CHRIS UHLMANN, PRESENTER: He's the software engineer who helped drive the personal computer revolution and his company Microsoft conquered all before it and Bill Gates became one of the richest people in the world. But Bill and his wife Melinda have committed to giving away over 90 per cent of their wealth, and he hopes that's another idea that will conquer the world.

Today, Scott Bevan sat down with Bill Gates for a rare interview.

SCOTT BEVAN, REPORTER: Bill Gates, welcome and thankyou for your time.

BILL GATES, PHILANTHROPIST: Great to be here.

SCOTT BEVAN: Now, a few years ago at the World Economic Forum, you described yourself as an optimist, but an impatient optimist. Now, bearing in mind those two words: impatient and optimist, whey have you pursued trying to eradicate stubborn diseases and trying to enlist the help of sometime stubborn political leaders?

BILL GATES: Well the improvement in health over the last 50 years is one of the great miracles of development. 50 years ago, over 20 million children died every year. And last year that was down below eight million. And the reason for that is that we invented great vaccines and then we had the generosity through aid programs to make them available to even the poorest.

SCOTT BEVAN: Now in your former life with Microsoft, you brought about or helped bring about radical change, global change, fairly rapidly. With that experience, with that thinking that would have developed through that process, how much is it a blessing, how much is it a curse in what you're dealing with now, takes time and change comes much slower?

BILL GATES: Well I think the IT industry at times does move very quickly, but we founded Microsoft back in 1975 and the personal computer revolution I don't think was evident to the population at large for over 20 years. And, it's only now, with the internet changing so much of how we do things, that people see, "Wow, this digital revolution's a big deal." There's still more to be done there - education, health, many areas are not yet revolutionised. And so as I focus now on the poorest and their needs, I can tap into the same kind of innovation, brilliant scientists, people who work in the field, and I can say that, hey, in 10 years we can reduce malaria by half. Three years or so, we should be able to get polio to be the second disease that's completely eradicated. So the timeframes aren't that different. It's not one political term that we can get these things done in, but if you think in terms of 10 or 15 years, we will be able to see immense progress.

SCOTT BEVAN: How hard is it to get that across to political leaders, particularly at the moment; say recently with the G20, the report you did there, where you reiterated the importance that donor countries stay the course, that they don't pull back on how much they give? How difficult is it to express to political leaders what you've said in that report and what you just said?

BILL GATES: Well anyone who's been out to see populations getting AIDS drugs or communities getting malaria bed nets, they'll be very sympathetic to these things, but the politicians and particularly the voters, very few of them have actually seen it in action. And their image of aid goes back to several decades ago where it was more about buying friendship than it was about putting the money where it could have the most impact. And so we need to get these success stories out. We're very pleased that Australia is increasing its aid generosity. It has a commitment by 2015 to get up to 0.5 per cent, which would put it at the average of what rich countries give - quite phenomenal, and those increases are going into very effective activities. They're a great partner on vaccines, great partner on polio. So I'm enjoying the fact that aid is getting smarter all the time and that's helping to back that it should be part of the budget, even in times where budgets everywhere are very, very tight.

SCOTT BEVAN: In your G20 report again, you propose certain taxes as a means of raising revenue for development, and you said, "Markets and governments should drive price carbon more explicitly through taxes and other means." Now, as you know, Australia is about to have a carbon tax. What do you think of it and what do you think it's likely to achieve, if anything, in regard to tackling climate change and the work that that involves in what you do with the foundation?

BILL GATES: Well I wish the world at large found it easier to get together on this because a carbon tax is a very important tool to encourage the invention of low-cost energy technologies that don't emit carbon. And to help that happen, a carbon tax is really a key piece. You wanna fund basic research so that the science is there and then you want companies thinking, whether it's solar or nuclear or wind. I wish the United States was stronger on the taxation piece, but I will say that it is funding research more than any other country in the world.

SCOTT BEVAN: So when Australians say - and there has been opposition to this carbon pricing - when they say, "What difference are we going to make on a global scale?"," how would you answer that by extrapolation of what you see in the poorest nations?

BILL GATES: Well, the - it's absolutely true that somebody has to lead on tough global issues, and if only a few countries do something, in this case it doesn't solve the problem. And so you have to believe that by setting a good example, that others will come in. The United States and China have to come in in a big way to this. Technology has to come along that makes the price premium for energy without CO2 omissions less than it is today. Now I'm a big optimist that that will happen.

