When environmental philosophy began in the early seventies, global warming was unknown. Several early participants, concerned about the loss of species and habitats, rejected anthropocentrism, preferring biocentric or ecocentric theories. Anthropo-centrism then made a comeback, and many prominent environmental philosophers now espouse it. However, the discovery of systemic global environmental problems (including ozone-depletion as well as global warming) raises the issue of whether an anthropocentric ethic can tackle them adequately. So does the issue of cruelty to animals, the ethics of which seem to require a non-anthropocentric theory, albeit possibly one no more radical than sentientism. Sentientism, however, is open to a range of objections, including Val Plumwood’s charge of desensitized rationalism, which already suggests that biocentrism is preferable. Tackling global warming, for its part, requires principles of equity, which may well warrant authorizing equal entitlements to emit greenhouse gases to all living human beings, up to an agreed ceiling, which would itself be lowered in the course of time (Contraction and Convergence). Issues that arise (and that are now discussed) concern the compatibility of biocentrism with Contraction and Convergence, and also whether biocentrism makes a difference to the solution that is needed. It is concluded that Contraction and Convergence can be reconciled with biocentrism, and that biocentrism strengthens the case for fxing the ceiling for greenhouse gas emissions below the actual current level. Ecocentrism is considered as an alternative ethic, but reasons are given for rejecting it. Biocentrism, it is concluded, is intrinsically superior as an ethic, and signifcantly strengthens the case for strong international action on climate change.