When you were born, you were the:2,371,597,646th person alive on Earth75,073,450,404th--- how do they know how many people??Who was there to count

A Big Picture look at the world’s population

On October 31, 2011, the United Nations is expected to announce a projected world population figure of 7 billion. This global milestone presents both an opportunity and a challenge for the planet. While more people are living longer and healthier lives, says the U.N., gaps between rich and poor are widening and more people than ever are vulnerable to food insecurity and water shortages. Because censuses are infrequent and incomplete, no one knows the precise date that we will hit the 7 billion mark - the Census Bureau puts it somewhere next March. In the last 50 years, humanity has more than doubled. What could the next decade mean for our numbers and the planet? In this post, we focus on births, but we'll be back with population-related content including it's affect on the environment and our food supply. -- Paula Nelson (47 photos total)

Yes i think water--clean water will be a problem in the future

7 Billion and Counting: Welcome to a PlanetWith Population Overload and Resources in Crisis [With Photos From National Geographic , see slides

( Population is a complicated topic. With the worldwide population slated to top 7 billion in 2011, we decided it was one we needed to tackle. But we wanted to do it in a way that gives readers room to think. We spread out our coverage over a year, with articles that take deep dives into specific issues—demographics, food security, climate change, fertility trends, managing biodiversity—
that relate to global population. Our reporting is collected here. Feel free to explore and share your thoughts on twitter at #7billion.)

special year-long series

7 billion seems a lot. But let's now see how this fits in terms of physical space.

Let's standardise the human being as a rectangular box of 170 cm high, 50 cm width, and 25cm depth. Such a box does contain a lot of air.

This volume is about 0.2 m3 and does contain a lot of air.

Let's now pile up these boxes.

If we build a first laye of 5'000 per 5'000 we have use 100 million boxes. We need then to pile 280 layers to get to 7 billion boxes.
Let's suppose that we put the boxes in a laying position then we will have a final rectangular volume as follows:

5'000 X 1.70 = 8'500 mt
5'000 X 0.5 = 2'500 mt
280 X 0.25 = 70 mt

This is a box 8.5km X 2.5 km and 70 meters high.

Now let's consider the bodily volume as such. An average weight of 70 kg would mean with a 1gr/cm3 density (water), a volume of 0.07 m3 which is much less than the box version which contains a lot of air. This corresponds to a box of the following size:

7 billion X 0.07 = 490 Million m3.

This boils down to a box the size of: 2.5 km X 2.5 km and a height of 78 meters.

If we compare to the surface of earth or the depth of the oceans, this is just an insignificant speck of flesh and blood.

Yes 7 billion is at the same time a lot, but compared to our planet it is just an insignificant speck of matter. What is strange is how this insignificant speck has the power to annihilate the whole planet.

It is like the tiny virus that can kill an elephant.