not a scientist or you have only worked with controlled systems. You also desperately need to read up on science philosophy and might want to start with the work by Thomas Kuhn. I also believe that this means that we can’t wait for the final evidence as that will never be there, our learning is infinite. To get back to the IPCC, the results presented in the IPCC reports clearly define uncertainty bounds. It has to be uncertain, the models are imperfect and they are simulating a highly uncertain system. However, despite all this uncertainty, the majority of the findings point exactly at the conclusions presented so many times to the public. To respond to Richard’s comment: If I was a politician I also would want to vet the results as I would want to make sure those B*$@ scientists are not scaring the general public with their fanciful model predictions. The fact that it has passed the politicians scrutiny (in many countries!) means that it probably is worse than is presented. This brings me to my last point.
4) Because of scientific uncertainty, and because we can’t wait for the final evidence we always have to take more precautions than we would like: this is “the precautionary principle”. This is standard practice in all engineering as well, you always over design the system to take care of the uncertainty. If people hadn’t done this in the past we would have never made it to the moon (or are climate sceptics the same as those that also think the moon landing was staged? In that case they are definitely not engineers or positivists…). Maybe a better example, the Netherlands would have been flooded a zillion more times and many dams in rivers would have failed miserably. On that point, do you know that all dams now are designed (by engineers!) based on the Probable Maximum Flood, a flood level they have never ever observed and probably never will, but it is still the engineering standard for all dams: just to be sure.
With climate change, I think we also should make changes in our lifestyle and pay some carbon tax: JUST TO BE SURE.
Marshall JD, Toffel MW (2004) Framing the Elusive Concept of Sustainability: A Sustainability Hierarchy. Environmental Science & Technology 39, 673-682.