[drumming] >> this is china's loess plateau. until recently, this was one of the poorest regions in the country. a land renowned for floods, mudslides and famine. but with the fanfare comes the hope of change for the better. 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 astounde