Our benefactors at Google were kind enough to make Google Earth Pro available for free. Just agree to the terms here and get the version that works on your system. Just use your e-mail and GEPFREE as the license key to start working.
Firstly make sure that you have the correct settings (Look under Preferences… in the Google Earth Pro Toolbar Menu. Here are mine:
You can customize the settings to your needs but ensure that the Terrain settings are the same as mine. Also ensure that the Terrain layer is turned on under the Layers box. You can turn the other layers off.
Then navigate to the area you want to consider. I wanted to look at Auckland, New Zealand.
Next, download this image file that I made. You could use any image file but this one is blue and square, which is perfect for our application. Then you need to insert this image onto the map using the Add Image Overlay tool in the toolbar at the top. That’s the one on the Left in this picture:
If everything looks good press OK. The map will look a bit splotchy but as soon as you zoom in the terrain data should resolve and the border between the land and the new sea-level should become clear.
This method is “quick & dirty”. The terrain data used in Google Earth is not super accurate. Also, I will leave the research up to you, dear reader, to determine what scenario of sea level rise is the most accurate. It works well for sea-level rise in the double digits but single digit rise does not even register above the inaccuracy of the terrain data. At some future date I will describe how to determine the sea-level rise more accurately using digital terrain data.