"Never travel without a wire coathanger." For some reason that's the one instruction that stayed in my head after a week's training in how to survive as a reporter in a war zone. You fold the hanger so it fits in a shirt pocket and if ever you stray into a Balkan minefield, you have what it takes to scrape away topsoil and expose landmines so that you can slide out on your stomach.

Since the wars in Iraq and Afghanistan this 1990s piece of advice seems to belong to the era of Scoop. Now not even an MRAP – mine-resistant ambush-protected vehicle – is a guarantee of protection for reporters in Afghanistan. Two western journalists embedded with US forces there have been killed in separate roadside bombings in the past month.

The deaths cap a horrendous year for the media. Seventy journalists were killed around the world in 2009, the highest toll ever recorded by the Committee to Protect Journalists in its nearly 30-year history. That fact alone must send a chill through newsrooms. It was not that long ago that foreign editors and bureau chiefs, including me, would send reporters off to war zones with little more than a press pass and their own wits for protection.

Now, no western news executive would dare dispatch a reporter or TV crew to cover conflict unless they had received "hostile environment" training and been fitted out with high-tech personal protection gear and communications. In the past decade or so, Britain has become a leader in training journalists and humanitarian workers for deployment in conflict zones. Private security companies, many employing former SAS members and Royal Marine commandos, train reporters in the UK and their home countries. The recipients of this lifesaving knowledge tend to be those working for news outlets with deep pockets. A one-week residential course such as the one I took with the coathanger sapper can cost thousands of pounds.

As we saw in Iraq, when western journalists begin to die, news media rely on local journalists. Those who are contracted as fixers (guides, interpreters, field producers etc) by foreign journalists are increasingly receiving safety training. But reporters working for small local outlets are often left to their own devices. For example, Somalia witnessed nine journalists' deaths last year, among them many from a small band of courageous radio journalists who tried to keep news on the airwaves despite the general mayhem of a civil war and targeted threats from the al-Shabaab Islamist fighters who wanted independent FM stations silenced.

International journalist associations and NGOs also provide free or low-cost training to journalists in developing countries but demand still outstrips supply. Despite all the safety training and heightened awareness, journalists' deaths are on the rise. Some of the reporters who were among the 57 people mown down in a jungle ambush in the southern Philippines in November had received security training. At least 29 journalists and two media workers were killed that day accompanying a convoy of supporters bound for the provincial capital of Maguindanao to file candidacy papers for a local political leader contesting the provincial governorship. The journalists deliberately travelled in a large group believing it would improve their security. They had also telephoned a senior local military commander ahead of time to request security, which was not provided.

These reporters knew they were working in a dangerous place and tried to mitigate the risk. But the danger for reporters in the Philippines is compounded by the ongoing failure of the state to protect the press by prosecuting those who kill journalists. CPJ ranks the Philippines as the worst peace-time democracy in the world because of its abysmal record of solving journalists' murders.

When law enforcement turns a blind eye it encourages those who are the subject of investigative reporting to hire an assassin rather than a libel lawyer. It's often cheaper and more effective. Murder is the surest form of censorship. For all the unfortunate deaths of prominent journalists in war zones, most reporters are not killed covering combat. Some 75% of journalist deaths are targeted murder.

In countries like Mexico, Russia or the Philippines not only are journalists assassinated, their killers are rarely brought to justice. Journalists are intimidated into avoiding certain stories. The public, deprived of vital information, is the loser. In the towns along the US-Mexican border, for example, many media outlets have given up trying to cover organised crime in any depth. Too many reporters have been abducted, tortured and killed, and their bodies dumped in the public square as a warning to others not to write about drug cartels.

So how do we avoid another year in which 70 journalists die? More and better security training is certainly part of the answer. Reporters are not going to stop going to Afghanistan or the Horn of Africa. That's just what they do. If it gets too dangerous to move among the local population, foreign journalists will embed with the military. Or, as in the case of Iraq at the height of the fighting between 2004 and 2008, they will work from guarded compounds and rely on local reporters as their eyes and ears on the street. It's essential that the media companies who engage those local journalists provide them with all the training and equipment that they would give to western employees. Body armour is no guarantee of safety and some local journalists may not want to wear it because it identifies them as working for foreigners. But they should have the choice.

It's also vital that individual freelancers, who may not have the requisite awareness of the local security and political landscape, don't expose local fixers to danger. Foreign reporters who are detained by militias or security forces for covering conflict are usually released and go home. Their journalist guides, interpreters and drivers sometimes don't have that luxury.

The other key component in reducing media deaths is the battle to end the culture of impunity. It's daunting when you look at cynicism that lies behind the assassinations of journalists in Russia or Mexico. But CPJ's campaign against impunity has begun to notch up a few small successes. Since we took the campaign to the Philippines two years ago, we have helped win changes of venue in the trials of several suspects accused of involvement in journalists' murders, allowing witnesses to testify without fear of intimidation. We also secured a commitment last September from Russian authorities to see investigations into all 17 journalists murders documented in a special report by CPJ, brought to a successful conclusion. We will be back in Moscow in nine months to hold them to their word.