How the earth has changed: decades within a "timelapse"

The most popular satellite image viewing service on Earth, Google Earth, has added a new Timelapse function which allows users to observe how large areas of land have changed over recent decades. This feature allows users to select a geographical area and view satellite images of it collected over more than 35 years - archived and mapped by Google itself.

Timelapse can be used, on the one hand, to research specific areas of the planet; on the other, to observe a selection of location chosen by Google and divided into thematic areas. It’s possible, for example, to observe the territorial changes that occur due to deforestation, mining and the construction of new infrastructure grids, as well as the effects of climate change on glaciers; at the same time, it is also possible to observe this decade-long evolution in certain metropolises, such as Osaka, Beijing or New York, among others.

To create Timelapse, Google added about 24 million satellite shots to its service, collected over a period of time between 1984 and 2020. The images were then blended and superimposed over each other, so that the locations matched up in their evolution. The images from the early 1980s are less clearly defined than the more recent ones, but we can still observe and appreciate the continuous changes in the area, particularly on a large scale.

A function similar to the current Timelapse did already exist previously, but more complicated to use and more limited on the service’s browser format. The new feature, which was launched in mid-April 2021 for Earth Day, was also made possible by the availability of numerous public domain satellite images provided by Earth observation programmes and consortia to study Earth from space, such as Landsat from the US and Copernicus from Europe.