Earth Is Not Random

The great filter is whatever obstacles stand in the way of simple dead matter eventually giving rise to a visibly expanding interstellar civilization. It is now confirmed that a non-trivial chuck of that filter is in planets having special orbits that let climates be stable over time:

Planetary anthropic selection, the idea that Earth has unusual properties since, otherwise, we would not be here to observe it, is a controversial idea. This paper … [compares] Earth to synthetic populations of Earth-like planets … [for] high (or low) rates of Milankovitch-driven climate change. Three separate tests are investigated: (1) Earth-Moon properties and their effect on obliquity; (2) Individual planet locations and their effect on eccentricity variation; (3) The overall structure of the Solar System and its effect on eccentricity variation. In all three cases, the actual Earth/Solar System has unusually low Milankovitch frequencies compared to similar alternative systems. All three results are statistically significant at the 5% or better level, and the probability of all three occurring by chance is less than 10^-5. It therefore appears that there has been anthropic selection for slow Milankovitch cycles. This implies possible selection for a stable climate, which, if true, undermines the Gaia hypothesis and also suggests that planets with Earth-like levels of biodiversity are likely to be very rare.

Regions of Earth that have stable temperatures (e.g., tropical rainforests) have high levels of biodiversity. The hypothesis that this link is direct and causal is reinforced by the observation that the deep ocean seafloor also has high biodiversity, even though the conditions are, stability excepted, poor and biological productivity therefore low. Further evidence of a link between rapid climate change and loss of species richness has been gleaned from studies of Earth’sglacial-interglacial cycles. The most recent ice ages have resulted in reduced biodiversity within the temperate zones where the greatest changes in climate occurred. There are, therefore, two independent lines of evidence that support the proposition that biodiversity is, in general, lower when climate change is significant. …

I concentrate on the climatic influence of Milankovitch cycles, that is, the periodic variations in Earth’s climate that are induced by changes in Earth’s orbit and orientation in space. The key factors here are axial precession (time varying axis orientation), orbital precession (time varying orbital orientation), and time variation in orbital eccentricity (circularity of the orbit). Note that changes in obliquity (the tilt of Earth’s axis relative to its orbit) are the consequence of interaction between axial precession and orbital precession, and this important factor is therefore included in the following analyses. The evidence that Milankovitch cycles affect Earth’s climate is secure. (more)

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  • Allan Crossman

    “there has been anthropic selection”

    I really do despair. This sort of language makes it sound like the anthropic principle has some sort of causative effect.

  • Carl Shulman

    Not to mention an early step.

    • erisiantaoist

      Yes; it’s nice to suddenly get a bump up in our chances of taking over the light-cone instead of dying out.

  • nikki_olson

    So, the great filter is likely the climate change due to axial rotation that is upon us.

  • Patrick L

    One of the common themes of the last year or two has been Robin’s posting of ‘the great filter is in the future’, only to have a fairly decent amount of criticism and pushback on those topics. I remember those being much more actively critical of Robin’s position than his usual topics.

    Do you still believe the great filter is in the future?
    Do papers like this make you appreciate those commentators more, or less? Was their criticisms at the time baseless, or written in a way pushing you further away from the position this paper points to, or were they laying the ground work for you to be more wiling to accept something like this? What could commentators have done to push you towards this position sooner?

  • Hedonic Treader

    I welcome these news. If I interpret them correctly, it means that significant parts of the great filter prevent not just intelligent civilizations, but the evolution of sentient alien wildlife. Which means there’s probably less of it than we would have assumed otherwise. This knowledge reduces the expected value of involuntary suffering on other planets, lowering the need for cosmic rescue missions to re-structure or destroy life there.

    With this utility factor reduced, we can put a stronger focus on earth-originating sentient life and its possible future when we make decisions.

  • I’m trying to work out how this could impact simulation arguments. At the least, I’m guessing it increases the chance that we’re in a simulation not dedicated to solving a forthcoming great filter/existential risk problem, but rather something more mundane.

  • The Great Filter is ahead of us and I don’t think we will survive it. I think we have a better shot at it than other alien civilizations because of some idiosyncratic aspects of Earth and human physiology, but I don’t think they are enough. There are some that can see and understand what those difficulties are, but collectively humans can’t address them because not addressing them is more profitable and produces more short-term benefits than addressing them.

    I think we are in the midst of a filtering event right now, and that we collectively can’t address it is symptomatic of why eventually there will be a filtering event that we don’t survive. The current filtering event is AGW, but a microcosm of that is the current balancing of the US budget on the backs of the poor.

    There is an editorial that mentions what the root of the problem is; subsidizing the most wealthy at the expense of the less wealthy (but not in so many words). It is the externalizing of costs and the internalizing of profits. The privatization of profits and the socialization of losses.

    The liability cap that nuclear power plants have is an enormous subsidy that is pretty easy to see. The limits on corporate liability are no different. Lobbying by corporations that reduces their taxes is just another subsidy. The government has to be funded by something, when the wealthy avoid being taxed, the tax burden falls on the less wealthy. That is a subsidy.

    When individuals prioritize their own comfort (note it is “comfort” not survival) over the survival (note it is “survival”, not comfort) of arbitrarily many other humans, it sets up an unsustainable dynamic where the many survival seekers will eventually be compelled to destroy the individual comfort seekers in order to survive. That is the dynamic going on in Libya which typifies one of the rules of conflict. Never wound a king. Never deal a non-fatal blow to someone who can mobilize sufficient resources to fight back and kill you.

    The tragedy of the commons is an example of trying to externalize your costs while internalizing your profits. That only can work so long as there are external resources that can be tapped. When there are no external resources left, consumption has to go down. That is why essentially every fishery that has been exploited has been overexploited until it was destroyed.

    Dealing with AGW is a cost that producers and consumers of fossil fuels have externalized. Externalization doesn’t make the cost go to zero, it just makes it zero on the balance sheet of the entity that has externalized it.

    • From what I’d heard about AGW, it mainly threatens to kill a lot of people in places like Bangladesh. I’d appreciate links on the existential risk it poses to humanity as a whole, and the first-world in particular.

      Our tax system is overwhelmingly based on the contributions of the wealthy. They subsidize the majority of the populace. The tax credits corporations get is indeed a subsidy, but it is basically one group of wealthy interests at the expense of other high earners. In so far as these kinks in the tax code are distortionary, the rest of us may seem some interest in fixing it, but we won’t be direct beneficiaries.

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  • Me

    so true