my name is john d. liu. i've been documenting the changes on the plateau for 15 years. i first came here in 1995 to film an ambitious project where local people were constructing a new landscape on a vast scale. transforming a barren land into a green and fertile one. the project certainly changed my life, convincing me to become a soil scientist. the lessons i've learned in the last few years have made me realize that many of the human tragedies that we regularly witness around the world, the floods, mudslides, droughts and famines, are not inevitable. here on the loess plateau i've witnessed that people can lift themselves out of poverty. they can radically improve their environment. and by doing so, reduce the threat of climate change. >> [singing] >> when i first came to the loess plateau, i was astounded by the degree of poverty and degradation. and i wondered, "how could the chinese people, the largest ethnic group on the planet, and my fathers, and my own ancestors come from a place that was this barren?" china's loess plateau is a region that stretches for 640,0