Summary
Highlights
Initially, a world without microbes seems ideal, free from bacteria, viruses, and illness. Surgery could be performed anywhere without fear of infection, and sexually transmitted diseases would cease to exist. This scenario presents a seemingly flawless environment for those wary of germs.
However, the absence of microbes would immediately impact human life. We would lose the ability to produce fermented products like beer and wine. More critically, our digestion would suffer, as microbes aid in breaking down food and producing essential vitamins, leading to malnutrition. Our endocrine and nervous systems, regulated by microbes, would also be disrupted, potentially causing hormonal imbalances and affecting mood.
Beyond human health, the global ecosystem would rapidly collapse. Plants would die due to lack of soil nutrients generated by microbes, leading to massive food shortages. Livestock would starve as they couldn't digest plant matter. Lakes, rivers, and oceans would experience mass die-offs of fish and other aquatic life, turning into stagnant, lifeless bodies of water.
Without microbes, the crucial process of decomposition would halt. The world would become a graveyard, buried under animal corpses and leaf litter that would never decay. In such a dire situation, human starvation would become widespread, making cannibalism a likely and grim societal endpoint, as bodies would be free of pathogenic bacteria.
The ultimate consequence would be a dramatic reduction in oxygen levels. Many microbes, particularly those in the ocean, are critical oxygen producers. Their disappearance would lead to global suffocation. Coupled with mass starvation and ecological collapse, this scenario ultimately signifies game over for all life on Earth. Microbes, therefore, are not just beneficial but absolutely essential for our existence.