As a natural resource, sand is second only to water in consumption worldwide, but its removal, mainly for the construction industry, is not subject to an international regulatory framework. Last year, the UN called for more sustainable sand mining in its resolution.
"The amount of sand we are removing from the environment is significant and has a big impact," UNEP's Pascal Penducci said at a press conference attended by Reuters.
Showing an image of a dredger he described as a "giant vacuum cleaner" on the screen, Penducci said these vessels "essentially sterilize the seabed by removing sand and crushing the micro-organisms that fish feed on".
In some cases all the sand is removed down to the underlying bedrock, meaning "life may never return".
Although the 6 billion tonnes removed per year is less than the amount of sand carried by rivers to the sea each year, in some areas sand dunes are exceeding the natural rate of replenishment, the report points out.