Green MPs will always fight against fracking, new roads ploughing through our countryside and expensive private homes chewing up the green belt. They'll always fight to ensure that climate action and social justice are dealt with together.
In seven months' time the most important climate negotiations ever will take place in Paris.
At those negotiations world leaders will sit down and decide the fates of millions around the world. Clear, bold action on climate change is possible - but it's far from inevitable.
Lord Stern has said that what's on the table is inadequate but there is still time to improve it. And even after Paris, we're going to have to keep campaigning, keep improving global initiatives to protect our environment.
You need to elect Green MPs to make sure there's a strong voice for action from the UK.
Climate change - a clear and present reality
We're already seeing the impact of climate change on our planet, on our wildlife, and on our communities. A study just last month found that extreme heatwaves and rainfall events are now at least four times more likely than before as a result of climate change.
Around the globe peoples' lives - and particularly the lives of the poorest and most vulnerable - are afflicted by rapidly increasing temperatures and increasingly unstable weather patterns. Year after year we're seeing violent storms, from Eastern Asia to the Caribbean, rip through communities.
In many parts of the world we're seeing farmers unable to feed their families or supply their communities, as crop failures become the norm.
And here in the UK, with summer temperatures rising, we're seeing older people suffer, and even die, from the excess heat, while floods menace communities in vulnerable areas.
We know we have to act, and we know we have to act now. And we need to act not just for environmental reasons, but also to tackle pressing economic and social concerns.
Leadership in arms sales, fracking, nuclear power and fuel poverty?
After five years of the sad sick joke of the "greenest government ever" - which the Centre for Economic Performance says has left us lagging behind most other OECD countries in clean technology take-up and innovation, Britain stands at a crossroads.
This election represents a decision point. What path will our economy, our society take?
Will it choose a dangerous, destructive dead-end, that will ultimately leave us stranded internationally, economically and environmentally? Or do we offer hope to the rest of the world, lead by example and embrace 21st century solutions to the problems that we face?
We're now a world leader in arms sales and in the fraud-ridden, dangerously unstable financial sector, with its heavy investment in the fossil fuel industries.
These industries threaten our collective futures. They are no kind of foundation for our economy or our society. Yet they are at the heart of plans offered by Labour, the Tories and the Lib Dems.
All three parties want us to pursue the fantasy of fracking as an energy source, ignoring the need to decarbonise our electricity supply by 2020. Conservatives and Labour want to build new roads and expand airports, ignoring the environmental and social impacts on communities.
None of the 'establishment parties' have the bold plans to improve energy efficiency on the scale that we need to both tackle fuel poverty in Britain and to cut our carbon emissions.
None have plans to break up the oligopoly of the Big Six energy firms, to democratise our energy supply and put it in the hands of communities and small local companies.
None have acknowledged that nuclear power is another failed 20thc entury dinosaur. Blow after blow hits the nuclear power sector. The two European plants under construction are wildly over schedule and over budget, and may not generate a single watt.
But the nuclear lobbyists still find government doors swept open before them, while policies fail to deliver for our renewable future.
Or real leadership for a green and sustainable Britain?
Only the Green Party is setting out the policies that could make Britain a leader in the technology we need to build a low carbon future, which is the only future we can have. It would be a future of tremendous possibility, of good, stable jobs and warm, comfortable, affordable-to-heat homes. A future with a stable climate.
The Green Party has set out how we can take real action now to help people live lower carbon lives. That's why we'd insulate 9 million homes in Britain - helping to end the scandal that is fuel poverty, and cutting household energy bills in the process.
It's why we'd renationalise our railways, and cut fares by 10% - to give people a positive alternative to using their cars. And it's why we'd invest 1% of GDP in research - to ensure that Britain is at the forefront of building the technology we need for the 21st century.
The truth is that we can't afford not to take action on climate change. The investment we make now, paid for by cutting new road projects, scrapping HS2 and ensuring that the richest pay their fair share in tax, will save us all money in the long run. The cost of inaction is far, far greater.
And my message to the people of Britain today is: if you want action on climate change and if you care about protecting our shared environment for generations to come - vote Green.
Voting Green can never be a 'wasted vote'!
By voting Green, you've got a chance to show whoever the next Prime Minister is just how much the fight against climate change matters to you. You've got a chance to send a message, loud and clear, to whoever is negotiating on your behalf in Paris.
Green MPs will do all they can to stop a Tory Government taking office, but if they do get back in you can rest assured that Greens will be on their case, holding them to account and exposing their shortcomings.
But, with a Labour minority administration looking increasingly likely, you've got a chance to elect a strong group of Green MPs who can have an effective influence on Ed Miliband on issues like fracking, home energy efficiency and breaking up the influence of the big six energy companies.
Green MPs will always fight against fracking, they'll always oppose new roads ploughing through our countryside and expensive private homes chewing up the green belt. They'll always fight to ensure that climate action and social justice are dealt with together.
On Thursday you've got a chance to send a clear message, and to send Greens MPs to Westminster.
Across the country, from Brighton, to Bristol and Sheffield, in my own constituency in Holborn and St Pancras in London, and here in Cambridge, our campaigns are strong and our commitment is unbending.
Vote Green - and Britain can lead the way in tackling climate change and building a sustainable future.
Natalie Bennett is Leader of the Green Party of England & Wales.
This article is the text of her speech given in Cambridge yesterday, 5th May 2015.