As of yesterday, the population of the US is approximately 283,695,000, and for the entire world, the population is approximately 6,131,322,000. So nearly 1 out of every 22 people on Earth resides in America, the world's third most populous country. Since the US has about 1/16 of the world's total land surface, it could be argued that we have a bit more room to fit in more people. New York and Los Angeles are two of the world's 15 most populous cities, but the only other city in North America that makes the top 15 is Mexico City - the most populous city in North America. Two of the world's 15 most populous cities are on island nations, Tokyo in Japan and Jakarta in Indonesia, and South America and Africa also each host to 2 of the most populous 15. The remaining 6 of the world's most populous cities are found in Asia. This shouldn't be shocking news since Asia is by far the biggest and most populous land mass on Earth. Surprisingly, however, according to the 2,000 census, none of the big cities in either Europe or Australia made the list.

In 1950, only 7 cities boasted of a population of more than 5 million people. Today, 36 cities have that many residents and by 2025, the United Nations projects that there could be 90 cities with that many people. Most of this unbridled growth will occur in the undeveloped or so called Third World regions. The exploding growth of emerging nations and in some developed nations as well will likely outrace available resources. However, in some instances predicted growth has not occurred at the rate expected. In the mid 1980s, there was a concern that the population of Mexico City could reach 30 million by 2000, but that figure is about 12 million shy of the actual population.

Nighttime lights, as revealed using satellite instruments sensitive to light in the visible wavelengths, give some indication as to where we live and a sense of the world's burgeoning population. Urban centers on these satellite images stand out like bright stars in a moonless sky, and in densely populated areas, constellations of the city lights stretch across the hidden surface. Indeed, in the most densely populated areas of the world, the city lights look like the Milky Way when viewed with binoculars. The eastern US, eastern China, western Europe, and the Indian subcontinent are teeming with lights.

In fact, the outline of India is easy to make out from space by looking at only the nighttime lights. The coastline of the Arabian Sea and Bay of Bengal are illuminated by the lights of dozens of cities and towns, but to the north, the sparsely populated Himalayan Mountains and Tibetan Plateau are bereft of light. There's a stark contrast between the darkness of the seas and mountains with the hundreds of points of light in India, Pakistan and Bangladesh.

Four of the brightest light spots in this region emanate from the cities of Karachi, Pakistan, Bombay (Mumbai) and Calcutta, India, and Dhaka, Bangladesh. These are 4 of the largest 15 cities in the world. With an estimated population of 10 million, Dhaka is the smallest of the 4 (Bombay is the largest - about 17 million). In these 4 cities alone, there are 50 million people! Just 1,5000 miles separates them, about the distance between Washington and Denver. India's population just recently exceeded 1 billion people. Though a distant 2nd to China (about 1.2 billion) in terms of total population, India is only about 1/3 the size of China - it's also about 1/3 the size of the US. An average of about 777 people live on every square mile of surface in India. For the US, the average is 85 people for each square mile of surface. Compared to the US, India is stuffed to the gills. Approximately 1 of every 6 people in the world live in India, yet it comprises only 1/45 of the Earth's surface!.

How can the nations of India, Pakistan and Bangladesh sustain such large numbers of people? Despite the fact that these 3 countries seem to be aglow on the nighttime satellite images, amazingly, most of the people don't live in cities. For example, nearly 3/4 of India's inhabitants live in rural areas. One reason for this inclination to live away from urban environments is the need to grow lots of food. In contrast to the US, where relatively few people are required to produce the food we eat, in most areas of the world, farming is very labor intensive.

Several major river systems flow through India, Pakistan and Bangladesh. The largest are the south-flowing Ganges, Brahmaputra and the Indus Rivers, each more than 1,500 miles in length and originating in the Himalayan Mountains/Tibetan Plateau, which carry rich, alluvial soil to the plains below. The Gangetic Plain, a belt of flat and fertile lowlands as much as 200 miles wide, bordering the Ganges River, includes some of the most productive agricultural land in India. In many of the river plains, groundwater is rather plentiful and close enough to the surface to make irrigation possible. Even in areas removed from the alluvial deposits, much of the land is receptive to the plow - approximately 54% of the land in India is arable.

An important key to sustenance in India, Pakistan and Bangladesh is the reliability of the wet monsoon. In June, the prolonged dry season is broken as the wind shifts from the north and northeast to the south and southwest, ushering in welcome monsoon rains that typically last into September. Agriculture is heavily dependent on the normal arrival of the monsoon. When it's late or weak, famine results, but if it's early and unusually vigorous, flooding can ruin crops and wipe out villages. The monsoon rains are also very important in replenishing ground water. Without it, irrigation is a must. Although the major rivers will still flow even when the summer rains are erratic, since they're fed by glaciers and melting snow, the land will be quickly parched if the monsoon is late arriving.

Because the Himalayas act to block incursions of cold air from central Asia, agriculture is not so much limited by low temperatures as it is by lack of moisture. As a result, if rainfall is sufficient, 2 or 3 harvest of wheat and rice per year can be expected from the primary agricultural regions. In order to feed 1 billion people, multiple harvests per year and reliable sources of groundwater are absolute necessities.

Although the majority of people in India, Pakistan and Bangladesh have a vegetarian diet, there has been more of a demand for meat in recent years. However, cattle require large tracks of pasture land, and per acre, more people can be fed with rice than with beef. With the population expected to increase about 25% by 2050, yields must increase substantially over what they are currently just to achieve minimum subsistence levels. A host of problems are facing this region, and unfortunately there are no easy solutions, but the overwhelming number of people living there will likely continue to burden development.

01 March 2001