Natural world, runner up: Green steps, Ly Hoang Long, Vietnam. Terraced paddy fields for rice require large quantities of water and have an adverse environmental impact because of the amount of methane gas growing rice generates. World methane production due to paddy fields is thought to be between 50m and 100m tonnes a year.

CIWEM, the Chartered Institution of Water and Environmental Management, sponsors an Environmental Photographer of the Year Exhibition. "Over 1,400 pictures were entered into the competition, examining issues such as poverty, climate change, human rights, leisure, culture, biodiversity and natural beauty. The categories were Changing Cli...