Human populations have an economic attraction to the water. Whether it be oceans, lakes, or rivers - these bodies of water can prove to be effective points of transportation, and that leads to trade and commerce. Just look at the location of many of the major cities worldwide and you will typically find a water connection.
So, with the slow but study increase in sea level being brought about by climate change, particularly the effects of global warming on the Arctic and Antarctic regions, there are some very serious economic and socio-political issues that will be brought to the forefront in the next couple of decades.
Tropical regions, like the low-lying Maldives, are having to wrestle with the reality of someday being totally submerged - it's people becoming immigrants from a nation that literally no longer exists. But rising seas levels will impact more than a handful of tropical islands. As reported in the May issue of National Geographic, the heavily populated nation of Bangladesh is already feeling the effects of rising sea levels with high tides that are now bringing a foot of water into coastal homes, rising levels of salinity which impact aquifers, and river flooding becoming more destructive (three major rivers come together in Bangladesh to form the Ganges River Delta).
Bangladesh is a country with one of the highest population densities - more than half of its 164 million population live in an area smaller than the US state of Utah. As sea levels continue to rise, where these people are supposed to go and what economic infrastructure can travel with them is a big question. And if they are forced to immigrate, in that particular part of the world, who is prepared to take them in?
But rising sea levels is not an issue confined to lower income or developing nations. Major cities like Miami and New York would also have to contend with this problem. Would they need to prepare themselves, like New Orleans, with dikes and levies? We have seen the impact of walls that fail with the destruction in New Orleans following Hurricane Katrina in 2005. What will it take to protect a city like London when the Thames River overflows its banks, which some have predicted as early as 2025?
Within the scientific community, the vast majority do not dispute the reality of climate change and the impact of global warming. International organizations like the United Nations' Intergovernmental Panel on Climate Change (IPCC) are wrestling with the social, political, and economic implications. Perhaps it will be those issues, more so than purely environmental implications, that will drive nations to take action. The challenge is that it is an insidious, incremental, and long-term threat. Cities won't be swallowed up whole immediately and, as a species, we seem to react better to immediate threats. But if we wait until water floods Piccadilly or we find ourselves rowing a canoe to work in Times Square, it may very well be too late.