Cosmos Recap: The Big Damn Climate Change Episode

Cosmos Recap: The Big Damn Climate Change EpisodeWe are down to the last two episodes of Cosmos: A Spacetime Odyssey, already. You can pretty much bet that this week’s episode, The World Set Free, is going to be the one that gets talked about the most, and probably shown in more classrooms than any other, because after making passing mentions of it in several previous episodes, this is the one where Neil de Grasse Tyson brings out the Big Science guns and talks for the full hour about climate change. This is the episode that you can tell has probably had the most editorial meetings behind it to plan out how to make the case, firmly and clearly, that climate change is real, it’s already here — not off in some distant future — and not only is the science not in dispute, but none of the “alternate” explanations hold water. And for the most part, it works impressively well.

Tyson starts us out on Venus, explaining that for the first billion years or so of the planet’s existence, things were probably a lot like conditions on the early Earth — liquid seas, the occasional asteroid strike, maybe even the beginnings of life. Almost a paradise, until the planet’s atmosphere became too filed with carbon dioxide from volcanic eruptions, which eventually led to a runaway greenhouse effect. Heat from the sun was trapped in the atmosphere, and the planet grew hotter and hotter — and not merely because of its closer proximity to the Sun. In fact, Venus’s thick cover of clouds, mostly made of sulfuric acid, would actually make its surface ice-cold, were it not for the high levels of sunlight-trapping CO2. As it is, the Venusian atmosphere is hot enough to melt lead.

tyson dover 1

When they formed, Tyson tells us, Earth and Venus had similar amounts of carbon. The difference between the two planets is largely in the form that carbon took. On Venus, it’s mostly CO2 gas, while on Earth, it’s been stored in solid form, as rocks, like the white cliffs of Dover, which make for a pretty nice shooting location — and this time, Tyson’s actually there, not just in front of a green screen image. (after he walked around on “Mars” last time, we worried that maybe Tyson never leaves a studio. And MAYBE HE DOESN’T!) The limestone and chalk cliffs are nothing more than the remains of trillions of tiny algae that absorbed atmospheric CO2 and stored it, as they do on seabeds worldwide, leaving Earth’s atmosphere with only trace amounts of CO2 — less than .03%, or as Tyson visualizes it with three colorful butterflies, “less than three molecules out of every ten thousand.” If there were no atmospheric CO2 at all, Earth would freeze; double it, to just .06%, and Earth would be a much hotter planet with no ice caps, but still far from becoming Venus. For that matter, the amount of CO2 in the atmosphere varies cyclically during the year — the planet “exhales” CO2 in the winter, when the northern hemisphere’s forests lose their leaves and they decay, and “inhales” it in the summer, a cycle only discovered in the late 1950s, when accurate measurement of CO2 became possible. And that’s when we also discovered the increase in atmospheric CO2 since the start of the industrial age.

And how do we know? Ice — cores taken from glaciers in Greenland and Antarctica, with a clear record of ancient air, trapped for 800,000 years. Until the early 20th Century, the CO2 rate never went above .03%, but after that, it’s risen sharply, with 40% more CO2 in the atmosphere than before the Industrial Revolution. Simply put, we’re “exhaling” more CO2 than the planet can “breathe” in. The Earth, warmed by the Sun, radiates heat. The more CO2 in the atmosphere, the more heat is retained, and the more the Earth warms. Says Tyson,

That’s all there is to the greenhouse effect. It’s basic physics — just bookkeeping of the energy flow. There’s nothing controversial about it.

