Story · Europe map · about 4 min
Europe after dark
Satellites have photographed Europe’s lights at night since the 1990s. This tour uses the year slider on the lights layer to see where the lights came on, and why you should be careful what you read into a change from one year to the next.
Europe in 1992
In 1992 the lights are in the west. Counting a square as lit when it reads 12 or more on the layer’s 0 to 63 scale, about 27% of Germany’s 1 km squares were lit, 15% of France’s and 11% of Spain’s, but only 10% of Poland’s and 2% of Romania’s. These early years come from American weather satellites whose images blur, so towns look larger than they are.
The east switches on
By 2013, still the same satellite family, Poland reads 26% of its squares lit, Romania 8%, Bulgaria 7% and Hungary 13%, against 10%, 2%, 4% and 7% in 1992. Those old satellites are noisy from year to year (Poland reads 52% in 2010, 32% in 2011 and 44% in 2012), so trust the long climb more than any one year.
A drop that did not happen
Now drag from 2013 to 2014. Germany’s lit squares fall from 37% to 16%, France’s from 27% to 16%, Poland’s from 26% to 15%. Nobody switched off Europe: in 2014 the series changes from the old weather satellites to a newer instrument, converted to look like them, and the conversion does not match. Never compare years on either side of that join.
Since 2014, on one instrument
From 2014 to 2024 the series is steadier. Romania’s lit squares rise from 6% to 13%, Bulgaria’s from 7% to 15%, Spain’s from 18% to 26% and Portugal’s from 35% to 45%. Part of any rise can be lamps changing: LEDs give a different light, and the satellite sees it differently.
Ukraine, a lead and not a measurement
In Ukraine the share of lit squares was 5% in 2021 and 2% in 2024, the same instrument both times. Power cuts and damage since the war began in 2022 are one possible reason, but the layer cannot tell them from cloud, snow or fires. Treat it as a pointer for other sources to confirm.
For classrooms and curious minds
Questions to talk about, alone or in a group.
- Germany’s lit area appears to halve between 2013 and 2014. What changed, and what did not?
- Why is a share of squares above a cut-off a poor way to read one year against the next, and what would you look at instead?
Try it on the map: Switch on the lights layer, set 2013, then drag to 2014 over Germany. Then drag from 2014 to 2024. Which of the two changes would you trust, and why?
The figures above are calculated from the datasets listed on Data & sources and are approximate: many map layers are modelled or interpolated. Read each layer’s caveats on the map.