Reality Check: Earth to Venus Unlikely

July 5, 2017

I have some good news and some bad news.

Even absent a Permian Extinction wipeout – Earth’s paleoclimate history shows that possible outcomes of a strong greenhouse warming include some pretty dire scenarios.  Avoiding a 90 percent extinction event is nice, but not exactly a “win”.
We’d like to stabilize at something a bit like what we are used to.

Still, recent headlines about Stephen Hawkings warming of a “Venus” scenario for earth, (raining sulphuric acid, etc) need to be addressed, and I see Mike Mann retweeted a necessary corrective on this, excerpted and linked here.

Above, I’ve reposted my video of last year, a sobering enough warning from paleo scientists on the actual science of an ongoing, accelerating extinction, right now.

LiveScience:

Earth could turn into a hothouse planet like Venus, with boiling oceans and acid rain, if humans don’t prevent irreversible climate change, physicist Stephen Hawking claimed in a recent interview.

“We are close to the tipping point, where global warming becomes irreversible. Trump’s action could push the Earth over the brink, to become like Venus, with a temperature of 250 degrees [Celsius], and raining sulfuric acid,” he told BBC News, referring to the president’s decision to pull the U.S. out of the Paris climate agreement.

Most climate experts say that scenario is a dramatic and implausible exaggeration: Relative to Venus, planet Earth is much farther from the sun and will never have such a thick carbon dioxide atmosphere, so it could not likely reach temperatures of 482 degrees Fahrenheit (250 degrees C) that Hawking described in the interview, they say. [Doomsday: 9 Real Ways the Earth Could End]

However, the general trend of runaway and catastrophic climate change is a real concern, experts said.

“Hawking is taking some rhetorical license here,” climate scientist Michael Mann, at the Pennsylvania State University, told Live Science in an email. “Earth is further away from the sun than Venus and likely cannot experience a runaway greenhouse effect in the same sense as Venus — i.e. a literal boiling away of the oceans. However Hawking’s larger point — that we could render the planet largely uninhabitable for human civilization if we do not act to avert dangerous climate change — is certainly valid.”

Though most humans take for granted the relative constancy of an Earth-like climate, our planet has undergone dramatic changes in its 4.5-billion-year history. During the great oxygenation event, around 2.5 billion years ago, photosynthetic cyanobacteria fueled a huge rise in oxygen in the atmosphere. Around 650 million years ago, the entire planet froze, in a phenomenon known as “snowball Earth.” And during the age of dinosaurs, the planet was on average 19 degrees F (10 degrees C) hotter than it is now, with a carbon dioxide-rich atmosphere. And huge “carbon excursions” have led to massive extinctions in the past — such as the end-Permian extinction, when roughly 95 percent of sea life died out due to ocean acidification. [Photo Timeline: How the Earth Formed]

So it’s not unreasonable to contemplate the possibility of a runaway climate scenario, Robinson said. Still, most experts, including Robinson, see that possibility as incredibly unlikely.

While in theory, a similar process to the one experienced on Venus could take place on Earth, the process would most likely occur over hundreds of millions of years, most experts believe, Robinson said. There are also very low odds that Earth’s oceans could literally boil away like Venus’ primeval oceans did, Robinson said.

Earth, meanwhile, is protected from solar radiation by an atmosphere that is dramatically different from the one on Venus.

“Venus’ atmosphere is about 100 times thicker than Earth’s atmosphere, and composed almost entirely of CO2 [carbon dioxide],” Robinson said. By contrast, Earth’s atmosphere is mostly molecular nitrogen and oxygen, with less than 0.04 percent coming from carbon dioxide, Robinson told Live Science in an email. [Infographic: Earth’s Atmosphere from Top to Bottom]

Without a thick carbon dioxide atmosphere and the extra dose of solar radiation from the sun, only willful malice is likely to cause a runaway greenhouse scenario, said Kevin Zahnle, a space scientist at NASA Ames Research Center, who has analyzed runaway greenhouse projections for the planet.

“There is no rational expectation of a runaway [greenhouse effect] in the facts as we know them,” Zahnle told Live Science in an email.

For one, there were much warmer climates on Earth in the relatively recent past, such as the Eocene epoch (between 56 million and 34 million years ago), and no signs of a runaway greenhouse effect, Zahnle said. At that time, CO2 levels were likely three times higher than they are now. Even imagining a future with cars, planes and air conditioning on full blast, no climate projections predict such high levels of CO2 in our atmosphere, he said.

“A runaway greenhouse effect is not in the cards,” said Kevin Trenberth, a climate scientist at National Center for Atmospheric Research in Boulder, Colorado.

Of course, there is always the possibility of deliberate sabotage, Zahnle said.

“Dr. Evil might consider an engineering solution akin to the engineering solutions proposed to terraform Mars, but the scale of the effort would be stupendous,” Zahnle said. “You’d need fluorocarbons — so Dr. Evil would need to create a worldwide religion dedicated to the sacred use of hairspray and underarm deodorants,” Zahnle said. (In the past, some consumer aerosol products contained fluorocarbons, though the U.S. has since banned the ingredient.)

