Sunday, January 24, 2010

Climate change and doubt

Why do many people have great difficulty believing in 'global warming'? If you listen to the convinced/converted it often seems that they attribute others' doubts to stupidity and/or a willful disbelief of the obvious... While this may be true for some small percentage, a much larger number simply are not equipped to understand the science... Climate science is incredibly complex, especially when you are talking about it on a global scale... a large number of different phenomena that have varying effects, and which interact with one another in different ways, and differently at different points in time, etc. Unfortunately the very difficulty in neatly explaining this complexity has resulted in attempts to encapsulate and/or recap the overall effect that have not been very useful. A prime example is the term 'global warming.' This 'short-hand' is hard for folks to grasp and/or believe when there is so much variation in temperatures - people see record cold snaps in many areas and have trouble squaring their observations with the notion of 'global warming'.... It doesn't help to point out to them that they have to think in terms of decades or centuries; that they have to distinguish between individual variations and the long-term trend; and so on.

OK, so 'climate change' is a better term. Changes in climate are occurring across the globe. For example, some areas are getting hotter and others colder; some are seeing increased precipitation while others are seeing an increase in droughts; the changes happening differ at the various latitudes and at different elevations; and the changes happening also differ on the surface of the oceans versus in the depths. The important issues that we need to understand, and the questions that we need to answer are re how these are connected, what the various trends are, what the longer-term trends are, and (very importantly) which of these are natural and/or cyclical versus which ones of these are caused by human activity. And if we are able to fully understand and answer these questions, the next thing to determine is what we should do about it, if anything.

The overall scientific consensus appears to be that there is an overall warming trend, and that this has been exacerbated by human activity (most importantly the use of fossil fuels)... and that unless very significant changes are made in the way we do things, this trend will reinforce itself and continue, with significant detriments to the future of mankind. While this is an overall consensus there is an argument by some re whether this is 'settled science', and even among those who do believe the consensus there are differences in emphasis and degree...

Like many others, as a lay person this blogger doesn't know the answer. He struggles with a number of issues, including:
  • Given the complexities briefly touched upon above, it is extraordinarily difficult to have the time, inclination, or background to vet the science on an individual basis. As a result a large part of the argument in support for the consensus agreement is based on an appeal to authority. We are asked to take on faith that the climatologists and other scientists have studied this in sufficient detail; that they have constructed sufficiently detailed models and have taken into account all the appropriate variables; that they have the best data; that they have crunched the available data and applied their models; and that the simplifications, interactions, and assumptions built in the models work accurately to produce results that not only explain past events (something that is always much easier to do) but also can be used to accurately predict the future (something that is exponentially more difficult, as can be attested to by any economist!). At the same time one has to believe that there is a sufficient degree of rectitude and self-disinterest among the postulates of the consensus position, something that this blogger and many others may find difficult to do automatically - based primarily on a somewhat jaundiced view of the general human condition (i.e. that most people act in their self-interest), but also not helped by instances such as this or this...
  • The sources of information on the topic (e.g. the press ) often purvey incorrect and/or contradictory information, leading this blogger to scratch his head re what to believe. An example here would be the spate of articles (e.g. see this) saying that the earth is in for a period of cooling, immediately followed by other articles attacking the earlier ones as an incorrect reading of the situation (e.g. see this).

  • On a fairly regular basis, new theories and/or data points pop up that do not necessarily fit neatly with the consensus position.. A recent example would be the observations regarding the cycles with which the Bering Strait is free from or closed off by ice, see Global Ice Age Climate Patterns Influenced by Bering Strait. While the article by the NSF says "... the findings do not directly bear on current global warming ..." it also says "... "If we can improve our understanding of the forces that affected climate in the past, we can better anticipate how our climate may change in the future ..." Another example would be from this finding, Sunshine speeded 1940s Swiss glacier melt: scientists, which seems to indicate that in this specific case solar radiation at one point might have been a better explanation for melting of the glaciers in the Alps than temperature... Note: this disagrees with the thrust of the consensus position that it is carbon dioxide levels (worsened by human activity) and the associated higher temperatures that are the main reason for the loss of glaciers rather than solar radiation (natural i.e. no human intervention). Now it is true that the article also says that "... this should not lead people to conclude that the current period of global warming is not really as big of a problem for the glaciers as previously assumed ..." But how often can we accept these 'outliers' and/or exceptions and still say "it does not change the consensus"? At what point are there sufficient numbers of these that we need to admit to some doubt of the underlying models?
  • The last item that this blogger will discuss is the putting forth of very specific examples of "the effects of climate change." For example, see "Angry Greenhouse Gas Victims Demand Action.' Here, proponents of the consensus theory have identified specific areas that have been adversely effected by human-induced climate change in very specific ways. So, apparently farmers in the Kericho District of Western Kenya have been adversely effected by decreased rainfall compared to twenty years ago, and the WWF somehow "knows" that their plight has been caused by human-induced climate change and puts them forward as "greenhouse gas victims." Now, this blogger has no trouble believing general propositions such as "if current trends persist then crop outputs will decrease by x percent by 2050'"and other similar predictions. But identifying current "victims"? The WWF has managed to do this with such specificity and has managed to rule out all other contributing factors? This blogger has a hard time swallowing this... And, in fact, the putting forward of such propositions to support the consensus view is something that he feels undercuts rather than enhances its likelihood of acceptance!
The bottom line: a very complex issue. This blogger is inclined to believe the consensus view, but admits to periodic doubts raised by the issues noted above, among others...

How to Talk to a Climate Sceptic
Global warming hike may be steeper: research
Global Ice Age Climate Patterns Influenced by Bering Strait
Earth could be entering global cooling for the next 30 years
Addressing "Global Cooling"
Sunshine speeded 1940s Swiss glacier melt: scientists
AGU stunner: Aircraft Vapor Trails Responsible for 15-20% of Arctic Warming
Climate Change: Angry Greenhouse Gas Victims Demand Action

Chart source: Spiegel

Previous blog entries on climate change:
Meet... Dr. Rajendra Pachauri - Jan 23rd, 2010
We wuz wrong - Jan 23rd, 2010
Saving the day... - Dec 20th, 2009
Skimmed milk masquerades as cream - Dec 17, 2009

Chart source: Spiegel

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