And then Tyson sets to work debunking the claims of climate change deniers. Could volcanoes be at fault? Nope — the amount of carbon dioxide from all the world’s volcanoes is about 2% of the amount emitted by fossil fuels each year. And the amount of CO2 in the atmosphere matches quite nicely with the amount of fossil fuels we consume. And the rate of global warming also tracks to the amount of CO2 in the air. This isn’t politics. It’s math, and physics. To illustrate how much carbon is dumped into the air annually, Tyson uses a nice visual trick — CGI and green screen at last: if that annual amount, about 30 billion tons of CO2 gas a year, were compressed into solid carbon, the mass would be similar to that of the cliffs of Dover, and so we get to see the cliffs double in size, and then some, year after year. The chief byproduct of our way of life also happens to be the gas that regulates our planet’s temperature. If we could see CO2, Tyson says, then maybe we’d have more incentive to do something about it.

cosmos CO2 visible

But is the Earth really warming? Yep. Surface temperatures, atmospheric temperatures, and oceanic temperatures. And, Tyson notes, it’s not as if we didn’t see it coming. We get a brief review of climate observations, going back to the 1890s, when a paper first predicted that a doubling of CO2 could lead to the melting of the polar ice caps, to a 1938 paper noting that average global temperatures were increasing proportional to CO2, through a 1958 TV program in which a scientist warns, “even now, man may be unwittingly changing the world’s climate through the waste products of his civilization.” Carl Sagan’s 1960 PhD thesis was on Venus’s greenhouse effect, and in 1980 he too warned that we risked destabilizing our atmosphere. This stuff didn’t come out of nowhere, and never mind that one Time Magazine cover in the ’70s that speculated about Global Cooling. And since then, we’ve added another 400 billion tons of CO2.

Tyson then uses a lovely little set-piece to illustrate the difference between climate and weather, answering the idiotic “well if there’s global warming, how could we have a record cold winter last year, HUH?” (Except Neil is way too nice to call anyone an idiot.) It’s really simple: weather varies from day to day, year to year. Climate is the long-term trend of the weather’s behavior over time.

And when we’re making policy, we need to think about climate — the steady long-term trend — not the short-term variability of weather.

And then we get to the scary stuff: the melting ice caps, the rise of the oceans, and, oh dear, since ice reflects sunlight and open ocean absorbs it, the more open ocean there is, the more warming, and the less sea ice — a positive feedback loop. There’s some genuinely Oh-My-God time-lapse photography of a section of Arctic shoreline — land and permafrost — peeling away and falling into the sea, and Tyson explains another feedback loop: as the permafrost thaws, plant matter that had been frozen for millennia rots, releasing more CO2 and methane (an even worse heat trapper) into the atmosphere. More erosion, more storms. We genuinely could be tipping past a point of no return.

OK, but what if it’s not our fault? Can we blame the Sun? Nope. Solar energy output hasn’t changed, and we’re warming more in the winter than in the summer, the opposite of what you’d expect if solar heat were to blame. It keeps coming back to the stuff we burn to make our machines run, to make electricity. Ah, says Tyson, but the Sun is the solution, and then we get a couple of brief animated segments about early inventors of solar technologies: Augustin Mouchot, who in 1878 demonstrated a solar powered boiler that could run an ice machine — ice from the sun! Unfortunately for Mouchot, coal was cheap and plentiful. And then there was Frank Shuman, an American who in 1913 hoped to make the Sahara Desert bloom with solar collectors that ran water pumps — but then oil was cheap and plentiful, and WWI broke out. Schuman’s solar arrays were torn up and scrapped to make weapons.

After driving home the massive bummer of just how precarious our situation is, Tyson closes with hope, and not unrealistic hope, either. Solar and wind technologies are becoming more economically competitive, and have virtually none of the environmental consequences of fossil fuels. (Wind turbines may “whoosh” some, and that upsets people, we’ve read.) Like Sagan before him, Tyson is worried, but a cautious optimist. We are, after all, a remarkably adaptive, inventive species, and we’ve managed some impressive feats of survival. We’re no longer on the brink of incinerating ourselves in a nuclear war, for instance. Mutual Assured Destruction is largely just a phrase to be learned in history classes. And even from that madness, we also launched the Apollo program, and the race to build bigger and better rockets to deliver warheads evolved into the machines that allowed us to see our home planet, that pale blue dot, from the Moon. And out of the Cold War came the iconic image of a world full of life, against the blackness of space, the only home we have for the foreseeable future. From deadly competition, we at least saw the possibility of peace.

