Shadmar helped make the heat waves effect.
To tune the size of the wobbles you can decrease or increase these values :
Code: [Select]
textureUV.x += range*sin(time+textureUV.x*600)*0.001f;
textureUV.y += range*cos(time+textureUV.y*600)*0.002f;
For example decrease 600 to 200 or experiment with other values.