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Rain is an integral part of our planet's functioning, and Earth genuinely relies on water to survive.
Rain constitutes a fundamental aspect of the water cycle, a series of intricate processes where water evaporates into the atmosphere before condensing and returning to the surface. On average, around 99cm of rainfall occurs annually across Earth's surface—though, in reality, its distribution has never been even.
According to the US Geological Survey, while much of Earth's surface is covered by water, only 3% of the total water on our planet is freshwater. Unfortunately, most of this freshwater lies in inaccessible regions. Many life forms on Earth, including humanity, depend on just 0.5% of the total water on Earth to exist, and rain serves as a critical source among them.
An article published in the journal Nature Communications elucidates how long-term climate change is affecting global water availability. Reduced rainfall could profoundly impact vast land areas, but if rain were to cease entirely, what would the repercussions be? Would a rainless world swiftly transform into an extremely arid and uninhabitable place?
Widespread Drought and Desertification?
If rain permanently ceased to fall from Earth's skies, the first consequence would be horrendous droughts worldwide. The summer of 2022 offered a glimpse into how the absence of rain would lead to severe repercussions globally. Regions in Africa have endured severe famine, while rivers and reservoirs have begun to dry up across Europe, East Asia, and North America. The outcome is dead fields, yellowing grass, and increasingly frequent and severe wildfires.
Similar to ecological impacts, droughts can exacerbate water scarcity as entire communities struggle to find clean water to survive. As UN Water explains, water scarcity has been a problem in many parts of the world, and in a world without rain, that issue would become much worse.
Serious droughts could become widespread by 2050, even if rain continues to fall. Without rain, the situation would quickly turn into a crisis. But on an Earth where rain no longer falls, even the worst droughts would only be the beginning of global disasters.
Will Rivers Run Dry?
If rain stopped falling entirely, droughts would worsen. Quickly, rivers would begin to dry up, and both human and wildlife populations dependent on them for survival would be seriously threatened.
According to The Guardian, Europe has faced some of its worst droughts in half a century, leaving even some of the continent's largest rivers dry enough to walk across in many places. Dried-up rivers have had a major impact on human industry and society, as crucial waterways suddenly ceased to function, cutting off the supply.
Some of the most severe impacts, as explained by The Rivers Trust, are environmental. Water scarcity when a river dries up can devastate entire ecosystems, while severely degrading the quality of any remaining water sources.
Tropical forests would undoubtedly be affected if the rivers on Earth began to dry up. As noted by Mongabay, tropical forests are linked to some of the largest and most famous rivers in the world, such as the Congo, Orinoco, Mekong, and Amazon. If these rivers cease to flow, the entire forests they support will begin to die, and there will be no tropical forests on Earth without rain.
Will Oxygen Levels Decrease?
Without rain, there will be no vegetation. And if there is no vegetation, Earth will have no oxygen. As rain disappears, vegetation will begin to die en masse, and the atmosphere will soon begin to feel the effects.
Marine plants on Earth produce 50% to 80% of the world's oxygen, while terrestrial plants, mainly tropical forests, produce about 28% (according to National Geographic) - meaning that the oxygen concentration in the air will decrease sharply without them.
Animals Will Perish!
As vegetation begins to wither and die due to lack of rainfall, it will severely impact Earth's food supply. According to National Geographic, plants are the foundation of the food chain. Known as autotrophs, they are among the few organisms on Earth that can directly harvest raw energy, in the form of sunlight. Without them, the entire food chain will collapse. Once plants die off, herbivores will also perish.
Meat-eating animals can survive on a diet solely comprised of meat, but if there's a shortage of herbivores to prey on, the populations of meat-eating animals will decline significantly. Some may persist for a considerable period by hunting each other. However, extinction is inevitable.
The Oceans Will Slowly Evaporate!
Until now, it seems that the oceans would be a safe haven for life in a world without rain. Unfortunately, they won't last forever. NASA notes that Earth's oceans have a close relationship with rainfall. About 86% of global evaporation comes from the oceans, and 78% of rainfall helps replenish them. Without that rainfall, sea levels will start to decline. According to NASA's Earth Observatory, about 108,000 cubic miles of water evaporate from Earth's oceans each year.
As ocean water continues to evaporate, it will become increasingly salty. As Scientific American mentions, many fish species can only tolerate a narrow range of salinity. In other words, if the salinity of the water changes too much from what they naturally live in, fish will start to die. Eventually, as the oceans continue to dry up and there's no rainwater to replenish them, they will become hyperalkaline.
