Although the global climate experienced a cooling phase of perhaps as little as one degree during the Little Ice Age), it had a large impact on agricultural production.
The cooling phase brought with it wet conditions and heavy rainfall, which shortened the growing season by up to two months.
The kinds of seeds growing at the time were not able to withstand the extreme changes in the weather, leading to a shortage in usable crops.
Wheat and rye experienced a significant drop in production across Europe.
Snow could be found on the ground late in the spring, encouraging the parasites that devastated crop growth.
There was also less hay to feed livestock, and straw or pine was used as a substitute.
Much of the livestock had to be slaughtered to feed starving nations, and famine began to spread around Europe.
Thanks to Bill Sellers for this link
This would make a good home-school primer, says Bill.