ABSTRACT
Climatic changes come on several different timescales. Between short-term fluctuations lasting a few years such as El Niños, and changes extending over thousands of years such as glacial and interglacial periods, there are variations over a few centuries that may have profound effects on natural phenomena and human affairs. It is variations on this scale, stretching over several generations, with which we are mainly concerned in studying the Little Ice Age. It was a period that may be seen as beginning in the thirteenth and fourteenth centuries (Porter 1986, Grove 2001b) and culminating between the mid sixteenth and the mid nineteenth centuries when glaciers were bigger than they were in the twentieth century or had been in the tenth to twelfth centuries. It was also a period of lower temperature over most of the globe, sufficiently marked to have had important consequences, especially in certain sensitive areas in high latitudes and at high altitudes where conditions for plant growth and agriculture are marginal.
