Portraits of Peru: Why supermodel Helena Christensen returned to her roots

When I imagine the horrible effects of climate change, I think of icebergs shrinking in Antarctica. But last month, I travelled to tropical Peru to see a hidden side of a global crisis.

I will admit I didn't even know tropical glaciers existed – they sound like an oxymoron – until Oxfam invited me to see how rapidly they are disappearing. I looked up at the Auzangate Glacier near Cusco in the south of the country to see a white patch at the top of the mountain. Not so long ago, it stretched all the way down into the valley below.

People all over the world are being deeply affected by something that many of us don't really consider in our day-to-day lives. In Peru, whole families of farmers depend on the water running off glaciers and into rivers. But because of the changes in temperature caused by global carbon emissions, the glaciers are retreating and the rivers are running dry. The farmers live on the crops they grow in the mountains and the yarn they spin from the coats of their alpaca herds. But they can no longer predict the seasons and the alpacas are leaving – it is almost as if they can sense the disaster faster than we can.

I'm half Peruvian. My mother was born in Lima and sailed to Denmark with her Danish stepfather when she was 18. During the five years they stayed, my mother met my father and when the rest of the family returned home, she stayed. Throughout my childhood we made trips to Peru, but it wasn't until I returned about three years ago to that I felt a sense of belonging. I'm grateful that by taking photographs of what I see I have the opportunity to raise a tiny bit of awareness about what is happening.

In Peru, I met a woman called Elizabeth Ayma, who told me that because the changes are so drastic her family has less food to eat and less produce to sell. She can't afford to pay her children's school fees and their health is being affected. Elizabeth told me that she had no idea why these changes were happening – they see them as horrible and strange but they are not aware of global warming. They look at the problem from a religious perspective and feel that they are being punished. In some places we were breaking the news to them that it wasn't their fault. I almost felt that left them more shattered. Before, they saw the answer in praying more or trying to treat the soil better; now they've learnt the problem is global, they feel powerless.

But there are local solutions, and Oxfam runs many projects that help people make a difference. I met other women who were taking part in a reforestation programme in the Anta valley. They are being paid to plant tiny trees in areas of land provided by the government. They plant them one by one in plastic bags full of soil – thousands of them. We travelled to a second farm where the trees are brought to full size ready to be moved back into the forest. This stops the corrosion that has been caused by deforestation. The indigenous trees are also a more sustainable alternative to the versatile but water-hungry eucalyptus trees that have been planted in many areas. It's a plan that will take decades, but soon 10 years will have passed and they will have their trees.

Until conditions for farmers improve they are being forced to adapt, and many try to tap into tourism. Some try to attract visitors to the mountains by creating pools near hot springs but few can match the farming income they have relied on for hundreds of years. Increasingly, mothers and their children are being forced to relocate to cities like Cusco. There they join huge groups of other displaced people. Many scrape a living by selling rugs, knitted hats, gloves and jewellery, but they often sell the same things and there is a sense of desperation in the way they sell. There are also huge groups of people with no work at all. You see young people wondering around not knowing what to do, facing a whole new set of challenges and dangers.

Some young Peruvians are luckier. In the Huacarpay valley I visited an incredible school. Education is vital on a local level and increasingly it's the children who are being taught about climate change and the importance of recycling. They're taking that knowledge home and teaching their own parents, who were never informed about any of this. Climate change can be a complicated thing, but simple solutions, like teaching awareness in schools, can make big differences.

But, although education has a role and there is a lot that Peruvians and other communities around the world can do to help themselves, in many ways their hands are tied. I was in London last night to launch an exhibition of my photos. I've also shown them in New York, but next month I'll be going home to Copenhagen for what I believe will be our last chance for a long time to make the drastic changes Peruvians and the rest of the world desperately need. The Copenhagen Climate Conference will host leaders from all over the world and the power lies in their hands. We can do as much as we can to raise awareness by filming, photographing and documenting the effects of climate change, but change also needs to come from the top. It's not as if they're going to look at my photos and spring into action – they already know what needs to be done – but I think it's important to show people what we are about to lose. That way we might encourage the people with power to turn talk into action.

In the meantime, as well as doing what we can in our own homes and lives, we can put pressure on our leaders. The more weight we add, the more they remember they have to live up to our expectations. We elected them and I believe this is the most important issue we're dealing with. There'll be marches during the conference and in cities all over the world before it happens. In Britain, the Stop Climate Chaos Coalition is staging huge demonstrations in Glasgow and central London on 5 December, the day before the summit starts. Rising temperatures are already changing the lives of Elizabeth and the other people I met in Peru, but when I looked up at that tiny glacier, it became clear to me that this is going to affect the rest of us very quickly. We need to do something now.

Meltdown opens today at the Proud Gallery, 32 John Adam Street, London WCN 6BP, and runs until 29 November, admission free