Views of the World at Night

The Sendai earthquake in Japan sparked a debate about sustainable energy supplies of industrialised countries – with a controversial discussion about the safety and sustainability of nuclear power. The book ‘Sustainable Energy – without the hot air‘ by David MacKay is an outstanding read in this regard, outlining the all key issues that matter for our future energy need (the digital version is free, although I recommend the paperback which can even be read without wasting any electricity).
Switching the lights off was not a matter of choice for many people in the North of Japan after the devastations of the earthquake also affected the energy supplies (not only because of the Fukushima accident, but also because of a widely destroyed basic infrastructure). Another image featured in the NASA Earth Observatory takes a closer look at the electricity losses that occurred after the Earthquake by creating a composite image of two images of lights observed in 2010 and after the earthquake at March, 12 this year. As a highly industrialised country, the illuminated areas in Japan usually show the places where people live (see worldmap below), while dark areas are the unpopulated regions, hence the reprojection on a gridded population cartogram results in a dominantly bright image. Using NASAs display of the electricity losses therefore gives a good representation of the number of people affected by the power losses (and largely also the Tsunami and Earthquake itself) in the Northeast: The redrawn version of the image shows these as the red areas, while the brighter yellow areas in the South and West show the regions that has a similar illumination compared to the previous image. This is how ‘Japan at Night’ looked after the 2011 Earthquake:

Japan at Night after the 2011 Earthquake displayed on an Equal Population Cartogram
The colours shown here are explained in more detailed by NASA as follows:

This composite image compares observations after the earthquake to images of lights observed in 2010. Yellow indicates lights that were functioning in both 2010 and 2011, and includes Tokyo and areas to the south and west. Red indicates power outages detected on March 12, 2011, compared to data from 2010. Areas of power loss include Sendai, and coastal locations north of Tokyo. Blue indicates clouds, and that blue also tints some of the yellow-lit areas to green. Magenta (visible south and west in the large image) indicates lights obscured by clouds. Bright green spots also may indicate new lights detected in 2011 that were not observed in 2010; some are visible in coastal areas north of Sendai. (Quoted from NASA)

The above map should not be interpreted in too much detail: The resolution of the underlying population grid does not match the resolution of the original composite image, and especially in the southern region the georectification is inaccurate (note the slight offset there). It should be taken as a general view and is meant to highlight the relation of impact of power losses in the North to the population. A more detailed version of the Japanese Population Cartogram is featured on the page about Global Earthquake Intensity which shows the population distribution in relation to Japan’s topography in very high detail (and precision). That page also shows a map of global earthquake risks in relation to population.


These views connect to WWF’s Earth Hour campaign which takes place around the world today. It is a symbolic event that serves as a reminder that earth is a planet with limited resources. Earth Hour has become very popular since it has been launched in 2007, although one may criticise that it is of very limited use, while the international community struggles to find global solutions for the environmental problems. Especially those countries that consume most (not only from their own resources) find it hard to change their way of life, while a large number of people on the planet has very limited access to this wealth. My redrawn version of the Earth At Night shows this is a very striking way: The night lights that can be seen from space are not those places, where people live, but those places, where people live who can afford to have light at night. Many people in the poorer countries live in darkness, while the affluent world illuminates the night sky. It is those people who are asked to switch off their lights and reflect on their way of life and work on solutions for a better and fairer planet.
The following little interactive map shows the redrawn earth at night map which uses the iconic NASA night view of the planet projected onto a gridded equal population cartogram – as many maps on this website, that means that each person living on the planet has the same amount of space on the new map, while the geographic reference is retained by the underlying grid. The slider that appears in the image allows to compare that map to a pure depiction on the gridded population cartogram without the lights – which is the view how the world probably looks during Earth Hour tonight. The slider can be moved to show each of the maps in full extent (See here for an updated and more detailed version of this map):

Dividing line on/off

While Earth Hour is about raising awareness for sustainability, there is another campaign that connects to the Earth at Night map and coincides with Earth Hour: The GLOBE at Night campaign 2011 runs from March 22 – April 4 for the Northern Hemisphere and March 24 – April 6 for the Southern Hemisphere. Like Earth Hour, this campaigns is also backed by the International Dark-Sky Association. This is what it aims to achieve:

With half of the world’s population now living in cities, many urban dwellers have never experienced the wonderment of pristinely dark skies and maybe never will. Light pollution is obscuring people’s long-standing natural heritage to view stars. The GLOBE at Night program is an international citizen-science campaign to raise public awareness of the impact of light pollution by encouraging everyone everywhere to measure local levels of night sky brightness and contribute observations online to a world map (find this and more information on http://www.globeatnight.org/).

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