People are generally aware that their actions contribute to climate change, unless they choose to deny it for ideological reasons. They are just unwilling to make lifestyle sacrifices because of it. Most people value their personal comfort and the comfort of their family above the (statistical) lives of strangers.

You see exactly the same phenomenon every time a professional chooses to live in comfort instead of donating most of their income to charity. That's how people work, that's what they value, and that's why collective action is the only way of dealing with large-scale problems.