Utopian plan for weather-changing landscapes
Own initiative, in cooperation with Bart Bomas
Year: 2016
Published in Trouw newspaper
Interview on National Radio, Radio1
The climate changes, and almost everybody agrees that we have something to do with that. Fossil fuel, CO2, greenhouse effect, melting poles, floods, droughts and typhoons.
What almost nobody realises is that we influence the climate much more directly – by building cities.
Cities can increase rainfall, an effect that scientists call ‘urban rain’. When we look at the long term map of rainfall in the low and almost flat Netherlands for instance, we can distinguish both the scarce hilly areas of the Netherlands ánd the big cities such as Rotterdam and Amsterdam, as areas where it rains remarkably more than in the surrounding areas.
Cities are the Dutch mountains, and they have the same effect on the weather: the phenomenon that mountains push up humid air from the sea – which then cools down, condensates and turns into rain (orographic lift) apparently also applies to cities. The high buildings lift up the sea-winds, the relatively warm air in the city helps this upward drift, the turbulence created by the chaotic skylines increase the instability of the air and the dust from the city helps the moist to condensate. The effect: more rain on Rotterdam. Skyscrapers apparently literally tickle the clouds until they cry it out.
Unfortunately more rain was not something the Dutch were particularly waiting for, but we can think of many places on earth where a bit more rain would be more than welcome! The simple question is: if cities –like mountains – can make it rain, why not make cities –or mountains- where we want it to rain?
Let’s look at the northern coast of Africa, where the Sahara meets the Mediterranean Sea. Almost all of the green areas on the shores of Africa, where crops grow and orchards blossom, are on the feet of relatively low mountain chains. These areas supply the food for these nations. These hills, about 400 to 800 meters high, collect the moist from sea winds coming from the Mediterranean see, create rivers and irrigate the coast areas, making agriculture – and thus life – possible.
Other parts of the North African coast are not green at all; there the desert meets the sea. The hill ridges lower than 300 meter that lay here apparently aren’t high enough to create rainclouds. But the hills that do so are only two- or three-hundred meters higher!
So if we want the desert to blossom, if we want to turn useless land into food producing arable land, if we want to create new places where people could live – raising these just-not-high-enough-mountains by just some hundreds of meters could turn thousands of square kilometres of desert into new useful land.
Until now our influence on the climate is always seen as something bad or scary, and we shóuld be concerned. But in the mean time we influence the weather much more directly than we know – and we do nothing good with it. Well-positioned cities and artificial hills that bring rain and prosperity – that’s no scary geo-engineering, that’s doing what we always do, but than in a smarter way.
