SR: It’s evident now that climate change is going to have a big impact, in the relatively short term, on the way we live. However, the level of mobilisation and campaigning around it is pretty low – for example the 2012 demonstration was the smallest in years. Why do you think this is?

NB: It’’s distressing how little movement there has been in the last ten years over climate change. While the BBC are still stuck in a rut giving climate deniers airtime, the scientific evidence, most recently from the Arctic, shows that we are heading for a “climate cliff”.

Unlike in the international cooperation over CFCs and the ozone layer, tackling climate change involves a fundamental economic shift. That makes the debate far more than a single environmental issue and involves confronting vested interests.

There is a consensus among the scientific community that climate change is a clear and present danger, and millions of people in this country are deeply concerned about the effect it will have at home and abroad but many people feel powerless. In that context, the yearly demonstrations can feel abstract. If Blair could ignore 1.5 million people marching over Iraq, how big would a demonstration have to be to provoke this government to overturn our economic system?

During a prolonged recession, many people are understandably more concerned about where tomorrow’s lunch money is coming from, or next month’s rent or mortgage payment. The challenge is to show how fixing our environmental crisis goes hand in hand with fixing the economic crisis. The penalty for ignoring climate change will be far greater hardship for the poorest.

The upside is that organisations like Transition Towns have shown that people are willing to take local action, and that there is a broad range of voices from across the political spectrum who still care about the issue – even though they don’t see an annual demonstration as relevant to the practical action they are taking. This focus on building real projects can be extremely inspiring, whether that’s community owned renewable energy, local councils rolling out free home insulation or co-housing projects – these modest, practical initiatives should give us hope that the big changes we need to make are at least possible.

SR: There is always a tension in environmental politics between individual lifestyle choices and the constraints put on us by living a capitalist economy. How do we reconcile these two things?

NB: Ultimately climate change, soil degradation, air pollution or the erosion of the Green Belt are all political problems. We can’t solve them through swapping our light bulbs or wearing more ethically produced shoes.

However, if we want to build a movement of people committed to the kinds of fundamental change we need we have to engrain that politics into our lives. These are not abstract issues of interest only to academics and that means doing as well as talking. If changing your electricity supplier leads you to having conversations and raising awareness then I’m all for it – as long as we’re careful not to fool ourselves or others that it is by any means enough.

Some lifestyle changes are only ever going to be open to those who can afford to pay a bit extra, or have the time and energy left over after work, kids, etc. to be able to think about which brand to buy. We need to make the environmentally friendly option in every aspect of our lives the cheapest, easiest and obvious choice. That’s a political change, not an individual one. That takes on the power of Tesco rather than advising people which shelf to pick from.

SR: There was a moment, immediately after Caroline Lucas was elected to Westminster, when it looked like the Green Party had the potential to be a radical anti-cuts voice and to grow from articulating that opposition. From the outside, it doesn’t look like that happened. How do you plan to position the party in the run up to the next local and general elections?

NB: After coming third in the London Mayoral / Assembly elections and with some positive by-election results I think we’re in a good position to do well at these elections. The party membership has doubled in the last four years and the presence of Caroline in Westminster as a hugely effective MP has greatly improved our profile.

However, the state of our economy and environment demands that we move much faster. We can’t be satisfied with one excellent MP. In the 2014 European elections if the Greens can win just 1.6% more at the polls we can treble the number of MEPs we have, I think we can do that.

While the media and the Labour Party have simply accepted the Coalition’s rationale for cuts it has been down to the smaller voices to inject economic sense. It shouldn’t be down to the Green Party alone to make the case for a fairer economic model, and that’s why we need allies in the movement. UKUncut, Occupy and a host of campaigning NGOs have made fantastic contributions to this.

The Green Party should be and is one voice of many putting the case against austerity, and I certainly value the work those outside the party have done here. Together we have started to turn the economic arguments around.

SR: Once a party gets people elected it has to start making choices. In local government this is currently expressed as “making painful cuts fair” and in Brighton Green councillors supported a cuts budget. Should MPs and councillors vote for cuts and do they have a role in organising against them?

NB: I don’t think there’s any way to make these savage cuts in government spending which are hitting the poorest, hardest “fair”. Green Party members across the country are involved in local campaigns to defend specific services, libraries, nurseries and Sure Start Centres. We think the nationally led austerity measures are more about ideology than economics – the Tories want to privatise and shrink the state no matter what the cost to the economy and society.

