I trace my first stirrings as a ‘green’ to the unpromising-looking surroundings of a 1950s demountable classroom at the University of Sydney. The subject was soil science, the lecturer a painfully, awfully shy man, whose didactic method was to face the blackboard and talk to it, while writing equations we couldn’t see since he was in front of them. Despite that, I left the course with the clear understanding that Australian agriculture was not farming its soils, but mining them; European farming methods brought from that continent’s relatively deep, rich, constantly renewed soils were (and still are) wreaking havoc on Australia’s ancient, shallow, fragile ones.

The next awakening moment was a couple of years later. As a young country journalist, I was writing about a local biodynamic farm. Shovel on shoulder, the farmer took me into the middle of his wheat field, casually leaned on the implement and then turned over a humus-rich, moist loam teeming with earthworms. I was astonished. In my experience, a ‘normal’ wheat field in the Australian summer would have required a very strong person with a large pickaxe to even break through the surface, and the result would have resembled crushed concrete.

I am not allowed now to talk too much about soils – since it sounds a bit geeky and specialist – but the fact is that the degradation of one of the very foundations of ecology is one of the great under-covered environmental issues. And we are only just beginning to catch a glimpse of the complexity of soil ecosystems – how fungi help plant roots draw up nutrients, how bacteria digest those nutrients, how the carbon stored in agricultural soils has collapsed due to industrial farming methods.

Thirty years ago, when I was studying soil science, there was little awareness of any of this – soils were a subject for chemists. I think of this example of the severe limits of our understanding whenever some bright-eyed proponent of geo-engineering pops up with a grand scheme to solve climate change by deploying reflecting space mirrors, or iron filings in the oceans – as though the Earth were a predictable machine.

But my early green thoughts took time to bear fruit. An earlier personal politics – feminism – was my primary political focus in my twenties and early thirties. I trace it to age five, when my aspirational working-class grandmother (who if she had stated a hope for me then would probably have said something like “be presented to the Queen”) ensured that I didn’t have a bicycle because it wasn’t “ladylike”, although I was told if I had a brother, he’d be able to have one.

At that moment a feminist was born, although I wouldn’t know the word until a decade or so later, when as a babysitter I found The Women’s Room hidden in the back row of a neighbour’s bookcase (along with The Joy of Sex and other ‘unsuitable for the suburbs’ books), and thanks to this I discovered that other people thought the same way I did about the restricted, frustrating lives of my mother and her friends.

That passion took me to Thailand as a volunteer in the National Commission on Women’s Affairs, after which my daytime profession of journalist brought me to Britain, where I worked first on The Times, then The Independent, and finally as editor of The Guardian Weekly. For many of those years I was working nights, and it was only when that ended, and I started to run a similar schedule to most of the world, that I looked around to think what else I could do to contribute to society, to change how things were. The science again came to the fore as I looked at the state of the world’s ecology, and so, on 1 January 2006, I joined the Green Party.

I am typical, I think, of most members of the Green Party in that politics wasn’t in my blood, wasn’t in my family experience, and I didn’t join with any particular ambition in mind. A week after I joined I was door-to-door canvassing in Highgate, in the ward where we’d elect our first two Green councillors for Camden a few months later. A few months after that I was – almost accidentally – a member of the national executive, which was the point at which the Green Party took over my life. If you’d told me that would happen when I resolved to “do something” on New Year’s Day 2006, I would have been astonished.

We don’t tend to get career politicians in the Green Party, for obvious reasons: representing the Green Party isn’t the simplest route to an ‘easy life’ in Westminster or even on your local council. With the election of Caroline Lucas as the UK’s first Green MP, in Brighton Pavilion in 2010, we showed it is possible to overcome our grossly unrepresentative first-past-the-post electoral system – as more than 140 councillors around the country have also demonstrated – but it is always a challenge.

Human motivations are rich and complex, but I think one thing that unites members of the Green Party is an understanding that things cannot continue as they are – that our current economic, environmental and social model is broken. Globalisation, neoliberalism, outsourcing, privatisation, three-planet living – the driving forces of political decision-making, political promises and political hopes over the past few decades – have put us on a path to destruction. They can’t continue in their own terms – the economics has failed – and they can’t continue in environmental terms: the planet can’t carry the continued weight of excess, of waste, of destruction.

We need to rebuild the local, the community, the fair. In practical terms that means bringing food production back to Britain, bringing manufacturing back to Britain (and beyond that relocalising economies globally), bringing jobs, homes, schools and leisure facilities together in sensible clusters, greatly reducing the disparity between those with the most and those with the least.

I am not talking about autarky, or anything like it – I like my morning coffee, and exotic spices, and some things, like hi-tech medical machines, need to be made on a global scale – but it does mean the end of flying beans from Kenya and peas from Peru, ‘this year’s fashion’ in home furnishings, and shipping endless containers of plastic tat and ‘cheap’ T-shirts from China.

This requires a reshaping of how we think and act towards the material world, to improve its quality and our own quality of life.

