A New Constraint on the Drake Equation
online.liebertpub.com
online.liebertpub.com
Today, we can kill everyone off with an exchange of the already existing nuclear weapon inventory. But that requires a reasonably large number of people to make mistakes or take action.
We're in the process of killing everyone off by screwing up the natural climate process which requires a large number of people to commit to inaction.
Within this century we will have the means and the understanding for a single individual to craft a DNA based pathogen that can infect and kill nearly everyone on the planet.
These are the three tests for graduation into the club of "long lived intelligent species." Fail any one of them and you don't make it. I call them:
* Action of the group
* Inaction of the group
* Action of the individual
Which just leaves the people who want to exterminate part of humanity.
As for runaway climate change - it's definitely a possibility. Current models don't try to estimate potential coupling between the effects of methane and CO2.
It doesn't seem to be considered likely. But a lot of scientists are already surprised by the speed and scale of climate change, and the fact that we're seeing effects in a decade or two that weren't expected until the end of the century.
Worries about runaway climate change may be pessimistic, but they're certainly not unscientific. Considering the stakes, more research would be wise.
We have exhausted all the easily accessible minerals and fossil fuels (i.e. those resources that can be extracted using stone age tools). Any break in our current technological systems might make it impossible to recover for 10s of millions of years.
We may also want to invest in creating some "breadcrumbs" for a future civilization to build up from. Say, a reserve of easily accessible fossil fuel and other raw materials, and some long-lasting guideposts that indicate where to find them.
A lack of accessible fossil fuels is likely to be the major factor as it would be really difficult to get an industrial revolution going without access to the easy energy provided by fossil fuels. We could easily find a rebooted society gets stuck in a pre-industrial state with no way of breaking out.
All sorts of food stocks simply die. No corn, no wheat, no cows, chickens, or pigs (in year 2) and no vegetables. Fruits from the tropics perhaps but another huge die off in that vegetation as well as temperatures drop into the 40's at night. There is no "other place" to go, so generally you see (depending on your model) 70 - 85% of the population outside the middle lattitudes die from starvation and general unrest. If you are lucky, you get someone smart enough to create a defensible space in the mid lattitudes that can support the population inside of it. The fisheries will crash in year 3 as the remaining survivors use what is left of the world wide fishing fleet to haul in ever more valuable food (aka fish). Then the people in the defensible spaces need to hold off the people outside those spaces until those outer people die and are no longer a threat. That can take a while and since the outside people will be scavenging weapons from the whole frozen world they will have a lot more ammo and war fighting resources than the people in the defensible spaces.
If it changes fast enough, the people trying to survive kill off everyone. It has happened in colonies before and it can presumably happen on a more global scale.
Would bands of indigenous jungle tribes survive? Good question, anything that moved would be hunted as food, jungle would clear cut to make farmland as quickly as possible.
If it happened slowly? Like over a couple of decades? Sure that would probably allow people to survive relatively intact save for their ability to actually make any new things of any level of technological sophistication.
Look at maps of the late Pleistocene where the glaciers were and plot those out on a modern globe. Now look at what is under those glaciers and try to figure out how long it would take to relocate that capability south. More importantly how long it would take to relocate it south. That sets the parameters for the maximum rate at which the species could tolerate the onset of a new ice age.
Do I actually think this is going to happen? Not really. Are we recording unprecedented levels of greenhouse gases? Yes. Is the climate we're experiencing similar to the climate that was in effect when those levels occurred in the past? Not really, the early Pleistocene was much warmer than it is now. Moore's paper from 1980 was probably pretty influential here. He, like others, is/was really interested in why we had ice ages in the first place.
The point though is that we talk about "global warming" which implies to a lot of people who don't read the papers that our inputs into the climate will only cause increased heat, but it is more accurate to say "climate change" since we don't have good non-linear models for how the planet responds to all the forcing functions we are throwing at it.
We casually throw around terms like "hottest temperatures ever recorded" or "lowest ice levels on record" but some times lose sight of the fact that the "record" we've been keeping in terms of climate change is, according to ice cores, and other geologic carbon dating of glaciation events, perhaps 2% of a cycle. (assuming 100kyr cycle and 2kr of nominal human recordings). Remember that 2% of a year is one week. We can't take a week's worth of measurements and even imagine all of the variations we'll see that year, so we have to be careful about extrapolating with the amount of data we have. Pretty much everyone (except some really hard liners) can agree that climate can and will change, its understanding that change which we can only develop as we go along. And the latest contribution to our understand was the Nature paper that said, in essence, don't try to model this stuff with linear models.
[1] http://www.nature.com/nclimate/journal/v5/n5/full/nclimate25...
[2] https://www.researchgate.net/profile/Ted_Moore/publication/2...
As a result we have a lot of research which clearly indicates that humans are destabilizing the climate which will induce it to change, but no one that I have found has been willing to stand up and claim they could drive the climate in a particular direction or speak definitively on what the eventual result of our destabilizing influences will have.
Our ability to predict outcomes is limited by our understanding of the complex interactions (which is why I like the recent Nature article, it really gets to that point) We can make fairly mechanical predictions of the form "If this much fresh water was dumped into the ocean, it would go up by this many meters." Some have also speculated that the increased weight on the mantle of all that water will cause a massive increase in volcanism as magma is compressed.
The most definitive statement I have ever read from an actual scientist is that by generating fewer green house gases we will destabilize it less. The elephant in the room then is without human participation the planet has seen warm spells and ice ages. So at best, our influence is eradicated and it goes back to what ever was previously changing the climate before we came along.