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22 Responses to “Reality Check: Earth to Venus Unlikely”

  1. Gingerbaker Says:

    It doesn’t matter if full runaway is not plausible. There remains the very real possibility of partial runaway, ie, an increase of 10, 15, even 20C+ increase in average temp.

    We simply do not know what may happen if we are unlucky, as these precise conditions have likely never occurred in the past. But there is plenty of terrestrial CO2 and methane sitting there waiting to cause a human extinction event.

    And, frankly, we don’t even need to get close to such temperature excursion to end civilization as we know it and plunge ourselves into the worst dystopian future we could imagine.

    OTOH, there does appear there might just be a method of reducing atmospheric CO2 quickly and at a low enough cost to justify the expense – accelerated olivine weathering:
    It doesn’t matter if full runaway is not plausible. There remains the very real possibility of partial runaway, ie, an increase of 10, 15, even 20C+ increase in average temp.

    We simply do not know what may happen if we are unlucky, as these precise conditions have likely never occurred in the past. But there is plenty of terrestrial CO2 and methane sitting there waiting to cause a human extinction event.

    And, frankly, we don’t even need to get close to such temperature excursion to end civilization as we know it and plunge ourselves into the worst dystopian future we could imagine.

    OTOH, there does appear there might just be a method of reducing atmospheric CO2 quickly and at a low enough cost to justify the expense – accelerated olivine weathering:
    It doesn’t matter if full runaway is not plausible. There remains the very real possibility of partial runaway, ie, an increase of 10, 15, even 20C+ increase in average temp.

    We simply do not know what may happen if we are unlucky, as these precise conditions have likely never occurred in the past. But there is plenty of terrestrial CO2 and methane sitting there waiting to cause a human extinction event.

    And, frankly, we don’t even need to get close to such temperature excursion to end civilization as we know it and plunge ourselves into the worst dystopian future we could imagine.

    OTOH, there does appear there might just be a method of reducing atmospheric CO2 quickly and at a low enough cost to justify the expense – accelerated olivine weathering:

    http://www.innovationconcepts.eu/res/literatuurSchuiling/olivineagainstclimatechange23.pdf

  2. Canman Says:

    The Earth’s been a lot hotter in the geological past and had much higher concentrations of CO2. The argument for turning into Venus rests on the Sun increasing in brightness over geological time. James Hansen takes the idea seriously in his book, Storms of My Grandchildren.

    • neilrieck Says:

      Not sure why this meme keeps floating around but it is wrong (and was proven by planetary astronomers (like Carl Sagan) who were working with what was once known as “the Venus anomaly”. So here are a few facts: Even though Venus is ~ 5% smaller than Earth, being ~ 28% closer to the Sun results in Venus collecting 1.74 times more solar energy. If Venus had an atmosphere similar to Earth’s then you would expect Venus’ mean temperature to be 499 K (1.74 x 287) rather than 735 K which is 1.47 (735 / 499) times hotter than it should be. Some people claim the hotter temperature is only due to the higher atmospheric pressure (Boyle’s Law) but with gravity similar to that of Earth there is no gravitational mechanism for higher pressure. In this case the higher pressure is only due to temperature which is why planetary astronomers refer to the Venus problem as a “runaway greenhouse effect”

      • neilrieck Says:

        I just remember an important fact: although Mercury is closer to the sun than Venus, the surface of Venus is hotter than Mercury. When you switch over to the Kelvin scale you will see that Venus is twice as hot as Mercury. (and it’s all due to CO2)

        • funslinger62 Says:

          The average temperatures are 167°C for Mercury and 462°C for Venus. Mercury’s sun side reaches about 427°C but because it has no atmosphere to speak of the far side is as cold as -180°C.


  3. Hawking guilty of Rhetorical License? Sure. But Mann admits ‘Hawking’s larger point — that we could render the planet largely uninhabitable for human civilization if we do not act to avert dangerous climate change — is certainly valid.”

    People aren’t responding to alarm bells. At all. Well, except for the ones on their phones. Most attention in America is directed at a screen, consuming curated content, not at the destabilization and disintergration of Earth’s life support systems (Polar regions, glaciers, oceans, forests, etc). Extend and pretend is spirit of the age… No country on earth is taking the 2 degree limit they agreed to 3 years ago seriously. What they agreed to commits earth to at the very least 2.7c of warming in 80 years. Earth may not become Venus, but the only home we have will be largely UNINHABITABLE FOR HUMANS, because we are not acting to avert catastrophic climate change. That should be the story, not correcting a fracking genius on his use of hyperbole. YEESH.


    • Or even more directly to the point, we need to get some broad based support, to capture the public’s imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. Correct?

      • Torsten Says:

        No Russell. Sticking to the science, and addressing questions that are raised, even by saying “we don’t know” where that is the correct answer, suffices for most people. Reality is scary enough. It’s the scientifically illiterate and wilfully ignorant who can’t be reached.


