So, someone that I showed some of my notes to asked why are Eco-Purists still a threat after all this time... and, well, it isn't pretty. By the time the Cataclysm happened, eco-terrorism was becoming more and more violent as the situation deteriorated. As the world fell apart, they gained equipment and technology that would severely screw humanity over. While the ideology of Eco-Purity is self perpetuating (as those of the ideology have hidden themselves quite well) with their own hideouts and bases across the planet, the efforts that the various factions have put into annihilating this ideology would have killed it by the modern day.
To get into why Eco-Purists haven't been annihilated, we must go with some history. Russia during it's pre-Cataclysm days was ruled by an oligarchy and that oligarchy is ruled by a handful of former intelligence department leaders and officers, the most visible of which is one Vladimir Putin. Putin -no one has a complete picture of this era thanks to Grigor Stoyanovich destroying as much as he could when Karyavin Yuliy Vadimovich 'pulled a Napoleon'- initiated a program that would turn things like freedom of the press and freedom of information against the target and the more 'open' these freedoms are, the worse the effects. From the mid-1990s AD, this slowly evolved into a comprehensive program utilizing mimetic weaponry and was first used in Brexit and the US 2016 Presidential Elections alongside the more traditional 'Active Measures' program that the Russian Foreign Intelligence Service (SVR) had perfected into an artform with.
To say that this worked beyond expectations would be an understatement. Brexit caused a disastrous cascading effect with the European Union, as it caused an incredibly punitive Brexit to be implemented. This punitive Brexit not only caused North Ireland have The Troubles again -although what little specific information from that period that is left indicates that mimetic weaponry was used to cause this, but this can't be completely confirmed thanks to the destruction of important documents by Stoyanovich's regime- before loosing it completely but also cause the military to reinstate the monarchy at gunpoint. The punitive Brexit caused ripples within the EU, which led to a series of economic and civic meltdowns across key members of the EU and caused it's dissolution in the late 2030s AD.
The United States on the other hand fared somewhat better. The Trump-Russia Investigation managed to cause an unprecedented series of court cases started by the Supreme Court that would destroy not only Trump, his family, and his associates (Donald would only survive a year in ADX Florance while serving a life sentence) but also for all intents and purposes annihilate the GOP and it's propaganda infrastructure alongside curtailing social media in general. While this did cause minor bouts of insurrection, it went more or less roughly... before the status of the world became -more or less- defined as 'on fire'.
Putin then authorized an expansion and perfection of this new form of weaponry. This is where one Chayka Mili Yegorovich enters the picture. Chayka Mili Yegorovich and his team developed a whole new mimetic weapon technology from scratch within eight years and developed an entire suite of mimetic weapons out of that technology. What Chayka Mili Yegorovich and his team managed to create is the closest thing to mind control as one could get. The technology could make anyone who is receptive to the meme into a Manchurian Candidate. The rate that the process takes hold of a person differs wildly from victim to victim, and it has only been discovered recently that those with inactive psionic genes are the most vulnerable (and even then, it is it's own spectrum, as the more powerful the inactive psionic gene, the faster the process goes), but it is 100% effective on those that it takes hold. Now, Chayka Mili Yegorovich and his team understood the implications of this, and decided to defect to the United States. With the help of the remnants of MI-6, the CIA, Poland, Germany, and a handful of others, Chayka Mili Yegorovich and his team managed to get to the US safely with a detailed manual on the technology with the original software and what little of the hardware they could smuggle out.
Chayka Mili Yegorovich and his team's fate would be that they died after helping the FBI and NSA on creating very basic countermeasures with everything related to the project stolen and let loose across the internet. This coincided with a rash of attacks by a now-dead hactivist group who believed that all information must be free. To say that this technology getting into the wild was disastrous would be the understatement to end all understatements. While most of the ideologies that would spawn from these would be brutally put down, it would cause greater bloodshed later... as what would become known as the Eco-Purists would perfect this technology into it's current form.
That is how the Eco-Purists have managed to stay alive for so long. With careful planning, they could turn anyone into an Eco-Purist fanatic. That is why things like the freedom of information is heavily restricted and privacy has been annihilated.
That wasn't the only horror that the Eco-Purists would be responsible for... for it is the eco-purists -more specifically a faction within the ideology known only as the 'Riders of the Apocalypse', a faction that most other Eco-Purist factions hated and feared and whose sole define purpose is to annihilate humanity and everything it created- that caused the Earth to snowball.
Taking data from various weather manipulation projects that various nation-states were doing (the leaders of the field would be the US and Russia with China bringing up the rear), the 'Riders of the Apocalypse' created a series of technologies that would cause the entire Earth to Snowball in an effort to doom humanity to extinction. The 'Riders of the Apocalypse' managed to go basically comic book villain and created a superweapon that was straight out of a comic book. When this weapon was first activated, it didn't do anything within the first two years like their models predicted... and it wouldn't be until a decade and a half after activation that the effects started to show themselves, which was one of the causes of the Cataclysm. At first, it was only notable for the uptick in polar vortexes... which got worse every year until it caused entire swaths of the US Midwest to be uninhabitable during winter time. That was when various nations started building what would become the Citadel-Arcologies, in preparation if these polar 'super' vortexes get even worse and cover a wider area.
Sadly, this won't save everyone...