Coming out of lurking hole on this one again... AHH ITS BRIGHT OUT HERE!

Going to possibly cause some paradoxical effects with with suggestion so I apologize.
If we do literally go into the past... we would usually take away time being linear unless we throw in the possibilty of Destiny and gods that aren't subject to our physical laws.
So if it was always our destiny to go into the past and be there at those echo moments, nothing was changed, we were always there since that moment existed. Therefore the axe-swing in an Echo wont cause a hurricane in the present. Hope that made sense.
I'm sure there are 1000 examples of why this wouldn't work... but I thought I'd share it anyway.