Transitions aren’t easy, Tyson says, over an aerial view of ancient terrace farms in the Philippines — moving from life as nomadic hunter-gatherers to life as farmers took adjustments (and no doubt, there were some who said it just couldn’t be done — if we stay in one place, we’ll run out of game!). There are no scientific or technological barriers to stopping and even reversing climate change, although of course it won’t be easy. The question, he says, “is what we truly value… and whether we can summon the will to act.”

So will Cosmos change minds? Every week after watching, I read the Reddit discussion of the latest episode. And this week, this is the top-rated comment:

I am a conservative libertarian (not that it really matters what my political ideology is lol), I have always kind of doubted that us humans are the cause of the warming. I’ve always thought that we have just been going through another cycle that the earth has always gone through. And I thought this issue was just so politicized (which to be fair, it is highly politicized) that I just didn’t know how to even begin to get a straight answer on this issue.

This one episode has totally changed my mind on this issue. There was no political rhetoric to try to sift through. It was JUST the science, explained in a simple way so anyone can understand. Neal DeGrasse Tyson went through all of the reasons that earth could be heating up, and explained why they could or couldn’t be a contributing cause. There was one graph that really shocked me. It was the one showing the amount of CO2 in the atmosphere, and it showed how insanely high it sky rocketed in the 20th century.

This is exactly what I needed to be able to see that yes, we are doing this, and we need to fix it. I love this show, and I learn something every time I watch it. I never thought my mind would be changed on such a polarized issue like this.

So there’s one mind, changed. It’s a good start.

Cosmos: A Spacetime Odyssey airs on Fox 9:00 Sundays Eastern/Pacific, 8:00 Central/Mountain. Reruns Monday on National Geographic Channel 10:00 Eastern. Episode 12, “The World Set Free,” online at

TV Show: Cosmos

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  • laineypc

    My poor 9-year-old. After I explained that no, a “positive feedback loop” is not necessarily a positive thing, and why, his entire body language said “we’re doomed”.

    • doktorzoom

      For what it’s worth, that was largely my 17-year-old’s reaction, too. But the end of the episode helped.

  • Poly_Ester

    Curiously, 0.03% is also the percentage of deniers who have some understanding of the science.

  • PubOption

    FOX and science are opposed on this issue. 3% of FOX programming (Cosmos) states that climate change is real, while 97% denies it.

  • Jay B.

    And I thought this issue was just so politicized (which to be fair, it is highly politicized)Did he ever ask himself why it is highly politicized? Does he think it’s because Al Gore wanted to be crowned Emperor of Earth? Or because University science geeks wanted to live the sweet life of grant graft? Or maybe, just maybe, because of massive amounts of bad faith science and politics bought and paid for by billions of dollars of petro-money made climate change “controversial” to begin with? I mean he’s right, the science is simple and obvious. JUST LIKE IT ALWAYS HAS BEEN. But yes, let a thousand minds bloom because a libertarian has finally addressed basic reality.

    • TJ Barke

      Right libertarians have no relationship with reality. If they get one they stop being libertarians.

    • Mojopo

      Right on, Jay B. I agree with you, and it’s hard not to smack my head and scream “DAH!” But, for those who are only familiar with bad science and the political controversy surrounding climate change information, I appreciate the way this one person can help us de-escalate the amount of hatred (some) people have for the subject matter involved. We get the diplomats we deserve, and we kind of deserve this guy for allowing climate change deniers to get a leg up. They should never have been allowed to be taken seriously.

  • Señor Skwerl

    HI, Squirrely McOil here: Tyson is right, we must frack. Fracking is fun for the whole family. Breathe the fumes in deeply… everything is nice and warm with global non-warming… Forget what the mean ol’ Dok Zoom said… There we are — nice long sleepy time.

  • TJ Barke

    All Hunter gatherers didn’t just decide to start farming. Some did, then they mostly genocided the rest.

    • SOOoooo….are you suggesting that we address climate change, and genocide the deniers? THats so crazy IT JUST MIGHT WORK!

      • TJ Barke

        Well the deniers, by delaying mitigating action on global warming, will all essentially be responsible for genocide. So would that make it a preemptive strike?

