I finally had a chance to watch the twelfth, penultimate episode of Cosmos, "The World Set Free." I was out of the country in June when it originally aired, but since there's no doubt the series is headed into the schools and remains relevant, I'll take this opportunity to comment. The episode stands out from most previous installments. Just when we've grown accustomed to circuitous narrative threads with obscure segues from one topic to the next, we get an episode that focuses like a laser on one subject: global warming.
Of course, since the series is called Cosmos, the producers needed to justify devoting one-thirteenth of the total running time to such an Earth-bound topic. So the story begins, not with Earth, but with Venus.
"Once there was a world," host Neil deGrasse Tyson tells viewers, "not so very different from our own."
We see footage of attractive seascapes and landscapes, which represent what Venus might have looked like during the first billion years of its existence. It was apparently pleasant for a while, like the big island of Hawaii. But then, bad things started happening -- volcanoes, lava, smoke -- which released heaps of carbon dioxide into the atmosphere, setting off a runaway greenhouse effect. "Once things began to unravel," Tyson explains, "there was no way back." This, not the proximity of Venus to the sun, is why the planet is now hot and oceanless.
From Here, the Script Writes Itself
On Venus, most of the carbon dioxide is in its atmosphere, which makes the planet's surface boiling hot. In contrast, most of the carbon on Earth has for eons been trapped in its rocks and moderated by the oceans. Our comfy abode has had just the right amount of carbon dioxide in its atmosphere so that it's not too hot, not too cold. Until, that is, we started "belching" that extra carbon into the atmosphere by burning coal and oil. Around the turn of the twentieth century, the amount of atmospheric carbon dioxide exceeded three hundred parts per million (ppm), and has continued to go up since then (it's now near 400 ppm). "The Earth," Tyson says, "has seen nothing like it in three million years."
Cue worrisome visuals and narration: Lots and lots of smoke stacks apparently spewing carbon dioxide into the air (most of what we see is probably steam but let that pass.) As a result, it's warmer now than in the nineteenth century. The oceans are heating up. The ice caps are melting. Permafrost near the Arctic Circle is melting, allowing plants to grow where they haven't grown for a long time (apparently that's bad). Rising sea levels are giving rise to floods, including floods in which water flows down stairs inside buildings. There will be mass extinctions. The planet will look browner.
And why? Because we're careless and greedy. That's not a paraphrase. Here's Tyson: "Our carelessness and greed put all of this at risk."
Fortunately, there's a solution. After hearing a superficial argument for why the sun can't be responsible for the recent warming, we learn that we've had the solution at hand since the beginning of the industrial revolution, namely, solar energy. "The sun isn't the problem, but it is the solution." French inventor Augustin Mouchot showed how to use solar energy to heat steam way back in the 1870s. But since the price of coal plummeted, Mouchot's funding was cut off. Later, cheap oil continued to crowd out opportunities for solar energy.
As if that weren't enough, there's also a lot of wind we can harness. "Wind farms take up very little land," especially since we can put windmills on the ocean.
Perhaps you think that such a radical transition to new forms of energy is unworkable, but Tyson assures us that it can be done. We've done great things in the past, after all, even when our motivations weren't noble. For instance, Cold War competition led us to develop rocket technology to deliver deadly nuclear warheads to the other side of the globe. But that same technology allowed us to go to the moon. And from that vantage, we looked back and "realized our community."
"There are no scientific or technical obstacles to protecting our world and the precious life that it supports," Tyson insists. "It all depends on what we truly value. And if we can summon the will to act."
The closing visuals are "Jetsons green." We see the Arctic ice cap expanding, the Earth getting greener. There are fancy new solar facilities and wind farms. There are bountiful fields growing on top of skyscrapers in a futuristic city that looks like it might have those cool flying cars (though none are seen). For narration, we hear the inspiring 1961 "moon" speech by President John F. Kennedy: "We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."
For the viewer ignorant of the issues, it's probably inspiring stuff. For the well-informed critical-thinker, however, it's frustrating. I'm tempted to provide a line-by-line response to this episode, but I'll stick to a few of the most glaring problems.
Jousting with Straw Men
As with previous offerings, this episode provides a decent scoop of straightforward science and visuals smothered with a gravy-boat-sized helping of ideological bias and conventional wisdom. In this case, the ideology is not the tired science vs. religion trope to which we've grown accustomed in this series. It's the current fashion for catastrophic, human-induced climate change scenarios. (Well, last year's fashion. Apparently the producers didn't know that they're supposed to talk less about "global warming" and more about "climate change" or "climate disruption.")
And once again, Tyson and the producers have chosen the risk-free company of straw men over a rough-and-tumble encounter with real critics.
Throughout the episode Tyson responds to skeptical objections that virtually no serious person raises. For instance, he dutifully explains that we know about the past composition of Earth's atmosphere because we can analyze ice cores. But all the key players in the debate know about ice cores and paleoclimatology.
