A forest may appear still, yet it breathes without end. Trees drink water and return it to the sky. That vapor becomes clouds, travels thousands of kilometers, and falls as rain on distant lands. A recent study published in Nature revealed that this breathing of the forest is not merely an internal cycle within an ecosystem but an atmospheric network that connects the Earth’s entire climate and food systems.

The atmosphere is another kind of river. Water does not only flow across the land into the sea — it also rises into the air through trees and flows again. This is what scientists call the '“atmospheric river,”' the stream of water vapor that moves through the air.

Through satellite data and climate modeling, researchers confirmed that water vapor evaporated from large tropical forests — such as those in the Amazon, the Congo, and Borneo — travels thousands of kilometers by wind and directly influences rainfall in distant regions.

For instance, vapor from northern Amazonia creates rain over soybean farmlands in southern South America, while moisture from Southeast Asian rainforests regulates monsoon rainfall across eastern India.

In other words, forests are not merely “carbon sinks” that absorb carbon dioxide — they are 'living organs that create rain.'

When a single tree sends hundreds of liters of moisture into the sky, that small vapor alters the crops and river levels of another country.

The most important implication of this research is 'climate connectivity.' When the forest of one region is destroyed, the damage is not local. Once the flow of water vapor is disrupted, rainfall patterns in distant regions collapse, droughts occur, and food production declines.

Scientists call this phenomenon 'climate teleconnection.' The Earth’s atmosphere functions like a single organism. Deforestation in Brazil can reduce corn yields in Africa, and forest fires in Southeast Asia can weaken rain clouds over Australia.

There are no longer any “national borders” for forests. Environmental problems are no longer regional phenomena, but must be understood as 'fractures in a globally interdependent system.'

A tree is not merely a biological being — it is 'the circulatory organ of the Earth.' Plant evapotranspiration carries moisture from the soil to the sky, forms clouds, and returns it as rain. This is the core of the 'local hydrological cycle' and the foundation of climate stability.

The research team quantified this process. If major forest zones disappear, annual rainfall in nearby areas could drop by up to 20%, and the impact could spread to other continents along prevailing wind paths. In other words, when forests decrease, water disappears — and when water disappears, crops vanish.

This discovery transforms our perception of forests merely as 'carbon sinks.' Forests not only purify the air but also serve as 'invisible infrastructure that designs the climate and nurtures food.'

In an era where climate change and deforestation are unfolding simultaneously, this study delivers a clear warning:

The loss of forests means the 'loss of food.' When forests that generate rain disappear, the ecological foundation of agriculture collapses.

According to FAO reports, over 40% of the world’s farmlands have experienced 'water stress' over the past 30 years.

It is not merely that rainfall has decreased — it is that 'the pattern of rain itself has broken.' This phenomenon is directly connected to forest loss.

Therefore, forest preservation is no longer just environmental protection — it has become a 'strategy for food security.'

Future agricultural policies must consider both climate modeling and vapor transport pathways. To manage rainfall is, in essence, to manage forests.

The water vapor produced by forests is a shared asset of humankind. Yet no responsibility is attached to protecting its flow. When one nation clears its forests, farmers in another nation must endure drought. This is the new challenge of 'Climate Ethics.'

Water vapor in the atmosphere has no nationality, but our choices do have boundaries. Climate justice must now extend beyond carbon to include 'the distribution of water and rain.'

To protect forests is not merely to save trees — it is to protect the rivers of the sky. Rain is the memory of the forest. When that memory disappears, the future of humanity grows dim.

Rodriguez, M. et al. (2025). 'Forest Evaporation and Transboundary Precipitation: How Vegetation Shapes Distant Rainfall Patterns.' 'Nature', September 2025.