We do not want a world in which we step backwards, replacing comfort with sackcloth, and homes with caves. But we don’t need a new mobile phone, containing expensive minerals wrenched hideously from the earth in the Congo, every two years, when we can instead simply upgrade software every six months, or plug in a new silicon chip every few years. And instead of buying a T-shirt made in this week’s fashionable shade in a dangerous Bangladeshi sweatshop (and discarding it a couple of weeks later), we can choose to purchase a carefully, locally tailored shirt of high-quality fabric that will last for years.

We as a party, and all of us as individuals, must restructure our working lives, so that instead of spending miserable hours commuting, we can take a short stroll or cycle to work. We must replace the current dispiriting office ‘presenteeism’, zero-hour contracts and call-centre slavery with decent jobs that you can build a life on, and in which you’re able to feel you are doing something worthwhile and are being valued.

And quality of life is vital, too. Instead of our long-working-hours culture, which is such a blight on British life, we should be thinking of cutting back on work. Green Party policy calls for a 35-hour working week as standard, but I find the New Economics Foundation idea of gradually working towards a standard 21-hour working week very appealing. As Caroline Lucas says, no one lies on their deathbed saying: “I wish I had spent more time in the office.”

The ‘lump of labour’ fallacy is demonstrably a nonsense – there’s not a fixed ‘lump’ of labour available to share around – but we do need to share our work – and its rewards – around far more fairly.

That means many jobs must be much better paid, and ‘the 1%’ described by Occupy need to hog a much smaller share of the cake. They can cope: one statistic that shocks audiences wherever I speak is that Britain’s wealthiest 10% got 11% richer in 2012, while the rest of us – particularly the poorest – got poorer.

But the challenge for a political party is to determine how we can restructure: how we will reshape our laws, our politics, our ways of acting as individuals, communities and a society to get us there. That means pinning down policies, developing from ‘how it should be’ to ‘how we get there’. And this is something the democratic decision-making process of the Green Party is working to explore and develop.

Our vision takes in everything from the transformation of our tax system to ensure multinational companies and rich individuals pay their taxes (check out Caroline Lucas’s 2011 private members’ bill on Tax and Financial Transparency for much more on that), to a citizens’ income (also called a basic income), which ensures that every member of society has their basic sustenance guaranteed, and a land value tax, which would ensure far more efficient use of land.

It includes returning to public ownership a range of essential services – renationalising the railways, restoring buses to local control, developing community ownership of energy generation, and infrastructure. And it means ensuring that every item that goes on sale is marked with its real price – one that reflects its real cost of production, whether it’s the emission of greenhouse gases, consumption of water or generation of waste.

There’s lots of great work being done in developing policies on these vital issues, yet like many campaigners I am frustrated that we have a government that is heading in so many wrong directions all at the same time. It is currently being pulled into knee-jerk, dangerously divisive policies by the reactionary politics of fear of UKIP, and at the same time continues to represent the interests of multinationals, not voters. It is heavily influenced by the interests of finance, pharmaceuticals, the arms trade and the petroleum industry – which is hardly a surprise given that many of its ministries are staffed by representatives of those same interests.

It is clear we aren’t implementing the clearly evidence-backed policies on renewable energy and energy conservation, even though economic organisations including the Confederation of British Industries have confirmed that these policies carry clear economic as well as environmental benefits. These policies would also create jobs, tackle fuel poverty and cut carbon emissions.

Instead, the government marches us all ever deeper into trouble with its austerity measures – a policy that is no way to tackle a financial crisis brought on through mismanagement of the financial system. And the Green Party, which has been saying this since 2010, is not alone: even the IMF has made it clear that austerity does not work, cannot work, and is not working.

And what of the Opposition? The Labour Party is snuggling up as close as it can get to the Tories – trying to be even more authoritarian, more repressive on human rights and law-and-order issues – stuck in the old model of ‘appeal to the Daily Mail’s swing voters to get elected’ – and still wedded to the old economic models.

I am frustrated, too, when I meet campaigners from Occupy, UK Uncut, or even passionate RSPB members, who say they don’t vote and are content not to get even minimally involved in electoral politics because they don’t see the point. Campaigning, whether scaling giant chimneys to protest against emissions, developing a local community food-growing scheme or signing a petition, is vital, and does sometimes get results, but ultimately it is in your local council, the London or Welsh Assemblies, Westminster and Brussels that decisions are made and the future path of your locality, your country, your world decided.

Lobbying, campaigning and protesting haven’t yet put us on the right path with politicians who profoundly do not understand that the current economic model is broken, that we need a radical transformation of all of our systems – of production, of consumption, of education, of employment, of living.

Only electing representatives who think like this – who fundamentally, in their hearts, understand and believe that we cannot go on as we are – is going to bring real change to the heart of governments. Believing that, and trying to achieve it across the country, is what now gets me up in the mornings, drives me through days and weeks on our overcrowded, creaking rail system, and propels me through such questionable delights as debating with Peter Lilley, Simon Hughes and Nigel Farage on national television.

We as a society, as a species, as a planet, need to change – and we need to change fast.

The Green Party has upset all the odds to advance to modest electoral success. But we must now move much faster, step on the ‘change accelerator’. To do that we must explain how we can deliver a better life for voters – and be in a position to secure their future, and that of their children and grandchildren.

Natalie Bennett is Leader of the Green Party of England and Wales. www.greenparty.org.uk