The tilt of the axis is why latitudes greater than 66° N don't receive any sunlight in the winter, or have any darkness in the summer. Earth currently makes a full rotation every 24 hours (the basis for our day). Higher angle (more direct) sunlight warms Earth more effectively. As around Shanghai, Jakarta, and Singapore, we seen a new urban form that in some cases even transcendsnational boundaries a city-region on a vast scale, networkedexternally on a global scale and internally over thousands of square kilometres.The angle at which sunlight hits Earth is one of the most important factors impacting the average temperatures in a region. The resulting city-region is highly networkedthrough its multiple nodes and links - but there is a recognisable urban hierarchy. The result in many large cities, observable over many decades, is an increasingly polycentricurban structure. City-regions are characterised by concentrated deconcentration- business activities disperse over the scale of the wide city region, but simultaneously reconcentrate at particular nodes within it. Some meeting places are clustered around transport nodes like airports.

Business activities may no longer need to be located in traditional CBDs (central business districts). Systems for electronic exchange allow business people to operate effectively up to about 2 hours' travel time from metropolitan cores (or major airports), conducting many exchanges electronically, but travelling to face-to-face meetings in these cores (and others).

Technologyand high-quality transportationnetworks are crucial. Therefore, polycentric global mega-city regions should be defined in terms of both their internal and externallinkages. Global cities are defined in terms of their externalinformation exchanges.

In global city regions: quizlet