        • Force Crater

          Trying to revive the Bush doctrine? (No, thanks!)

  • raptorjesus

    Um, excuse me. How can there be ice cores that are ALLEGEDLY 800,000 years old when God created the earth 6,000 years ago hrmmmm? How do you know for sure they are 800,000 years old? WERE YOU THERE?

    • Joseph

      Which asks the question how do you know god created the earth 6000 years ago? Where you there?

      • willi0000000

        well, he has a book . . . and it’s infallible . . . and it’s older than your book . . . and his book was written by divinely inspired bronze-age goatherds . . . and the inspiration was done by his personal god* . . . but your book was written by a mere mortal scientist inspired only by a majestic sense of wonder and a burning desire to explain, if only to himself, the vast universe he found himself QED that motherfucker!* who ripped most of it off from the Sumerians.

  • Force Crater

    I don’t believe the comment.

    • Greg Comlish

      Yeah, it sounds like somebody concern trolling the conservatives. For what it’s worth I have never, not once in my life, encountered a denier who changes his mind when presented with facts. Invariably they just shift from bullshit argument to bullshit argument and then start ranting about Al Gore. Maybe there are a few sincerely mistaken conservatives out there, perhaps a few HS kids, but most of those people are hopeless.

      • Yep.

        Yep. I’ve used all these same exact arguments before, back when I gave a fuck. I would explain how CO2 just IS a greenhouse gas — whether you like it or not. Take 2 glass domes, trap regular air in one and place it over a thermometer. Trap CO2-only in the other and place it over a thermometer. Place both under the same heat lamp. See which thermometer shows the highest temp. Shut the lamp off and see which dome’s thermometer stays the warmest the longest. Doesn’t matter if Al Gore’s in the room or not. Then I’d talk about the ice cores….But these rubes just clung to the baseless idea that their modern lifestyle has no effect on the environment.

        • Greg Comlish

          Why do you use a heat lamp in the experiment? Wouldn’t you want to use a light concentrated in the visible spectrum, maybe halogen, and place an absorbent black background under the glass domes? If you use a heat lamp the CO2 in the dome is going to reflect much of the inbound heat before it even makes it to the inside. And why use two domes? Just use one dome and fill it entirely with CO2.

          • Yep.

            The dome with regular air is a control. Heat lamp, lamp, candle in the motherfuckin wind, concept is same.

