In The Giver, what evidence suggests that Jonas and Gabe do/don't survive the ending?

It is important to realise how the ending of this
excellent novel is completely ambivalent: Lowry seems to not want to give any clear
indication either way as to whether Jonas and Gabe survive or not. Note how they are
absolutely exhausted and cold, and as Jonas starts on the final sledge ride he feels
himself "losing consciousness." As they go down on the sledge to "the Elsewhere that
held their future and their past," the fact that Jonas had always felt this place
waiting indicates that it could be a possible afterlife. Certainly the hearing of music
at the end suggests some kind of supernatural destination, which could be what happens
to them after their death.

However, at the same time, the
destination is also described in concrete terms:

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He forced his eyes open as they went downwards,
downwards, sliding, and all at once he could see lights, and he recognised them now. He
knew they were shining through the windows of rooms, that they were the red, blue and
yellow lights that twinkled from trees in places where families created and kept
memories, where they celebrated
love.

Jonas feels sure, from
this quote, that they are headed to a concrete destination, where, unlike the community
he has just fled, memories are kept and cherished, and where love exists. The way that
Jonas hears music from "behind him," from "the place he had left," could suggest a happy
ending for the community to, that somehow Jonas and Gabe are able to transform their
home into the kind of place where they are heading to.

At
the end of the day, however, you need to take your pick about what you think happens at
the end of this story. The author provides us with enough evidence to suggest both
endings. What do you think?