Goldilocks zone, planet, idea

I was watching the BBC’s marvellous ‘Wonders of the Solar System‘ documentary series the other day. Somewhere within it (I can’t recall exactly where), Brian Cox, the charismatic presenter of the series, refers to our Earth as ‘the Goldilocks planet‘. This little infonugget has been trundling about in my noggin ever since, and I finally realised why: it reminds me of a rather poorly phrased comment I made on Lack of Environment some time ago (I can’t find the comment).

In my comment, I referred to what I think of as the ‘Grand Experiment’ of homo fatuus brutus — our tinkering, in recent times, with the very air we breathe. Our combined inability to admit that this is unwise (such admission, naturally, being a prerequisite to actually doing something about it) may be the biggest mistake we’ll ever make. The ‘poorly phrased’ part was the suggestion that this mistake might be our last, if our actions were to succeed in, as I recall putting it, “moving the Eaarth outside the Goldilocks zone“.

Habitable zone relative to main star's luminosityIn retrospect, my reference to the Goldilocks ‘zone‘ was a poor choice; that zone is the region around a star within which planets are capable of supporting life-as-we-know-it. Recent research does suggest that our own planet is much closer to the inner boundary of our solar system’s ‘Goldilocks zone’ than previously thought (see eg here, although I admit I’ve “done a James Delingpole” — I haven’t actually looked at the research). And the additional heat being absorbed by our biosphere as a side-effect of our polluting activity is truly colossal (around four Hiroshima atomic bombs worth of heat every second).

Even so, suggesting that our actions could physically alter our planet’s orbit was a poor metaphor. My comment, on the face of it, should quite rightly have been dismissed out of hand as being made by a total and utter phlyarologist (by the current dictionary definition, ie ‘one who speaks nonsense’). I should have referred to our Goldilocks planet, not the Goldilocks zone in which it sits. Rest assured that I have slapped myself on the wrist for making such a dumb mistake.

What I was actually trying to say, as opposed to what I said, makes sense when one considers the Goldilocks concept, which is based on the “not too hot, not too cold, just right” principle from the tale from which the label arose. If our planet is indeed close to the inner edge of our sun’s habitable zone, then this means our biosphere is almost (but not quite) ‘too hot’ by dint of its position relative to the source of most of our energy — the sun. What this suggests, though, is that it wouldn’t take much to tip our biosphere over the edge, into the runaway greenhouse effect (the one that James Hansen believes is inevitable if we continue on our present course of inaction against the causes of climate change).

Which, of course, would mean that the ‘Grand Experiment’ could well be the biggest mistake we’ll ever make — since it would also be the very last one.

I’ve come to conclude that if we burn all reserves of oil, gas, and coal, there is a substantial chance that we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty.

Dr James Hansen (2009) Storms of My Grandchildren p236

[edit 10May2014]
This is one of those rare and wonderful blogglings in which the comments add much to the original offering. Having admitted one mistake already, I am indebted to ccgwebmaster for having pointed out that Dr Hansen has recently clarified the position regarding the possibility of the Venus syndrome on Earth. (Read on for more…)


About pendantry

Phlyarologist (part-time) and pendant. Campaigner for action against anthropogenic global warming (AGW) and injustice in all its forms. Humanist, atheist, notoftenpist. Wannabe poet, writer and astronaut.
This entry was posted in ... wait, what?, Climate, Communication, Core thought, Culture, Education, Energy, Environment, GCD: Global climate disruption, History, memetics, Phlyarology, Science, Strategy and tagged , , , . Bookmark the permalink.

5 Responses to Goldilocks zone, planet, idea

  1. That was a wonderful series I remember. Alas, I have no time to develop any personal views on the matter right now. Cheers pedantry!


  2. ccgwebmaster says:

    It may be somewhat of a technical quibble, but I didn’t think Hansen exactly said the earth would turn into Venus. I think he addresses the question quite well here:

    That isn’t to say that significant warming isn’t possible, or even a thermal catastrophe along end Permian lines where most life on earth dies, or a planet where 90% of the currently inhabited surface no longer remains within survival wet bulb temperatures for humanity – just that we aren’t (to my knowledge) at any risk of literally turning the Earth into Venus just yet.

    As the sun gets hotter with age (presumably due to the changing nature of the fusion reactions sustaining it, as it progressively synthesizes heavier elements), we do indeed potentially approach such cases, but you’re looking into a rather distant future there even on geological timescales.


    • pendantry says:

      Thank you very much for the link to that article by James Hansen:

      “So Venus-like conditions in the sense of 90 bar surface pressure and surface temperature of several hundred degrees are only plausible on billion-year time scales. […] Earth is not now near a runaway situation, but the idealizations are still sufficient that the studies do not provide a picture of where Earth is headed if all fossil fuels are burned. […] At least one sentence in “Storms” will need to be corrected in the next edition: even with burning of all fossil fuels the tropical ocean does not “boil”. But it is not an exaggeration to suggest, based on best available scientific evidence, that burning all fossil fuels could result in the planet being not only ice-free but human-free. […] the transient climate phase this century, if we continue business-as-usual fossil fuel burning, is likely to cause an extended phase of extreme climate chaos…”

      James Hansen (2013) ‘Making Things Clearer: Exaggeration, Jumping the Gun, and The Venus Syndrome’

      While the potential for loss of all life on Earth may have retreated somewhat in my own mind, the impact on our civilisation of our current course remains dire. Perhaps I need to dial down from “hysterical panic” to “we need to transition from fossil fuels with the utmost urgency (though there is still no indication that we ever will)”.

      Hansen’s words towards the end of this article provide something from which to take heart: “I believe all the individual actions occurring at many places are very important and the sum of them may help turn the tide to clean energies.”

      But he does also provide the important caveat that is the key to the conundrum:

      “How can we pass from “jumping the gun” to unavoidable deleterious consequences without passing through demands for common sense policy actions?” Delving into that matter requires getting into how our government functions and fails to function.


      • ccgwebmaster says:

        There are some lifeforms we can be fairly confident can survive the very worst case outcomes. People are not automatically one of those, of course. Actually, complex life even managed to survive the end Permian extinction – so we need to keep survivability in perspective somewhat in my view.

        It’s one of my pet peeves, when people use defeatism to justify inaction. The Venus outcome is sometimes one of those things but more often it’s Guy McPherson telling everyone near term human extinction is inevitable (an allegation I can find no credible basis for, but supported by a base of knowledge in his case exceeding that of most of his audience, tending to lead to people to defer to him as an “expert”). People find the perceived hopelessness of the situation a convenient fig leaf for their inaction and denial (not just of if it is happening but of what they can do – per

        To be sure, I do believe the situation is rather dire – my personal view (unscientifically speaking) is that we will lose between 90 and 99%+ of the human population (and a very large chunk – most – of the planet we once knew). I’m not sure I expect to live to see that though (climate change will likely continue for centuries now), and don’t believe it to be unsurvivable (though actually the very worst case outcomes are pretty unpleasant once you get into things a bit more – and not in ways most people think about immediately).

        All that is of course why I pitched my battlelines where I did, to try to retain civilisation (in some guise, certainly not the modern pretence) for people in the future.


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