SCOTT BEVAN: Let's talk about philanthropy in Australia. The whole culture of philanthropy, or perhaps the lack of it, has been discussed lately and been criticised by some prominent Australians such as Dick Smith. And once again, the Australian of the Year Simon McKeon said at a recent speech, "It is the elephant in the room," and that our wealthy, our very wealthy are far from generous. And he said, "Our culture is one that supports the rich being selfish." How do you reaculturate a population or a wealthy part of that population?

BILL GATES: Well I know there's a lot of great philanthropists in Australia. The goal should be to grow it and grow it at a reasonable rate. You know, you want people at all parts of society to feel like they can give back, whether it's volunteering their time, their voice or some financial resources. It helps if those who are the most successful, some reasonable percentage of them are setting an example. And so everyone that joins that I think will encourage more to join in with that, and certainly our foundation is very willing to talk about what's work and what's not work.

SCOTT BEVAN: We do have 35 billionaires apparently in Australia. Some of them with the resources boom are growing richer by the minute. Would you consider holding a meeting like you have done so in India, in China, to try and give the advice and kick-start this and kick along the culture of philanthropy among the very wealthy in Australia?

BILL GATES: If somebody was organising a meeting that was gonna get a number of those people come, I'd be glad to join in and share my experiences. I don't know the people so I won't organise it myself, but, yes, that's - willingness to participate in a meeting like that is something I enjoy a lot.

SCOTT BEVAN: To give us a sense of why you give, is there a particular moment, a particular person, a particular face that has been seared into your memory that constantly reinforces to you in the quietest moments, "That's why I give"?

BILL GATES: Well there's many different ways you come at giving. I remember thinking quite logically that I didn't want to spoil my children with wealth and so that I would create a foundation, but not knowing exactly what it would focus on. And then when I got married, Melinda and I both knew that would happen, but we wanted to find out was there something we could do that was dramatic? So, it's personal, it's seeing it, it's thinking about it numerically, and the next thing you know, it's - you're full-time work and you're not even questioning it because it's so exciting and yet when it goes slower than you want, you get impatient and you try to be creative about pushing it along.

SCOTT BEVAN: More exciting than anything that you achieved in Microsoft and with Microsoft?

BILL GATES: I'd say equally exciting. I mean, the - in my 20s and 30s, that work was thrilling. And I worked day and night, I loved it. We believed in something that most of the world didn't see, and that revolution continues. Now I get that same kind of satisfaction in my foundation work.

SCOTT BEVAN: Time magazine's person of the year just announced, the The Protester, in recognition and acknowledgement of the enormous changes brought globally this year by protests and popular movements. For someone who's trying to change the world along another avenue, another path, what do you think of this other avenue of change and how do you assess the success of the protest?

BILL GATES: Well the protester I think is a very powerful thing. It's basically a mechanism of democracy that, along with capitalism, scientific innovation, those things have built the modern world. And it's wonderful that the new tools have empowered that protestor so that state secrets, bad developments are not hidden anymore. The Protestor I think will speak up for the world's poorest. Why did we get the attention at the Gleneagles G8 summit that led to a huge commitment to the poorest people? Well there was a set of protestors who came together. There's no cause more just than the need to care about the very poorest. And - so I think it is a powerful tool. I think young people want to get behind these causes, and so they - some protest about aid issues'll be a real friend of the causes I believe in.

SCOTT BEVAN: Finally, the Russian writer Leo Tolstoy said more than a century ago that, "money is a new form of slavery". By giving away or pledging to give away billions of dollars, how liberated do you feel?

BILL GATES: Well I feel it's great. You know, it's gotten me away from the title of being the richest, and that's a nice thing. But, it's also a responsibility. You want to do it well. I think you need the same type of diligence that you had in being able to make a great fortune. Picking people to work with, picking goals, being honest about the limitations of what impact you can have. So, it's fun, but I also take it quite seriously.

SCOTT BEVAN: Bill Gates, I wish you and your family a wonderful Christmas in Australia.

BILL GATES: Thankyou.

SCOTT BEVAN: Thankyou for your time.

CHRIS UHLMANN: Scott Bevan with Bill Gates.