Yeah, and I imagine the sea-people as being something much cooler than simple pirates, 1500 BC vikings!
It would be nice to have a cause for the Bronze Age Collapse that accounted for the Sea Peoples. If they were a mixture of many groups speaking different languages and coming from many different coastal regions, we need a mechanism for setting them into motion. One possibility is that their various home lands are being invaded by other groups who have moved towards the Mediterranean. A possible problem with that sort of pressure is that places such as Crete, which the Bible suggests was the original home land of the Philistines, could only be invaded by sea. Thus we may be forced to postulate a domino effect amongst the Sea Peoples themselves.
Another possibility would be a sudden but widespread crop failure. Faced with famine, any group having ships and adequate military skills might be tempted to try to seize food or wealth to buy food from other lands. The initial poster assumed that climate change was the driving force which is possible. However, it is not the only possibility.
Several years ago I noticed that the suggested mechanisms proposed for causing the Bronze Age Collapse depended on the expertise of the proposer. Thus ex-soldiers proposed military innovations while geologists proposed earthquakes etc. As I was a biochemist, I felt inclined to propose a disease of wheat and barley causing widespread famine. The case of Egypt may or may not help. Before the collapse, grain is exported to the Hittites. Later we have graffiti from the Valley of the Kings complaining that the workers had not received their barley. However, the Egyptian collapse occurs later than the collapse of the Aegean Civilizations. It could be that we are seeing simply the success of Ramesses III in repelling the Sea Peoples. However, it might also fit a crop disease that did not arrive in Egypt until after it had caused famine to the north.
What is striking about the collapse is that the size and number of settlements around the Mediterranean falls and remains low for several hundred years. We are not just seeing a collapse of political structures or of literacy. This seems to fit explanations such as climate change rather than explanations involving military technology or migrations.