In June 2014, the Supreme Court of Canada held that Aboriginal title should be granted to the Tsilhqo'tin Nation over a portion of its traditional territory in British Columbia.1 This was the first time that a Canadian court had granted Aboriginal title to a specific land area. The court noted that Aboriginal title is collective title held for present and future generations and that, consequently, the land cannot be developed in a way that would "substantially deprive" future generations of its benefit. The court also noted that a government seeking to use Aboriginal title land for development or other purposes must seek the consent of the title holders; if the title holders do not give their consent, the government must establish that the proposed use is justified under Canada's "Constitution Act, 1982." These norms give Aboriginal title holders a prima facie legal right not to have their land used by the government for development or other purposes without their consent, or so I argue. I then turn to the United Nations Declaration on the Rights of Indigenous Peoples. Several UN member countries, including Canada, did not sign the Declaration when it was approved by the General Assembly in 2007. Canada had concerns about provisions which it interpreted as giving indigenous peoples a "free, prior and informed consent" veto over state measures affecting their land. I argue, partly by reference to recent work on consent by the Oxford philosopher Derek Parfit, that indigenous peoples occupying ancestral lands within the borders of a broader state should not be treated as having a veto over state use of their land, but should be treated as having a prima facie moral right that the state not use their land without their consent. This right, being prima facie, can be overridden. I propose a set of candidate override conditions which, I claim, would be considered plausible if judged from the perspective of an ethic of sustainable development broadly conceived in a way I outline. These conditions are based in part on those that the "Tsilhqot'in" judgment says the state must show to be satisfied if it is to be justified in using Aboriginal title land for development or other purposes in circumstances in which it has consulted with the title holders but they have not consented to the proposed use. [This is a revised version of a paper presented at the Oxford Round Table's "11th Annual International Session on Environment, Climate Change, and Global Warming" held at Harris Manchester College, University of Oxford, July 22-25, 2015.]