Long-term climate moderation is commonly attributed to chemical weathering; the greater the temperature and precipitation the faster the weathering rate. To test this widely-held hypothesis, we performed a field study and determined the weathering rates of eight nearly pristine north-east Iceland river catchments with varying glacial cover over 44 y. Statistically significant linear positive correlations were found between mean annual temperature and chemical weathering in all eight catchments and between mean annual temperature and mechanical weathering and runoff in seven of the eight catchments. The runoff, mechanical weathering flux, and chemical weathering fluxes in these catchments are found to increase from 6 to 16%, 8 to 30%, and 4 to 14%, respectively, depending on the catchment for each degree of temperature increase. Positive correlations were found between time and mechanical and chemical weathering for all catchments. In summary, these results demonstrate a significant feedback between climate and Earth surface weathering, and suggest that this weathering rate is currently increasing with time due to global warming. © 2008 The Mineralogical Society.