If consciousness is the ability to perceive and feel, then all life is conscious. If, however, consciousness is the ability to conceive of one self and have subjective experience, then only humans are “conscious.” But that doesn’t mean human consciousness is special in any way. Despite becoming extraordinary, it could have been quite ordinary in origin.
Consciousness didn’t evolve as the ability to conceive of one self; it evolved as the ability to conceive of how others conceive of oneself. This ability was naturally selected for to improve social relations in tribal communities, as it was a survival advantage to both the individual and the tribe. Self-consciousness only arrived as a byproduct to other-consciousness. With the ability to think of what others are feeling, we inevitably think about what we were feeling ourselves.
From this ability of consciousness came all the good and bad of humanity: the art and the anxiety, the love and the depression, religion and science, existential wonder and dread, and the ability to contemplate the origin and purpose of consciousness.
Over time, consciousness essentially devolved into over-consciousness of oneself and existence and the inevitability of death. Religion and supernatural beliefs emerged as a means to cope with the existential crisis brought on by consciousness.
Humans are currently the only life form on Earth with this ability, but there's no reason AI can’t eventually become conscious as well. Trying to program consciousness from scratch may be near impossible, but much easier may be simply copying the human brain and genome then uploading it into digital form.
We may not yet (or ever) know the hard problem of how consciousness arises in the human brain, but we need not know the how or why. As long as we know consciousness exists in the brain, we can simply copy the brain and upload it into a computer. Then, that consciousness will exist digitally and can be copied into any machine.
AI may never gain consciousness on its own, but human consciousness can, in a sense, become AI.