This world we live in - Susan Pfeffer

It's been a year since a meteor collided with the moon, catastrophically
altering the Earth's climate. For Miranda Evans life as she
knew it no longer exists. Her friends and neighbours are dead,
the landscape is frozen and food is increasingly scarce. Mirand
and her family are on the edge. And then a small party of surviors
arrives on their doorstep, threatening to stretch supplies to
dangerous limits. Alex Morales is amongst them, and he and Mirada
must put aside their differences in order to fight for food -
with all of the odds against them...