He squanders several minutes arguing that human activity is the source of recent carbon dioxide increases in the atmosphere. Again, this is a widespread point of agreement.
More significantly, Tyson burns up valuable airtime explaining the historical and scientific details of the greenhouse effect. He even returns to the point near the end, referring to the patron saint of the Cosmos series, Carl Sagan, whose PhD thesis dealt with the runaway greenhouse effect on Venus, and who warned us of the dangers of a similar runaway greenhouse effect on Earth.
Virtually no one active in the climate debate disputes the basic physics of carbon dioxide and the greenhouse effect. The most obvious reason for such a long digression is to give naïve viewers the impression that climate change "deniers" don't understand basic physics and chemistry.
Self-Serving Codswallop
In reality, almost the entire debate about "climate change" among the scientifically literate centers on how significant the effect of carbon dioxide is on global climate. In particular, how much warming should be expected as a result of adding carbon dioxide to the atmosphere? By itself, we could predict about one degree of warming centigrade for every doubling of carbon dioxide in the atmosphere. Read that again. For every doubling. In contrast, human beings are adding some two parts per million per year. By itself, then, adding carbon dioxide to the atmosphere won't lead to catastrophe. That's the basic physics.
There is even a case to be made that rising carbon dioxide combined with a concomitant modest warming is a net social benefit. In fact, satellite measurements made over the past thirty years show that the Earth has measurably greened as a result of the rising level of carbon dioxide.
So why all the panic? It's because most climate models assume that there are all sorts of positive feedbacks that magnify the effects of adding carbon dioxide to the atmosphere, at least when that happens over short, human-scale periods of time. Tyson provides one such example (but without making the distinction clear between direct climate forcing and feedbacks): the reflective properties of water, land and ice. All things being equal, ice reflects more light back into space than either land or water does. So, if added carbon dioxide in the atmosphere warms the surface a bit and melts some ice, then the subtraction of ice will itself lead to less warming light energy being reflected back into space. And hence, more warming will result.
But just as there can be positive feedbacks, so too can there be negative feedbacks. These are effects that mitigate rather than magnify the direct effects of the carbon dioxide. Certain types of cloud cover seem to qualify.
The real debate centers on the proper understanding, knowledge, and potential ignorance of the various feedbacks. So Cosmos ignores it entirely.
The climate models we hear so much about assume that most of the feedbacks are positive, and so they have predicted greater warming as more carbon dioxide finds its way into the atmosphere.
But speculative predictions based on models can only get you so far. What we want to know is what's actually happening. The short answer is that the models predict continued warming, but reality hasn't cooperated. There's been little to no measured warming since the late 1990s. Some continue to deny this, but most catastrophists concede the point and offer ad hoc reasons for why the warming isn't observed. The point, however, is that the models that predict a global hothouse are increasingly out of sync with observations.
Tyson claims just the opposite: "The observed warming is as much as predicted from the measured increase of carbon dioxide. It's a pretty tight case..." Secondary predictions aren't cooperating either. Although viewers are told the Arctic ice caps are disappearing (and that is just what was predicted), that hasn't panned out.
Add to that the evidence from paleoclimatology. We know that the Earth has at times had vastly more carbon dioxide in its atmosphere, and yet no runaway heating took place. There are lots of complicating factors of course, but it suggests that Earth's climate has some way to compensate.
What Intellectual Honesty Would Look Like
I'm not claiming there's absolutely nothing to worry about. Honest people can disagree on the question of climate change. It involves about a hundred different issues, many of which simply don't admit to certainty. I am saying that an intellectually honest treatment of the subject would inform viewers of the full range of evidence and experts' views. It would admit that the predictions and the observations have diverged, and would allow for the possibility that there's something wrong with the models.
The intellectual dishonesty continues in the treatment of solar and wind energy. This section is fingernails-on-a-chalk-board for anyone with basic knowledge of the physics and economics of energy. Obviously if solar and wind energy were superior to oil, gas, and coal, we'd all be using it, even if, as Tyson seems to think, most of us were motivated entirely by greed.
That hasn't happened because, for most uses, solar and wind are very dilute sources of energy, and require huge energy collectors for measly output. The amount of the sun's energy reaching the planet's surface is no more relevant than the amount of energy bound up in the Earth's crust. What matters is how much of that energy we can access, and at what cost.
Those windmills anchored to the ocean floor are extremely expensive to build and maintain, and provide comparatively little energy. And then only when the wind is blowing. That doesn't mean we should ignore these technologies. We can and should seek to innovate. Unless we get some radical tech breakthroughs, however, wind and solar simply cannot, and will not, replace hydrocarbons for most energy uses anytime in the near future.
This is Intro to Energy 101 stuff. The fact that Tyson and the producers of Cosmos blithely ignore all of it is yet one more example of how much they are willing to allow a biased ideology to trump scientific evidence. Not exactly the ideal way to bring science to the masses.
