Earth (some stuff you should know)

I had an interesting discussion yesterday which touched briefly upon a few of these subjects, so I decided to take a closer look at the data just to make sure I wasn’t completely wrong about the stuff I thought I knew – and now I’m glad I did as I seem to have somehow picked up a mistaken idea about the land area of the Southern Hemisphere (I thought it was even smaller than it is). Now, if you asked a random guy he wouldn’t know most of these numbers or even the relevant neighbourhood. Somehow I feel like people should. So here we go, most of these numbers are pulled from wikipedia:

1. Asia covers 8.7 % of the Earth’s total surface area and hosts ~60 % of the world’s current human population. It covers 29.5 % of the land area of Earth.

1a. Africa covers 6 % of the Earth’s total surface area and hosts ~14-15 % of the world’s population. It covers 20.4% of the total land area.

1b. North America: 4.8 % of surface area, 8 % of population. 16.5 % of total land area.

1c. South America: 3.5 % of surface area, 6 % of population. 12.0 % of total land area.

1d. Antarctica: 2.7 % of surface area, 0 % of population. 9.2% of total land area.

1e. Europe: 2 % of surface area, 11.5 % of population. 6.8 % of total land area.

1f. Australia: 1.5 % of surface area, 0.5 % of population. 5.1 % of total land area.

2. Russia covers 17,075,400 square kilometres. Europe and Australia combined make out ~17,8 mio. square kilometres, a number which incidentally is about the same as South America. So if we for a moment disregard the fact that Russia already makes up 40 % of the total area of Europe, it’s large enough to almost cover the two smallest continents combined.

3. According to a 2010 census, the population of China was/is 1,339,724,852 – which is more than 19 % of the population of Earth. This is a higher population than that of any single continent which is not Asia. The population of China is significantly larger than the combined populations of South America (385,7 mio), North America (529 mio) and Australia (31,26). It’s larger than the combined populations of Europe and North America. Here’s a neat image comparing sizes and populations of the continents.

4. This source notes that: “In the Northern Hemisphere, the ratio of land to ocean is about 1 to 1.5. The ratio of land to ocean in the Southern Hemisphere is 1 to 4.” Translating those ratios into percentages of the hemispheres, it turns out that in the Northern Hemisphere 60 % of the area is made up of ocean and 40 % is covered by land, whereas only 20 % of the Southern Hemisphere is covered by land and 80 % is covered by ocean. Oceans cover roughly 70,8 % of the total area of earth and land masses cover 29,2 %, so these numbers are probably ok. Here’s an image from Wikipedia:

About 90 percent of the human population lives on the Northern Hemisphere – the combined human population of the entire Southern Hemisphere is smaller than the population of Europe.

4a. The Pacific Ocean covers a larger area than all land masses of Earth combined.

4b. The Atlantic Ocean covers as a very rough approximation the same area (106 mio. square kilometres) as the total land area of the Northern Hemisphere. It covers an area corresponding to more than 70 percent of the total land area of earth.

4c. The Indian Ocean covers 68,556,000 square kilometres, approximately the same area as Asia and North America combined.

4d. The average depth of the world oceans is about 3.8 kilometers (link).

5. I can’t copy the image, but go here for a really neat illustration of the surface elevation of the areas of Earth – I’m really annoyed I can’t copy this and put it in the post. Antarctica has by far the highest mean elevation of all continents. According to this source, the mean elevation of the continent is 2,286 m. Disregarding Antarctica (which can be considered somewhat an outlier because of the ice-thing), it seems that there’s a connection between the area of a continent and its mean elevation – i.e. the larger the area of the continent, the higher the elevation. Here’s a relevant paper.)