ABC: Well I think it's an enormous problem; it's a huge practical problem, it's a huge moral problem, and the International Energy Agency calculated a couple of years ago that the next quarter of a century would see an increase of over 60% in carbon emissions worldwide with the expansion of the Indian and Chinese economies and unless we are able to effect serious concrete reductions immediately, the problem really is vast.

RH: You say it is a moral question. Now, there was a report last week by the government's development department, DfID - which we in the BBC obtained through freedom of information - which says, in effect, our lifestyles are killing the poor through droughts and floods, and through in the future, sea level rise. I mean that is a very serious moral question.

ABC: Quite clearly. I think that if we see the kind the kind of water level rises being talked about in the next couple of decades then any possible agricultural development in, say, the Indian sub-continent is completely undermined by that. So yes, there is a moral question here; it's a question if you define morality as something which looks beyond just the interests of yourself and your immediate neighbours, then it's, I think, a profoundly immoral policy and lifestyle that doesn't consider those people who don't happen to share the present moment with us.

RH: Well, whose responsibility is it? Because when you talk to international leaders they will say, 'well the problem has got to be solved globally'. There is no point us cutting our emissions, if say the Chinese and the Indians don't cut their emissions. Where exactly does the moral responsibility lie?

ABC: I think in the first instance the moral responsibility lies with absolutely everybody, not only in terms of examining our own lifestyles and asking what, concretely can be done, but also in sending a message to governments that this is recognised as a priority by the public.

RH: Well I am not sure that the government yet does feel that. I mean, a lot of the delay about the climate change strategy is been because the government didn't want to take on vested interests in society. So clearly, they don't feel the populous is yet ready for the sort of measures that would be needed, if we were really to tackle climate change.

ABC: So there's a real priority about educating people as to this priority; and I think the urgency has to be conveyed to people - it's not a marginal question, it's about everybody's justice, everybody's life in the future. I think as I say we have to recognise the fact that it's not an optional extra, it's not a marginal question, and that we are in several areas now going on a very serious collision course; I mean if we think simply about the question of fuel use, it's obviously the case that the shortage of fuel supplies for high-fuel economies in developed nations, heavy car using economies to put it bluntly, is going to be a factor in destabilising the global political situation in the next decade or so. It's been pointed out by a number of economists, I think absolutely correctly, that high oil-producing areas are at the moment almost all in areas of major political instability.

RH: You are making a case self-interest for us to wean ourselves off oil. But I mean, there are many difficult choices in the meantime. If we look the government's climate strategy review, this was supposed to be published last summer. It was supposed to show how the government was going to hit its 20% target. Now, as far as I understand it, the measures in the strategy review, even at the very best case, won't add up to 20 %. And the delay is been caused because the Department of Trade and Industry don't want to disadvantage British business, they say 'well why don't motorists do something?' And the Department of Transport say 'well, we don't want to take on the motorists, why don't householders do something?' And it goes around in circles - there is a massive problem, there is a leadership issue, I guess.

ABC: I suppose so and it certainly is to some extent about who takes, who's prepared to take executive responsibility, for example, looking at questions about the enforcement of speed limits. But as I said earlier, it's also a question fundamentally about each one of us and about the step changes we can each make and which each organisation can make too. And I say that because it's something, which I know that the Church of England is having to look at quite seriously in just those terms. We can't talk about this in abstract as if we occupied a high moral ground; we have got to look at our practice too.

RH: Let me go back to what you previously mention there, about speed limits. The government has calculated it can save almost a million tons of carbon a year, if it strictly enforced the 70mph speed limit. Yet when that proposal was made, ministers instantly backed off because they could see the bad headlines that would head their way. Do you have a position on this in terms of what the government's responsibility is, vis a vis the changes that will happen in other parts of the word that you mentioned earlier, the floods and the droughts?

ABC: I think this is something in the long run that government simply has to brazen out. I mean nobody likes talking about in government, coercion, in this respect - whether it's speed limits or anything else. Nobody, for that matter, likes talking about enforceable international protocols and yet unless there is a real change in attitude, we have to contemplate those very unwelcome possibilities if we want to the global economy not to collapse and millions, billions, of people to die.

RH: You think it is that serious - for billions of people to die? That's very strong...

ABC: Well I think that's what it comes to. I think that if we have a situation in which, let's say, the agricultural economy of the Indian sub-continent is gravely affected; if we have rising water levels in the Indian sub-continent, quite clearly we're looking at death from starvation and from flooding. If we look more generally at desertification as a global problem we can see that there are issues there which clearly have to do with sustainable development and agriculture - the delivery of the Millennium Development Goals, which are so important to this government and so many governments, becomes unthinkable and so we're looking at rising spirals of hunger and deprivation.

RH: When you look at the international situation things are very, very difficult to achieve on an international level because the Americans simply will not agree to any cuts whatsoever. President Bush is a Christian; are his actions compatible with Christian ethics?

ABC: I don't think it's compatible with a Christian ethic to ignore the environmental degradation that we face; it is a long term moral - well not a long term, a medium term - moral question for everyone and therefore a present imperative. It's perfectly true that nearly a quarter of carbon emissions on the face of the globe are attributable to the usage of the United States, and the leadership of the United States has been very slow to catch up with this; however I think it is quite significant that in the last twelve to eighteen months quite a number of Christian bodies, conservative Christian bodies in the US have begun to talk about climate change and about environmental issues, and have begun lobbying on Capitol Hill. President Bush is, it seems, listening to the voices that are beginning to push in a different direction here. I look forward with interest to developments on that because clearly there's been a real sea change in attitudes among some Christian quarters here.

RH: Let's project forward and assume that, given the current rate of change, we don't change fast enough to prevent climate change. How will God judge those leaders who did not move quickly enough to prevent the deaths of millions - perhaps even billions of deaths that you forecast?

ABC: I think if we look at the language of the Bible on this, we very often come across a situation where people are judged for not responding to warnings. It's very deeply built in; there are choices we can make, each one of us, to change things now and I think what the Bible and the Christian tradition suggests is that those who have that challenge put before them, but not only the challenge, but the evidence for it, and don't respond, bear a very heavy responsibility before God.

© Rowan Williams 2006