There are moments to talk and moments to act. Almost four years ago, sixteen Greenpeace activists agreed that the huge risk posed by the Cofrentes nuclear station near Valencia, Spain, required concrete and public action.

On 15 February 2011, they entered the nuclear power plant and painted "Peligro Nuclear" (Nuclear Danger) on one of its cooling towers.

Tomorrow, the sixteen activists and an independent journalist who was documenting the action are facing trial for their actions that could sentence them to almost three years in jail. Moreover, Greenpeace Spain may have to pay a fine of about €360,000.  It will be the harshest trial in 30 years of peaceful activism in Spain‎.

I repeat. There is a time for talking and a time for action. Yesterday afternoon, the Greenpeace delegation at the Conference of the Parties (COP20) in Lima, Peru, decided to take a stand in solidarity. We want to believe that climate negotiations are a place of action! This is why we call for your support – media included – by holding up and spreading the message "#Cofrentes17" in solidarity with our 17 activists. Anyhow, the Spanish Constitution is on our side. Article 45 explicitly says, "Everyone has the right to enjoy an environment suitable for the development of the person, as well as the duty to preserve it".

#Cofrentes17 protest at COP20, Lima, Peru

That said, we ask the negotiators present in Lima to take this message back home and guarantee the right to protest everywhere in the world. In the 21st century we cannot allow any country, not Spain, not Peru or any other country, to disrespect the right to protest as a means of influence and transformation. The biggest revolutionary tipping points have been as the result of protest – from the abolition of slavery to the recent uprising for more democracy in Europe and around the world.

At COP20, world leaders must identify and commit to actions that will avoid the worst impacts of climate change. The #Cofrentes17 – as thousands of supporters know them in social media – acted to bring attention to the dangers of nuclear power: the most expensive, risky and centralized energy source. It cannot be considered a solution to climate change or an option to fulfill the global goal of universalizing energy access.

We are confident that the court in Valencia will hold up Article 45 of the Spanish Constitution and we expect the activists to be acquitted from all charges. We hope that this trial will reinforce the right to peaceful protest in Spain and everywhere, while putting a spotlight on the high risks associated with nuclear power.

Spain needs to undertake a transition from nuclear energy and fossil fuels like coal, gas and oil to safe and clean renewable energy. If we want to avert the worst effects of climate change and prevent environmental disasters, e.g. the one close to the Mediterranean coast near Tarragona, Catalonia, a few days ago, we have to phase out dirty energies and phase in solar and wind energy.

To protect the environment, and boost the economy, we need to start a just transition towards a system based on 100% renewable energy for all in 2050. It should be made a priority in Spain and is one of Greenpeace's main demands during COP20 in Lima.

We hope to build on the #Cofrentes17 legacy and abandon the era of fossil and fissile fuels.

We look to a future that is fair and sustainable and supports freedom of speech and democracy. A future in which citizens benefit from an energy community unified by renewable energy.

The dream of a green and peaceful future gives us the strength and courage to take action and keep the future of humanity in our hands.

Mauro Fernández is a climate campaigner with Greenpeace Argentina and is based in Buenos Aires. He is following Latin American perspectives during the limate talks in Lima.

Note: This blog was updated on 5 December 2014 to clarify the text extract from Article 25 of the Spanish Constitution.