That means that the challenge is not just about cuts but about what sort of society we want. We don’t just want to go back to the budgets of 2006 at the end of the boom, when more than 20% of pensioners and children were living in poverty. While Greens want to see less spending on nuclear weapons, war and zombie road building, the fact is we need to invest in a fairer society. These cuts are economically illiterate false economies.

The challenge at a local level is that more and more power has been shifted into national government and that many of their functions act almost as the administrative arm of the national government, with budgets and ring fenced spending dictated from Westminster. Local councillors can and do make a difference but not in conditions of their choosing.

In Brighton and Hove the minority Green Party council proposed a council tax rise to offset the majority of the Tory / Lib Dem cuts on top of an unprecedented public consultation on how residents wanted to see their city run. When Labour allied with the Tories to vote down that modest rise they introduced a £17 million short fall in the budget – this was reckless and irresponsible, but until we have a majority on the council the power is not in our hands to overturn that decision.

The Labour Tory block in Brighton and Hove is playing politics with public services.

One silver lining is that this gave a number of councils across the country, ironically including Tory-run ones, the confidence to follow Brighton Greens’ lead and raise council taxes to preserve services.

Of course some of the savings that have been made are not so bad. The Greens are bringing outsourced services back in-house, they sold off the Mayoral number plates to create a poverty fund and addressed executive pay. I’m also proud that Brighton and Hove now pay the living wage to their staff and are almost alone in the country in building new council homes.

SR: What is the Green Party’s response to the economic crisis in Britain?

NB: We need to invest in the future to create a new low-carbon, jobs-rich economy. We need to bring food production and manufacturing back to Britain and introduce the desperately needed banking and tax regulation that none of the largest Parliamentary Parties seem willing to propose. We need long-term solutions that build strong local economies.

I’d like to see an economy built around small businesses and cooperatives with national investment in manufacturing and technology to create meaningful jobs that contribute to solving the climate crisis.

The power of multi-nationals and the banks has pushed our economy towards a toxic and unstable mix of low wage precarious employment while ignoring social and environmental imperatives. Millions have little hope of a job that they can build a life on.

SR: A challenge for all political organisations is ensuring that women’s voices are heard at least as clearly as men’s. This is particularly true when the austerity offensive is disproportionately affecting women more severely. Is the fact that the Green Party has had two female leaders due to an actively created culture in the organisation and does it affect what the party says about austerity?

NB: The Green Party has a long tradition of strong female leadership and institutional frameworks like quotas in list selections that have ensured that women have the opportunity to be heard. It’s also why we’re in favour of ensuring a minimum of 40% women on major company boards, on the Norwegian model.

When I helped set up Green Party Women five years ago it was to help support women active in the Green Party and make links with outside women’s groups. It’s also firmed up our feminist policies on everything from maternity services, prostitution, abortion, equal pay and violence against women. This informs everything we say on the impact of austerity on women but also goes beyond reacting to the current crisis to how we build towards social equality.

SR: There’s a sense that we have a bit of a vacuum on the left of Labour in terms of a party that represents working people and takes a clear stand against austerity. Where do you think the Green Party fits into that picture and how do you see it relating to other radical strands of opinion?

NB: As I said in my inaugural speech to conference “we are the opposition”. Labour are in no position to attack the government on PFI, ATOS, academy and free schools or privatisation. Nor incidentally can they provide a voice against war, nuclear weapons or neoliberalism.

The Green Party is clearly a left of Labour Party. Whether that’s on making the minimum wage a living wage, tackling executive pay and bankers’ bonuses or opposing zero hours contracts. We’re for abolishing the anti-union laws, greatly enhancing industrial democracy, ending the UK’s role in the arms trade and oppose the destructive dismantling of the NHS.

Whether the Greens are part of the traditional left is more open to question. We don’t have the same ideological legacies and pride ourselves on having a looser, more pluralist approach to what it means to be a member of the Green Party. It’s a strength that we don’t all rely on the same texts and traditions, which has allowed the party to build a far more stable, long term project with real community roots in our strongest areas.

The danger of the current period is that people’s anger and opposition to the Coalition government will fall into the lap of the Labour Party, despite the fact that on many, if not all, of the most critical issues they are coming from a very similar place as the government.

Labour will not reverse many of the most harmful policies of this government, which means we need to build credible alternatives to the stifling Westminster consensus – although that is certainly easier to say than do!

Greens and others on the left recognise the problems, and face similar difficulties in making our voices heard. We often work well together in local campaigns, although there’s less of a tradition of national level cooperation. I’ve no interest in spending time attacking people with whom I fundamentally agree on many points – the Greens aren’t looking to win a bigger share of the left vote, we’re trying to persuade everyone of the need for an entirely new economic and environmental direction.