WHAT happens now that we’ve marched? An estimated four million people in 150 countries took to the streets on Friday – and will take to the streets again this Friday – demanding that governments the world over start tackling climate change in a serious and meaningful way.

The risk is that this becomes one great radical chic gesture – that pressure abates after the mass demonstrations and nothing changes. That we waved placards and then went home.

The problems of climate change are so profound that it’s easy to show we care, but very hard to do anything practical about it. The stark truth is that individuals recycling, cutting down on flights, using public transport or buying locally isn’t enough. Far from it. It will help – if every single one of us change our lifestyle – but alone, individual action is inadequate.

The aim of the climate strikes is simple – to save the planet. If we’re serious about that – and why wouldn’t we be – we need to face the fact that we have to radically alter the way we run our societies and economies. The bottom line is: we need to consume less as people and nations. That may sound easy, but it isn’t – it will entail massive disruption to our lives and economies. The challenge is: are we brave enough to accept these changes to make the world safe for our grandchildren?

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We fixate on oil and gas as if they’re the only demons in the climate change debate. The energy industry is certainly the greatest polluter of the planet by far, but we forget that farming produces 13.8% of the world’s carbon emissions. It takes 1000 litres of water to make one litre of milk. Road travel alone accounts for 10.5% of emissions. Deforestation 11.3%. Cement production produces 5% of the world’s carbon emissions. The chemical industry creates 4.1%, printing 1.1%.

So the great problem to be figured out is: how do we rein in production and consumption in order to tackle climate change, while still maintaining economic growth, the guiding light of every government?

The collapse of the travel company Thomas Cook sits slap bang in the middle of this debate. Of course, Thomas Cook wasn’t destroyed by consumer choice linked to climate change – it collapsed due to commercial challenges from internet rivals. But the collapse proves two things: firstly, people aren’t travelling less, they’re just travelling more cheaply with online companies not high street ones. So even as climate change becomes the biggest global issue, people are still not changing their lifestyles in any meaningful way. They might recycle but cutting out a holiday? No thank you.

Secondly, can we face more losses like Thomas Cook in order to tackle the climate threat? If we do become serious about change – if we feel production and consumption must be reined in to lower carbon emissions – then we’ll inevitably have to face some companies suffering and perhaps closing. Is the answer a dreadful utilitarian choice: will some people’s lives have to be ruined today to save the planet for the rest of us tomorrow?

Let’s look at ‘fast fashion’ as a case study. Cheap disposable clothing is a major problem when it comes to climate. The United Nations says the fashion industry creates 10% of all global carbon emissions. Are we comfortable with a high street fashion chain going under as a casualty of our climate struggle? Are we OK with people losing their jobs? Are we happy with the knock-on effect? For every redundant shop worker there will be fewer sandwiches sold in delis, fewer drinks in pubs after work. Less money.

This brings us to the issue of ‘degrowth’ – the biggest dilemma which we must debate as we try to go forward and tackle climate change. If you read economists who’ve put their minds to the question of how we fix a planet which is at risk due to overproduction and overconsumption, there’s little escape from the logical answer: we need to accept a limit to economic growth.

This is a hard battle to fight. Degrowth can and will be portrayed by business and industry as a recipe for poverty. It’s also an almost impossible sell to the public. Humans are inherently self-interested and short-termist – we can’t think of the next decade let alone next century. And the governments we elect are precisely the same.

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However, the other side of the argument is that recalibrating the economy away from oil and gas to green energy could trigger new economic opportunities. New energy sources like renewable hydrogen may well create new jobs. The narrative doesn’t need to be about decline and redundancies.

With will and ingenuity, we could do the same for other industries like food, fashion and travel. But that takes fierce collective action, and we need a paradigm shift in our thinking. Some say that the move toward a green world will take a step-change in human consciousness along the lines of the leap from kingship to democracy. When Athens started playing with democracy in the sixth century BC, the rest of the ancient world thought the city demented. The idea that rulers were servants of the people seemed absurd.

Can the intellectual leap we need to take to deal with the climate happen overnight? It seems impossible.

And we are yet to properly debate the fact that many parts of the developing world are still going through industrialisation while we in the Global North obsess – rightly – over climate change. Is it fair that Western nations which had their industrial revolutions 250 years ago should tell poorer countries not to develop?

No philosopher, economist, or political thinker has answered these questions. There has even been discussion around ‘green authoritarianism’ – the idea that only a strongman-style of government, which tramples over individual rights, could achieve the goal of forcing people, society and industry to change in order to save the planet in the time we have left to take meaningful action.

What climate protestors have done is start a conversation. The people have called for action. Now governments must respond with policies and put them to the people. Then we’ll find out if all of us who say we care about the climate are willing to accept the necessary sacrifices needed to save the planet.

Neil Mackay is Scotland’s Columnist of the Year