As the UN's COP 20 climate negotiations in Lima slowly progressed last month, I went on a journey through the Sacred Valley of the Incas, a valley close to Cusco, the capital of the Incan empire of the fifteenth and sixteenth centuries.
I wanted to see how climate change is already affecting the Peruvian Andes. Through images and interviews, this feature shows how researchers are working to evaluate the effects of climate change and help locals who are adapting to them.
My first stop was Moray, an archaeological site that lies about 3,500 metres above sea level. Moray hosts what may have been an agricultural research centre in the age of the Incas.
Scientists believe that the area of concentric terraces was used by farmers to experiment with growing different species of wild plants at different heights. In this way, the Incas could work out which plants would grow best at different altitudes and temperatures.
The snow-capped mountain of Chicon in southern Peru can be seen clearly from the hills surrounding Moray. Chicon is in the Vilcabamba mountain range of the Andes that extends about 260 kilometres northwest of the city of Cusco.
Researchers from the National Service of Natural Areas Protected by the State (SERNANP) have observed that the glaciers in the range have lost nearly a quarter of their volume in the past few decades.
The region of Cusco has 508 square kilometres of glaciers, the largest area of any Peruvian region. At Moray, I asked Harol Miguel Alagón, my guide at SERNANP, what is making the glaciers melt.
He explains that the causes remain uncertain, but there are signs that the regional climate has changed, causing for example an abnormal warming of surface ocean waters in the eastern tropical Pacific known as El Niño.
"The average temperature in the Andes rose 0.8 degrees over the course of the past century and in the last 40 years there has been an increase in the frequency and intensity of the El Niño phenomenon," Alagón says.
The retreat of the Andean glaciers is likely to be reflected in tropical glaciers around the world if atmospheric temperatures continue to rise at the rate seen in recent decades. According to the World Bank, Peru is home to 71 per cent of the world's tropical glaciers. However, in the past 30 years the surface area of Peru's glaciers has shrunk by 22 per cent.
On the four-hour drive to the Incan city of Machu Picchu, I talked to Alagón about how shrinking glaciers would affect local people's lives.
"Most of these glaciers are small, less than two square kilometres," he explains. "However, they provide much of the water used to sustain agriculture, to supply Andean cities - especially in autumn and winter, the driest period of the year - and to produce electricity."
Alagón tells me that the lack of water may cause conflicts between local people, given that they depend on this precious resource to irrigate their crops as well as for basic sanitation.
Much of the melted ice in the Andes runs down to the Urubamba River, which supplies the hydroelectric station of Machu Picchu.
The glaciers on the eastern side of the Andes are also the source of streams that feed into major rivers in the Amazon Basin to the east. These glaciers are an important contributor to the rivers' nutrient-rich sediments that support the area's rich biodiversity.
In the foothills of the Andes, where the Amazon plain begins, researchers from the Villa Carmen Biological Station - a station to the north of Cusco run by NGO the Association for the Conservation of the Amazon Basin (ACCA) - are helping local people adapt to climate change by developing a technique to produce biochar, a form of charcoal used as fertiliser.
To make biochar, bamboo is burned in an oven at about 800 degrees Celsius while limiting the oxygen supply. Five hours later, the burned bamboo is removed, cooled with water and ground into smaller pieces. The whole process takes about seven hours.
Yngrid Espinoza Villaruel, the agricultural research coordinator at Villa Carmen, explains how it works. "On contact with the earth, the biochar acts as a magnet, retaining important nutrients," she says.
"This helps increase soil fertility, aiding the growth of several varieties of plants." Biochar's porous surface is particularly hospitable to the bacteria and fungi that plants need to absorb nutrients from the soil. It also retains water and increases the fertility of the soil by making it less acidic.
About 5,000 tonnes of biochar are needed to fertilise one hectare of farmland. This technique is quite common in China, but was only introduced in Villa Carmen two years ago. As a result, the researchers are still testing to check if it benefits the soil.
I was interested to know how readily locals are adopting it. Espinoza tells me that the early signs are promising, but biochar production is still being tested in Villa Carmen's plantations. "The goal is to develop and improve the technique and then distribute it to local farmers," she says.
But the station's studies show that it is already bringing financial benefits to local people. Heather Nobert, a biochar research assistant at Villa Carmen, says the researchers buy the bamboo they turn into biochar from local people. "We pay 1.5 sols [about 50 US cents] for each bamboo they bring," she says.
Researchers are currently testing the effect of biochar fertiliser on crops such as cassava, maize, peppers and sugar cane.
The Villa Carmen researchers are working to improve local farming practices. Many farmers grow non-indigenous crop varieties that aren't suited to the local soil and gradually reduce its fertility. As a result, farmers soon find crops will no longer grow. "They then open new areas of pasture, often using fire to clear the area of trees," Yhilbonio Farfán, a Villa Carmen worker, tells me.
In Latin America, the clearing of forest for agriculture contributes to climate change. Researchers at Villa Carmen tell me that this practice is altering the microclimate and water cycle in this region of Peru.
I ask Farfán if local farmers are already feeling the effects of climate change. "The rainy season in the region is no longer as before," he says. "It rains less at times when it should rain more."
The major drivers of forest loss remain logging and cattle ranching. Deforestation in the Peruvian Amazon increased significantly in 2013.
About 145,000 hectares of rainforest were cleared last year compared with an average of 113,000 hectares a year since 2001, according to figures presented at COP 20 by Gustavo Suárez de Freitas, who coordinates the National Forest Conservation Programme for Climate Change Mitigation within Peru's Environment Ministry.
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With this in mind, we set off for a 3,000 metre climb to ACCA's Wayqecha Cloud Forest Biological Station in Cusco region. Wayqecha means brother in the indigenous language Quechua. The research centre sits at the main entrance to Manu National Park, which shelters a moist, species-rich forest habitat.
In Peru, such 'cloud forests' are mainly on the Amazonian slopes of the Andes. Although some are in protected areas, many others are vulnerable to deforestation or have already been heavily cleared.
I talked to Carlos Manuel Zariquiey, the science coordinator for both the Wayqecha and Villa Carmen stations, about efforts to reforest degraded areas of cloud forest. "We cultivate species of local plants and trees for replanting," he says. "We have chosen local species because they do not cause any kind of soil stress and they are easier to grow."
Inside a greenhouse, Zariquiey shows me the seedlings of aliso, Queñua, llama llama and Chachacomo trees.
Cattle ranching and landslides are the main causes of land degradation in the area. "By replanting the species cultivated in Wayqecha, we are trying to limit soil erosion," Zariquiey explains.
To help cultivate the seedlings, the researchers at Wayqecha have built a biodigester that turns organic matter into liquid fertiliser. The plant also provides biogas to supply the station with energy.
With its work, ACCA provides the people of the Andean and Amazonian regions with sustainable ways to cultivate crops without affecting soil quality and without clearing forest for agriculture.
The goal is to help local people adapt to new environmental conditions, develop models to predict future changes and better understand the behaviour of forests, climate and animal species.