As a result I don't think telling anyone to accept lower growth and poorer health by curtailing fossil fuel use is a reasonable strategy. You can tell them that the more energy efficient they are, the better their economy will be able to support them. Telling them to suffer because it will stop climate change does them a disservice. Telling them to get off fossil fuel because they will be healthier and more prosperous if they can live on renewable sources benefits from being demonstrably true.
[1] http://www.nature.com/nature/journal/v457/n7229/abs/nature07...
I'm not convinced we can. For starters, the nuclear weapon inventory is a lot smaller than it was back in the 80s when those sorts of statements were popular. And secondly, as I understand it, it was always a bit of a lie, an estimate based on some silly assumptions (e.g. that everybody in the world lives in cities), which in repetition eventually lost those assumptions.
And yes, I agree with the other poster that it's pretty much impossible to kill everyone on earth with climate change.
Species-ending diseases I do worry about, but maybe that just means I don't know as much about immunology as I do about nuclear weapons.
In effect there was a nuclear war, it's just that all the bombs were exploded on "friendly territory" like Australia, the pacific islands and Nevada.
The cause isn't the nuclear radiation per se. It is the extreme destruction of many large urban centres simultaneously. The problem is that all of those cities burning simultaneously would send up a tremendous amount of ash and smoke that would block the sky for quite a while.
This would cause a reduction in the amount of sunlight that would be available for growing crops and combined with the almost total destruction of global economy could result in the destruction of the entire human race through mass starvation.
[0] http://onlinelibrary.wiley.com/doi/10.1002/2013EF000205/full
The nuclear arsenal is predominantly hydrogen bombs, and they are insanely powerful. The Hiroshima bomb was 16 kilotons. A W-87 and W88 warheads are a bit under half a megaton, or roughly 30X more powerful. The W-78 is about 350kilotons, about 20X larger. The B-83 bomb lets you dial in just how spectacular you want a return to neolithic life to be, all the way up to 1.2 megatons, about 70X larger than the Hiroshima bomb. There are fewer than 250 cities with over 1M population. With just the ready US arsenal you could blanket most of the populated parts of the planet.
In 1967 the US maintained an arsenal of about 30,000 (!!!!!) nuclear weapons. You have to wonder. Now the stockpile is about 4500 and about 1500 are deployed and ready at a moment's notice.
PaaS: Panspermia as a Service
"Like Dropbox, but with DNA"
For all we know, it may be the only long term path of survival for an intelligent species is to accept absolute dictatorship of a genocidal/eugenicist bent. I hope it's not, but if the 20th century's taught us anything, it's that any kind of non-evidence based wishful thinking towards an abstract ideal is probably the most dangerous thing.
That said, I'd be interested to understand how you reason from "the 20th century's teachings" to "absolute dictatorship of a genocidal bent". I would also like to understand the characterization of 'non-evidence based wishful thinking'. Happy to walk through the reasoning behind global thermonuclear war resulting in extinction, and sudden massive climate change resulting in the same. Similarly the reasoning for an individually created pandemic can be traced back to the general availability of DNA printers[2] and the ever increasing understanding of genetics and how one might use viruses modify the genetics of living humans [3].
[1] Trust me, the last thing I'd want to do is get into an argument about what constitutes sentience.
[2] http://www.npr.org/sections/health-shots/2015/05/07/40446024...
It would also involve wiping out or sterilizing 98%-99% of the species, but in terms of stabilizing the population and avoiding the possibility of a boom-bust extinction or nuclear war, that would be a solution both "hateful" and geared towards species longevity. I think it's better to risk extinction than to actually do that, but if one's sole concern is to avoid extinction...
Meanwhile, a european nun who chooses to live and work in Africa is definitely filled with genuine love for humanity, but their social and economic views would probably destroy our species and certainly any hope of technological progress if practiced universally.
http://stephenschneider.stanford.edu/Publications/PDF_Papers...
"...the Drake equation can have any value from “billions and billions” to zero. An expression that can mean anything means nothing. Speaking precisely, the Drake equation is literally meaningless, and has nothing to do with science. I take the hard view that science involves the creation of testable hypotheses. The Drake equation cannot be tested..."
-Crichton
We know a lot more about exoplanets now than we did in 2003. We're moving on to find out how many are in the Goldilocks zone, or how many contain water. Our idea of what to plug in is slowly getting better.
Pointing out that the Drake equation is technically not science since it doesn't involve testable hypotheses is pointless pedantry. Call it statistics then. Or metaphysics. Or a thought experiment.
"Unfortunately", that's nailing down the one parameter that nobody has ever particularly questioned. There's some lines of thought that our solar system might be unusual in relevant ways, but nobody has ever seriously argued that the only planets in the galaxy are in our system, or anything related to that that would make that parameter small.
It's all the rest of the parameters where the mystery is.
So before taking this article to mean that life is actually pretty likely, consider that an event having to occur at least one in 10^24 odds is actually extremely difficult for complex probabilistic phenomena. Who knows how likely life is, but we can't just assume it's higher than one in 10^24.
(edit: I just looked up the pop article I was complaining about. It was in the new york times and the title was literally "Yes, There Have Been Aliens." Hence my crankiness.)
I wonder how they turn a statement based on a probability into a statement that is an absolute truth (no probabilities involved).
Drake equation or not, seems such a big place that it seems hard to imagine that this tiny little spot is in some way unique.
But maybe, if everyone only spoke French, it wouldn't occur to us that other languages were even possible. We'd be trying to estimate how many French speaking aliens were out there.
Deoxyribonucleic acid is our French. Because it's all we know, we think it's special. But the possibility space is much bigger.
A vimana, which from googling appears to be some kind of flying temple in Sanskrit myths, does not appear to have actually existed.
> a collective memory of having once DESIRED to fly in ancient times