Why does climate science deny this reality ?

That Guy: Ha! Ha! The question was well within the scope of 'climate science'. Too bad you don't know what you are referring about.

Cloud seeding is old and has various methods. You will never know if it was used. If it were proven that it was the cause of a flood, do you really think the officials would let that out? The legal mess that would cause would be a lawyer's dream.

Weather modification is something that has been tried now for many decades. Back in the days of the Cold War the Soviets experimented extensively as they were hoping they could use the weather as a weapon of war. Despite large scale investment and a lot of research they didn’t achieve much.

The main focus of attention has been on increasing the probability of rain and the usual procedure has been to seed the atmosphere with tiny particles, often of silver iodide. The particles act as the condensation nuclei around which gaseous water vapour condenses to form droplets of liquid water in the hope that this will precipitate out of the atmosphere as rain.

What it doesn’t do is to increase the amount of rain, for that to happen there would need to be more water vapour in the atmosphere. Instead, the idea is to increase rainfall in the target location which would decrease rainfall elsewhere.

If this technique could be successfully implemented it would mean that rainfall could be induced in drought stricken areas or diverted away from areas at risk of flooding.

But as I said, it’s not been all that successful. There is some doubt as to whether it has worked at all. Despite many thousands of trials in different atmospheric conditions and using various nuclei, the results are inconclusive.

If it does work then all it can do is to trigger rainfall where the probability of rain is already relatively high. The atmosphere is already filled with condensation nuclei, the deliberate release of further particles just adds to those that are already there; rather than acting as the catalyst that induces rainfall these further particles simply increase the probability.

Furthermore, it’s not the presence of condensation nuclei that induces precipitation, it’s the reaching of saturation vapour pressure – the point at which the maximum physical limit for the presence of water vapour in the atmosphere is reached. If the objective is to induce rainfall then the best bet would be to cool a near saturated air-parcel, this would reduce the SVP and the threshold for condensation would be exceeded.

Other experiments along similar lines have been tried, not so much to make it rain but to create clouds. The principle of using condensation nuclei is the same.

In fact, one suggestion that has been proposed as a solution to global warming is to induce the formation of marine stratocumuli clouds. These clouds tend to form higher in the atmosphere than most clouds and are found over the seas and oceans to the west of continental land-masses.

The proposal is to inject high pressure jets of sea-water into the atmosphere, the water would evaporate in the lower and warmer part of the atmosphere leaving sodium chloride crystals suspended in the air. Through normal mixing these would be carried higher into the atmosphere where they would act as condensation nuclei and enhance cloud formation. The proposal favours the use of these types of cloud because they are much brighter and more reflective to incoming solar energy than their darker counterparts.

Other geoengineering or climate modification schemes have been suggested but they haven’t been implemented – largely because of the scale and costs involved.

For those of you in slow class

Climate and weather are not the same thing

Scientists don't deny the reality that people attempt weather modification. It may work on small scales, it may not--personally I don't think there's much convincing evidence that it does.