Too often in recent decades, the two big "e" words -- ecology and economy -- have been used as though they represented opposing concerns. Yes, we should be glad to do more about the environment, if only this didn't interfere with economic development and the liberty of people and nations to create wealth in whatever ways they can.

Or, we should be glad to address environmental issues if we could be sure that we had first resolved the challenge of economic injustice within and between societies. So from both left and right there has often been a persistent sense that it isn't proper or possible to tackle both together, let alone to give a different sort of priority to ecological matters.

But this separation or opposition has come to look like a massive mistake. It has been said that 'the economy is a wholly-owned subsidiary of the environment'. The earth itself is what ultimately controls economic activity because it is the source of the materials upon which economic activity works.

That is why economy and ecology cannot be separated. Ecological fallout from economic development is in no way an 'externality' as the economic jargon has it; it is a positive depletion of real wealth, of human and natural capital. To seek to have economy without ecology is to try to manage an environment with no knowledge or concern about how it works in itself – to try and formulate human laws in abstraction from or ignorance of the laws of nature.

It is time to look seriously at the full implications of this. We need to start by recognising that social collapse is a real possibility. When we speak about environmental crisis, we are not to think only of spiralling poverty and mortality, but about brutal and uncontainable conflict. An economics that ignores environmental degradation invites social degradation – in plain terms, violence.

It is no news that access to water is likely to be a major cause of serious conflict in the century just beginning. But this is only one aspect of a steadily darkening situation. Needless to say, it will be the poorest countries that suffer first and most dramatically, but the 'developed' world will not be able to escape: the failure to manage the resources we have, has the same consequences wherever we are. In the interim, we can imagine 'fortress' strategies (with increasing levels of social control demanded) struggling to keep the growing instability and violence elsewhere at bay and so intensifying its energy.

And we are not talking about a remote future. There are arguments over the exact rates of global warming, certainly, and we cannot easily predict the full effects of some modifications in species balance. But we should not imagine that uncertainty in this or that particular area seriously modifies the overall picture. On any account, we are failing.

It is relatively easy to sketch the gravity of our situation; not too difficult either to say that governments should be doing more. But governments depend on electorates; electors are persons like us who need motivating. Unless there is real popular motivation, governments are much less likely to act or act effectively; there are always quite a few excuses around for not taking action, and, without a genuine popular mandate for change, we cannot be surprised or outraged if courage fails and progress is minimal. Our own responsibility is to help change that popular motivation and so to give courage to political leaders. And this means challenging and changing some of the governing assumptions about ourselves as human beings.

One of the reasons sometimes given for not being too alarmed by predictions of ecological disaster is that we are underrating the possibilities that will be offered by new technologies. But to appeal to a technical future is to say that our most fundamental right as humans is unrestricted consumer choice. In order to defend that, we must mobilise all our resources of skill and ingenuity, diverting resource from other areas so that we can solve problems created by our own addictive behaviours. The question is whether, even if this were clearly possible, it would be a sane or desirable way of envisaging the human future.

All the great religious traditions, in their several ways, insist that personal wealth is not to be seen in terms of reducing the world to what the individual can control and manipulate for whatever exclusively human purposes may be most pressing. Religious belief claims, in the first place, that I am most fully myself only in relation with my creator; what I am in virtue of this relationship cannot be diminished or modified by any earthly power. In the environment there is a dimension that resists and escapes us: to reduce the world to a storehouse of materials for limited human purposes is thus to put in question any serious belief in an indestructible human value.

We have to return constantly to what sort of structures and sanctions might assist in making effective a change in our motivations and myths. We could imagine, for instance, a 'charter' of rights in relation to the environment – that we should be able to live in a world that still had wilderness spaces, that still nurtured a balanced variety of species, that allowed us access to unpoisoned natural foodstuffs. It may be that the time is ripe for an attempt at a comprehensive statement of this, a new UN commitment – a 'Charter of Rights to Natural Capital' to which governments could sign up and by which their own practice and that of the nations in whose economies they invested could be measured.

A manageable first step relating particularly to carbon emissions, supported by a wide coalition of concerned parties, is of course the 'contraction and convergence' proposals initially developed by the Global Commons Institute in London. This involves granting to each nation a notional 'entitlement to pollute' up to an agreed level that is credibly compatible with overall goals for managing and limiting atmospheric pollution. Those nations which exceed this level would have to pay pro rata charges on their excess emissions. The money thus raised would be put at the service of low emission nations – or could presumably be ploughed back into poor but high-emission nations – who would be, so to speak, in credit as to their entitlements, so as to assist them in ecologically sustainable development.

Election campaigns seldom give much space to environmental matters; governments need strengthening in their commitments and need electoral incentives to be involved in the sort of internationally agreed aspirations But it is because the ecological agenda is always going to be vulnerable to the pressure of other more apparently 'immediate' issues that it cannot be left to electoral politics alone. We still need a steady background of awareness and small-scale committed action, nourished by some kind of coherent vision.

Ecologists have argued regularly that some religious attitudes are part of the problem; once again we have to ask whether religion is part of the solution. Religious faith should steer us away from any fantasies we may have of not 'interfering' with the environment (the first planting of grain was an interference), but it tells us that our interaction with what lies around can never be simply functional and problem-solving.

Religious commitment becomes in this context a crucial element in that renewal of our motivation for living realistically in our material setting. The loss of a sustainable environment protected from unlimited exploitation is the loss of a sustainable humanity in every sense – not only the loss of a spiritual depth but ultimately the loss of simple material stability as well. It is up to us as consumers and voters to do better justice to the 'house' we have been invited to keep, the world where we are guests.

© Rowan Williams 2005