Mary Alice Haddad writes:

".The total change in CO2 emissions from energy consumption in Japan by sector 1990-2009 Total= +0.03% change

Sectors that increased their emissions:
Waste 14.1%
Transport 5.4%
Residence 26.9%
Offices 33.6%
Energy industries 16.2%

Sectors that decreased their emissions:
Industrial Processes -30.4%
Manufacturing -19.9%
.
It is very clear that the building sector, both household and offices, is the area where the greatest improvements can be made. Since improvements in this area are relatively cheap and easy, as others have pointed out, it is somewhat startling that more has not been done." (2012/04/04)

A comparison of 1990 and 2009 emissions is misleading because the 2009 figures reflect the massive downturn in economic activity triggered by the 2008 financial crisis. All sectoral CO2 emissions took hits, but industrial sector emissions, which decreased marginally between 1990 and 2007 but with significant fluctuations that most likely resulted from fluctuations in economic activity, plummeted in 2008 and 2009. Here's a graph
(http://www.jccca.org/chart/chart04_05.html) from a reputable source. I found the corresponding manufacturing (and mining) production figures from another reputable source (http://www.meti.go.jp/statistics/tyo/iip/result-2.html
), which according to my casual guesstimate suggest that somewhat less than half-1/3?-of the emissions reductions in manufacturing over the 1990-2009 period resulted from efficiency gains loosely defined as reduction of emissions over value added. (I'd be happy to come up with firm numbers for the right money.) Likewise, the even greater drop-off in industrial processes emissions appears to be largely attributable to the decline in cement and blast furnace steel production.

Still, those were real savings, and the same thing can't be said for offices and residences. But if it ain't happening, maybe it's a little premature to assume that "improvements in this area are relatively cheap and easy". In fact, current household and office consumption reflects lifestyle changes that may not be easy to reverse. (Fellow Tokyo denizens who managed to work through this winter wearing a coat and typing with tipless gloves will know what I'm talking about.) Housing and building stock do not turn over that quickly, and retrofitting must make economic sense for homeowners and institutional bean counters. (Nothing is "cheap" if you lose money on the deal.) Finally, proprietary occupants and landlords face very different incentives when it comes to capital costs and operating expenses.