      • Rebecca Johnson

        “For what it’s worth I have never, not once in my life, encountered a denier who changes his mind when presented with facts.”I did. It took me a while, though – I can’t really point to one particular argument that made me change my mind. I should probably explain first that I was raised by parents who were moderately conservative in politics and mildly socially conservative, but very strongly Christian fundamentalists. (Yeah, there’s a difference, but it doesn’t really matter for this discussion.) I grew up homeschooled, and my parents kept a pretty close watch on what kind of media we were exposed to. We didn’t have cable and we weren’t allowed to watch broadcast TV except for educational shows – but we were told to disregard anything they said about evolution. (I remember visiting with some homeschooling friends and their mom fast-forwarding through the Bill Nye episode about dinosaurs.) We could pretty much read whatever we wanted to. I can only remember one time when my dad took a book away from me (it was Catch-22, and he only did it because my mom made him). But the books and textbooks that we had, for the most part, were written by young-earth Creationists and the like. Most of my friends and acquaintances, whether they went to public school or not, believed in creationism and rejected evolution. By the time I went to college, I totally and completely believed in Creationism. I deliberately avoided taking classes where I felt that my beliefs would be challenged, so I skipped biology and took physics and astronomy, which I loved anyway. And the teacher only briefly touched on creationism and the age of the universe, etc. There were definitely times when I felt like I was being attacked or mocked by teachers because of my background but this wasn’t one of them.It was in the astronomy class where I first realized the problems with my beliefs. If the world was only like 1400 years old, how could we see the light from stars that were millions of light years away? I understood basic physics, so I knew that the speed of light was constant. I never really understood carbon dating and other measures of the earth’s age (I still don’t, really), so I could accept the explanations that they were inaccurate. But I realized that if the measures of the distance to the most distant galaxies were accurate, then the universe was much older than the Bible said.I basically decided that there were three possibilities: one was that the Bible had a big inaccuracy in it, and since I had been raised by people who believed that the Bible was the literally inerrant Word of God, this was a Big Deal. This would be undeniable physical proof that the central tenant of my faith was untrue. The second possibility was that the measures of the distances was inaccurate.The third possibility was that God created the universe with the light already on its way to the Earth. I rejected this as being a dick move; basically, a God who created a universe to make it look like it was evolution and then sent people to hell for believing in evolution was so much of a dick that it was inconsistent with the way God was described in my religion as being merciful, patient, all-loving, etc. (I wouldn’t want to worship a god like that anyway, even if I do go to hell.)I thought it through in my dorm room, and deciding to look up how distances in the universes are measured, and I read Wikipedia articles about the luminosity of quasars, redshift, Hubble’s law, and looked at pictures of the gravitational lens and read the mathematical equations. I felt like I had a mental tally of the evidence for and against me, and the more I learned, the more evidence against me stacked up. When it got to the point where I felt like it was about 94% to 6%, I decided that I was wrong about the age of the universe. I realized that the age of the universe is difficult to estimate and that predictions varied among scientists, but whatever young earth estimate I was using was definitely ruled out.And, you know, I think it was a lot easier for me to dismiss things like carbon dating because half-life ratios are pretty hard to understand and I can’t measure them myself. I’d always been taught that it’s okay to be skeptical about things that you can’t see for yourself. I think I felt kind of resigned to not understanding some science because at that point I had been convinced that I was terrible at math (that’s another story). But I did understand the basic laws of physics. And I couldn’t say that Einstein’s theory of relativity was “just a theory” when it had been confirmed via experiment and I could look at the picture of the gravity lens myself. I mean, it was right there. So I admitted to myself that I was wrong.It was painful, though. I know that this isn’t the case for everyone, but my view of religion had always been based on the idea that the Bible is the inerrant literal word of God; to me, this meant that if I could find even one mistake in the Bible, that would disprove all of Christianity. I mean, if part of it is wrong, any of it could be wrong, and why believe it? And so I stopped believing that God was real in that moment, and that had a lot of psychological consequences for me because religion had been a pretty big part of my identity. I was pretty depressed for several years, in fact, though there were other factors involved. I remember mostly feeling like I was adrift in a suddenly meaningless universe. I had no idea how to approach the world without using religion. All of my decisions had been based around the idea that the Bible is like the Walkthrough FAQ of life, and now I had nothing to go on. I had to reevaluate basically everything.Ultimately, though it did hurt a lot, I think that being wrong and realizing that I was wrong was actually good for me. I remember being in sort of a daze for a while, thinking, “How could I have been so wrong about something?” I wasn’t anywhere close to right. And I started wondering why I had persisted in believing it for so long. I’m still pretty fascinated by these questions of why people believe what they believe and how error correction takes place and how it feels and why it feels the way it feels. But though I am gradually regaining self-confidence, I think I’m a much more humble person now, and I hope that I keep that. I don’t just know in theory that I can be wrong; I was wrong, for a very long time. I have a lot more compassion for others. I can see why they don’t want to change; it does hurt.Anyway, in addition to not believing in evolution, I didn’t believe in global warming – because the Bible has a pretty clear narrative of how the world will end, and it’s pretty freaking bizarre but CO2 doesn’t play a role. I’m pretty sure this is why most people reject climate change in the U.S. (I think it’s more of an unconscious motivation than their reasons for rejecting evolution – something that they don’t really think about but would agree if you asked them about it.) I had a lot of stuff to sort through, and I didn’t get to global warming/climate change for a while after I became an atheist. I literally kept pushing it back on my to-reexamine list like “Nope, no time for that now!” I remember getting really confused by the debate in the meantime. When I got around to it, it was pretty simple to look at the graph of global temperatures and global CO2 and go, “Oh, okay, that’s pretty clear.” At that point, it wasn’t some kind of dramatic reimagining of my identity but more like establishing a fact that I was unsure about.

