Mexico City, Aug 11 (IANS): The threat to humanity posed by the loss of biodiversity is as great or even greater than that posed by climate change, a Mexican biologist said.

Jose Sarukhan, coordinator of the Mexican government's National Commission for the Knowledge and Use of Biodiversity (Conabio), said the main source of pressure on what he termed "natural capital" was the exponential growth in the human population, which has tripled since 1950.

"That's been hard. But in many countries, and countries that have an enormous impact not only due to their size but also their economy and political strength, what's multiplied even more is the rate of consumption," he told Efe news on Thursday.

By way of example, he said that compared with a person born in the US in 1900 each American today "consumes 16 times more of everything: energy, water, food, fibre".

"If we also consider what's behind this, which is an economic system based on the need to maximise production so there's maximum consumption, we're facing a scenario that's not the most hospitable for life," Sarukhan added.

The expert's comments are in line with arguments contained in an article published last month by the academic journal of the United States' National Academy of Sciences, which revealed drastic vertebrate biodiversity losses indicative of a "sixth mass extinction".

The authors -- Gerardo Ceballos, Rodolfo Dirzo (former students of Sarukhan's) and Paul Ehrlich (his frequent collaborator) -- say the engines of this "biological annihilation" are human overpopulation and overconsumption.

They said the loss of billions of regional or local populations of wildlife was damaging ecosystem services that are crucial for civilization, including the provision of water and food and climate regulation, stressing that the window of time to act was very short, probably two or three decades at most.