At https://phys.org/news/2019-11-climate-crumble-ancient-world-powerful.html … and https://phys.org/news/2019-11-felled-great-assyrian-empire-team.html … and even https://phys.org/news/2019-11-climate-fueled-demise-neo-assyrian-empire…. … which is basically three separate takes on one paper published in Science Advances (Nov 2019) – see https://doi.org/10.1126/sciadv.aax6656 … and if you are a devil for punishment, https://advances.sciencemag.org/content/5/11/eaax6656.full … and all the links are provided as SIS has a very vibrant interest in ancient history and chronology. Basically, anything to do with climate change will get your work published and this team of researchers have used climate change to assess the collapse of the Assyrian Empire, not long after its apogee. As anyone that keeps up with the subject will know, periodic phases of drought plagued the Assyrians throughout the Neo Assyian era – and even more so during the Middle Assyiran and earler periods. Hence, the claim that it was wet in the 9th and 8th centuries and unusually dry in the 7th is basically a misnomer (in the nitty gritty of history) but may possibly emphasize the severity of the drought in the second half of the 7th century. As the team used speleotherms we may wonder how exact they might be – which may account for missing out the well recorded droughts and civil unrest that litter the first half of the 8th and the bottom end of the 9th centuries BC. The result of course fits nicely into the modern climate change agenda which may also have coloured the conclusions.
It is all a bit simplistic to say that drought brought the Assyrian empire to an end. What we know from a historical point of view is that Ashurbanipal was extraordinarily successful in controlling the empire at its maximum extent but mid way through his reign, after about 642BC, he seems to have disappeared from public life. Why that was so has never been adequately explained – apart from the idea that it may be reflected in a Biblical story concerning Nebuchadnezzar. He is said to have vacated the throne for a number of years, wearing sackcloth. However, we have a record of all the years Nebuchadnezzar was active and he never at no time disappeared – but in contrast, Ashurbanipal did. We already know that the Hanging Gardens of Babylon story was based on Sennacherib's engineering feats at Nineveh and we also know the subsequent Babylonian Empire (until it was conquered by the Persians) was basically an extension of the Neo-Assyrian Empire (minus the Assyrian heartlands which seem to have been left in ruins). Therefore it is possible the story applies to Ashurbanipal – an equally impressive warrior king (in comparison to Nebuchadnezzar). If so we have to think in terms of a disease such as leprosy (or something similar) and perhaps wonder if an epidemic brought the population of Assyria to crisis levels (unable to man their armies adequately against the threats of the Medes and Babylonians, until then relatively easy threats for Assyria to contain). A combination of drought and an epidemic would explain the collapse much better than simply climate change – no matter how popular that meme may be in the modern world (or at least in the western world as most of the rest of the world are quite happy to ignore it). In addition, other factors may come into play as we don't really know what triggered the litter of droughts that punctuated history in Mesopotamia and the Levant during the first millennium BC. Neither do we know what kind of epidemic may have broken out – but it must have also affected other nations besides the Assyrians.
The article in Science Advances can therefore be seen as a useful addition to the historical perspective – but far from the final conclusion on what happened to bring about the fall of the Assyrians in such a dramatic fashion.