The Fifth Mission Statement urges the Anglican Church to be, or become, involved in the world-wide effort by all thinking people, of any faith or none, to find workable ways to alleviate the global environmental crisis. As it stands, however, the Statement is an incompatible mixture of contemporary scientific and religious environmental concern set against a Biblical background that had no such concern. Therefore, public exhortations based on the Fifth Mission Statement taken at face value are unlikely to succeed, especially if addressed to secular audiences. The environmental crisis is a moral issue, because it concerns the process of reaching communal decisions about the allocation between competing groups of common resources in short supply, such as finance for conservation, access to forests, fisheries, clean water, clean air, etc. The relevant context for understanding the moral dimensions of environmental protection must include contemporary biological and philosophical knowledge, because we need to understand what decisions are required, and the origin and nature of the ethical context of those decisions, as well as the reasons why so many people ignore the interests of the environment on which we all depend. In this thesis I have explored some ways in which the insights of secular science can be incorporated into the Fifth Mission Statement, which will help Christians make a constructive contribution to the secular debate. From economics we can learn why the current free-market model is so subversive and why management of environmental common goods is so difficult; from game theory, why the personal restraint for which green activists plead is often not rational, except within the context of stable community life; from primatology, what are the evolutionary and social bases of morality and intelligence; from anthropology, how the combination of intelligence and socially-mediated morality as a conditional strategy has coaxed our primate and tribal human ancestors over time from rampant xenophobia through cautious trading of goods and ideas through to the philosophical analysis of true human ethics. The biological account of the origin and general operation of morality is very different from the theological and philosophical one, but is backed by a large and growing body of empirical evidence. It must be considered by any moral exhortation intended, like the Fifth Mission Statement, to be credible to non-Christians. The Christian understanding of true altruism (charity) remains a matter that goes beyond biology and into the realms of grace. An updated Christian theology of creation, and further development of the Fifth Mission Statement along these lines, will arm the Church to play a leading role in the environmental debate. Christian theologians should be among the very first to respond to E.O.Wilson's call for consilience between all branches of learning (Wilson 1998), since the unity of all knowledge is an ancient belief of the Church. Rational, passionate and updated Christianity could make a real contribution to developing some solution to the environmental crisis, to the extent that any solution is possible: otherwise, it will remain, as in the past, part of the problem.