You really are a dunce, Grondine
Where are clathrates mentioned in this BBC article? Do you know the difference between pure solid CO2 that condenses directly out of Mars' atmosphere and subsurface deposits of clathrates, methane hydrates, etc.? Moreover, have you even read Nick's paper in the journal Astrobiology? Well, I have; in fact, I sent Nick a PDF reprint of his own paper. Maybe you should try reading (and especially comprehending) it as well. Hint: look under "A" in the journal index.