Earth will be uninhabitable not long into the future on an evolutionary timescale. Without action from humans, oceans will boil away within 1 billion years due to the increasing brightness of the sun, and most life will likely die off within about half of that. So in some sense, the suffering of animals will not be for much longer compared to history.

Humans will need to either learn to:

- Terraform the Earth and keep it cool -- this can keep the Earth habitable for maybe 1-2 billion years at most instead of a few hundred million which is the current expectation. After that it will be of no use and the sun will eventually engulf the Earth in ~4 billion

- Not rely on other species or the oceans to survive, and find artificial ways to manufacture food

- Evolve into (i.e. develop) an intelligent but inorganic life form that can withstand higher temperatures and carry on the legacy of intelligent civilization

- Move to Mars or beyond, terraform it, and take animals with us

Considering the complex inter-dependencies of various species (e.g. humans need to eat plants, plants need insects and worms but their numbers are kept in check by birds, birds need huge plants to reproduce, plants also need to eat shit from animals, animals need yet other plants to make said shit, etc.) I have most hope in creating an inorganic lifeform that can reproduce given only light and raw materials available on planets, and without dependence on other life forms.