<I will take a candle and light it, then I will put my finger in the flame and keep it there until I can no longer stand the pain, then I will find a source of gamma radiation and will keep my finger in front of it until I can no longer stand the pain. After that I can compare the two fingers and see if there is any difference in the way they have burnt. That experiment should prove to me that the type of energy used to create heat makes no difference as far as the molecules of my body are concerned.

Ok, let me put it to you this way. If you are in the presence of a gamma source that can 'heat' your finger on the same time scale of a candle, charred finger if the LEAST of your worries.

A gamma ray is a high energy photon which will ionize molecules and can alter large organic molecules like DNA and other cellular constituents. In this case, let me be the first to plead, DO NOT PLAY WITH WHAT YOU DON'T UNDERSTAND! It's more complicated than you seem to understand, when dealing with biological systems.

In the atmosphere, it doesn't make a whole hell of a difference. If you ionize a Nitrogen molecule, it may pick up some speed and then and electron to neutralize, big deal.