Repeat photos show change in southern African landscapes: a citizen science project


Paper by Timm Hoffman and Hana Petersen: “Every place in the world has a history. To understand it in the present you need some knowledge of its past. The history of the earth can be read from its rocks; the history of life, from the evolutionary histories and relationships of its species. But what of the history of modern landscapes and the many benefits we derive from them, such as water and food? What are their histories – and how are they shifting in response to the intense pressures they face from climate change and from people?

Historical landscape photographs provide one way of measuring this. They capture the way things were at a moment in time. By standing at the same place and re-photographing the same scene, it is possible to document the nature of change. Sometimes researchers can even measure the extent and rate of change for different elements in the landscape.

Reasons for the change can also sometimes be observed from this and other historical information, such as the climate or fire record. All of these data can then be related to what has been written about environmental change using other approaches and models. Researchers can ascertain whether the environment has reached a critical threshold and consider how to respond to the changes.

This is what repeat photography is all about…

The rePhotoSA project was launched in August 2015. The idea is to involve interested members of the public in re-photographing historical locations. This has two benefits. First, participants add to the number of repeated images. Second, public awareness of landscape change is raised.

The project website has over 6,000 historical images from ten primary photographic collections of southern African landscapes, dating from the late 1800s to the early 2000s. The geographic spread of the photographs is influenced largely by the interests of the original photographers. Often these photographs are donated to the project by family members, or institutions to which the original photographers belonged – and sometimes by the photographers themselves….(More)