Species and populations need to adapt to recent global environmental change. Thisimplies that body size and color might change due to changes in the environment. Inthis study I examine whether and how body size and melanism vary among andwithin old and contemporary populations of the peppered moth, Biston betularia. Ihypothesize that 1) individuals should be large and dark in cold climates and smalland light in warm climates (since large individuals have a higher thermal inertia anddark individuals have low reflectance) - as has been stated by the temperature sizerule and postulated by the thermal melanism hypothesis. 2) In accordance with thepredictions of industrial melanism there should be a higher degree of melanism inold samples and within populations located in proximity of industrialized areas.Data was collected for 15 populations in Denmark and southern Sweden from twotime periods (1952 to 1977 and 2018). Wing size (measured as male wing area) anddegree of melanism (measured as male wing darkness) were compared within andbetween populations, within and between time periods, and along a latitudinalgradient. I found that size and melanism were not associated. Size decreased withincreasing latitude, and size did not change over time. Populations were lighter athigher latitudes in old samples but did not differ in darkness according to latitude inrecent samples. In summary, populations have become brighter and brightness doesnot change with increasing latitude in contemporary populations. Size isindependent of time and latitude. I conclude that populations have become lighterand environmental change is probably driving populations to change in darkness tobe better suited for non-polluted environments.