With the United Nations' Intergovernmental Panel on Climate Change (IPCC) issuing its latest report on the dangers of global warming, it's a good time to ask: is there anything worth arguing about when it comes to global warming?
It's often said that there's a consensus among scientists about global warming, but what exactly do they agree on? There are, after all, many components to the theory.
Two Sides To The Story
Firstly, "warming" is a relational concept: X is warmer than Y. But global warming advocates don't always specify what it is they're comparing today's temperatures to. Is it warmer now than a century ago? Five centuries ago? What is the relevant standard of comparison? Or is it a hypothetical, counterfactual relation, claiming that temperatures are warmer now than they would have been if not for all the carbon dioxide we emitted? Or is it a claim about human well-being, stating that temperatures are (or soon will be) warmer than what's good for our species?
These are all different claims, and we need to be clear which one of them we're arguing about before we delve into the second aspect of the global warming debate, which is the temperature record. Our understanding of Earth's temperature is complicated by the fact that we've used a variety of instruments - from mercury thermometers to infrared satellite imagery - to measure it. Beyond that, we also rely on temperature proxies: things such as tree rings and ice core samples, which are affected by temperature (though not only by temperature).
Thirdly, there's the issue of causation. This is actually two separate questions: did humans cause global warming, and can humans reverse it? Just because the answer to one of these questions is "yes" doesn't necessarily mean that it's also the answer to the other one.
Lastly, there's the issue of a cost-benefit analysis. Global warming will involve costs, but so will combatting or reversing it. So which set of costs is worse, for us here and now and for future generations? This gets hard to assess: one future generation might not like higher sea levels, but a later one might appreciate the mitigation of the next ice age.
A Reasonable Position
Maybe all of these issues have been settled in the debate about global warming that takes place among academics. But, even if they have (which I doubt), they're certainly not settled in the popular debate about global warming. The vast majority of the population doesn't have the time to go through all the research relevant to climate change, so how are they to be convinced about it?
The problem is that the theory of global warming isn't like the theory, say, of electromagnetism. Most people don't really understand electromagnetic theory and radiation and so forth. But they believe it's true because they see it at work every time they use a cell phone, a radio, or microwave oven, or when they get an X-ray or an MRI scan. Whatever the mysterious details of the theory, we see that it consistently makes accurate predictions.
Not so with global warming. Maybe the theory is true, but its predictions haven't panned out the same way: in the 1970s climatologists were worried about global cooling; there has been a lull in hurricane and tornado activity in recent years, despite the belief that global warming would have the opposite effect; and there was a marked flattening, even decline in temperature from about 1940-1980, and another since 2000, despite a consistent increase in CO2 emissions.
Perhaps, in the academic debate, all of this can be made consistent with the theory of global warming. But until the theory of global warming yields in a set of easily recognizable, true predictions that can be seen by those of us who don't have the time or expertise to pore over reams of academic research and statistical permutations, the theory will continue to be doubted. Its predictions aren't clear, straightforward, or unambiguously true. Rather, they're routinely revised and amended. Rarely do they speak for themselves.
Far from being "anti-science" or a crime that should be punished, popular skepticism about global warming is entirely reasonable. For the masses to accept a complicated theory, you have to show them results. You can't just blame them all for not being climatological experts.
Alasdair Denvil graduated Virginia Commonwealth University with a B.A. in Philosophy, and attended NYU's graduate program. He has written for Facts on File and PolicyMic.