        • doktorzoom

          Thank you. That was amazing and beautiful.

          • Rebecca Johnson

            Ha, is that sarcasm?

        • Dave Plumb

          What graphs? The ones showing the last 150 years of weather data? That’s one part in 30,000,000 of Earth’s climate history. Do you not think the other 29,999,999 parts are relevant? In all your university studies did you ever come across the concept of “statistical significance”?As to all the religious stuff… I’m undecided about intelligent design but evolution by natural selection makes sense to me. so I wonder… assuming there is a “God” – by whatever name you wish to bestow – and that we accept the typical religious tenet that we are created in the image of the Creator, how does it make any sense to believe that, but not believe we would have other characteristics in common as well? Why wouldn’t we?What I’m getting at is the way we go about creating and improving things ourselves. We employ a process of “continuous improvement” all the time. A 2015 Lincoln Continental wasn’t an option rolling off the end of a 1924 Model T Ford assembly line, now was it? A lot of continuous improvement got us from a 1924 Model T to a 2015 Lincoln Continental.So, since we employ continuous improvement and if we are willing to suppose we would share other attributes with a Creator in whose image we are created, why would we not suppose the Creator would also employ continuous improvement? What if the Creator’s continuous improvement plan for the life the Creator created is evolution by natural selection? Would that not suggest that evolution by natural selection argues more in favour of intelligent design than against it?I have no idea. Just sayin’…

  • devo-T

    Sure, you and I already know and accept the science behind global warming/climate change/whatever. But I daresay it’s a fairly complex issue for the average American. I hate to disparage my fellow citizens, but let’s face it… as George Carlin once said,

    “Think of how stupid the average person is, and realize half of them are stupider than that.”

    And those people are probably not interested in watching Cosmos, much less hearing Obama’s blahhh cousin Tyson explain the issue.

    I think the majority of people that can be convinced about global warming have already come over to this side. What really needs to happen is to give the fat, lazy populace of this country (and the greater Western world) a reason to go out of their way, to get that electricity and fuel for their modern conveniences from a different place — to actually want that. Which is a much tougher battle than debating climate science (I mean, even most of us who believe CO2 is the culprit can’t make this change).

    Carl Sagan and Neil de Grasse Tyson should be worshipped as neogods. Because physics!

    • Rebecca Johnson

      “Sure, you and I already know and accept the science behind global warming/climate change/whatever. But I daresay it’s a fairly complex issue for the average American.”More CO2 = temperatures rise is not a complex issue, actually. You only have to understand the fundamental concepts of “more of a thing” and “getting hotter.” Deniers are the ones who like to make things unnecessarily complicated.I don’t think I’m being unrealistically optimistic here either! At one point, most of the human population refused to believe that the earth went around the sun. I mean, that’s pretty complicated to understand; the earth doesn’t look round and you can see the sun moving around while the earth doesn’t. (Plus, it says in the Bible that the sun held still, not that the earth held still!!!!!!!) I’m sure that plenty of scientists said that the whole “orbits” and “gravity” thing was just too hard for the average person to understand, and it would always be that way. It’s not, and it isn’t, and they don’t. What percent of the population believes that the earth is flat?

  • jaz hentai

    “I am a conservative libertarian (not that it really matters what my political ideology is lol), I have always kind of doubted that us humans are the cause of the warming. I’ve always thought that we have just been going through another cycle that the earth has always gone through. And I thought this issue was just so politicized (which to be fair, it is highly politicized) that I just didn’t know how to even begin to get a straight answer on this issue.This one episode has totally changed my mind on this issue. There was no political rhetoric to try to sift through. It was JUST the science, explained in a simple way so anyone can understand. Neal DeGrasse Tyson went through all of the reasons that earth could be heating up, and explained why they could or couldn’t be a contributing cause. There was one graph that really shocked me. It was the one showing the amount of CO2 in the atmosphere, and it showed how insanely high it sky rocketed in the 20th century.This is exactly what I needed to be able to see that yes, we are doing this, and we need to fix it. I love this show, and I learn something every time I watch it. I never thought my mind would be changed on such a polarized issue like this.”great! only millions of motherfucker’s minds to change to go!

