[hirundo]

> Why would objectivist care about climate change which will have effect in 100 years, but requires them to sacrifice something today?

Because one of the selfish personal goals of an individual is the thriving of their progeny. Heinlein defined love as the state in which another person's happiness is essential to one's own. Thus one can be utterly selfish during a single minded pursuit of another's happiness, because your own happiness depends on it.

It is typical of our species to sacrifice your own body's needs to achieve the intensely personal goal of making your childrens' lives better. This can be interpreted as a form of selflessness, but I see it as Randian selfishness, where the self is an extended phenotype that can encompass multiple organisms.

In this sense, altruism is about sacrificing to help others that you do not love.