Climate Change Deniers

Increased flooding is one of the most common extreme weather consequences of global warming. 

I came across the tired old arguments of climate change deniers recently, in a Facebook group as it happens.  As usual, a few folks were parroting back the usual logical fallacies like "when it's -15 degrees, nobody talks about global warming."

Actually, scientists do. Science is about explanations that are consistent with observed facts, updated as observed facts become more and more accurate.

We know that the Earth is warming. We know that carbon dioxide is a greenhouse gas. We know that about twice as much carbon dioxide is appearing in the atmosphere as what the Earth can take back out via natural processes. We know that industry in general, and fossils fuel industry in particular, emits huge quantities of carbon dioxide. We know that the parts per million of CO2 in the atmosphere has been going up since the beginning of the industrial revolution.

We know that water vapor has significantly more effect as a greenhouse gas than CO2, but stays in the air for only a few days whereas CO2 stays for decades. We know that warmer air has more carrying capacity for water vapor and that the water vapor mostly resides in the upper atmosphere (meaning that what happens on the ground, like drought, it not particularly relevant because it is a local/regional thing). We know that water vapor concentrations at high altitude have been climbing at a statistically significant rate. So, the warming caused by the elevated CO2 is amplified, reinforcing itself because the warmer air holds more water vapor, causing even warmer air.

We also know that in the past, when the temperature was higher, the CO2 in the atmosphere was also higher. We know that there are natural sources that can cause increases in CO2, notably volcanoes, but the number of volcanic eruptions and other natural sources in the last century is not sufficient to explain the observed increase in CO2 and other less significant greenhouse gases.  Similarly, the deforestation of the Amazon has reduced the ability of the planet to turn CO2 back into oxygen, but not enough to fully explain the CO2 increase.

So the question is "what is the source of the excess CO2?"

The hypothesis that man-made CO2 is NOT the cause of global warming is NOT consistent with the facts. Human industry is CLEARLY producing large amounts of CO2. If man-made CO2 is somehow not the determining factor, then where is the excess CO2 coming from?

Those who would try to shrug global warming off as a "natural cycle" are not explaining anything.  A "natural cycle" still has causes and effects that can be studied and understood, particularly when they are happening NOW and not in the ancient past.

The natural-plus-man-made CO2 is causing the planet to warm. This is disrupting long-term weather patterns.  One result is more extreme weather events.

And, yes, some places DO get colder or more snow in the winter, because shifting currents and winds take arctic air to places it has not been before.

Some thoughts about solving the problem in my next post.