Yesterday I read a post on LifeHacker describing the newest release of Google Earth. A video offered within this site describes new features available in version 5.0. You can locate the download at the Google Earth site. A new feature I found intriguing allows the investigation of changes over time.
Rather than duplicate the examples discussed, I wanted to test the tool using a situation I have experienced. I happen to be watching a local outdoor show a few days ago. The guest was a resort owner from Devils Lake, North Dakota, who was talking about the interesting history of the lake. He described the tremendous changes in the level of the lake that have occurred over time and told his own personal story as a short term example. He described working at the Creel Bay boat launch as a youth. At the time it was one of the few locations on the lake where you could rent a boat or purchase bait. He described that the facility was now gone as the location was submerged in the rising waters. This caught by attention. When I first came to North Dakota 30+ years ago a few colleagues from the department and I would go fishing from the Creel Bay marina in the summer. My brother later moved to Devils Lake and lived near this location. He left the area and I stopped taking trips there, but I knew the story of the rising waters.
I decided to examine this phenomena using Google Earth. My strategy was simply to locate Devils Lake in Google Earth and capture a picture of the area. Without changing the area shown, I using the “clock” tool to change the date and attempted to capture the same area of the map. 
Recent image (2005)
Older image (1997)
I found my assumptions regarding how easy this would be were somewhat naive. It turns out you cannot find images for any given date. The most recent I could locate for Devils Lake were from 2005. The images were generated by different organizations. I also assume that the time of year the images were taken would influence what was observed. In other words, precise control was not possible. However, if you look carefully, you can detect change. I have identified a common area in a small section of map that shows how a greater area of land is submerged in the more recent image. Science is like this – it is difficult to control all variables and demonstrations are often more difficult to produce than one expects. This is a very interesting tool and certainly available for personal experimentation.
More information describing Devils Lake is available online.
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