Sir David Attenborough’s lasting legacy may be to galvanise efforts to tackle climate change, writes Joyce McMillan.

The title itself is a small work of genius: the words ‘Blue Planet’ remind us both of those heart-stopping images of our glowing blue world spinning in space – first seen by human beings just 45 years ago – and of the truth that our oceans are the dominant feature of that world, vast, beautiful, and still full of exotic and incredible forms of life.

And in recent weeks, the world of social media has been full of people responding passionately to Blue Planet II, David Attenborough’s second BBC series on the Earth’s oceans; voices full of wonder at the astonishing natural world the documentary reveals, and of anger at its increasing destruction through global warming and the pervasive presence of human-made plastics even in its farthest depths.

Some respond with tears; some are inclined to despair. Yet many also launch petitions and begin to campaign; and slowly, governments are at last beginning to act, talking about forcing the recycling of plastics rather than their single use, or promoting the development of new biodegradable forms of the material that, just 40 years ago, seemed to be the key to our future.

Human beings often learn slowly, particularly where big money and big profits are involved; but we do have the capacity to learn, to invent, to create anew. And when Attenborough’s astonishing life as a broadcaster finally comes to an end, he will have left a mighty legacy, if his latest series helps to mark the moment when we finally cease to believe that the world’s consumption of plastics, and of hydrocarbons in general, can simply continue on its present path.

It may not be pure coincidence that this week, President Emmanuel Macron of France chaired a conference to mark the second anniversary of the historic Paris Agreement on climate change, and to increase the pressure on the 195 remaining signatory nations – Donald Trump announced the US would no longer participate earlier this year – to begin to make the accord a reality. In the course of the meeting, Mr Macron was able to announce not only a series of awards to climate change scientists – many of them from the US – as part of his cheekily named “make our planet great again” programme, but a landmark decision by the World Bank to stop funding upstream fossil fuel-based projects from 2019.

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This week also saw a striking victory by Exxon Mobil shareholders – led by an intriguing alliance between the Church of England Commissioners and the Comptroller of New York State – compelling the company’s management to adopt a planning process that begins to position it for a low-carbon future. In other words, this recognises that many of their reserves of fossil fuel will not, and can never, be extracted and exploited.

No one involved in the campaign to meet climate-change targets can possibly be complacent about progress so far, of course. Eighty-five per cent of the world’s energy consumption is still fossil fuel based; this week, a series of relatively small accidents to gas pipelines and supply systems across Europe came as a sharp reminder of our continuing extreme dependence on this particular fossil fuel.

Even governments with the strongest theoretical commitment to the low-carbon transition – including the Scottish one – struggle to escape the logic of the carbon-fuelled economy we have known for the last 250 years. Meanwhile, the news from those monitoring climate change is ever more grim. This week, scientists announced further alarming figures on the melting and thinning of Arctic sea ice, and on the possible melting of the huge Greenland ice sheet.

Yet still, there are reasons for hope. Even in the two years since the Paris Agreement was signed, the costs of installing and operating renewable energy plants have plummeted worldwide, with many countries beginning to bypass the hydrocarbon phase of economic development, and moving straight to solar power in particular.

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Many major car manufacturers have signalled their intention of switching entirely to electric car production, as technological improvements steadily overcome the traditional objections to electric cars; and while US politicians continue to equivocate and resist, both major companies and city and state governments across the US are beginning to switch investment towards renewables for purely practical and financial reasons, as well as in the effort to control climate change.

And alongside those economic changes, we can also glimpse something else; for just as we can see, looking back, that the ages of coal and oil forged our societies into particular patterns of industrial and corporate power, so renewables have the potential to change our society again, and perhaps to bring a vital aspect of the lives of individuals and communities back into their own hands.

Hope is possible, in other words; and it’s also true that despair is a waste of time. Interviewed by CBS this week, before the Paris meeting, Mr Macron had plenty to say – in a distinctly Blairite vein – about topics from terrorism to his personal relationship with Mr Trump. When it comes to the main threats to our global environment, though, he is right; and apparently willing – alongside other nations now making huge investments in renewables – to take a welcome and much-needed lead.

“If we decide not to move, not to change the way we produce and invest and behave, de facto we decide to condemn billions of people in the coming decades,” he told CBS. “And we will – I mean all of us – be judged for that. We do know that if we don’t react, we will be responsible for billions of victims. And I don’t want to be a leader in such a situation; so let’s act, right now.”

And he also said that one of the key tasks of politicians now is to offer people a vision of that sustainable future, and a way of contributing towards it; to protect, retrain and support people, as they make the transition to a new economy. All of which seems, in the time of Trump, Brexit, and other florid rebellions against 21st century reality, like something of a social-democratic pipe-dream; until we remember what our own history tells us – that we can, if and when we want to, make social-democratic dreams come true.