There has been much worry about the possibility that anthropogenic (human-originating) global warming will cause the ice caps to melt and flood our coastal cities. Virtually every metropolitan area with over 10 million people is located on the coast.

Is human industrial activity causing the earth is get warmer? This is certain to some degree, but there are disagreements about the extent to which global warming is anthropogenic or just part of a natural climate cycle. There is a great incentive for people with political or environmental causes to warp the data in a desired direction. There are many on both sides of the divide.

But let's say that global warming is anthropogenic, and it does occur. How much would this cause the ice caps to melt?

Most of the world's ice is in Antarctica. The continent is covered by an ice shelf 2,133 meters (7,000 feet) thick. If the entire ice pack melted, the world's oceans would rise by 61 meters (200 feet). But since the average temperature in Antarctica is -37°C (-35°F), this is very unlikely to happen. More likely is that only a portion of the ice melts, increasing sea levels by a few feet or meters.

The results would still be catastrophic. A rise of a couple meters would flood the streets of many coastal cities, necessitating their evacuation. Low-lying countries such as many in Indonesia could be almost entirely submerged. The new standing water would be ideal for the breeding of mosquitos and other insects, spreading diseases such as malaria.

Much farmland is located at low elevations. If it were flooded by salt water, the crops and land would be ruined and there would be a food availability disaster. Farmers would need to move to more elevated, rocky land, which on average is less suited to growing crops.

What is not possible is that all the world's land would be covered, as in the movie Waterworld. There is simply not enough ice on earth for this to happen. Even in a severe flood, only a small percentage of the world's land would be lost - but of course this could translate to millions of square miles or kilometers.

To avoid global warming, world leaders have come up with a variety of strategies to encourage reduced emissions of CO2, which is said to be the main cause of anthropogenic warming. Emission limits for various countries have been willfully accepted. A long-term strategy is to exploit alternatives to fossil fuels, which are rampant polluters.