  • willi0000000

    Neil de Grasse Tyson is, primarily, an educator, more so than even being a cosmologist/scientist. if we could get the majority of the population to tune in to programs like Cosmos and Through The Wormhole With Morgan Freeman life would be a lot easier to improve.[unfortunately, both those guys are blah, so . . . ]

  • Ron

    It’s not like you could google that CO2 graph or anything for the past decade. I mean, when the only source of information is the internet, how can one learn anything about an issue?

  • Andres Fernandez

    I’ve loved this show since the beginning (and loved Sagan’s Cosmos as well), but THIS is the episode I’ve been waiting for. Finally, no punches pulled.I think to force action on climate change and energy issues will take a multi-pronged approach. We need the scientific appeal to the masses, which Tyson handles so well, but we also need to emphasize American independence/patriotism (no more supporting foreign oil powers, let’s create a new homegrown industry), American exceptionalism/leadership (we put men on the moon, why not this?), and even touch on the spiritual (if you believe in a creator, then respect his creation).I used to be a libertarian but have become more of a progressive/populist over the years… basically, my distrust of government evolved into a distrust of any overly concentrated (or secretive) power, and while that still often includes the government, when it comes to energy issues we’ve been following the money of short-sighted interests, rather than being guided by vision and the honest desire to leave the world a better place for subsequent generations.Reform won’t necessarily be fun or easy, but it’s the right thing to do. Isn’t that supposedly what makes us American?

  • James Donnaught

    “There was one graph that really shocked me. It was the one showing the amount of CO2 in the atmosphere, and it showed how insanely high it sky rocketed in the 20th century.”That graph has been right there all along, for anybody to look at, for years. Just not on Faux News, which is where this dolt must have been getting all of his “information”. No small irony that the Faux News script is being undermined by another Fox network program.

  • Dave Plumb

    Atmospheric CO2 on Venus: 96.5%. Average global temperature: 464 degrees Centigrade.Atmospheric CO2 on Mars: 95.3%, which does not include all the CO2 frozen into polar ice caps; otherwise, the atmosphere of Mars would probably contain even more CO2 than the atmosphere of Venus. Average global temperature on Mars: -64 degrees Centigrade.So, two planets in the same solar system with essentially identical atmospheres containing 96% CO2, give or take a fraction of a percentage. Average global temperature difference: 527 degrees Centigrade.Question: If atmospheric CO2 is so all-fired important in making Venus as hot as it is, then why does the same process not work to essentially the same extent on Mars? Why is Mars so damn cold?Tyson tells us it’s all about atmospheric CO2 and has no bearing on a planet’s distance from the sun. Guess he missed the lecture on the Inverse Square Law in Astrophysics 101. He neglects to mention Mars in support of his argument because Mars categorically refutes his argument.I do understand the Inverse Square Law as well as a lot of other really major, critically important factors Tyson does not seem to understand – importance of planetary spin and a mobile liquid core to create a magnetosphere to retain planetary Hydrogen (and thence, water); importance of gravity to retain planetary Hydrogen; importance of Milankovitch Cycles (cyclical changes in eccentricity, obliquity, and precession of equinoxes) in combination with polar distributed land masses to explain ice ages; variation in solar output, which does matter despite Tyson’s claims to the contrary; importance of plate tectonics and the lessons of geologic history re: repetitive forming and splitting apart of supercontinents. And the list goes on…Bottom line: Mars is 120,000,000 Km (75,000,000 Miles) further from the sun than Venus is, and that matters immensely. Mars receives only about one-fifth as much solar heating as Venus because of distance from the sun and the Inverse Square Law. Atmospheric CO2 is such a small contributing factor as to be essentially inconsequential.The reason Mars and Venus have such high concentrations of atmospheric CO2 is that they are both less massive than Earth (lower gravity) and neither one has a magnetosphere. This has resulted in loss of nearly all planetary Hydrogen from both planets, leaving behind the heavier atomic component of H2O (water), being Oxygen. The Oxygen is very reactive and, having no Hydrogen to bind, it binds with Carbon instead to form CO2. It has very little to do with the greenhouse effect; it’s just basic physics and chemistry but I guess Tyson missed those lectures as well, although this stuff should be covered in any half decent high school curriculum. Earth still has its planetary Hydrogen and, thence water – trillions of tons of the stuff; because of that, until the sun explodes outward in its dying days a few billion years from now, Earth cannot become remotely like Venus even if we burn all the fossil fuel on the planet tomorrow.

