As we sat by the campfire, Gervais, a ranger from the forests of Malawi, slowly pulled back his hair to expose a 20cm scar left by a machete attack that nearly killed him. Poachers, he told me.

I was at an international rangers’ conference, held 13 years ago in a national park on the southern tip of mainland Australia. Another ranger, Jobogo Mirindi from the Democratic Republic of the Congo (DRC), showed me a photo taken five years before. Arranged football team-style were 30 or so of his smiling colleagues. Six rangers’ heads were circled in red; those were the only ones still alive.

I was shocked. How could I not know such extreme violence was happening to my colleagues and friends around the world? As a ranger myself, I knew that protecting wildlife could be dangerous – but I had no idea just how deadly their situation was. This was a war.

Since that pivotal moment, I’ve worked with rangers on six continents through the Thin Green Line Foundation, which supports these brave men and women and their families. I am consistently inspired by their humour, dedication and humility.

I’ve also come to know that two to three rangers die each week in the line of duty. Last year 112 paid the ultimate price; in the last decade, more than 1,000. About 65-70% of those who die are murdered by poachers seeking to steal our collective heritage.

I have seen too many reports and images of rangers slain. To an extent, I have had to turn off emotionally. But every now and then one gets through, and I find myself silently weeping. Sometimes it is someone I have worked with, or even someone who has saved me from attacks by poachers or militia – a debt I can never repay.

In the DRC in 2008, a ranger named Venant Mumbere Muvesevese and 15 of his colleagues guided me safely out of an ambush, as five militia laid in wait for my vehicle. Just two weeks after I had left the park, those same militia, now 50 in number, stopped a vehicle on the way to the market. It was carrying 20 people, including rangers and their families. There were no demands and no questions – they just opened fire on everyone, injuring many and killing a ranger’s wife and daughter. This year, Venant himself was gunned down by armed rebels.

Protecting wildlife is no longer just a case of stopping poaching by poor local villagers. Illegal wildlife crime is now estimated to be worth more than $20bn (£16bn) per year, ranked only behind drugs, weapons and human trafficking in the criminal value chain. Rangers face well-organised criminal gangs and hardened armed militia. Rebel groups often use poaching as a way to fund their operations. We are now seeing reports that terrorist groups do too.

But wildlife poaching isn’t the only threat rangers face. When Mohammed Akram, a community ranger in the mountains of Pakistan, confronted timber poachers he was offered bribes worth half his yearly salary to disappear and leave them to their work. Akram refused and told the poachers that it was not about money but his duty to protect his forest. They shot him six times with their AK47s, and when that didn’t kill him they decapitated him.

This honourable man, this humble ranger, who lived in a tent with his family, gave his life for conservation. This should shock you and I wouldn’t blame you if you wanted to stop reading now. But please honour these rangers by hearing their stories.

Esnart Paundi will stay with me the most. Esnart was a ranger from Zambia. As she and her colleague arrested two poachers, they were overpowered by a third hiding in the bushes. Her fellow ranger was struck down with a machete in front of her. Esnart ran, but the poachers tracked her and murdered her. She left behind five children, aged from three to 15.

Venant, Mohammed, Esnart: I suspect that is enough tragedy for one article. But every week more rangers die, doing a job that the rest of the world wants and expects them to do: protecting our wildlife and our most precious wild places.

Just this week I received another email with images of a ranger shot and killed while on an anti-poaching patrol in Cameroon. RIP Ranger Ngongo. We will support your family.

The news of these sacrifices deserves our attention. There are also as many inspiring stories of rangers and their fight. Yet both good and awful go almost completely unreported by media in the west.

Surely if a country lost 100 of their soldiers, each and every year, we would call it a war and report it as such. This is a war to protect nature, fought silently by men and women who go under-resourced, under-trained and under-equipped.

These tireless warriors put their lives on the line to defend this planet every day. It is about time that we stood with them and gave them the support, recognition and respect that they deserve. They fight on behalf of us all.