Sentence:  Meanwhile, soaring oil prices and plummeting real energy yields from liquid fuels have already left economic carnage in their wake, as a fragile global financial system perched on a <WSD>Matterhorn</WSD> of debt has been dealt blow after blow by the failure of the real economy to expand as expected. 
Meaning of the word marked with <WSD> tags:  Something difficult to achieve or to surmount.