One and a half degrees celsius of warming is a decade away — going by conservative estimates. Previous estimates of the 1.5 degree mark have been brought forward, so the countdown is more than on. Though we continue to hurtle towards environmental and social breakdown, shoots of hope have started to emerge. The urgency and scale of the crisis is finally being realised, leading to a surge in popularity for a Green New Deal (GND). In a UK context its parameters are hotly contested. We need to find progressive consensus on it soon, otherwise it will be vulnerable to co-option.

The popularity of the GND owes largely to the latest phenomenon in US politics, Alexandria Ocasio-Cortez (AOC). She, supported by the Sunrise Movement, has brought the interrelation of our ecological, social, and economic crises to the fore. In doing so, she has made a truly historic contribution to the debate around systemic change. Her framing of the policy programme has been instrumental to its popularity; as a programme for radical transformation of the economy, and an ambitious yet pragmatic plan to transition to a low carbon economy.

AOC’s Green New Deal takes its inspiration and name from Roosevelt’s New Deal — a policy programme created in reaction to the Great Depression. Both programmes aim to shift the economic paradigm; the New Deal catalysing a transition from laissez-faire economics to Keynesian liberalism, and the GND aiming to guide America out of neoliberalism into a just, sustainable, and democratic socialism.

AOC’s proposal guarantees the total decarbonisation of America’s economy in a decade, and the guarantee of quality jobs to realise this. The resolution on the deal put forward to the House of Representatives promises US citizens access to high quality healthcare, energy efficient housing, healthy air, water, and food, education, a clean transportation sector, and limits on monopolies. Its policies prioritise improvements for vulnerable communities, aiming to alleviate poverty, racial injustices, and many other social inequalities. It is, in short, a clean break with the path the world’s largest economy has travelled in recent decades.

But it’s not just in America that a Green New Deal holds resonance. Progressives across the globe have been paying attention to its evolution, leading some to dub it the most fashionable policy in the English speaking world. In fact, its original comprehensive definition came from the UK-based Green New Deal Group convened by the New Economics Foundation in 2008. Scuppered by the financial crisis and insufficient support, the policy programme never broke through to the mainstream.

Fast forward a decade, with the UK’s problems mirroring those in America, it has returned in Britain with new-found confidence and, crucially, support. Public concern about the environment is at a record high. It is seen as the third most pressing issue by the UK public (after Brexit and health), for the first time ever polling above the economy, crime, and immigration. It makes sense, then, that a Green New Deal should be supported by MPs across the House of Commons.

But, depending on whom you ask, the central features of UK Green New Deal look quite different. Among progressives, there are debates around the extent to which it should, as a truly just programme, begin to compensate for the extractive model integral to the Global North’s economic success and provide reparations to the Global South. There are differences in the deal’s remit, some advocating for a pan-European or even pan-Western GND, as the only feasible approach to tackling the inherently international climate crisis.

The GND’s flagship policy of decarbonisation is perhaps the most hotly contested. First, there is the question of defining what exactly decarbonisation means. Is it zero emissions, which would mean potentially closing UK airports, for example, or is it net zero, the cumulative total of greenhouse gases we emit and take from the atmosphere being zero? Then there are wildly differing opinions on the date on which we achieve this. Extinction Rebellion are calling for 2025, Labour for a Green New Deal say 2030 while other progressive voices have argued it must happen by 2050. The implications for policy, lifestyle change, and investment needed are poles apart under these scenarios.

The final area of disagreement around a UK GND is its attitude towards growth. Some are in favour of de-growth, others clean growth and yet more are what we might call ‘growth agnostic.’ All are united in believing in the need to change an economic orthodoxy that is pro-growth at all costs, but consensus on what exactly to do about growth — which is the basis on which we measure economic success today.

To prevent a UK Green New Deal becoming simply a catch-all, or worse a catchphrase, I propose four immediate priorities: red lines, a political strategy, consensus on framing, and a stronger emphasis on adaptation to environmental breakdown. Without these, there is a strong risk of any coalition breaking apart on contact with political reality and, thus, momentum being lost for the initiative.

On red lines: we need to define what exactly a UK GND is. Not all the debates above need to be settled, but some do. Consensus on a target decarbonisation date is a logical starting point, after which decisions can be made on speed of sectoral decarbonisation, cost, resources, and so on. Practical considerations must be taken into account — to give one example, the scaffolding needed to retrofit homes with insulation to make a 2025 net zero target does not currently exist in the UK.

After this, a feasible political strategy must be developed. The beginnings of this can already be seen in plans like Labour for a Green New Deal’s conference motion (Tribune readers should get behind this at labourgnd.uk). As AOC’s model shows, with hope and ambition much is possible. But it’s also clear that her proposal is struggling to get off the ground in the US Congress — a socialist-led Labour government gives us a far greater chance of making a breakthrough. But to do this we need to honestly assess where it would fall in that government’s list of priorities, who its strongest backers would be, how to win over those wavering — particularly comrades in the trade union movement concerned about members’ jobs — and how to isolate its staunchest opponents.

Third, we need consensus on how a UK Green New Deal is framed. The name, for a start, is worthy of debate. ‘Green New Deal’ does not have the same resonance in the UK, with a poll in March showing over 90 per cent of citizens had heard ‘not much’ or ‘not at all’ about it. In the same poll, the majority of people had no idea what it could be about, and only a third of people thought ‘environmental issues’. This is a significant problem in an era when the public are more open to bold climate solutions.

Finally, to have longevity, a UK GND must have a greater focus on adaptation to the environmental breakdown. The crisis we find ourselves in will not have a quick fix. Most likely we will still be polluting for decades to come, and environmental, social, and economic crises are will compound over our lifetimes. Any GND should prepare for this, looking for answers to questions around exponentially increased global migration, civil unrest, and food shortages.

We are living through a time of political danger and opportunity. The challenges above are surmountable, and the Green New Deal could be an antidote to our crumbling system. Progressives need to act strategically and ambitiously to seize this moment — or we face the reality that much nastier alternatives will emerge.