Eleanor Hall reported this story on Tuesday, December 3, 2013 12:26:00

ELEANOR HALL: While the Federal Government focuses its climate policy energies on repealing the carbon tax, a book published today paints a terrifying picture of a world that's four degrees warmer and recommends a dramatic increase in Australia's carbon reduction target.*



The book's editor is Associate Professor of Environmental Policy at Melbourne University, Dr Peter Christoff.*



He says he will meet Australian politicians from all parties to stress the urgency of the problem.



He joined me from Melbourne this morning.



Professor Christoff, what do you say to those who say it's simply alarmist to be talking about four degrees of global warming, twice the level that world leaders have identified as dangerous, and are working to keep below.



PETER CHRISTOFF: Well, two years ago or four years ago, it would have been regarded as science fiction to think about a world heading in that direction. But frankly, given the pace of negotiations and the projections that are being made on current levels of emissions and also projected changes to those emissions, four degrees is pretty much about the centre figure that is being projected by the IPCC, the scientific body looking at climate change.



So four degrees unfortunately is now a very realistic prospect by the end of this century.



ELEANOR HALL: You say we should use the best available evidence. What does it tell us about the earliest possible date we'd be looking at a four degree warmer world?



PETER CHRISTOFF: Well a great deal depends on the rate at which emissions either increase or decline. If those emissions increase, then we're looking at four degrees being perhaps as early as 2070. If they decline, but not sufficiently, then we're looking at around the end of this century.



Of course that doesn't mean that that's when the warming stops. Warming would continue to occur for some time, for some centuries after that. But at this stage that's the projection that we're looking at.



ELEANOR HALL: The planet has warmed only about 0.8 of a degree since the industrial revolution. The latest IPCC report shows the pace of warming has actually stabilised in recent years. Isn't this just too extreme an analysis to be taken seriously?



PETER CHRISTOFF: Look, the stabilisation that has occurred at the moment is regarded by most climate scientists as temporary. These sort of projections that we are now looking at the moment are not alarmist at all. I think they're actually probably conservative under the circumstances. They don't factor in a number of other feedbacks which may occur as warming continues and as we move past certain tipping points.



ELEANOR HALL: So if this four degrees of warming or worse were to take place, which parts of the globe, which populations, would be most at risk?



PETER CHRISTOFF: You'd probably have to say that most parts of the globe would be at risk. That's four degrees of average warming, but there would be warming that is in excess of that as you move towards the polar regions in both hemispheres.



You've got to say that Australia as a country which has always had a fairly fragile environment, would be one of the continents and one of the countries most at risk. Certainly it's the most vulnerable of the industrialised countries.



But then you have continents like the Indian subcontinent and also China, which are very vulnerable because of their large populations who are extremely susceptible to changes in drought and therefore in food availability.



ELEANOR HALL: What is the most frightening aspect for you of a four degree warmer world?



PETER CHRISTOFF: Oh look, that's a terrible question to which one only has to give a terrible answer. There are a set of compounding problems that emerge when you start moving towards four degrees. You start to see a world in which there are substantial extinctions.



The oceans have become warmer, are becoming more acidic. So there's a very significant chance of the collapse of significant marine ecosystems like coral reefs, the Great Barrier Reef, for example, is probably doomed when you get to four degrees. There are very substantial problems with food availability planet-wide and in a country like Australia which used to be capable of producing a surplus of food, by four degrees, would probably be facing food security problems with a larger population, but also a hungrier population.



And then you have the issues of extreme weather events, floods, more intense storms, bushfires, all these things particularly in the Australian context, I think leave us with a shatteringly different sense of what Australian can and would be like.



ELEANOR HALL: The physical effects are one part of this. What could the changes in the resource availability then mean for security? Will it inevitably mean more wars?



PETER CHRISTOFF: The projections are at four degrees that you would have significant displacement of population. If you have mass hunger occurring, populations will move to try and find food. Most of those movements, and the projections go from 65 to 250 million people by the end of this century. Most of those movements are likely to occur with countries, but there would be also the prospect of people moving over their borders and looking for resources elsewhere.



