[By Jiao Haiyang/China.org.cn]

The modern world has long thought of refugees in strictly political terms, victims in a world riven by competing ideologies. But as climate change continues unabated, there is a growing population of displaced men, women and children whose homes have been rendered unlivable thanks to a wide spectrum of environmental disasters.

Despite their numbers, and their need, most nations refuse to recognize their status.

The 1951 UN Convention Relating to the Status of Refugees defines a refugee as a person with a genuine fear of being persecuted for membership in a particular social group or class. The environmental refugee - not necessarily persecuted, yet necessarily forced to flee - falls outside this definition.

Where the forest used to be, torrential rains bring barren hills of mud down on villages. Crops wither in the parched earth. Animals die. Melting glaciers and a rising sea swallow islands and low-lying nations, flooding rice fields with salt water. Factories spew toxic chemicals into rivers and oceans, killing fish and the livelihood of generations. So people flee. Many become internally displaced, others cross any and all borders in order to survive.

Experts at last year's American Association for the Advancement of Science estimated their numbers would reach 50 million by 2020, due to factors such as agricultural disruption, deforestation, coastal flooding, shoreline erosion, industrial accidents and pollution. Others say the number will triple to 150 million by 2050.

'Environmental refugee'

Today, it is believed that the population of environmentally displaced has already far outstripped the number of political refugees worldwide, which, according to the United Nation High Commissioner on Refugees, is currently at around 10.2 million. Still, accurate statistics are hard to come by.

Because the term "environmental refugee" has not been officially recognized, many countries have not bothered to count them, especially if the population is internally displaced. Other countries consider them migrants, and therefore beyond the protection granted refugees.

Another factor obscuring the true scope of the population is the fact that their numbers can rise quite suddenly - such as after the Fukushima nuclear disaster last year, or Haiti's 2010 earthquake, which displaced more than 3 million people -which makes accounting for their number difficult, if not impossible.

In 1999 the International Red Cross put the number of those displaced by environmental disasters at 25 million. In 2009 the UN refugee agency estimated that number to be 36 million, 20 million of whom were listed as victims of climate change-related issues.

Two decades ago, noted ecologist Norman Myers predicted that humanity was slowly heading toward a "hidden crisis" in which ecosystems would fail to sustain their inhabitants, forcing people off the land to seek shelter elsewhere. After Hurricanes Katrina and Rita, however, the crisis became painfully obvious.