President Hollande of France called them “heroes” because they championed freedom. Fellow journalists and great crowds of citizens across Europe came out to pay tribute to the Charlie Hebdo journalists whose work cost them their lives. It has been an impressive first public response.

Has journalism got more dangerous? Yes, certainly, in that the jihadis in Europe, as well as the Middle East, have vowed to wreak ‘revenge’ for perceived insults or Western governments’ actions on many targets, including media ones.

The French magazine with the most biting satire was a known target, but it has still come as a thunderbolt to many that it was singled out for such a brazen and murderous attack, in which individual journalists and cartoonists were sought out and murdered in cold blood. Charlie Hebdo’s security defences proved useless against a military-style assault. And we now know that it could happen to someone else in another European city – not just in Syria, Iraq, Somalia or Mali.

Security measures will be reviewed by media houses as well as governments. At this moment it is worth reflecting that, while the scale of the horror is new, the massacre is part of a sinister and much wider trend. It should be understood in the wider context of the growing number and scale of threats and acts of violence by non-state groups – as well as in many cases by agents of state authorities – which are aimed at silencing critical or troublesome voices.

Data from non-governmental organisations shows that in most of the world doing journalism that challenges powerful interests has become increasingly dangerous for your health over the past couple of decades. And reporting on politics, corruption and abuses of state power is just as dangerous as reporting on wars. The single most bloody mass-killing of journalists happened in the Philippines in 2009. Thirty-two journalists were among more than 50 people ambushed and murdered in a case that has been linked to a powerful political clan.

According to Unesco figures, 81 journalists were killed because of their work last year. Syria, Ukraine, Iraq, Gaza and Somalia saw the highest death tolls.

For many years the great majority – nine out of 10 – of the journalists who have fallen victim to murder and assaults have been local. But 2014 saw a steep rise in deaths of members of the international media.

According to the Committee to Protect Journalists (CPJ), as many as one in four of the journalists and media workers killed on the job last year were members of the international press. CPJ has published a figure of 91 deaths, including 19 for which no motive has yet been established. And Western journalists are still among at least 20 still thought to be held captive in Syria by Isis fighters. CPJ also reported 221 journalists in prison in 2014, most of them on legally unsound anti-state charges.

Among those killed in the past year were Anja Niedringhaus, a German photographer for Associated Press covering elections in Afghanistan, and the US journalists James Foley and Steven Sotloff, whose horrific murders in Syria were used with chilling cynicism to intimidate and spread a bloodthirsty propaganda message. Like this week’s killings in Paris.

In short, the globalisation of the media now includes the spread of habitual intimidation and violence against critical or nosey media. That environment of threat has long been a fact of life for questioning journalists in many countries around the world. Journalists everywhere now have to confront the possibility of facing similar dangers.

Clearly the traditional respect for the neutrality of journalists in situations of conflict or tension is no longer there. Journalists in unstable or hostile environments are increasingly seen as unwelcome, or even as targets of attack or kidnap.

For example, last April Simon Ostrovsky, a reporter for the US VICE News network, was abducted in eastern Ukraine, beaten and held in a basement by his pro-Russian captors for three days. An estimated 80 Ukrainian journalists have suffered similar or worse treatment during the conflict there. In September aBBC team was attacked in southern Russia while investigating reports that Russian soldiers had been killed fighting in Ukraine and their bodies secretly returned to Russia for burial.

How to explain the spreading hostility to independent media, not only where militant Islam has taken hold but more widely? The term ‘new autocracies’ was coined in a recent report by former UK foreign office adviser David Clark to describe dozens of states which now rely on undemocratic levers and the threat or use of arbitrary state violence to keep strategic control of the information sphere. Egypt and Thailand are two examples of these new autocracies, which it is argued pay only lip service to democracy.

In Brazil in 2013 the then chief of the Supreme Court, Joaquim Barbosa, publicly accused members of the country’s judicial system of corruptly accepting inducements to let off some figures implicated in journalists’ killings. He blamed that culture of impunity for a marked rise in violent attacks against journalists. CPJ reports that three journalists were killed in Brazil for their work in 2014.

In Mexico, drugs barons have sometimes tortured or mutilated the bodies of critical journalists or social media activists as an eloquent warning to others not to challenge their thrall over whole districts of the country.

In these circumstances self-censorship has become a new normal among news media in many parts of the world. Respected journalists have suggested that the effective curbing of a free press can result from the shocking murder of even a small number of journalists, especially if they are famous, and the masterminds who ordered their killing are never brought to justice.

Examples cited include the case of the intrepid Novaya Gazeta journalist Anna Politkovskaya – killed in Moscow in 2006 – and the Sunday Leader editor Lasantha Wickrematunge in Sri Lanka, who was shot dead in 2009 in Colombo after predicting his own death in an editorial published after his death.

Last year many leading global news organisations, including the BBC and other major broadcasters, publicised their growing concern that anti-media violence and intimidation have become a real obstacle to their reporting of world events.

In the wake of the Charlie Hebdo killings a new dimension of the pre-existing threat has burst into the consciousness of everyone. Like it or not, the media and journalists are now part of the story.

UN marks ‘deadliest decade’ for journalist deaths

Other blogs by William Horsley

Journalists in danger: Symposium steps up pressure on safety