And how the world begins to handle a problem of that magnitude I think is something that we can only begin to contemplate. One doesn't know whether it would lead to more conflict. It certainly would lead to problems. I don't think we can understand what a world that looks like the one that's being projected looks like or how we're going to react to it. It's beyond human experience.



ELEANOR HALL: This sounds like a doomsday scenario. Could humans adapt to a four degree warming of the planet?



PETER CHRISTOFF: Well, humans are an extraordinarily adaptable species but if you're looking at a population of seven billion people trying to adapt to a world in which there's less water and less food, one would have to say that the prospects for an adaptation that would leave life looking roughly like it does for many people at this point in time is virtually impossible.



So there are already billions of people living in poverty or in water-stressed and food-stressed circumstances. In a four degree world, their situation would only get extremely worse. And even in extremely wealthy countries like Australia, adaptation I think would be very, very difficult to countenance.



There would clearly be some form of adaptation, but it wouldn't be life as we understand it at this point in time.



ELEANOR HALL: You say that Australia could be one of the most vulnerable continents. Where do you expect to see the worst effects in Australia of a four degree warmer world?



PETER CHRISTOFF: There will be the extinctions of species. There'll be a very substantial impact on agricultural productivity. So the issues of food availability will change. We probably have the wealth and the resources to begin to deal with some of the issues of water availability and desalinisation plants and so on. Everyday life will be very substantially different. There are projections for example of what would happen to just average temperatures over time. So in Melbourne for example, we have something like nine or ten days over 35 degrees at the moment. By the time you get to 2070, that's about 26 days.



When you're looking at Alice Springs, the temperatures are 90 days over 35 degrees now, 180 by 2070. And then you get to places like Darwin, which would move from 11 days to 308. You end up with parts of Australia which are virtually unliveable. And the projections are for example, that while Alice Springs would resemble the Sudan, Darwin will resemble like no place on earth.



ELEANOR HALL: What action would you like to see from policy makers as a result of your book?*



PETER CHRISTOFF: The clearest thing that this report suggests is that our current settings, current targets, and our current policies are inadequate. So Australia's committed to reducing its emissions by five degrees. We need to look at a much more substantial target, around 35-40, even 45 per cent below 2000 levels by 2020.



ELEANOR HALL: To go from 5 per cent to 45 though, that's a massive increase. Do you really expect the current government to take something like that seriously?



PETER CHRISTOFF: Well clearly there's a huge gap between our current political settings and what the science is suggesting we need to do. But at the end of the day if you look at the economic, the social and environmental outcomes, there has to be a bit of a reality check and I think that nature is going to give us that.



ELEANOR HALL: A 45 per cent reduction, what would be the cost of bringing that about. I mean, British economist Nicholas Stern's analysis that it would cost 1 per cent of GDP globally is now well out of date, isn't it?



PETER CHRISTOFF: It is out of date. But it's not that far off what one could still expect at this point in time. We're talking about billions of dollars. But in terms of the amount of money that is currently spent within the budget on education or defence and so on, it certainly wouldn't be a dramatic tension for the budget to be reoriented towards dealing with this problem.



ELEANOR HALL: Peter Christoff, as we've been going through this conversation you're reeling off statistics that really are quite extraordinary. How worried are you that we could actually reach four degrees of warming?



PETER CHRISTOFF: Extremely worried. We haven't seen the sort of focus and we haven't seen the sort of effort that's required to avoid exceeding two degrees in international negotiations, nor in Australia for some time. And I think that under the circumstances, unless there is a change, I think that the likelihood is that we will head towards four degrees, or more precisely that in 10 or 20 years time we'll start to panic and start to really begin to move very, very quickly to reduce emissions. But under those circumstances it will much more expensive and probably much less effective set of policies that we put in place.



ELEANOR HALL: Professor Christoff, thanks very much for joining us.



PETER CHRISTOFF: Thanks Eleanor.



ELEANOR HALL: That's Melbourne University's Dr Peter Christoff. He's the editor of; Four Degrees of Global Warming: Australia in a Hot World.*



EDITOR’S NOTE: (5 December 2013): The original broadcast incorrectly identified the publication Four Degrees of Global Warming: Australia in a Hot World as a report. The transcript has been amended.