We've been surveying the planet's most extreme deserts to discover the limits for life on earth. Our big breakthrough was discovering the only creatures that can survive the most hostile conditions in all the deserts, hot or cold, are little green single-cell plants called cyanobacteria. We were able to show that cyanobacteria were almost certainly the earliest form of terrestrial life on earth. Before they colonised the planet it was a noxious horrible place where complex life couldn't survive. They actually oxygenated the earth. Just like plants, they breathe in carbon dioxide and breathe out oxygen. In Antarctica today the dominant signs of life are these vast mats of algae-like cyanobacteria. If there was ever life on Mars it's probably long dead, but that's conceivably what it looked like.
2 How will Nasa find signs that life existed on Mars?
The next suite of missions in 2020 is the first to have a direct remit to search for chemical traces of life. The environment in Antarctica is identical to the surface of Mars so we're testing equipment there like this rover and remote-controlled plane (pictured). Up until now Nasa's mantra has been "follow the water" but we've been able to show that sandstone is a good place to find traces of microbes in Antarctica. That's useful on Mars where the Curiosity rover has found a sandstone-rich crater. Nasa's chief scientist Ellen Stofen has boldly predicted that Nasa will deliver proof of life on another planet within the next decade. The Europeans are also planning to search for traces of life when they launch for Mars in 2018. Their Rover looks just like Wall-e. Its going to be exciting.
3 Do you believe there has been life on Mars?
It's hard to avoid sounding like a crackpot when you talk about astrobiology. I'm not into aliens abducting people - that's firmly in the realm of science fiction but I do think it's important to find out if there was a second genesis of life. If we could prove that life once existed in our solar system for example on Mars or one of Jupiter's moons that goes right to the core of how we should view ourselves as human beings in universe.
4 You've explored the world's most extreme environments. Is the danger part of the attraction?
I'd be lying if I didn't admit that thrill-seeking and all the gadgets we get to use are part of the attraction. I've got the best of both worlds because I get to go out to these wild places and then come back to the laboratory and do experiments and write papers. I love my job.
5 You're English and have worked around the world. Why are you based in New Zealand?
My research focuses largely on Antarctica so there's no better place to be. The Kiwi Antarctic programme is the model of best practice for how we treat the Antarctic environment.
6 How does science in New Zealand compare to other countries you've worked in like the UK, US, Germany and Hong Kong?
This is one of the most inclusive and forward thinking environments for science I've ever been in, so hats off to the Government for creating that. There's a level of interaction between policy makers and scientists that doesn't exist anywhere else. I talk to Stephen Joyce and other ministers regularly and so do my colleagues. In large countries like the UK or US scientists are able to become the quintessential cardigan wearing, pipe smoking types who go off and indulge their own passions. In New Zealand we don't have that luxury. We identify priority areas through the national science challenges and target funding on big issues relevant to society. Scientists are accountable to the people that pay us so if I'm doing science that isn't a benefit to New Zealand then I'm not doing my job.
7 When did you realise you wanted to be a scientist?
Science was more of a necessity than a passion to start with. It was a coping mechanism. I had quite a traumatic childhood. I was sexually abused by a neighbour. I used to run off into the countryside in Sussex with my little Collins guide book. Concentrating on finding bugs and plants was a way to escape. I struggled to socialise and found the natural world much more interesting than the world of people. When I went to high school I was put in the remedial class because they thought I wasn't mentally capable but I just wasn't able to articulate myself very well. I had no self-confidence and got overwhelmed easily. Science became my passion and it has been my constant companion.
8 Of all the research you've done, what are you most proud of?
My first paper published in Nature, one of the 'Big 3' science journals in 2005. I proved these little green microbes could grow inside rocks and soil in Antarctica. I wasn't sure if I was really good at what I did, so being recognised as worthy by my peers was a very special moment. Something clicked and now you can't get me to shut up - I'm making up for lost time. It's still the most highly cited paper on microbes in Antarctica.
9 How has being a father changed you?
Beyond recognition. It's the best thing that's ever happened to me. Because I was violently bullied at school I've probably been overprotective of my son. I went absolutely ballistic one day when I saw him being bullied by two larger kids. I grabbed them by their ears and marched them up to their parents and almost got arrested.
10 Why have you been outspoken on vivisection in science?
There's a perception that animals killed in scientific experimentation are all being killed for the greater good and that's not always the case. Scientists are very ego driven and I have colleagues who routinely butcher rodents in the name of career progression. I don't disagree with farming or eating meat. Unnecessary cruelty is what I object to.
11 Most of your research these days relates to climate change. What's the biggest challenge for scientists?
Every time I meet people and they find out I'm a scientist, one of the first questions I'm asked is, "Do you think climate change is real?" A guy phoned into my radio show recently and called me a "charlatan". Scientists have shown irrefutably that climate change is here but what we haven't done so well is communicate that message in a way that the public can digest and trust. Politicians will only act if there is voting pressure to effect change so unfortunately scientists still need to convince the public beyond reasonable doubt that climate change is real.
12 How did you become one of New Zealand's leading science communicators?
I'd only been in New Zealand a matter of weeks when I was asked to join TV3's Science Chat series with Michelle Dickinson and Siouxsie Wiles. I think it's really important for scientists to communicate what they do in a way the public can understand so I created an on-demand video platform called Sci 21 where scientists talk about their research in an appealing way without the jargon and with a bit of humour. We've had over half a million hits already. I also blog on SciBlogs and host a weekly radio show on bFM called Dear Science which I release as a podcast because young people today don't want to be tied to a schedule.