EC writes in to add:
[R]emember that the chief agent in dissolving limestone and other carbonate rocks over geologic time is carbonic acid, which is formed as rainwater passes through the atmosphere and picks up carbon dioxide. The results of this weathering can be seen in typical sculpted outcrops in many parts of the world, made famous in the historical brush paintings of Southern China.
So, absent sulphuric acid from burning coal, and nitric acids from wherever, carbonic acid does its job of reshaping the Earths surface as it has for eons.
This process is similar to the formation of nitric acid.
Might we add this is just the kind of mail that you wouldnt get at the Daily Kos?
Божію Поспѣшествующею Милостію Мы, Дима Грозный Императоръ и Самодержецъ Всероссiйскiй, цѣсарь Московскiй. The Czar was born in the steppes of Russia in 1267, and was cheated out of total control of all Russia upon the death of Boris Mikhailovich, who replaced Alexander Yaroslav Nevsky in 1263. However, in 1283, our Czar was passed over due to a clerical error and the rule of all Russia went to his second cousin Daniil (Даниил Александрович), whom Czar still resents. As a half-hearted apology, the Czar was awarded control over Muscovy, inconveniently located 5,000 miles away just outside Chicago. He now spends his time seething about this and writing about other stuff that bothers him.