I recently asked an environmentalist this question: “If we found out that the planet was warming for purely natural reasons, would you be in favor of climate engineering to stop it, because the current temperature and sea level are the right ones for humans?”
He seemed appalled. “No, of course not, man,” he said.
“Thank you,” I said. And I meant it, because this fellow had just made a concession that is fatal to the central argument in favor of reducing carbon emissions: the risk of catastrophic climate change.
Climate alarmists are alarmed about the human impact on the climate. Most of them are not, however, actually alarmed about climate change per se. That is why they have proposed virtually nothing that would protect anyone from natural climate change. In fact, if it turns out that temperatures and sea levels are rising for purely natural reasons, most environmentalists would probably be against doing anything to stop it, just liked the fellow I asked.
Of course, not all climate alarmists agree. Some of them do think that rising temperatures and sea levels are alarming regardless of what’s causing them to rise. Such voices are in a tiny minority, however, and the policy prescriptions that follow logically from their concerns have nothing to do with reducing carbon emissions. If we are worried about global warming regardless of its causes, then the right policy is adaptation (i.e., help people adjust to life at higher temperatures) and prevention (i.e. planetary climate engineering, by altering the atmosphere in ways that neutralize natural climate change).
Many climate alarmists, however, are like the fellow who unwittingly admitted that he’s not actually alarmed about climate change in and of itself, just climate change caused by human activity. The most radical of these environmentalists flatly deny that temperatures and sea levels could be rising partly for natural reasons. In other words, they deny natural climate change. Call them “climate deniers” for short, since they are denying that the climate is doing now what it has always done, namely change for natural reasons.
Ironically enough, it turns out that these climate deniers are also science deniers. The UN’s Intergovernmental Panel on Climate Change (IPCC) summarizes all of the climate science that climate alarmists use to justify their anti-carbon policies. It is the most authoritative source for environmentalists’ claims about the scientific consensus on climate change. On the link between human activity and climate change, the IPCC has this to say: “It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together.” (Emphasis added.)
The same IPCC report says that current warming is “unequivocal” i.e.; there is virtually no doubt that the planet is warming. But the IPCC is not nearly so unequivocal about the causes. It cites human activity as the major cause of warming, but not necessarily the only cause. Scientists aren’t sure what the climate trend would be in the absence of human activity; it’s possible that carbon emissions have an even bigger warming impact than they fear, and the impact is being mostly absorbed by an underlying cooling trend; they just don’t know. The IPCC’s carefully qualified attribution statement recognizes that scientists don’t understand the climate well enough to quantify precisely the relative contribution of the various human and natural factors in the current warming trend.
Is Anything Wrong With Natural, Non-Man-Made Climate Change? – Forbes