ABSTRACT
Evidence for environmental change is widespread and commonplace. At the level of the individual we can all remember sequences of good or poor summers, and harsh or mild winters, while the view that over the span of several generations such variations have been considerable amounts to more than mere nostalgia for long hot summers and white Christmases. At a broader scale still, landscapes in many parts of the British Isles exhibit evidence for glacial erosion of a kind found today only in polar or alpine regions, while the exposure of submerged forests at low tide testifies to formerly much lower sea levels (plate IXa). More subtly, the present and past distribution of plants and animals can monitor climatic changes in quite a precise way. For example, the present distribution of the dwarf birch (Betula nana) is confined to the area where maximum summer temperatures do not exceed 22°C, namely the highlands of central and northern Scotland. However, fossilized grains of pollen found in lake sediments have shown that 11,000 years ago dwarf birch had a more widespread distribution which extended into southern England (fig. 5.1). Bones of reindeer (Rangifer tarandus), the quintessential animal of the tundra, have been found in cave deposits in Staffordshire dated to 10,000 years ago.
