Long-term changes in soil water tables over the past 4500 years: Relationships with climate and North Atlantic atmospheric circulation and sea surface temperature

A record of mean annual water table changes in England over the past 4500 y ears is derived from a transfer function applied to protozoan assemblages i n peat profiles. A 100-year running mean value based on three profiles show s short-term changes which are closely related to instrumental records of m ean annual temperature changes (past 300 yr) and documentary records of sum mer wetness and winter severity (past 900 yr). Long-term (> 1000 yr) change s in this composite record are positively correlated with the GISP2 ice acc umulation record, suggesting moisture budgets were in phase across the Nort h Atlantic region over at least the last 2000 years and probably changed du e to north-south movements of major pressure centres. This hypothesis is fu rther supported by comparisons with indicators of sea surface temperature a nd ocean circulation. Existing regional climate predictions may underestima te the impact of future warming on soil moisture status, with significant i mplications for agriculture and water supply in northwestern Europe.