To draw any conclusions about long range climate patterns, a much longer time frame is needed, according to our Reference, Maps and Standards Librarian, Barbara Wojtkowski. Many more such maps, in sequence, along with other information is required. Interestingly, much of this information is freely available via the web.
Check out these resources:
- The Atmospheric Circulation Reconstructions over the Earth or ACRE initiative
- Bureau of Meteorology
- Monash University Library Map Collection