Sea levels could rise around 20 cm by the year 2030 and 65cm by the end of the next century. As much as 20,000 km2 of land could be threatened with flooding, including some of the most economically productive land in Asia. Excess demand for irrigation water would severely limit the potential for growing two crops per year, and higher temperatures would shorten the time available for grains to mature. Poverty and high population densities would ensure that even small changes in land area crop productivity would have serious social consequences. Countries located partly or entirely in ecologically fragile regions, such as deserts, high mountain ecosystems, and arctic and sub-arctic regions are also at high risk.
Climate change poses an unprecedented challenge to human society.
The predicted impacts of climate change may lead to economic and political instability, making it increasingly difficult for countries to respond to these impacts. At the same time, growing social and economic burdens may divert attention away from the need to address the underlying causes as well. If the economic and social costs of climate change prove severe, conflict between the industrial nations of the North and the less developed nations. Often the south would provably increase. Disputes over limited or diminishing resources such as water and arable land would proliferate, both among individual countries and within them.