Freedom of expression is a universal human right that affects all of us.

As Greenpeace activists we affirm this right when we campaign to save the Congo Basin Rainforest from illegal logging, or when we take on industrial trawlers who are plundering our oceans in West Africa, and call instead for a sustainable locally-owned fishing industry.

But sometimes, during our protests, we are denied the right to freedom of expression. The Arctic 30 were detained for a crime they did not commit – exposing Gazprom’s dangerous drilling plans in the Arctic. The same thing happened to Pussy Riot, who were jailed for having a different opinion on Russian society, and then there are the journalists from Al Jazeera, currently held in an Egyptian prison, who are suffering the same fate: they are being held hostage.

Al Jazeera’s Global Day of Action: Journalists and Human Right activists hold a silent protest in Beirut, Lebanon

The journalists were accused by Egypt’s military government of having ‘links to a terrorist organisation’, they were jailed, and after months of no trial they finally appeared in court for the first time on the 21st of February. Their trial has since been adjourned to Wednesday the 5th of March.

Egypt has experienced widespread repression of journalism and civil society since the military government seized power, and the troubled North-African country has been ranked by The Committee to Protect Journalists as one of the deadliest countries in the world for journalists

The stories that have surfaced about the prison conditions these journalists are facing are disturbing: Stories of people being stripped naked and walked between two rows of twenty guards on either side, beaten and battered all the way, stories of these innocent journalists being locked up for 23 hours a day, and being denied their right to see the evidence against them.

Repressive governments and unethical corporations cannot be trusted blindly. I believe that investigative journalists make the world a better, more transparent place by exposing these villains as they really are, giving us - the public - valuable insights into the true workings and the true motivations of these institutions. In short: They give the power back to the people.

Speaking of people-power…

An online #FreeAJStaff campaign has had a quarter of a BILLION hits on Twitter. In addition, and as part of Al Jazeera’s recent global day of action, public protest events took place in diverse cities from Manila to Montreal, from Ankara to Amman, from San Francisco to Rio de Janeiro.

In Sanaa, Yemen, Tawakkol Karman, 2011 Nobel Peace Prize winner, joined human rights activists to demand the journalists’ release. The White House, The European Union, The United Nations, as well as a host of civil society organisations including Amnesty International have also called for the release of the journalists.

Many more thousands of individuals - ordinary people - from every corner of the world, are also standing up in support of this campaign, affirming theirs and everyone else’s right to freedom of expression, and helping to bring home the message that telling the truth is not terrorism.

You can join the movement too: Tweet with the hashtag #FreeAJStaff, and follow Al Jazeera online for information on public mobilisation events in your city.

For me the bottom line is that regardless of whether you’re an environmental activist, a women’s rights activist, a journalist, or a human rights activist, we need democratic space in order to function and make our voices heard. Without the space to voice opinions and create new ideas, all activists and change makers are repressed and stiffled. A threat to one is a threat to us all.

These journalists will not stand alone. The world is watching.