Volcano will probably not effect climate, unless...

Unless it gets bigger and lasts a lot longer.

http://www.climatecentral.org/breaking/news/icelandic_volcano

The ongoing eruption of Mt. Eyjafjallajokull in Iceland is disrupting flights across Europe, shutting down some of the busiest airports and aviation corridors in the world. But could it also disrupt the climate system, leading to a temporary cooling trend this summer?

Not likely, according to Rutgers University environmental sciences professor Alan Robock, an expert on how volcanoes alter the composition of the Earth’s atmosphere. According to Robock, the Icelandic eruption hasn’t contributed enough sulfur dioxide to the upper atmosphere to significantly alter the climate.

“From what I’ve seen from the observations so far, there hasn’t been enough put into the atmosphere to have a large climate effect,” he said in a telephone interview.