The Temperature of the Earth Would Increase :
Huge amounts of water evaporate from oceans, thereby preventing a drastic rise in Earth’s temperature during each day. If most of the surface was land, however, then the land would be extremely hot, turning most of it into deserts, while the ice caps would grow smaller, flooding all the nearby land.
The Climate Would Be Very Erratic :
If the oceans were converted into land, then the water cycle would be disturbed and the amount of precipitation on land areas would reduce significantly. This would lead to droughts and a high variance of land climate.
Composition of the Atmosphere :
About 50-70% of the oxygen in the air is supplied by aquatic plants. If the oceans covered less area, then the oxygen would not be replenished as fast as it was being used by land organisms.
Effect on Life :
Life would have come onto land much earlier in terms of the evolutionary cycle, because there would be less ocean real estate to act as a habitat. More organisms would move towards the land, since oceans wouldn’t be able to fulfill their energy needs. The size of animals would also be relatively smaller in order to cope with water scarcity.
Survival Would Be Difficult :
The length of a day would vary slightly, due to the increase in mass, namely because dirt is heavier than water. However, this slight change might cause ripple effects in the types of species and the general ecosystem.
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