Risk maps for the occurrence of the Lyme disease vector Ixodes scapularis. Expansion of I. scapularis-affected CSDs in Canada from the present (using 1971–2000 temperature normals) to the 2080s (using the temperature conditions predicted by the CGCM2 climate model under emissions scenario A2). In Figs a to d, the 'slow' scenario, the model assumes that by the end of each time period, only risk CSDs with an algorithm value in the top 10% will contain an I. scapularis population. In Figs e to h, the 'fast' scenario, the model assumes that by the end of each time period, all CSDs within the 'moderate' risk zone for I. scapularis establishment (risk CSDs) contain an I. scapularis population. For both scenarios, the time steps are 2000 to 2019, 2020 to 2049, 2050 to 2079 and 2080 to 2109. The 'high' risk regions for I. scapularis population establishment are indicated in red, the 'moderate' risk regions are in orange, the 'low' risk regions are in yellow, regions with no risk of established populations but some risk from bird-borne 'adventitious' ticks are in green, and regions with no predicted risk of either are colourless.