I’ve never written such a grand title for a blog before. Perhaps I should just have called it ‘the inevitable Brexit blog’. But portentous times call for portentous titles; if there was ever a moment to rethink the big questions, surely this is it.

Since last Thursday, like everyone I’ve been transfixed by the political tragicomedy unfolding by the minute. But I’ve also had half an eye on reactions from the environmental community. I won’t go into the details of the likely effects of Brexit for environmental policy. Matthew Spencer does that well, in his impressively lucid morning-after blog; as does Simon Evans with his unsettling ninety-four (yes, ninety-four) questions about Brexit, energy and climate; and then there’s this piece by Michael Jacobs. In the very short term, we seem to be ok. It was certainly very good to see, amid the turmoil, the government committing to further carbon cuts just a week after the vote.

But longer term, we need to reflect on what the results mean for the way we work. I’ve been thinking about two, linked tendencies of environmentalists (shared by many others in the world of policy and government). Tendencies which the referendum result has thrown into stark relief. The first is a tendency to groupthink; the second, an urge to do policy by stealth.

First, groupthink. The referendum campaign showed that those of us working on environmental issues, whether in politics, the third sector, business or academia, share a common outlook. Our world at work and home reaffirms our shared views and excludes different ones, further strengthened by the confirmation bias of social media. And we are overwhelmingly Remainers. Green Alliance did some great work putting forward the green case for the EU.  Scientists and university leaders were unanimous in their support for the Remain cause. But who did these messages reach? Did they make any difference to the result? That’s not to say that we shouldn’t speak out. Just that we shouldn’t expect to reach beyond our own supporters unless we work very hard to find different ways to engage.

Second, policy by stealth. I often hear people, including politicians, say that we don’t need a popular mandate to cut carbon or to protect the environment. Scientists and experts can tell policymakers what to do; we can shift from high-carbon to low-carbon without anyone noticing. We can call it something else: tackling congestion, economic regeneration, anything but environmental protection. In short, leave it to the experts. If you subscribe to this view, then the popular uprising of the referendum is more or less irrelevant. Hence blogs like this one, from E3G, arguing that the referendum wasn’t about the environment, that the fundamentals of the green economy haven’t changed, and that we don’t need to worry.

I am not so sanguine. These two tendencies, to groupthink and to do policy by stealth, are deeply problematic. We cannot, and should not, decarbonise our economy or protect our natural environment without involving and engaging people. The idea that we can transform transport and energy systems, and change consumption patterns, without people noticing, is nonsensical. The brilliant book by Deborah Mattinson, Talking to a Brick Wall, explains what happens when politicians don’t take voters seriously. She was one of the few people in my Twitter feed who wasn’t surprised by last week’s result. As she has been saying for some time, you can’t ignore or dismiss people’s genuine values and concerns, or leave them out of the debate.

What, then, can environmentalists take from this whole sorry episode? What do we need to do differently?

First, and most obviously, we need to engage and involve people. We should prioritise policies and projects which connect with everyday life. We should make connections with other causes, from tenants’ associations to local business groups. Two examples of this: the amazing work that Trafford Hall does, providing training and support to build sustainable communities; and the upsurge in community energy projects, which I’ve written about elsewhere.

Second, we need to advocate for, and contribute to, proper local and regional policy. Not just for the cities, where environmentalists tend to focus their attentions, but for the suburbs and the small towns, who feel forgotten. Green Alliance’s Constituency Voices programme, which brings MPs together with stakeholders in their local area to plan and advocate for low-carbon solutions, is one such example of this.

Third, and most promising, we need to acknowledge the generational shift. We all know that young people voted overwhelmingly to remain; they are also more worried about climate change, and more supportive of environmental action. For me, the highlight of an otherwise dismal few weeks was the We Are Europe campaign, run by young people (and supported by E3G, Jonathon Porritt, Caroline Lucas and others) with a relentless focus on the positive. Campaigns like this could form the basis of a recovery strategy for progressive politics.

I can see a way through this sorry mess, for our country and for the environment. But not if we just keep calm and carry on with the old ways. We owe it to ourselves to reflect, and to learn from the mistakes that we, and many others, have made.