A little over a decade ago, the world's population stood at 6 billion. By the end of October, it will reach 7 billion. With five babies being born every second, 78 million people are added to the global community each year. The population was fewer than 1 billion in 1800, 3 billion in 1960 and 6 billion as recently as 1999. According to the United Nations, the next landmark statistic will be 8 billion in 2025. Much of the dramatic increase can be accounted for by the world's poorest nations, which are expected to double their numbers over the next decade. "With the population still growing by about 80 million each year, it's hard not to be alarmed," said Robert Kunzig, author of an article entitled '7 Billion' in National Geographic magazine. "Right now on Earth, water tables are falling, soil is eroding, glaciers are melting, and fish stocks are vanishing. Close to a billion people go hungry each day." Researchers say the world's population will level off at about 9 billion in the middle of the century.