- Persistent trails that spread and linger are real and have become more common since the late 1990s.
- Chemtrails are modern contrails (condensation trails), not deliberate chemical spraying.
- The visible change is mainly due to modern jet fuel producing more effective ice-forming particles.
- These trails can turn into cirrus-like clouds and contribute to warming, but they are not geoengineering.
Introduction to Contrails/Chemtrails and Cirrus Clouds
To understand how trails form, it’s important to first understand some key concepts in atmospheric science, particularly how we use percentage numbers to describe the amount of ice in the atmosphere.
In everyday life, we think of 100% as the total amount, the “whole thing.” But in the atmosphere, things work a little differently, especially when we discuss Relative Humidity with respect to Ice (RHice).
What is RHice?
- The “relative” part refers to pressure and temperature, which scientists have already factored into their calculations.
- The “humidity” part refers to the amount of water vapour in the air.
When we talk about RHice, we’re really talking about how much water vapour could turn into ice, given the specific conditions of the air at the time. These calculations are well understood by science.
Sub-saturation, Saturation, and Supersaturation
- Sub-saturation: This is when RHice is below 100%. Ice crystals will disappear back into water vapour.
- Saturation point: When RHice is equal to 100%. This is the equilibrium point, where ice crystals will not grow, but none will dissipate either.
- Supersaturation: When RHice is above 100%. This is when ice crystals can grow into clouds.
The 100% RHice point is a calculated reference for saturation, and understanding the significance of the saturation point is key to understanding how cirrus clouds and trails form, grow and dissipate.
Why Can RHice Be Over 100%?
Ice crystals don’t usually form in perfectly empty air; they need something to start on. We see ice growing on surfaces, like a cold window, but not in the air in the room or outside. It’s the interaction with the surface that encourages ice to grow.
Because ice crystals resist forming without a surface, water vapour can build up in the air, and RHice can exceed 100% without forming ice crystals. The air then becomes supersaturated, meaning it is holding more water vapour than it can comfortably handle at those temperatures, but no ice will form until the conditions are right with the surface.
The Role of Ice Crystals and Nuclei
This is where ice nuclei come in. These tiny particles, like dust or microscopic matter in jet exhaust, act as the seeds around which ice crystals grow.
Without these ice nuclei, ice crystals would not readily form, even when the air is highly supersaturated.
Information from this website will prove that trails have very small sulfur-coated particles, which are extremely hygroscopic in nature. They attract moisture from the air and encourage ice growth when the air is still only subsaturated.