Hi Jane. In as much as volcanic eruptions are suspect in part to have contributed to the “mini ice age” that started around 1300 and ended around 1850 they could also cause a drought, or at the very least help bring it about.

“The Little Ice Age witnessed remarkable volcanic activity with an average of five major eruptions per century that equaled the intensity of the Krakatoa eruption in 1883. Such episodes inject massive quantities of microparticles and gases into the atmosphere, causing massive dust veils that dim the moon and sun and affect global temperatures.”

“The ash content of a central Greenland ice core shows that the years of the Medieval Warm Period between 1100 and 1250 were quiet volcanically. Between 1250 and 1500 and between 1550 and 1700, however, there were many eruptions, including a massive one in 1600 at an unknown location.”

“Many scientists are sure that volcanic activity produced brief climatic extremes during the five cold centuries. They know the eruption of Mount Pinatubo in the Philippines in 1991 low­ered the world's average temperature by about one degree for two years.”

“They also point to 1816, "the year without a summer," as proof of the power of volcanic activity. Between April and June 1815, Mount Tambora, a volcano on the island of Sumbawa in Indonesia, erupted massively. The explosion was heard in Sumatra, sixteen hundred kilometers away. Only twenty-six of the island's twelve thousand people survived.”

“Ash clouds fell in Java, over five hundred kilometers away. Tambora was the largest volcanic eruption in modern times. The exploding volcano pumped into the atmosphere ten times the amount of ash produced by the notorious Krakatoa. Huge quantities of dust and sul­phur dioxide produced a reverse greenhouse effect, forming in effect a sunscreen around the earth. Europe and North America shivered in 1816.”

“Glaciers in the European Alps advanced vigorously. Snow fell in New England in June and July, crops failed throughout Europe, and famine was widespread.”

It is felt by some that we may be close to the “mini ice age? “The North Atlantic is dominated by the Gulf Stream – currents that bring warm water north from the tropics. At around 40° north – the latitude of Portugal and New York – the current divides. Some water heads southwards in a surface current known as the subtropical gyre, while the rest continues north, leading to warming winds that raise European temperatures by 5°C to 10°C.”

“But when Bryden’s team measured north-south heat flow last year, using a set of instruments strung across the Atlantic from the Canary Islands to the Bahamas, they found that the division of the waters appeared to have changed since previous surveys in 1957, 1981 and 1992. From the amount of water in the subtropical gyre and the flow southwards at depth, they calculate that the quantity of warm water flowing north had fallen by around 30%.”

“When Bryden added previously unanalysed data – collected in the same region by the US government’s National Oceanic and Atmospheric Administration – he found a similar pattern. This suggests that his 2004 measurements are not a one-off, and that most of the slow-down happened between 1992 and 1998.”

“The changes are too big to be explained by chance, co-author Stuart Cunningham told New Scientist from a research ship off the Canary Islands, where he is collecting more data.” "We think the findings are robust." Take Care…Don in creepy town

http://www.whoi.edu/institutes/occi/currenttopics/ct_abruptclimate.htm

http://www2.sunysuffolk.edu/mandias/lia/little_ice_age.html

http://66.102.7.104/search?q=cache:x36eUqQJZtYJ:williamcalvin.com/readings/Fagan%25201999%2520chapter%2520on%2520LIA.htm+volcanic+eruptions+ice+age+1300+-+1850&hl=en