By Olaf Corry, The Open University

It is set to be one of the largest ever coordinated protests. The People’s Climate March is due to take place in cities all over the world this weekend to try and influence the UN climate summit that follows on September 23. The marches promise to be a major global event, billed by organizers as an “unprecedented mobilization”.

No doubt it will be enjoyable to take part in – but that’s no guarantee it will work. The anti-war protests in 2003 mobilized somewhere between 6 million and 10 million people across 60 countries but famously failed to prevent an attack on Iraq. There is of course a substantial risk that a climate change march will similarly have no immediate discernible effect on climate policy.

On the other hand, the 2003 anti-war demos may still be affecting debates about the use of force and security and ongoing efforts to take account of opinion. Popular protests have of course toppled governments and even political systems before. And sometimes it takes years or even decades to recognize what protests and revolutions really meant, including wider changes in values and priorities. So it is not that simple.

A better question is: when does protest work, and when not?

Sorting out clear causal effects and hard and fast rules in systems as chaotic as entire societies is of course nearly impossible. But social science research tries anyway. Current findings seem to indicate a few things which will have a bearing on the success or otherwise of the People’s Climate March:

Firstly, even if marches come and go without immediate effect, one review ventures that public opinion matters to policy-making “roughly three quarters of the times”, especially by making issues “salient”. If protests actually affect public opinion then they can work indirectly.

Obviously mobilization is then required: you have to be in it to win it. Among political sociologists “resource mobilization theory” emphasizes the importance of the ability to mobilize support and marshal resources effectively. Be big and beautiful as a movement. At the same time, tightly co-ordinated action has been linked to success, and efficient organizations therefore seem also to be a key factor.

Other research indicates that mobilization is not enough and organizations don’t matter much. A rival theory focused on “political opportunity structures” says that mobilization happens all the time – what matters is contextual factors and whether the system is ready. In particular, there have to be strong allies on the inside to convert pressure from the outside into policy change. These days media framings of protest appear also to be important, but they are rarely kind to direct action protests. Inevitably, timing also matters. A crisis moment can be a perfect moment to break down institutional barriers – although it may also make the system close ranks.

In sum: luck is when preparation meets opportunity, as Roman philosopher Seneca reputedly said (long before sociologists reached a similar conclusion).

To maximize chances of success, climate change marchers will need a lot of factors to come together: high mobilization and wide public sympathy, strong allies on the inside, a constructive media and perhaps a crisis of some description to weaken the defenses of the vested interests blocking decisive action.

How does this bode for the People’s Climate March? Overall, quite well.

Firstly, public support for climate action seems to have risen slowly but steadily over the past 20 years but evidence shows that globally awareness is patchy and there is clearly potential for more awareness and support to be garnered. If the march is to add to – rather than detract from – this then size, but also charm, will be important to winning over public opinion:

In terms of size, the march itself appears to be well co-ordinated: events are autonomously planned in more than 2,500 locations (compared to 600 in 2003). There are multiple agents in multiple cities and countries, with a clear message that is being communicated effectively via social media. It may beat the 2003 record set by the anti-war demos – but social movements are unpredictable entities.

In terms of beauty, organizers are committed to non-violence and peaceful demonstration, which is a good start. If the media focus on the festival rather than the fringes, even better.

Secondly, to be a success, the march should be adding its weight to some strong “internal” actors and institutions with similar ideas who can take things forward more consistently – what is sometimes called an “advocacy coalition”. The coalition is probably growing. The scientific community started it of course, and pressure groups and some politicians have taken it up. But businesses have begun to come on side as the opportunities for energy transition and new industries become apparent.

The march may be part of a coalition, but to be part of a winning one, it has to match – and eventually overcome – opponents to change. And there are still strong opponents and almost intractable problems in organizing collective actions as states wait for others to take the lead.

On the other hand, for some, the global fossil fuels industry is showing signs of a crisis of sorts, as record investments have failed to bring commensurate new supplies on stream. This could be the right kind of crisis, if renewables keep falling in price and utilities are left floundering – although another financial crisis triggered by a carbon bubble bursting probably won’t help much. In any case, urgency dictates that now is probably the best time to try to make headway.

However, the biggest problem in predicting success is perhaps that it is not clear what “winning” really would look like. Climate change is such a wicked problem, that it shouldn’t really be considered as a single problem at all.

Dealing with climate change means addressing numerous different goals and dilemmas, not all of which can be solved at the same time. Preventing more than two degrees of global average warming acts as a rough proxy, but for some this is too much and averages miss the point anyway.

But that should not worry the marchers on Sunday unduly. Their job is primarily to push the question, garner salience and apply pressure. And to enjoy themselves.

Olaf Corry, Lecturer in International Relations at The Open University, does not work for, consult to, own shares in or receive funding from any company or organization that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.