The physical complexity of global climate is evident. However, resolving the issue of global warming is also socially and politically complex. It is not an isolated problem with an easy solution, since almost every human action requires energy and/or land use (and thus results in climate altering emissions). In contrast, it is an all pervasive issue: Both the effects of unlimited global warming, and the proposed solutions to mitigate these effects, are potentially far-reaching. Because of the strong societal impacts and the inherent uncertainty surrounding them, people’s perceptions of these effects differ wildly. These perceptions are influenced by their ethical, ideological, cultural and political beliefs, by the way they balance different risks and by their belief of what constitutes well-being. That is ‘why we disagree about climate change’, as Mike Hulme explains in his book with the same title.
This may explain why the public debate about global warming is so vastly different than the scientific debate: Whereas the former has its roots in a clash of worldviews, the latter is about natural science, things we can measure and/or theorize based on physical principles. In the public debate, opponents may debate whether emission reduction schemes would wreck the economy, or whether unlimited climate change would destroy the support systems of society. In the scientific debate, opponents may debate the extent to which mechanical instability could enhance the melting of polar ice sheets.
Besides the differences in problem perception and strong interdependencies that characterize the global warming debate, there are other confounding issues, which together have earned global warming the label ‘super wicked problem’: The climate system responds very sluggish to changes in emissions, due to inertia in the carbon cycle as well as the thermal inertia provided by the oceans. Therefore, preventive emission reduction measures (if desired) would need to be taken before the full extent of the consequences becomes apparent. This means that the longer we wait, the harder it will be to address the consequences of global warming, since by then we have committed ourselves to more warming. As such, those who caused the problem are in the best position to solve it, but since the full consequences will not materialize until much later, they have the least incentive to do so.
Dynamics of the public debate
Sometimes advocates on either side of the debate emphasize the risks of the scenario they most wish to avoid and at the same time downplay the risks or difficulties of the scenario they prefer. E.g. advocates for stringent emission reductions may claim that transforming the global energy system is easy (whereas the mainstream position is that it is a tremendous challenge). Advocates for continuing emissions may claim that global warming will be advantageous for humanity (whereas the mainstream position is that the effects will be, on balance, negative). Motivated reasoning may play a role in this dynamic: When the solutions presented are perceived to conflict (be in line) with one’s worldview, one is less (more) likely to accept validity of the problem.
However, this does not mean that the truth is in the middle between these (or any) two extreme positions. Reality is not influenced by what people think of it. It is quite possible, likely even, that people with certain predispositions are more prone to resisting a specific reality than others. Different ideologies and worldviews each have different blind spots as to which parts of reality are hard to accept.
Polarisation and politicization
Since the occurrence and effects of global warming are not readily apparent, policymakers and the public depend on experts to describe and explain these. It is therefore not surprising that climate science plays an important role in the public debate. Some people started to vocally oppose the scientific consensus based on a variety of reasons (e.g. perceived errors or weak spots in the science, societal consequences which conflict with certain worldviews, psychological predisposition, cultural identity, vested interests, etc.). It also fits with a wider trend in society in which expert authority is not accepted as easily as it used to be. Taken to the extreme, some people argue that the whole field of climate science is fraudulent or heavily biased.
Some scientists, taken aback by the vocal display of distrust and in some cases even disgust, responded in ways that fueled rather than soothed the existing suspicions. This spiral of mutual animosity led to an increased polarization of views between proponents and opponents of the scientific consensus. A climax in this polarization was reached after a large amount of emails from the Climate Research Unit (U.K.) were spread via the internet (dubbed “climategate” by those who are suspicious of the science). The outcry that followed was further exacerbated by some mistakes that were revealed in the IPCC report of working group II (on climate impacts). Even though these events are now a few years behind us, the polarization is still alive and kicking, and the internet is rife with what could be regarded as hatespeech towards “the other camp”.
Simultaneously with this polarization, the recent climate debate is characterized by increased politicization: A sharp divide has grown along political lines about how one views climate change and climate science. This is most prevalent in the United States, though is to a lesser extent also apparent in Europe. Since there is nothing intrinsically political about the earth’s climate (what does a CO2 molecule care about your or my political outlook?), this is another indication that these apparent disagreements about climate science have their roots in differences in socio-political and cultural values rather than in science.
Scientific progress and uncertainty
Because climate science seems to be taking centre stage in the public debate on global warming, it is important to be clear about what is known with high confidence and what is more uncertain. The first thing to note here is that science never proves anything (in the sense that mathematics does), because it is based on observations and inferences. However, a scientific conclusion can be strongly or weakly supported by the evidence, and such distinctions are important to make. The existing uncertainty in several aspects of climate science provides different actors in the public debate with an excuse to focus on unlikely values on their preferred side of the probability spectrum. Such an argument implicitly ignores that uncertainty usually cuts both ways (though not necessarily in a symmetrical manner).
If over time the evidence for a particular hypothesis accumulates and counterevidence is found wanting, a scientific consensus will naturally emerge. This is the normal course of scientific progress. Hypotheses that are not well supported by the body of evidence slowly fade into oblivion, while the strongly supported theory slowly becomes common (scientific) knowledge. There are several examples in the history of science where public acceptance of science lags behind the scientific acceptance of said theory, so this is not unique to climate science. This societal inertia comes on top of the climate system inertia in setting a speed limit to how fast we can bend the global warming trend around.
This post is based on my entry in the Encyclopedia of Global Warming and Climate Change, 2nd edition. Minor edits 10-01-2014.