Using public surveillance cameras to detect evidence of climate change

Public cameras on Tate Britain wharf monitoring for purse snatchers (and possibly plant phenology). Image credit, AndyRob.Another strange but fascinating study looks at the use of emerging technology to conduct ecological monitoring in a way that would have seemed Orwellian a decade ago.

Eric Graham and fellow researchers from UCLA have tested out an approach of using public internet-connected cameras to monitor plant changes on a continental scale. The method may help scientists detect the signals of climate change.

Scientists believe that climate change may be causing shifts in the timing of plant phenology - i.e  the phases of plant A sample of public cameras used in the study. Credit, Global Change Biology.development such as flowering, budding, and senescence.

The monitoring of large-scale changes in plant phenology is typically done with satellite imagery, which can suffer from inconsistent quality due to cloud cover and other conditions making fine scale analysis challenging. Conversely, on-the ground monitoring is highly accurate but also very labor-intensive and prohibitively expensive to implement on a large-scale.

Graham and his fellow researchers hypothesized that the thousands of cameras associated with roads, airports, parks, etc. could be used to provide high-quality, low-cost monitoring of vegetation on a continental scale to detect changes in the onset of these plant phases.

While public cameras are installed with other objectives in mind - ensuring public safety, monitoring road conditions, etc - the images are often freely available online allowing researchers to commandeer them for other purposes.

The study authors tested out their approach by collecting twice daily images from over 1100 georeferenced public cameras across North America from February 2008 to 2009. They published their findings in the journal Global Change Biology.

They found that "public cameras had an equivalent or higher ability to detect spring compared with satellite-based data for corresponding locations, with fewer numbers of poor quality days, shorter continuous bad data days, and significantly lower errors of spring estimates."

They did run into some problems - mostly resulting from a lack of control over the cameras - such as widely varying image resolution; changed Internet addresses; removal of cameras; abrupt shifts in the view angle; etc.

Nevertheless the results are very promising and bode well for large scale ecological monitoring using public, internet-connected cameras. The authors write,

"Public cameras provide inexpensive, easily accessible, and high frequency monitoring (minute to daily image capture) at a wide number of locations, covering a much larger area than possible with traditional ground monitoring. Furthermore, active research in color detection, computer vision, and cyber infrastructure promises to streamline and automate digital camera-based monitoring in the future, further reducing human costs of field detection." 

--Reviewed by Rob Goldstein

GRAHAM, E., RIORDAN, E., YUEN, E., ESTRIN, D., & RUNDEL, P. (2010). Public Internet-connected cameras used as a cross-continental ground-based plant phenology monitoring system Global Change Biology DOI: 10.1111/j.1365-2486.2010.02164.x