Skepticism, traditionally, is the notion that one should suspend all judgment in the investigation of facts. Skeptics are those who use logic and reason in the pursuit of truth, relying on genuine evidence rather than on emotion and intuition. The great skeptic David Hume said:
“All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability”
Hume believed that we must be ever cautious in our assumptions and beliefs about the world. And while his harsh skepticism got him in a great deal of trouble with many groups, his wisdom in regards to our defense of untenable hypotheses is nonetheless something to always consider.
In current times, the term skeptic has been given a negative connotation, mostly by those who wish to advance the belief in anthropogenic global warming. They liken climate change skeptics to deniers of the holocaust and those who believe the Earth to be flat. The claim of such Goremongers is that the evidence is so strong, that to reject the hypothesis amounts to a complete loss of reason. They wish to make climate change skepticism seem like the opposite of genuine skepticism, based on preconceived notions or political and economic affiliations.
However, the point of skepticism is not necessarily to believe something once you find evidence. But rather, the point is to question the evidence when it seems that the evidence is contradictory or counterintuitive. To that end, climate change skeptics can be grouped into the following categories, based on which evidence they reject. For each group, there are subsets, and it need not be the case that a person fits into only one group.
1.) The Earth is not warming. This group explicitly rejects the notion that the Earth has warmed. It is the weakest position, since evidence indicates that temperatures have indeed increased over the last century.
2.) The Earth is warming, but the data…
a.) Is too corrupted by human influence, scientific adjustments and urban heat islands to be in any way meaningful
b.) When averaged to some nebulous global mean, is too imprecise to determine changes over small time scales
3.) The Earth is warming, but scientifically…
a.) The Earth is currently rebounding from the Little Ice Age, and that all through human history there have been cold and warm periods.
b.) The warming has stopped, and that over the last decade, temperatures have been dropping
c.) The climate system is too complex to understand, and too complex for there to be a reliance on the fallacy of a single cause, in this case CO2.
4.) The Earth is warming, and the effects will be…
a.) Good for humanity and the world in general, regardless of the cause. Higher temperatures allow for longer periods of vegetation growth, and certainly there is more danger and suffering as a result of low temperature.
b.) Negligible compared to the effects of enacting draconian controls on CO2 emissions.
c.) Nowhere near as bad as the dire predictions of Al Gore and the IPCC.
5.) Carbon dioxide levels…
a.) Historically trail increases in temperature.
b.) Are not linearly proportional to temperature increases. Instead, there is a logarithmic relation, as the ultraviolet absorption spectrum for CO2 is narrow, which leads to smaller gains in temperature as CO2 increases.
c.) Are at a historical low, and should be higher to ensure stronger and healthier plant growth, and thus a stronger and healthier human race.
6.) The science of global warming…
a.) Is based entirely on computer models that give different results, are unable to recreate historical data and have no basis in reality.
b.) Is politically and economically motivated
c.) Is shrouded in secrecy, and that climate scientists are unwilling to share their data and methods, in clear violation of the standards of scientific research.
d.) Relies on unverifiable assumptions and approximations.
e.) Focuses too greatly on CO2, while disregarding other greenhouse gases, such as water vapor.
I have no doubt that there other ways to group these skepticisms, and as stated previously, it is not necessary to agree with only one of them, or with all of them. Upon deeper evaluation, some of them might actually overlap. However, it is important to know what aspects of the “settled science” one is skeptical about before being able to engage those who fervently believe in the dangers of global warming.
Again, we should remember Hume, who also said:
“When men are most sure and arrogant they are commonly most mistaken, giving views to passion without that proper deliberation which alone can secure them from the grossest absurdities”