The region around the rivers Krems and Kamp with sites such as Stratzing-Galgenberg, Krems-Hundssteig, Krems-Wachtberg, or Kammern-Grubgraben is a key area of Upper Palaeolithic research, also thanks to the works of Christine Neugebauer-Maresch. Being part of an important hotspot of human activities in Lower Austria and Moravia, its occupation took place in a larger context of environmental change and demographic dynamics, receiving and sending developmental impulses with consequences for the cultural evolution of the region and beyond. This lecture presents regionally resolved demographic estimates from the Atlantic Ocean to the Black Sea with a special focus on Lower Austria and Moravia in seven consecutive periods between 43 and 12 ka. These estimates will be discussed against the background of environmental data, such as the start and length of the vegetation period, or spatial differences in the greening of the landscape in spring. By taking a multi-scale perspective and shifting between local, regional and supra-regional patterns of environmental, demographic, and cultural developments, the lecture explores the observable relations between (i) changing climatic conditions, (ii) the in- and decreases in size and density of human populations as well as their distribution and connectivity, and (iii) the material culture evolution of Upper Palaeolithic hunter-gatherers in Europe and the region of lower Austria and Moravia in particular. In so doing, general trends and their regional exceptions in environmental conditions will be made visible and discussed in terms of potential consequences for the distribution of hunter-gatherers, growth and disintegration of communication networks and, eventually, cultural evolution.