* World's fastest growing populations increasingly at risk

* Africa and Asia most vulnerable to more extreme weather

* Survey can help city planners, investors adapt to wilder weather

SINGAPORE, Oct 26 (Reuters) - Rapidly growing megacities in Africa and Asia face the highest risks from rising sea levels, floods and other climate change impacts, says a global survey aimed at guiding city planners and investors.

The world is becoming a hungrier place - consuming more food, fuel and material resources - as its population bulges. But the increase in consumption is not even and not driven by the same factors. China and India are consuming more because their populations have vastly increased in the past 40 years. The United States, Japan and many countries in Europe are having much less population growth, but the people are using more resources. Meanwhile, many in South American and African countries have had relatively small population growth and much less increase in consumption.

Global temperature rise could exceed "safe" levels of two degrees Celsius in some parts of the world in many of our lifetimes if greenhouse gas emissions continue to increase, two research papers published in the journal Nature warned.

LONDON, Oct 17 (Reuters) - The Earth's natural resources like food, water and forests are being depleted at an alarming speed, causing hunger, conflict, social unrest and species extinction, experts at a climate and health conference in London warned on Monday.

Increased hunger due to food yield changes will lead to malnutrition; water scarcity will deteriorate hygiene; pollution will weaken immune systems; and displacement and social disorder due to conflicts over water and land will increase the spread of infectious diseases, they said.

Recent global population growth estimates (10 billion by 2100, anyone?) plus slowing annual increases in agricultural yields have a lot of analysts worried that many of those new people will suffer from chronic hunger – and that much of the land that hasn’t been converted to agriculture will be plowed under to grow crops.