I was on the border between Israel and Gaza last Wednesday, in a place called Erez. I was sitting in a tin hut, a temporary holding room, as I waited for the Hamas border guards to stamp my passport. They had wifi in the hut. So I whipped out my iPhone and went online.
Naturally I follow a lot of fellow-photographers on Twitter. My timeline was packed with comments about a new photograph from the ongoing international refugee crisis. I tapped a link to the photo. When it came up, I froze. I had a physical reaction in my gut. It stopped me in my tracks. I was seeing it with my eyes but feeling it like a punch to the stomach.
I was in a conflict zone but I forgot where I was. I had come through the Israeli checkpoint. I'd crossed over a kilometre of dusty no-man's land. It was roasting hot. There were soldiers everywhere. But that photograph took me away from it all. I sat and stared at it for several seconds. I knew immediately that this was the one: this was the image that would resonate around the world. This was the image that would symbolise the humanitarian catastrophe of 2015. This is the defining picture of the great human exodus that is unfolding right now across the Middle East, northern Africa and parts of Asia.
Every modern war, every famine, every natural disaster generates tens of thousands of images. Most of them will be upsetting, distressing; some will be harrowing. But the sheer ubiquity of these images, their saturation across the global media, tends to immunise us against the shock of what we're seeing. There is just too much of it to take in; and there is only so much of it we can take.
It therefore takes a special photograph to break through our emotional fatigue and pierce us in the heart. It takes a special photograph to become the symbol of universal suffering.
And this was the one. A three-year-old boy washed up on a Turkish beach. Crouched, almost in the foetal position, as if he were sleeping. And this, I think, is the essence of the photo's power: its tranquillity. The scene is bathed in a sense of peace; of calmness, softness. A beautiful deserted beach with its romantic connotations of love and serenity; and a sleeping boy, curled up like a million slumbering children at home in their bedrooms. But the beach is a grave and the boy is dead and it is profoundly sad.
My work in association with World Vision Ireland has taken me, among many places, to Palestine, Israel, Lebanon, Jordan and several parts of Africa. I grew up believing in the power of photography. I never lost faith that a single photograph could change the world. Even in this age, when everyone with a camera-phone is a photographer, when multiple millions of images are posted online, and when truly great photographs get lost or overlooked in this visual deluge: I still believed that a special moment in time, captured by a skilled craftsman, could be of service to humanity.
I did my thesis on exactly this subject at college: the capacity of the visual image to change how we think and to change what we feel. Like many other aspiring professionals, I was inspired by the photographs that had become landmarks in 20th-Century history.
Robert Capa's famous 1936 photograph from the Spanish Civil War, for example, commonly known as the "Falling Soldier". Nick Ut's 1972 photograph of the nine-year-old Vietnamese girl, naked and running in agony from a napalm attack.
Michael Buerk's BBC report on the Ethiopian famine in 1984, with those shattering images that were filmed by a Kenyan cameraman, Mohammed Amin. The Tiananmen Square photo in 1989, one man against the tanks.
In 1993, a South African photographer named Kevin Carter was preparing to photograph a Sudanese girl dying from starvation. A hooded vulture landed beside the girl. Carter took the picture. Three months after winning the Pulitzer Prize for this photo, he died by suicide.
The photographer who captured the boy at the beach last week is a Turkish woman, Nilufer Demir. She has since said that her "blood froze" when she saw the body. "The only thing I could do was make his scream heard."
She has succeeded in that. It is the shot that has been seen around the world. And yet not every picture editor at every newsdesk was prepared to use the picture.
I have no doubt it generated debate in every newsroom that contemplated whether to publish it or not. Editorial staff were divided; valid ethical questions were raised about its dissemination.
For what it's worth, I believe those who did publish were right to do so. I don't think the public should have been kept in the dark about this. I think editors were right to put it on the record and let the people worldwide decide for themselves how to react to it.
And it seems that a lot of people had concerns about this decision; I guess they questioned the motives of the media in choosing to publish it. I also happen to think that the distress people feel when confronted by images like this, the natural human hurt, is sometimes vented through anger at the media for forcing them to face this reality. And that's fair enough too.
But I have seen these humanitarian crises with my own eyes. I have lifted my camera and recorded them. I have been in the Bekaa Valley in Lebanon and seen the vast shanty towns erected there, almost as far as the eye can see, and spilling over with hundreds of thousands of Syrian refugees. Conditions there are shocking. I have been to the enormous Azraq refugee camp in Jordan where another tide of human desolation confronts the visitor.
In these situations you use your camera not just as a recording instrument, but as a barrier, a defence mechanism to protect you psychologically and emotionally from the devastation around you.
The world has to see these realities. Who are we to decide that they cannot, or should not, see them? And ultimately it is the concerted reaction of ordinary people that moves governments to actually do something about these crises.
If these images make the masses uncomfortable, they also make the politicians and civil servants uncomfortable. They too are forced to confront the consequences of their own inertia and denial. If enough people are moved to anger, then finally those with the power to change the situation are obliged to do something meaningful.
We have seen this chain reaction already. The global horror that Nilufer Demir's photograph triggered has generated tremors inside the corridors of power across western Europe.
I have a five-year-old daughter. As a professional photographer and now a picture editor, I admire unconditionally Ms Demir's achievement.
As a father, the image of that boy on the beach will remain in my memory, probably for life. As a student of photojournalism, I know it will join the ranks of those immortal photographs that tilted the world on its axis.
Those images didn't stop further wars or famines or natural disasters, and neither will this one. But it stopped everyone who saw it last week. It made us see beyond the boundaries of our own little lives.
It made us reach out, in some way, to suffering humanity; it made most of us think that we need to be better, and we need to do more.
Watch videos from the Bekaa Valley in Lebanon and Azraq refugee camp in Jordan on Independent.ie and visit World Vision Ireland on www.worldvision.ie to see details of its charitable programmes