This has been my pet theory for a while. What if the actual great filter for an intelligent species is the difficulty of escaping your home planet _before_ you've consumed all of its resources? I will — naturally — have a human-centric view of this, but it does seem like a very hard thing to do, given the physical and technical challenges of getting out of the gravity well, and actually surviving for extended periods in the harshness of space. Not to mention the travel time of getting anywhere worthwhile!
It seems pretty clear to me now that we're not going to make it. We need to cut global emissions by 15% a year, every year, starting in 2020[1]. As a species, we aren't capable of the kind of global organisation and foresight it will take to achieve this. I'll suspect we'll continue hurtling headlong towards the edge of the cliff (although there's a good chance we're already over it, and currently hanging in the air like Wile E. Coyote) until there's a war over the last dwindling resources, or a simultaneous worldwide failure of food production.
I've wondered a few times that if we were to go back in time to the start of human civilisation, knowing what we know now, would we be able to direct our energies more appropriately, and make it off earth in sufficient numbers to enable us to become a spacefaring species? Then I remember that science predicted all of this back in the 19th century[2]. We did nothing then, and we're doing nothing now. Alok Sharma says it's a catastrophe, but "also insisted the UK could carry on with fossil-fuel projects."[3] We're in real trouble.
This is why I think escaping from a ruined Earth is fruitless if the tendency to grow and consume everything in sight is baked into our genes. We'd just ruin Mars, too.
We can't seem to escape from our own deeply ingrained instincts, only transplant them to every inch of untouched soil we can reach. I tend to see the overwhelming evolutionary success of humans as similar to a virus that is too powerful and kills the host.
My belief is that we will have to suffer the consequences first before the death instinct is ingrained politically and socially in every person in power who contributes to the destruction of Earth. We can continue feeling fine doing what we are doing right now because not enough people have died off yet to make the drastic changes worth it. Societies will be forced to become places where optimism is extinguished in favor of pragmatism. They will only become those places because the scale of death and destruction will cross an unwritten threshold that needed to be crossed first before that change in mindset could take place.
I believe this opportunity to save the Earth that's being proposed right now will not happen because no amount of hypotheticals or climate science fiction that warns of this will be heeded, because they have to remain just that by their own nature - hypothetical, instead of actual, lived human history. That includes what I am writing right now. Our imagination is an innovative evolutionary advantage, but it has ultimately failed us. Our instincts for growth have won out against any scenario of global collapse and catastrophe and heartbreak we can think of. That is just our nature as a species, and it is a sad thing to consider, but as a result, pretty soon everyone will have to hope that they're not going to be one of the billions of people that will soon die off from climate-driven warfare or famine or any other catastrophe that's about take place. But after the dust settles, we will gain the one precious, irrevocable thing whose absence is preventing us from taking action right now - history.
At that point, if we still don't have a better way of thinking of the environmental issues figured out, then I would consider our curious experiment in biological fitness finished, once and for all.
