Let’s talk about the dream, not just the nightmare. Imagine the cities and towns of the future: clean, green, with decent air quality, hospitable to walking and cycling, powered by renewables, with green space, not concrete jungles, and rewarding jobs in green industries. That isn’t just a conceit for the imagination but a tangible vision of the future produced today by Common Wealth, the thinktank of which I am a board member.

Tackling the climate and ecological crisis requires urgently reimagining how we live and work. A Green New Deal – conceived of in the UK, popularised by US congresswoman Alexandria Ocasio-Cortez and now powered by social movements here – should not just decarbonise today’s economy but build the sustainable and just economy of tomorrow. That’s why imagining a town transformed by a just transition to a low-carbon future isn’t just a nice piece of design, it is an essential symbol of where the climate movement now needs to take its case. That movement has an unprecedented chance to be heard as a result of the spectacular success of Extinction Rebellion and the school climate strikes in refocusing public attention on the urgency of action. But now, with people listening once again, our duty is to offer a compelling and attractive vision of the future.

The way we do this is by connecting the two great long-term crises that confront us today: the climate emergency and inequality. This is how we construct a broad and durable coalition that can sustain this unprecedented transformation. As well as truth-telling about the disaster that will confront us if we do not act, with the costs falling on those least responsible, ours must be a story of how we build a more equal, prosperous, democratic society.

For far too long, progressives – myself included – have talked about the climate emergency and economic justice separately

The lesson of history is that successful political movements that have confronted grave injustice have driven people forward through a sense of how we can surmount crisis and offer better lives on the other side. As Nicky Hawkins argued in the Guardian last week, Martin Luther King is remembered for proclaiming at the March on Washington “I have a dream” not “I have a nightmare”. We need to collectively outline that dream and decide what our society will look like.

For far too long, progressives – myself included – have talked about the climate emergency and economic justice separately. Tackling economic injustice has too often been discussed as if the climate crisis were not racing towards us like a runaway train, rooted in wider economic and political inequalities, notably the vested interests of the fossil fuel companies. On the other hand, the climate disaster has often been seen as a technocratic problem to be solved, ignoring the immediate and urgent needs that people face in their daily lives.

If we carry on with this approach, we will not succeed. Disaster avoidance in the coming decades is a moral obligation of the highest order. But if we simply offer sacrifice without hope, we are destined for carbon reduction to be seen as a luxury for those who can afford it and to send the message that economic injustice has to wait its turn. The truth is the opposite: those who can afford it will be able to avoid its worst impacts while the poorest and most vulnerable will pay the price. Despite the poorest half of the world’s population being responsible for just 10% of CO 2 emissions, developing countries will bear an estimated 75% of the costs of climate crisis on current trends.

‘Developing countries will bear an estimated 75% of the costs of climate crisis on current trends.’ Villagers in Bangladesh walk on a dry river bed. Photograph: Zakir Hossain Chowdhury/Barcro

Tackling the climate crisis offers a profound opportunity to create better lives for people. We need to change the way we heat 27m homes and power our industries, take 40m petrol and diesel cars off the road and plant tens of thousands of hectares of trees every year. In other words, we need the biggest peacetime mobilisation of labour, land and investment we have ever seen. From an economy that doesn’t work for the many, a green industrial revolution can provide meaningful, decently paid work, and we can pay for it in a way that is fair and confronts the big vested interests that would stand in the way.

This represents just the start of what we can achieve. Think of the quality of life improvements we can make if we take on air pollution, the silent killer of thousands of people every year. And once we begin to confront the way our economy is configured, how we measure and produce value, the hours we work, the way we consume, a truly different world is possible.

Net-zero emissions by 2050 should be the start of our ambition, not the summit. The Committee on Climate Change says the scale of private and public resources required for the long transition to 2050 is just 1-2% of GDP. Moving farther and faster will require greater focus, mobilisation and resources, but there are clear economic and environmental gains from doing so.

If this is the vision, the “how we get there” question becomes essential. That is the purpose of the cross-party Institute for Public Policy Research’s Environmental Justice Commission that I co-chair with Caroline Lucas and Laura Sandys. We are determined to provide a route map to the new economy, including a just transition for those who will be affected by the end of the fossil fuel economy.

David Bowie said that “tomorrow belongs to those who can hear it coming”. The risk is that the climate emergency overwhelms us and our children and grandchildren, and we will be remembered ignominiously. The opportunity is here to seize the chance to remake the country for the better. That is not only our moral obligation, it is the best hope of success.

• Ed Miliband is Labour MP for Doncaster North and a former leader of the Labour party