Health & development? Will climate change impact the right to: never before in human history has the world had such a wealth of knowledge, skills and resources invested in keeping its communities well. Why, then, is global health heading into a "perfect storm"?

• Author: Tarantola, Daniel
• Position: Report

On a dusty construction site in western China, Mr Tan is just another anonymous migrant labourer. But, the unassuming former farmer is also the face of a complex web of crises threatening global health.

On one level, 24-year-old Mr Tan is a symbol of China's economic success, and similar growth patterns over recent decades in other developing economies. Half a million rural Chinese migrant workers pour into Chongqing alone every year, making it the world's biggest city--and building site-fuelling China's growth engine, even if somewhat less vigorously since the global financial downturn. Long term forecasts suggest another 350 million rural villagers will converge on industrializing cities in China alone by 2025; some pulled by new opportunities, others pushed by poverty and food shortages caused, in part, by the climatic disruptions of global warming.

For Mr Tan, the lure of Chongqing is, in his words, "the big money". Living in a shed, amid the fine, choking concrete dust and surrounded by hectares of concrete, high rise skeletons, Mr Tan earns 1,000 yuan a month, more than ten times what he eked out of the land and enough to allow him to survive in the city and send money home to the village. His is a familiar tale of aspiration.

But, on Mr Tan's building site, a number of the world's most intractable and emerging health threats are converging. Just as the advances of the Industrial Revolution came at a cost to the millions who left the land for Europe's factories and slums, the very jobs which have pulled hundreds of millions out of abject poverty in the late twentieth and early twenty-first centuries also come with new risks.

For the world's marginalized communities, economic globalization often means less job security in itinerant industrial and labouring jobs and new toxic threats and accident risks at work. In urban shanty towns, inadequate sanitation and services combined with crowded living conditions greatly increases health risks and vulnerability to communicable diseases.

Then, there are new emerging threats, unique to our times. In Chongqing, and many cities like it, armies of male migrant labourers are cut adrift from village social structures for months and years at a time. With the erosion of social cohesion, high risk lifestyles of cheap sex and drugs can follow; undermining economic gains and threatening the transmission of HIV/AIDS and serious related infections such as drug-resistant tuberculosis.

At the same time rising population mobility resulting from mass travel facilitated by modern transport networks...