TV Review: Cosmos, Episode 12

(I’ve decided to review the new Cosmos series hosted by Neil deGrasse Tyson that’s airing on Fox. If you missed it, you can stream full episodes online.)

Cosmos: A Spacetime Odyssey, Episode 12, “The World Set Free”

For its penultimate episode, Cosmos returns to the subject of climate science, a familiar variation on a sermon it’s already preached more than once. I have some mixed feelings about this. With the series pressing against time constraints, I worry about the lost opportunities that inevitably result from retreading the same ground, when that time could have been devoted to the scientific advances that have come about since the original (for example, we’ve still heard nothing about dark matter and dark energy, or the proliferation of extrasolar planets). On the other hand, I can’t deny that climate change is by far the greatest and most urgent danger to our civilization, and gets nowhere near the media attention that it should.

And it opened with a striking visual: a flight over the surface of Venus, once a beautiful blue world like our own, now a hellish crucible, heated to a perpetual boil by a runaway greenhouse effect. The tipping point between heaven and hell is more delicate than you might think, a point brought home with a depiction of the molecular composition of the atmosphere as a cloud of butterflies. CO2 is a tiny part of the whole – for most of history, just three butterflies out of ten thousand – but its presence makes an enormous difference. Remove those three molecules, and we’d have no greenhouse effect; Earth would be a frozen snowball. But add three more, and the planet would become a sweltering hothouse. (At the moment, we’re actually at four butterflies.)

I’ve been learning one or two new things from each episode, and what I learned from this one is the surprisingly long time we’ve known that pumping carbon into the air could alter the climate. Svante Arrhenius predicted it as early as 1896, and scientists throughout the 20th century confirmed and extended his work – including Carl Sagan, who was one of the first to hypothesize that Venus was boiling hot and that the greenhouse effect was the reason why.

But what was once a prediction has become an accelerating reality. The amount of carbon we’re pumping into the air is the equivalent of a new White Cliffs of Dover each year, a point underscored by a visual of the cliffs rising like an express elevator. We also saw the famous “hockey stick” graph, as well as scenes of glaciers and permafrost melting in the Arctic, a sight which always fills me with dread. The thawing poles, invisible to most of us who live at lower latitudes, are a scream of warning that climate change is already happening at a rate that outstrips some of our grimmest predictions.

This episode addressed climate-denialist arguments in much more detail than previous outings, and did a good job of dismantling them. It explained how we know that global warming isn’t being caused by the sun or by volcanoes, as well as the difference between weather and climate: the former is short-term and chaotic, whereas the latter is long-term and predictable. As Tyson said, global warming isn’t even especially complicated science. It’s basic physics, a simple matter of bookkeeping for the planet’s energy budget.

But as bleak as our situation seems, all hope isn’t lost. Humanity once confronted an equally serious crisis, namely the Cold War and the nuclear arms race (exemplified by the USSR’s Tsar Bomba test). In the midst of this apocalyptic standoff, the moon landing was conceived as a demonstration of the power and precision of American rocketry. But though it was born of militarism and nationalism, it gave us a vision that transcended these: the unity, beauty and fragility of the blue world where we all live, “one earth, indivisible”.

We can escape doom again, and it’s not as if we don’t have the tools. In two brief historical segments, the episode pointed out that solar energy has been recognized as a viable power source since the beginning of the Industrial Revolution. We were led astray by cheap fossil fuel, but now, on the brink of climate disaster, we’re rediscovering its potential. As Cosmos again reminded us, the sun and the wind provide more energy than we could ever need. The obstacle isn’t the technology, but the political will to use it.

In a closing visual, this episode hinted at what Earth could look like in the future if we take heed: the Sahara flushed with green, irrigated by canals striped with solar panels; cities turned into living parks, with vast skyscrapers carpeted by green roofs. Surprisingly, one thing this episode didn’t dwell on were the consequences if we don’t act and global warming continues unchecked: rising seas, fiercer and more destructive storms, more droughts and floods, famines, mass migrations and wars fought over water and land.

Showing these possible futures side-by-side would have been a powerful way to dramatize the choice we face. The danger is looming, threatening to overwhelm us; but imminent disaster has often been the goad that unites humanity and inspires us to our greatest heights of achievement. Averting catastrophe, at this point, will take a collective effort that will dwarf the moon shot. But if we succeed, it will truly be our finest hour.

Image credit: COSMOS

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Adam Lee is an atheist writer and speaker living in New York City. His new novel, Broken Ring, is available in paperback and e-book. Read his full bio, or follow him on Twitter.

  • Naked Bunny with a Whip

    a flight over the surface of Venus, once a beautiful blue world like our own

    That sounds…incredibly speculative to me, to put it nicely. Has some sort of consensus about Venus’ early environment formed that I haven’t heard about?

  • Tommykey69

    Fair point. It should have had a qualifier, such as “which might once have been a beautiful blue world like our own.”

  • Tommykey69

    Unless I missed it, I would have like to have seen the “ice age scare” from the 70′s addressed. A lot of deniers will say “Well, they said we were going to have another ice age in the 70′s and we didn’t, so why should I believe them about global warming?”

  • Tommykey69

    A study of the atmosphere of Venus showed chemical signatures that would be expected if the planet once had water that was boiled away over time. It’s not known for sure if Venus had liquid oceans or if it was in the form of vapor, based on what I’ve read.

  • Elizabeth

    I believe that was because sulfur dioxide (H2SO4), a byproduct of burning coal has a cooling effect on the atmosphere. Scrubbers on power plants now keep it from getting into the atmosphere, but we have no such abatement for carbon dioxide (CO2).

  • Adam Lee

    My understanding is that the past existence of water oceans on Venus is something that’s widely believed, though not definitely established. Infrared data from Galileo could indicate the presence of granite, which only forms in the presence of water. See also.

  • Guest

    I’ve heard that the fear in that era was actually nuclear winter, due to the Cold War. And once or twice I’d heard climate deniers explicitly mention nuclear winter.

    That said, I’d like to stress the “heard” part of that statement – I wasn’t alive back then.

  • Izkata

    Well, that was interesting. I posted this, realized I responded to the wrong comment, then tried to delete & re-post it. As you can see, Disquis didn’t delete it, but instead told me I’d already made the same comment…

  • Izkata

    I’ve heard it was actually nuclear winter, due to the Cold War, that was feared around that time, and once or twice had actually heard climate deniers use that phrase specifically…

  • Naked Bunny with a Whip

    That’s cool. I was mostly concerned that too much speculation would detract from the point. When getting into a global warming discussion, I think it’s bad form to open yourself up to charges of over-extrapolating ancient environmental conditions, if you see what I mean.

  • Loren Petrich

    Sulfur dioxide = SO2, sulfuric acid = H2SO4

    However, SO2 + H2O + (1/2)O2 -> H2SO4 — something that makes a haze of sulfuric-acid droplets. This reflects sunlight, cooling the Earth.

  • Naked Bunny with a Whip

    That’s slick. I didn’t know about it. I do hope that some of this evidence was actually mentioned on the show at some point.

  • Loren Petrich

    Science writer Nigel Calder had mentioned some speculations about a fast around 1970 – 1974. I recall a documentary by him, “The Weather Machine” I think, which mentioned how an ice age can get started very fast. It would be by some year’s snow not melting and the next year’s snow piling up on it, continuing until it made a big glacier.

    But I’ve found a big collection of mentions of global cooling in the 1970′s: Science-type stuff