In a conversation with the Green Growth Knowledge Platform, a policy partner of the Centre for International Environmental Studies, Prof. Tim Flannery, the acclaimed Australian scientist, explorer and conservationist and currently Segré Foundation Distinguished Visiting Professor, discuss how negative carbon technologies can slow climate change.

1. Is there any one carbon negative technology that could make a significant impact?

It is now absolutely clear that we cannot stay below the 2C safety rail without the use of carbon-negative technologies. The main obstacle is one of scale, so the question becomes, what carbon negative technologies are potentially capable of delivering gigatonne scale reductions by 2050? Of course, it is impossible to see the future, but from the perspective of 2017 among the more promising are: 1) silicate rocks, 2) mid-ocean kelp farming, storage of CO2 in the Antarctic ice cap, concentrator thermal technologies to develop products like carbon fibre.

2. What made you change your opinion on the role of nuclear energy in the global energy transition?

My opinion changed as a result of the decline of nuclear in the global electricity generation sector, and the increasing competitiveness of renewables. I think that nuclear will continue to play as role where governments assume the risk and guarantee a price for electricity decades into the future. The best prospects are in places like China, where there is a massive industrial demand for electricity.

3. As someone with a very strong biology background, what is your take on the pros and cons of ecosystem services, natural capital, and the current efforts in accounting for nature and the valuation of natural elements and dynamics?

I think that the future of conservation in mixed-use lands is strongly determined by payments for ecosystem services. We make too little use of the concept I feel in developing countries. After all, we ask villagers to give up the use of a resource so that we can all enjoy the benefit, whether it be an endangered species of a carbon retaining forest. In places like Europe and Australia accounting for nature is more complex and involves government. We are still working out how to do this, but when we develop the system I'm sure the benefits will be huge.

4. Can new and more advanced computing technologies and tools like big data and machine learning create new insights and progress in the environmental arena as they have been doing elsewhere?

As a species, we are currently developing a global 'nervous system' in terms of monitoring stations. We now have millions of them, which are measuring everything from oxygen levels in the deep sea to soil moisture on farms. We are also building ever more powerful model worlds, which we can use to examine the consequences of various actions. Big data is central to both of these enterprises.

5. What has changed since your last book and do you think we are in a better place, progress and awareness wise, than we were 10 years ago?

The biggest thing that has changed is that we've emitted 500 million gigatonnes of CO2 equivalent in greenhouse gases in that time. But we have also signed a global accord on climate change and reduced the cost of renewables. We are in a desperate race against time and have now emitted so much that carbon negative technologies are now necessary. Our fate hangs in the balance.