Iceland has several likely future eruptors, Laki, Hekla, and Katla. Laki, a fisure volcano 17 miles long, in 1783 released 120 million tons of sulphur dioxide affecting the environment to France as recounted by Benjamin Franklin. Hekla released 3 cubic miles of ash in it's last eruption. Katla, an 18 square mile volcano, released 6+ cubic miles of ash and billions of tons of sulphur dioxide. Katla is the scientists next most likely eruptor in Iceland, it's overdue and is currently rumbling and the magma chamber is rising. If any of these do erupt their eruption will affect all of Europe and much of North America from the mason dixon line northward, the eastern portion mainly. There will be global consequences for sure if any of them erupt, lower global temps, but the immediate threats will be the sulphuric mists.