"It has been suggested that the current "climate change" issues are due to the earth moving through cosmic dust clouds. It could even be that such things as "chemtrails" are a result of such dust loading in the upper atmosphere."

Clube suggests that the reason for the climate issues are that the earth moves into a "band" of dust long before it begins to encounter impactors and that climate cooling itself is a precursor to more catastrophic activity.

Okay, now let's take a look at Victor Clube's summary of the problem. He writes:

Asteroid strikes, though important, are not the most serious short-term risk to mankind or civilization

Every 5-10 generations or so, for about a generation, mankind is subject to an increased risk of global insult through another kind of cosmic agency.

This cosmic agency is a "Shoemaker-Levy type" train of cometary debris resulting in sequences of terrestrial encounters with sub-km meteoroids.

While the resulting risk is ~ 10%, the global insults take the form of (a) multiple multi-megaton bombardment, (b) climatic deterioration through stratospheric dust-loading, not excluding ice-age, and (c) consequent uncontrolled disease/plague.

The sequence of events affecting involved generations is potentially debilitating because, whether or not the risk is realised, civilization commonly undergoes violent transitions eg revolution, migration and collapse.

Subsequently perceived as pointless, such transitions are commonly an embarrassment to national elites even to the extent that historical and astronomical evidence of the risk are abominated and suppressed.

Upon revival of the risk, however, such "enlightenment" becomes an inducement to violent transition since historical and astronomical evidence are then in demand.

Such change and change about in addition to the insult is evidently self-defeating and calls for a procedure to eliminate the risk.

Our technological ability to counter (a) multiple multi-megaton bombardment and (b) stratospheric dust-loading should therefore be explored.

The very short lead-time commonly associated with the detection of sum-km meteoroids approaching the Earth implies countering procedures which differ from those associated with catalogued km-plus asteroids and comets.

So, the question is: if there is even a 10 % chance that we are facing a Shoemaker-Levy type event, why isn't anybody doing anything about it?