If you want to determine whether a war affects the global economy, examine a few things -- One being the GDP of involved countries, two being the total import and export products/volumes, and three being geographical locations (whether the country's near shipping corridors or critical airspace for flight logistics).
And so with that, it shouldn't pose that large of a threat. Israel has a high GDP, Palestine does not. And Israel could effectively wipe Palestine off the map if they wish.
Israel's calling this a "war" for PR purposes and to rally countries around them. Is it really a war when one side is so outmatched?