It is the year something-something, and the Sol system has been colonized. The Sun is surrounded by a growing cloud of habitats, Venus is a veritable garden world, Jupiter is being fed mass from the sun so that it may one day turn into a brown dwarf, the Oort cloud is the new frontier, human lifespan is biologically indefinite, and Mars, despite being the least attractive candidate for terraforming, has turned into life-bearing world protected by a superconducting satellite that produces a magnetic field placed in the L1 Lagrange point.
It is a time of wonder and miracles.
Until it isn't.
Something caused the collapse of this civilization, and now only derelicts remain around the sun, the citizens of Earth, Venus and Mars had regressed back to a animalistic state while everyone else died, uploaded themselves into computer banks on Titan, or fled to the Oort cloud, and beyond.
Through out all this, the Satellite above Mars had persevered, keeping to its station like a sentinel of old with a shield of magnetic fields foreve-oh, never mind, got hit with a system wide Kessler syndrome event. Guess without Mars is doomed...Right?
Essentially, I'm wondering if it is possible to to have a a backup in case such an event where to occur. It's impractical to start up Mars's core so that's out. Perhaps having a mixture of genetically engineered life forms to create a specialized atmosphere more resistant to solar winds? If so, how? Are there other alternatives on the table? Do we have to go all Darwin IV on Mars?
Something to get out of the way.
Mars has been partially terraformed, there is a sea of liquid water, the air has been increased, though not to the level of earth's atmosphere and with, to Terrans at least, high levels of carbon dioxide. Plants and animals have adapted to these conditions.
First off, thank you to everyone who has commented so far it really helps.
Now, it appears that I may have been to unclear on what I was asking exactly. So! To remedy this, let me give a some more clarification than before.
The main point of debate is that there is need for a shielding due to the fact that atmospheric lose occurs over geological timescales. Thing is, the inhabitants of Mars in the setting would evolve into a post human species adapted to the red(?) planet (the bits of blue/violet and greenery ruin the image a bit) and that would take evolutionary timescales i.e. at least a millennia or more. Now, why have humans gone to such a state, that's a post for another time but suffice to say I have an interest in keeping the atmosphere intact for as long as possible, preferably as when the sun is big enough to non the Earth.
When I said life on Mars has 'adapted', what I meant to say was 'genetically engineered' then over the millennia grew accustomed to Mars. This is due to the fact Mars is in reality a very unattractive terraforming candidate for a carbon copy of Earth (Venus, once it was cooled down with mirrors, sped up with targeted comet strikes to produce a more 'normal' 24-ish day/night cycle, jump start it's magnetosphere, change the axial tilt slightly get some seasons in and funnel most of the CO2 and N out of the surface be used in the terraforming process, shipped to Mars, the space habitats or crushed into a sizeable diamond moon with bits of Mercury sprinkled in; the end result is a good candidate for colonizing, though bit on the tropical side;)), thus Mars was terraformed till it was 'good enough', meaning the deepest the deepest body of water is around 1.5-2 kilometers deep, the atmosphere was thickened though not Earths 14.7 psi of atmospheric pressure but enough to cause storms of some concern, so around 9-10 psi if my horrible knowledge of atmospheric science estimation is right. The life there, along with the human population, was genetically modified to handle lower pressures and the much higher CO2 levels (though the high CO2 levels would give an excuse as to why the colonists turned feral, though not a good one), and have overall better radiation repair, though that was added as a after thought following bureaucracy and the vocal minority calling "just in case!". However, life on Mars can live in more extreme conditions, though I would like to keep the conditions as stated above for as long as possible.
The question I'm asking is there a any way to keep such an atmosphere with without machinery and instead through some biological process, either naturally evolving by coincidence or through genetic engineering?