While the modern state is indeed stable, environmental change has an impact even if not through apocalyptic natural disaster.
A long term drought contributed to the civil war in Syria[1]. It may be the first of many around the world.
Both Ebola and Zika are exacerbated by global climate change[2][3].
According to the link, Egypt survived as a state for a century longer before it too fell. That was after transforming from a civil society to martial law. With the threat to pregnancy posed by Zika, I'm reminded of the propaganda in "Children of Men": "The World Has Collapsed: Only Britain Soldiers On"
1. http://www.nytimes.com/2015/03/03/science/earth/study-links-...
2. http://blogs.ei.columbia.edu/2014/09/04/how-climate-change-i...
3. http://www.vox.com/2016/1/20/10795562/zika-virus-cdc-mosquit...