I believe that potentially catastrophic events should always be viewed with caution. If possible, there should be technology and political resources reserved specifically for the purpose of avoiding or minimizing the impact of foreseeable disasters. 40 years from now is not an extremely distant future; the next generation will be severely impacted by this eruption.
Iceland sits atop a number of volcanos, and it is not unusual for one to erupt. Eruption of a volcano is a natural disaster, and citizens of Iceland need to be warned adequately, just as is done in other parts of the world for disasters such as hurricanes, tornadoes, and earthquakes. In addition, air travel in Iceland would be greatly affected and with more warning could be rerouted in a more organized manner.
The whole point of a warning system is that it picks up on tremors amd underground activity and gives people suficient warning so they can evacuate the area and avoid loss of life. The volcano in question has displayed a fairly regular pattern of eruptions and although the next one is by no means certain, seismologists are monitoring the area closely following two recent earthquakes.
The volcano warnings in Iceland are working just fine if we know that the largest volcano is getting ready to blow up. There's really not much that you can do other than get out of dodge until the whole thing is over. Hopefully takes heed of the warning and remains safe.