    • MikeNH

      The biggest difference is that Venus’ atmosphere is about 9000 times thicker than Mars (Earth’s is 100x Mars’ / 1/90th of Venus’). Also zero cloud cover on Mars.I don’t think NDT was saying the distance from the sun doesn’t play a role in the equation – he was saying that distance didn’t play a role in the change in Venus’ climate (b/c presumably Venus’ distance to the sun didn’t change significantly during it’s climate’s transition).

      • Dave Plumb

        In its formative years Venus experienced a runaway greenhouse effect based NOT on CO2 but on water vapour, which is also a strong greenhouse gas and by far and away the most significant GHG on Earth today.Venus, being so much closer to the sun, was too hot for water to condense. The water remained in the atmosphere as superheated steam, baking Carbon right out of the rocks, rising high into the atmosphere where solar ionizing radiation (“solar wind”) dissociated the Hydrogen and Oxygen in the H2O molecules and carried the Hydrogen off into space, leaving behind the heavier Oxygen ions. The Oxygen had to combine with something and there was plenty of Carbon available – voila! CO2.Venus has no magnetosphere because it spins too slowly. A day on Venus is 243 Earth days. That made it easy for the solar wind to carry away most of the dissociated Hydrogen. What was left behind combined with Sulfur to form H2SO4, otherwise known as Sulfuric Acid, which now forms thick clouds blanketing the planet, preventing the sun from significantly heating it further but the damage was already done and the thermal mass in the CO2 atmosphere – 92 times as dense as Earth’s atmosphere – keeps the planet really hot, although it’s much cooler than it was a few billion years ago at the height of the runaway H2O driven greenhouse effect.Water on Earth took a different path, raining for millions of years, covering the planet with oceans and washing over 99% of the Carbon out of Earth’s atmosphere. If we were somehow able (and sufficiently foolish) to re-aerosolize all Earth’s sequestered Carbon we would have an atmosphere much like that of Venus but it’s billions of years too late for that to happen on Earth.If we were able to harvest and burn all the known fossil fuel deposits on Earth today, then tomorrow we would have an atmosphere restored to what it was like in the Late Jurassic and early Cretaceous Periods, around 2,500 PPM. Earth did not self-immolate back then and it most assuredly would not do so now, and that’s a very worst case scenario when it comes to fossil fuel use. Life thrived and evolved robustly under those conditions. Certainly, restoring that atmosphere would be very climatically disruptive, leading to significant warming, sea level rise, super storms, and so on, but it would not be the end of life on Earth.

      • Dave Plumb

        Another thought re: your first paragraph observations: Right on! You have nailed the crux of the matter in the climate change discussion insofar as making interplanetary comparisons – atmospheric densities are exceedingly important and when we only discuss percentages of composition of various gases we mask the true differences because percentages ignore density.To be precise, in percentage terms the atmospheres of Venus and Mars are nearly identical in CO2 content at 96% give or take less than a percentage point. The atmosphere of Earth is about 0.04%. Doing the math based on percentages we could conclude that the atmospheres of Venus and Mars contain 2,400 as much CO2 as Earth’s atmosphere does.However, in terms of actual mass of CO2 Mars’ atmosphere contains 12 times as much CO2 as Earth’s atmosphere but Mars is a much smaller planet so that comparison isn’t even particularly apt. Venus is nearly the same size as Earth and its atmosphere contains – in terms of actual mass of CO2 – more than 227,000 times as much CO2 as does Earth’s atmosphere. I think that’s a fairly significant factor to consider in deciding just how realistic these sorts of comparisons are.