In any debate on global warming, the discussion inevitably deteriorates into hissing accusations of “You don’t believe in climate change?” or, “You don’t think the glaciers are melting?”
That’s unfortunate because it diverts attention from a larger question. What really matters is whether carbon dioxide (CO2) is the key driver of global climate, and whether it bears primary responsibility for a 20th century increase in global temperatures.
So, for those who are skeptical of man-made global warming, it’s more practical in such a discussion to agree that the climate has changed, and then to add, “…but I don’t think CO2 is the culprit.”
Here’s a good starting point. The planet has warmed by roughly 0.8 degrees Celsius over the past century or so. Thus, the root question is, “What caused this warming?”
For the climate community, CO2 is the only answer. But there is an equally strong possibility that elevated solar activity during the past 150 years has driven the observed rise in mean temperatures.
Unfortunately, solar activity is completely discounted in the theory of anthropogenic warming. And that’s a shame because evidence for solar variability emerges rather clearly throughout the climate swings of the past 2,000 years. Heightened solar output correlates remarkably well with both the Roman Warm Period (250-400 AD) and the Medieval Warm Period (950-1250 AD). And, diminished solar activity corresponds equally well with the cooler climate of the “Little Ice Age” (1350-1850 AD).
And so, when confronted with accusations of climate denial, a smart response might be: “Actually, I don’t deny that the climate changes. I think it has changed a lot, just in the past 1,000 years. But I think those changes are mainly due to variations in solar activity, not CO2.”
As for CO2, it possesses a glaring limitation as a greenhouse gas—namely, that it exponentially loses heat-trapping capacity whenever its concentration increases. Such a handicap completely contradicts CO2’s notorious reputation. But try asking the average citizen this question: “As CO2 is added to the atmosphere, does its heat-trapping ability increase or decrease?” The correct answer is that it massively decreases. But the general public has been led to believe the opposite.
That’s to be expected, noting the daily hysteria over “carbon pollution.” And climate scientists are of little help in the matter, since they’re loathe to admit that CO2 rapidly fades as a greenhouse gas. Conveniently, they’ve managed to compensate for the limitations of CO2 by predicating the bulk of their theory on the idea that increased water vapor in the atmosphere will create a positive feedback for catastrophic warming. Of course, additional water vapor will inevitably transform itself into cloud cover. And low-hanging clouds are very good at reflecting sunlight back into space, shading the Earth, and producing rain—three things that lower surface temperatures.
Notably, contemporary climate theory is built on this notion that cloud formation enhances the overall warming effect of CO2. And so, it’s always fun to ask concerned citizens if they believe that the net function of clouds is to warm the planet. They’ll likely answer with a slightly quizzical “No…”—not realizing that they’ve just contradicted the first law of the very theory they’re so dedicated to promoting.
On that subject, it’s also fun to ask someone if they can name the Earth’s primary greenhouse gas. The correct answer is, of course, water vapor—which is responsible for roughly 80% of the greenhouse effect. But CO2 invariably comes to mind first for most people.
Most useful, though, when debating global warming is to simply ask someone if they believe that changes in solar activity can affect the Earth’s climate. They’ll undoubtedly say yes—even though this puts them at odds with the very theory they’re defending.
The overall point is that debating whether the climate has warmed, or the glaciers have melted, is a distraction. The real issue is what causes “climate change.” And this matters, because right now CO2 is the exclusive culprit. But if solar activity bears significant responsibility, then the policies currently being enacted to curtail CO2 emissions are misguided and unnecessary. This is why the debate must focus on what really drives climate.