This will likely be completely ignorable by people outside of Iceland:

PSA: The pending Iceland eruption will not produce a colossal and long-lived ash cloud like the 2010 eruption of Eyjafjallajökull – you need an erupting into a glacier or ice sheet for that with this sort of magma – and it will have NO EFFECT ON THE CLIMATE WHATSOEVER.

(Dr Robin George Andrews, volcanology PhD)