        • So, you and the two down-voters of my comment so far disagree with what the late Stephen Schneider said? Apart from the first 7 words and the last one word, the rest are his words, verbatim. He was one of your people. You forget that?

          • Torsten Says:

            Yes Russell, I disagree with him. You seem to think that people who accept the science must mindlessly follow the rest of “our people”. That’s quite a silly position to hold. As I’ve told you several times, I’m swayed by what I read in the journals. The hyperbole used by some AGW alarmists is embarrassing. And I’m an alarmist. And by alarmist I mean that I understand the situation with the amount of CO2 in the atmosphere to be disruptive to our civilization, and by pointing that out, I am sounding an alarm. I hope that’s not too complicated for you to understand.

          • redskylite Says:

            Just watched one of your people (“Donald Trump”) give a speech to the president and press of Poland. Quite eloquent really, praised the historic bonds between the two countries and Poland for giving enough dough into NATO funds.

            Also took the chance in the media to criticize Obama for allowing the Russians to interfere in 2016 elections and that devilish revolutionary socialist news outlet “CNN”. Very statesman-like and commendable. Then talked trade, about USA exporting petroleum products to Poland, joining Russia and the E.C. Finally wrapped up with how the U.S.A has been blessed with great riches in the ground. A real man of the 19th and 20th century, (pity he wasn’t in power then). But wait it’s the 21st Century now.

      • dumboldguy Says:

        Here’s Russell, trying to appear relevant, and, as usual, fooling no one. Since he knows no science, he can’t begin to address the science as other commenters have, and simply spouts more of his weak denier BS.

        theoldspeak nailed it with “Earth may not become Venus, but the only home we have will be largely UNINHABITABLE FOR HUMANS, because we are not acting to avert catastrophic climate change. That should be the story, not correcting a fracking genius on his use of hyperbole.”

        I don’t worry about a “Venus” situation occurring, but don’t consider it “good news” that it’s considered “unlikely” at present. What worries me is the “largely UNINHABITABLE FOR HUMANS” possibility (and for most other living things as well).

        • funslinger62 Says:

          “Earth may not become Venus, but the only home we have will be largely UNINHABITABLE FOR HUMANS, because we are not acting to avert catastrophic climate change. That should be the story, not correcting a fracking genius on his use of hyperbole.”

          False dichotomy. We can do both.

          • dumboldguy Says:

            But we ARE “doing both”, aren’t we? Not doing enough to avert CAGW and also correcting a genius on his use of hyperbole (and that latter effort is something folks of average intelligence should not be doing—-there is a valid reason for hyperbole when it is wielded by someone who is smart enough to see farther and deeper).

  4. Dave Jewett Says:

    I’ve much respect for Stephen Hawking, but I kind of wonder if that beautiful mind of his is starting to wander off out into left field.

    • redskylite Says:

      Stephen Hawking is just repeating what he said years ago in this video accompanied by a Carl Sagan segment. He is not suffering from the onset of cognitive impairment due to old age. I for one am not going to argue with a man who is just about as brilliant as Einstein, be he labour, conservative or liberal.

      From the vaults of the greenman

      A lot of people still believe global warming is something Al Gore cooked up in 2006 to promote his movie.
      The thousands of expert climate scientists whose work forms the consensus have no celebrity, no street cred with the average person. But for a lot of people, the archetypes of scientific expertise, are more popular media figures like Stephen Hawking and Carl Sagan.


  5. For a book-length discussion of this topic, I highly recommend The Ends of the World, by Peter Brannen: http://peterbrannen.com/

    Our world can effectively end even without a “true” sixth mass extinction. But hey, the deniers say Brannen is an “alarmist”, so I guess there is nothing to worry about.

  6. redskylite Says:

    Patience please, all will become much clearer in a few hundred years or so – lets all meet up again around 2217 AD and review the situation.

    “Processes take time, even up to several hundred years, to really take effect — and because not enough time has passed since the Industrial Revolution for their signal to really develop, the historical record is what’s actually misleading at the moment.”

    https://www.washingtonpost.com/news/energy-environment/wp/2017/07/05/scientists-are-starting-to-clear-up-one-of-the-biggest-controversies-in-climate-science/?utm_term=.a721450bb10a

  7. Gingerbaker Says:

    Having trouble getting this comment to post, but try try again:

    It doesn’t matter if full runaway is not plausible. There remains the very real possibility of partial runaway, ie, an increase of 10, 15, even 20C+ increase in average temp.

    We simply do not know what may happen if we are unlucky, as these precise conditions have likely never occurred in the past. But there is plenty of terrestrial CO2 and methane sitting there waiting to cause a human extinction event.

    And, frankly, we don’t even need to get close to such temperature excursion to end civilization as we know it and plunge ourselves into the worst dystopian future we could imagine.

    OTOH, there does appear there might just be a method of reducing atmospheric CO2 quickly and at a low enough cost to justify the expense – accelerated olivine weathering:

    http://www.innovationconcepts.eu/res/literatuurSchuiling/olivineagainstclimatechange23.pdf


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