Bohemians live in alternative spaces, these are places that are not normally considered suitable for living in. They don't make wealth their priority. Money is only a means of survival, so they can live for their arts/craft/music/literature...etc.
What causes ice-ages? Fluctuations in the amount of insolation (incoming solar radiation) are the most likely cause of large-scale changes in Earth's climate during the Quaternary. In other words, variations in the intensity and timing of heat from the sun are the most likely cause of the glacial/interglacial cycles.
As the last Ice Age ended, the Antarctic ice sheets began to melt. This caused waters to rise, drowning previously raised sections of the continents. The moving water gradually heated up and caused a rise in the temperatures of many different areas, creating the beginnings of the climate enjoyed by humans today.