Screenshot resolution settings for retina display

I just realized that screenshots taken on my Macbook Pro are saving at 144ppi instead of 72ppi because of the retina display. This is actually a major problem for my workflow. Is there any way to adjust the screenshot capture resolution to 72ppi? Simply pulling the image into Photoshop and reducing it by 50% is probably not ideal because it can create pixelation/blur/artifacts.

Notice also that if you take a custom sized screenshot using CMD+Shift+4 and draw your perimeter, that the pixel measurements are at 72ppi, but once you open the saved screenshot, your pixel dimensions are doubled. This actually really *****.

Any help would be much appreciated.