. >> benjamin morales is a glacierologist. he remembers the glacier in its heyday when people even skied here. >> until--it stretched all the way down. >> we walk where once ice hundreds of meters deep now the glacier has receded all the way back to the face of the mountain. >> we're losing time because all the glaciers, it's going to the sea. >> it is a stunning science but full of danger. new lagoons of ice is forming, increased threats of mudslides and flooding disasters. >> they say this glacier is melting at such an incredible rate that it could be gone in 30 or 40 years, and across peru all the nation's tropical glaciers are disappearing at ever increasing rates. that's creating an enormous problem for those who rely on this as a water source. >> down the mountain the crops are growing, but things are changing. >> we've seen climate changes in the last four years. it's become much hotter and our soil dries out more quickly. there are cold winds from the mountains and plants are less resistant to the climate change. >> ni