I want Britain to stay in the EU because I believe that we flourish when we work together on the shared challenges we face. That's not to say I don't understand why some Greens are sceptical; a cursory glance at what's happening in our continent shows that the EU isn't always beneficial to progressive environmental and social justice policies here in Britain.
A closer look reveals that the picture is not black and white, though. Whilst the EU too often reflects the current British government's zeal for privatisation and deregulation, historically there is a lot to celebrate. Even today, our EU membership offers us protection from the Tories' worst instincts. And - crucially - the EU offers us a way of working across borders to make things better and to achieve social and environmental progress, which simply would not be possible if the UK were to walk away.
TTIP - A taste of things to come if Britain was to go it alone
One cause for scepticism is the transatlantic trade deal, TTIP. This epitomises everything that's wrong with the neoliberal economics that dominates Europe: back-room decisions, corporate power, and threats to workers' rights and public services.
But those who hope that leaving the EU would make Britain's trade policy fairer are, to be frank, fooling themselves. The UK has already signed bilateral deals incorporating investor-state dispute mechanisms (ISDS) allowing companies to sue states for risking their 'future profits'. Indeed, the Tory government is a driving force for TTIP - and David Cameron one of its top cheerleaders.
If we left the EU, then we could be left with what pro-Brexit MPs describe as the 'WTO Option', which could mean the roll-out of multiple TTIPs on steroids as Britain negotiated trade deals across the world.
Mounting pressure from citizens, campaigners and progressive politicians has forced the EU to open up TTIP to more scrutiny. Eventually, MEPs will vote on the final deal, and we must make sure they know they won't get away with waving TTIP through.
The attack on Greece - right-wing governments enforcing austerity
Another concern is the imposition of austerity on Greece - and the deep damage it's caused. But to lay the blame simplistically on the EU is short-sighted. With the European Council made up of ministers from each EU country, it often simply reflects the prevailing currents in European politics. The imposition of austerity in Greece shouldn't be surprising considering Merkel's right-wing government and the Tories' slash and burn policies here.
Institutions like the European Central Bank or Council are anti-democratic, but to give people a real say in Europe, we must prise open the doors of power, not throw away the one structure that could regulate the cross-continental market's excesses.
Brexit would do nothing to help the Greek people. We need more pan-European solidarity, resistance, and collaboration - not less.
Environment - cross-border challenges need cross-border solutions
Not infrequently, I'm furious that EU environmental and climate policies don't go far enough, but we must remember that some of our dirtiest power stations have been closed, our beaches are cleaner, our air less polluted and our wildlife far safer because of EU rules and directives.
Pollution and environmental degradation don't respect national borders. I'd rather be working hard to ensure EU decisions deliver bolder cross-border solutions than spend the next three years scrabbling around to salvage scraps from the nature directives.
Doing things differently - a new EU
Ultimately, I believe that the European story should be celebrated. Countries with different histories and cultures have come together, sharing sovereignty while keeping their own traditions, to work together for the common good. The most profound achievement of the EU - helping to maintain the continent's lasting peace - mustn't be forgotten either.
Walking away from the EU would put at risk our rights at work, our environment and our ability to influence the rules that will still affect us. Added to that is the profound risk that Brexit poses to our multicultural and multinational society. But if we're going to stay in the EU, we need a vision of how we can improve things.
The EU will only change if we work together with people from across the continent. Earlier this year, campaigners and politicians from across the continent gathered in Berlin to discuss how we'll win Europe back for the people. For a start, that means democratising the EU structures - making top meetings like the European Council open to the public through livestreaming, giving more power to elected politicians over unelected commissioners, and ending the culture of secrecy. It means further clamping down on corporate lobbyists - something that's already begun in the EU, and which Westminster could learn from. And it means thinking big about EU policies that would make all our lives better, such as cross-border minimum wages (adjustable to ensure everyone earns enough to get by on where they live). Much is still to be decided - but these talks are a solid start.
We've also seen the launch of a number of exciting campaigns here in the UK, from Environmentalist for the EU, to Another Europe is Possible and Students for Europe.
The Green Party also has its own campaign - Greens for a Better Europe - which is making our own case for 'In', keeping the emphasis on how we can improve the EU. The progressive case for British membership of the EU, side-lined for too long, is now being made loud and clear.