From the beginning, it was clear that the biggest problem with freezing was the formation of ice.
Liquid water tends to trap heat more effectively than ice, which in turn discourages the future formation of ice.
With further warming, they say, broad open-water expanses will prevail in the summer followed by the formation of ice in the winter.
The method involves injecting clouds with substances that encourage the formation of ice crystals heavy enough to fall, thereby speeding up the production of rain.
The compounds also act to inhibit the formation of ice or sugar crystals in foods and can be used to encapsulate flavour compounds.
The formation of ice in rivers is more complex than in lakes, largely because of the effects of water velocity and turbulence.
In winter months a rapid formation of ice or the establishment of strong winter thermal stratification may significantly inhibit the replenishment of oxygen.
Stabilizers and emulsifiers are added in small amounts to help prevent formation of ice crystals, particularly during temperature fluctuations in storage.
The transition could begin with some small seed in one location of our universe, in the same way that, on our frozen windowpane, small dust grains helped seed the formation of ice crystals.
Cloud seeding dates from experiments in 1946 at the General Electric Laboratories in Schenectady, N.Y., and usually relies on silver iodide as a seeding agent, providing nuclei for the rapid formation of ice crystals that may eventually produce raindrops.
There, it was found that lightning in the plume was only triggered if temperatures fell below -20C, which implied the formation of ice was significant, because this is the temperature at which the supercooled water droplets freeze in the air.
