The Economist is an excellent publication. However, as I have communicated before on Climate Science, it is occasionally inaccurate in its coverage. This occurs very clearly in the June 23rd-27th issue in an otherwise very good article.
The article is “Arnie’s uphill climb” and the error is in their insert “Where smog comes from”. The data that they present is “California’s greenhouse-gas emissions by end-use sector, 2004%”.
However, it is incorrect to refer to “greenhouse-gas” as “smog”! As defined by the American Meteorological Society’s Glossary of Meteorology, the definition is
“smog—As originally coined in 1905 by Des Voeux: a natural fog contaminated by industrial pollutants, a mixture of smoke and fog. Today, it is the common term applied to problematical, largely urban, air pollution, with or without the natural fog; however, some visible manifestation is almost always implied. Smogs are constituted in great variety, but a major dichotomy exists between the photochemical smogs of nitrogen oxides and hydrocarbons emitted mainly by automobile engines and, on the other hand, the sulfur-laden, sometimes deadly, smogs produced by the large-scale combustion of fuel oil and coal. Both types contain carbon monoxide, carbon dioxide, and a variety of particulates. See Los Angeles (photochemical) smog, London (sulfurous) smog.”
It is unclear if the author of this figure unintentionally used the wrong word, or if it was used to draw a greater attention to the figure. It either case, it is an error.