This is probably one of those occasions.
But in a running attempt to stimulate serious thought at a denialist blog, I got a question that has been rather common, and a question which indicates the deep serious misunderstanding denialists and even some well-meaning, overly-skeptical sensible people have:
Why worry about climate change, since the climate is changing all the time? Especially, why are people like Al Gore urging that we stop climate change, when CO2 has no great direct effect on human health? Shouldn’t environmentalists be cheering climate change on, since it’s a “natural process?”
The short answer to why we worry about climate change is that, as with almost all environmental protection, we are worried first about the quality of life of humans, and ultimately about the ability of human life to survive at all.
No, you’re not a little confused. You’re a lot confused, greatly misinformed, and not thinking hard.
We worry about CO2’s effects on climate only because we worry about the future of humanity. Many of us who have children and wish them the same blessings of having children and grandchildren, have thought through the truth of the matter that we don’t possess and rule the Earth for ourselves, but instead act only as stewards for future generations.
No Earth, no humans; but at the same time, no habitable Earth, no humans. In the long run, Earth doesn’t care. It’ll do fine — without humans.
We can’t damage the planet. We can only damage its habitability for humans.
I don’t know what sort of dystopian Randian future you and other Do Nothings hope for, but it’s a future contrary to human life, American values, and all known religions.
We’re talking about the future of humans. I tell “skeptics,” “If you don’t care, butt out. You’ll be dead in the short run anyway, but that’s no reason to stand in the way of action not to ensure a livable planet for our grandchildren.”
You also fail to understand chemistry, pollution, and how the world works. CO2 is indeed a toxic gas. For about a century now we’ve had indoor air standards that require air circulation to keep CO2 down below concentrations of about 500 ppm, because at that level it starts to have dramatic effects on humans working. It clouds their thinking and causes drowsiness. CO2 is a conundrum, in that it is also necessary to trigger mammalian breathing. If CO2 drops too low, we don’t take in enough oxygen and may pass out. Too much oxygen in place of CO2 is a problem in that regard. A substance can be both essential and a pollutant, at the same time. (This has vexed food safety experts for years, especially after the 1958 Delaney Clause; substances we know to be essential nutrients can be carcinogenic, in the same concentrations, or in the same concentrations with a slight twist in chemical formula — how do we regulate that stuff?)
CO2 is toxic in much greater proportions — it was a CO2 cloud that killed thousands in Cameroon 30 years ago or so, if you know history.
Clearly you did not know that we’ve regulated indoor CO2 for decades. Clearly you haven’t looked at the medical journals‘ discussion on CO2 — and I’ll wager you’d forgotten the Cameroon incident, if you ever knew about it.
CO2 is a toxic gas (the dose is the poison); CO2 has dramatic effects on human health — too little and we die, too much and we die.
The fact that humans were not around when CO2 was much higher is exactly the point. That was presented here, as it is in most venues, as support for a claim that we don’t need to worry about CO2 pollution. Well, that’s right — if we don’t care about a habitable Earth. But when CO2 was higher, life for humans was impossible.
I think it’s reckless to run an experiment on what would happen with higher CO2 levels, using the entire planet as a testing place, and testing the hypotheses on just how much CO2 will kill us all off, and how.
How about a control group, at least?
In the past, massive CO2 created massive greenhouse effects that would devastate us today — not as a toxic gas, but as a result of the warming that greenhouse gases do.
Let us understand the physical conundrum of CO2 here: Without the greenhouse effect from the human-historic levels of CO2, this would be an ice planet. Our lives today depend on the greenhouse effects of CO2.
Consequently, anyone who claims there is no greenhouse effect fails to understand physics, chemistry, biology and history. (Heck, throw in geology, too.) Life would be impossible but for the greenhouse effect. Life is impossible without water, too, but you can’t live totally surrounded by water.
Can it be true that there can never be too much of a good effect, with regard to greenhouse gases? Ancient Greek ideas of “all things in moderation” applies here. We need a Goldilocks amount of CO2 in our atmosphere — not to much, not too little; not too hot, not too cold.
To the extent that higher CO2 levels didn’t produce a total runaway greenhouse effect, as some hypothesize exists on Venus, we know that was due to other feedbacks. Early on, for example, CO2 began to be reduced by photosynthesizing life. Animal life today would be impossible but for that occurrence. Few if any modern chordates could breathe the very-low oxygen atmosphere of the early Earth, and live. Those feedbacks and limiting situations do not exist today.
So now we face a double or triple whammy. The reduction in CO2 in the air was accomplished through a couple billion years of carbon sequestration through plants. In fact, a lot of carbon was sequestered in carbon-rich fossils, stuff we now call coal and oil. Oxygen replenishment was accomplished with massive forests, and healthy oceans, with a great deal of photosynthesis. This created a rough CO2 equilibrium (with fluctuations, sure) that existed we know for at least the last 50,000 years, we’re pretty sure for the last 100,000 years (we know that from carbon-dating calibration exercises).
Today we have removed fully 30% of the forests that used to replenish oxygen and lock up a lot of CO2 (some estimates say 50% of the forests are gone); modern plant communities cannot pluck CO2 out fast enough. Plus, we’re releasing a lot of that old, sequestered carbon in coal and oil — at rates unprecedented in human history.
Will more CO2 warm the planet? We know from the fact that the planet is warm enough for life, that more CO2 will warm the planet more. Anyone who says differently does not know physics and chemistry, nor history.
Is there anything that can stop that effect? Sure — healthy, massive forests, and healthy oceans. Reducing carbon emissions could help a lot, too. But we’re committed for about a century. CO2 in the atmosphere doesn’t fall to the ground like particulate pollution. it drifts until it is incorporated into something else, either through photosynthesis or other chemical reactions. It takes a mole of CO2 a couple of centuries to come out of the air. We’re stuck with elevated and elevating CO2 regardless our actions, for a century or two, even if we are wildly successful in reining in emissions and creating sequestration paths.
What happens when CO2 levels get higher than 350 ppm? History, physics and chemistry tells us glaciers will melt, rainfall patterns will alter dramatically, sea levels will rise, carbon will be absorbed by the seas in increasing amounts (causing acidification — simple chemistry).
It’s a very exciting experiment. The entire human race is at stake. How much CO2 will it take to produce the effects that kill us all? It’s likely that changing rainfall patterns and rising sea levels will produce wars over resources, long before CO2 itself starts being physically toxic. That’s what the Pentagon’s big thinkers say. That’s what the Chinese big thinkers say, which is why they are working to reduce emissions even without an enforceable treaty.
As experiments go, I think it’s immoral to use humans in experimentation without getting their consent, and without passing the entire experiment through the Institutional Review Board to make sure the experiment is useful, necessary, and done ethically.
Do you have those consent statements? All seven billion of them? Have you got approval from the research overseers of the institution?
If you don’t have permission to proceed with this progeny-killing experiment, why do you propose to proceed? Many people believe that, if the courts on Earth don’t get us, a higher court will.
How will you plead wherever the call to justice is delivered?
Posted by Ed Darrell 
Millard Fillmore's Bathtub 