For those interested in the influence of water vapor and water cycling on climate, and in the worldwide loss of soil moisture, this is an important read. In Slovakia, the authors describe how the water cycle has been compromised by urbanization (impervious surfaces), large-scale agricultural drainage, and deforestation. Soil moisture has been depleted over large areas, leading to increasing heat buildup and a loss of rainfall in the lowlands, which the authors attribute to an impaired “small” or regional water cycle, where water falls close to where it has evaporated or transpired. In Slovakia, there has been an increase in rainfall in the highlands, which exacerbates flooding.
The new water paradigm they advocate involves understanding the water cycle, not just the supply or deficit which is the usual focus of water policies. The new paradigm shares much in common with the understanding of the water cycle described in Allan Savory’s book Holistic Management: A New Framework for Decision Making, but lacks the dryland dimension, and overlooks the supreme importance of the condition of the soil surface (presence of litter, organic matter, etc.) to well-functioning water cycling.
The energy carried by the water cycle dwarfs the energy captured by photosynthesis, which in turn is far greater than all industrial power use. The water cycle transports immense amounts of thermal energy from one place to another.
The authors estimate that, worldwide, soil moisture makes up about .005% of earth’s water. The atmosphere only holds a fifth as much in the form of clouds and vapor. Because water vapor is the most significant greenhouse gas, the balance of soil and atmospheric moisture is of major importance. A warmer atmosphere holds more vapor. Soil that holds more moisture for longer periods will be a critical part of global warming solutions. In addition, a well-functioning water cycle will favor the development of soil organic matter, and soil is the largest carbon sink over which we have some control.
For anyone who aspires to understand the water cycle or climate change, this is an important book.
Soil Carbon Coalition is a 501(c)3 nonprofit organization