Climate Change poses serious threats not only to humans but also to non-human animals, plants and microorganisms. For example, increased levels of atmospheric CO2 caused by human emissions are likely to cause increased ocean acidification, a severe threat to coral reef ecosystems and the organisms that rely on those ecosystems. Is this likely result of human emissions morally significant? Do humans have a moral obligation to avert such harms to non-humans?
One’s answers to these questions depend on which entities one thinks deserve moral consideration. One might hold that only humans deserve moral consideration. However, ethicists such as Peter Singer (for example, in this article) argue that limiting moral consideration to humans is arbitrary and analogous to racism and sexism. Instead, Singer suggests that all entities capable of feeling pleasure and pain deserve moral consideration, which means that the suffering of non-human animals (but not plants) is ethically significant. On this view, humans have a moral obligation not to harm animals, which implies that humans should avert increased ocean acidification as caused by CO2 emissions.
But why should the capacity to feel pleasure and pain be the criterion of what deserves moral consideration? Others (for example, Paul Taylor) suggest that plants deserve moral consideration as well, because they are living entities with goods of their own, and it would be arbitrary to respect some entities’ goods (for example, those of human and non-human animals) while not respecting other entities’ goods (for example, plants).
Despite this disagreement, both Singer’s and Taylor’s accounts seem to converge in implying that humans have a moral obligation to avert increased ocean acidification. Whether this is for the sake of animals alone (Singer) or for animals and plants (Taylor), both positions imply that humans should avert increased ocean acidification because it threatens entities that deserve moral consideration. Of course, one might deny that any non-human deserves moral consideration, but then one should show how this position is not a case of arbitrary discrimination against non-humans, and it is not clear how this challenge might be met.