Green building industries could create millions of jobs and add hundreds of billions of dollars to the economy, according to a new report (PDF) from the U.S. Green Building Council (USGBC).

Prepared by Booz Allen Hamilton, the consulting firm, the Green Jobs Study predicts that nearly 8 million “green construction market” jobs will be created in the next four years, adding $554 billion to U.S. GDP.

What, exactly, qualifies as a green construction market job, you ask? The report takes a fairly wide interpretation, drawing from a 2008 definition from McGraw Hill:

We define green building as one built to LEED standards, an equivalent green building certification program, or one that incorporates numerous green building elements across five category areas: energy efficiency, water efficiency, resource efficiency, responsible site management and improved indoor air quality. Projects that only feature a few green building products (e.g., HVAC systems, waterless urinals) or that only address one aspect of a green building, such as energy efficiency, are not included in this calculation.

A few months ago, there was considerable debate over what constitutes a “green job” (see here, here and here), so it’s reassuring to see that the report’s authors nip that question in the bud (they address the issue of mushy definitions on page one of the report).

As for the numbers themselves, they’re the product of a macroeconomic modeling platform that discerns between direct and indirect impacts of the green building activities:

Direct effects are the initial economic changes to the industry impacted (e.g., a general contractor who constructs a green building). Indirect effects represent the increased economic activity generated for downstream businesses that provide supplies and raw materials for the industries directly affected (e.g., the general contractor purchases supplies from steel and lumber companies). Finally, induced effects capture the economic impact from the increased income of households that are directly and indirectly affected by green building expenditures (e.g., employees of the general contractor, the steel supplier, and the lumber supplier use their additional income from green construction spending to purchase products and services from food and gas to healthcare and education).

I, for one, wouldn’t know where to begin when trying to calculate how much an individual’s buying power increases because he/she lands a new (and presumably better paying) green-building job. Nor would I know what, in general, their purchasing habits would be and how that would, in turn, impact the overall growth of the U.S. economy. But I’m not an economist. Luckily, the teams from Booz Allen Hamilton and the USGBC have a few competent ones on staff.

The report was released two weeks ago at Greenbuild 2009 in Phoenix.