Depression increases your risk of a number of diseases and other conditions by, for example, increasing levels of stress hormones such as cortisol or adrenaline. Depression can affect the immune system, making it harder for your body to fight infection. Vaccinations are even less effective in people with depression.
The total surface area of the Earth is about 7008510000000000000â 510 million km2 (197 million sq mi). Of this, 70.8%, or 7008361130000000000â 361.13 million km2 (139.43 million sq mi), is below sea level and covered by ocean water.
Total Landmass of Earth. Earth is a watery place, with around 70 percent of its surface covered in water, the vast majority of which is salt water. This leaves around 30 percent of the planet's surface as potential farmland, totaling just over 57 million square miles.