I’ve just returned from a Corbynesque country, where the state owns and runs the railways, where productivity is 27 per cent higher than in the UK despite workers having more annual leave, and where the top rate of income tax is 45 per cent for earners over £110,000 (US$170,000).

This country is France, and just yesterday in its great city auditorium in Paris, the French Foreign Minister, Laurent Fabius, respectfully addressed over 200 trade union delegates from every continent on our shared hopes and fears for the United Nations Conference on Climate Change that his government will host in Paris in 80 days’ time.

Fabius is a key figure because he will preside over the UN’s climate negotiations in December. The attitude in his address towards trade unions as a social movement could not provide a starker contrast to the hand shown by Prime Minister David Cameron’s government in the UK.

To the question of the role that unions can play to help secure a successful climate change treaty, Fabius said: "Paris is a turning point for our planet… The role of trade unions will be absolutely decisive."

To reach an agreement in Paris there needs to be a mobilisation of all of society’s forces. "For today, in aggregate, national plans to cut carbon emissions are leading us towards 3 degrees of global warming by the end of the century," he said.

Fabius candidly acknowledged that trade unions are on the front line of industrial transformations that lie ahead, whether in coal mining, power generation or industrial sectors. Yet in retraining and new job creation, "unions are in a great position to be a part of the transformation that workers are facing."

Turning to the migration crisis that Europe is facing, counted in the hundreds of thousands of refugees, Fabius said:

"If we can’t act on climate change, with whole nations facing inundation, can we imagine what that would mean for migration? We would have to add zeros to that number."

And as he addressed his audience in such respectful and warm terms, my mind returned for a moment to another country where the prime minister had just that week launched an ideological attack on trade unions, and where his chancellor is dismantling the state’s renewable energy strategy.

This country is the United Kingdom. As Frances O’Grady, General Secretary of the UK’s Trades Union Congress (TUC) stated at its annual congress this week:

"History will remember this Conservative government’s Trade Union Bill as the biggest attack in thirty years. Not just against trade unions, but against our best chance of raising productivity, pay and demand. Because here is a simple truth: you can’t create wealth without the workforce. And you can’t spread that wealth around fairly without trade unions".

The 2015 TUC Congress supported the trade union mobilisation around the Paris climate talks and promised to back the national march for climate, justice and jobs on 29 November in London.

In Paris, the conference host, International Trade Union Confederation (ITUC) General Secretary Sharan Burrow, set out the "top trade union line demands" for the UN conference, aka COP 21:

• Raise ambition and realise the job potential of climate action
• Hold global warming to below 2 degrees above pre-industrial levels
• Deliver on the US$100 billion of climate finance a year by 2020 for developing countries to help counter climate change impacts
• Commit to securing a just transition for workers and their communities

Burrow told Fabius that "we want to see workers and their families at the heart of this agreement….we have to set the planet on a just and sustainable path….social dialogue is essential to the industrial transformation that lies ahead".

Once again, the ITUC emphasised the importance of including the operational language of just transition and decent work as objectives of the Paris agreement.

A Ghanaian delegate to the conference, Kingsley Ofei-Nkansah, General Secretary of the Agricultural Workers Union of Ghana, asked the Minister how the UN conference will deliver the financing and energy transition needed in Ghana? With unemployment accelerating, especially among the young, and the impacts of climate change growing, he told Fabius:

“We count on you to deliver on investment and justice, to tackle the climate change impacts happening not now but yesterday….What firm assurances can we have?”

Social movements including trade unions are mobilising for major national demonstrations in cities across the world on the weekend of 29 November, on the weekend before the UN deliberations begin. Under the banner, It’s Time to Act UK unions including UCU, PCS and Unison and the FBU are preparing to be represented on the UK national demonstration in London.

This is an edited version of an article that first appeared on the TUC’s Touchstone blog.