Yes there is. The evidence is that people - most people - claim to experience it. That is subjective, but all measurements are ultimately subjective: when I read a thermometer, I cannot "prove" that the thermometer is actually there, and that I am not in a simuation that contains a thermometer.

The near universal claim of conscious experience is not proof of what consciousness is; but it is nearly irrefutable proof that there is _something_ to consciousness.