Napa Valley Register: Napa County now has a ballpark estimate of its greenhouse gas emissions, credited as the source of global warming. The numbers are daunting. Residents, businesses, agriculture and pass-through travelers were responsible for 1.2 million metric tons of emissions in 2005, the most recent year for which data was available, the Napa County Transportation and Planning Agency reported. The figure puts Napa County emissions lower per capita than those in most Bay Area counties. But the local …