Green building construction is on track to make up a quarter of the US construction market this year, according to a new report from the US Green Business Council (USGBC) released this week.

The report, prepared for the USGBC by Booz Allen Hamilton, found green construction in the US has generated $167.4bn in the last three years, supporting more than 2.1m jobs and yielding $147.7bn in earnings for construction workers.

It forecasts the green building construction market will grow 15.1% annually – outpacing the 9% expected growth in overall construction starts this year – from $150.6bn in 2015 to $224.4bn in 2018. By 2018, more than one third of all construction will be green, the report predicts.

“Estimates of the economic impact of green building construction for 2015-18 show a significant increase in impact on GDP, jobs and labor earnings as compared to 2011-14,” the report’s authors wrote.

From 2015 to 2018, green building is expected to support 3.9m jobs, bring $268bn to industry workers and add $303bn to the GDP, according to the report.

That could mean huge cuts in energy and water use, as well as a reduction in the use of toxic materials for construction. Or, it could mean business as usual.

“It depends on how you define green,” said Henry Gifford, a cofounder of Architecture and Energy Limited and a vocal critic of The Green Business Council and its Leadership in Energy and Environmental Design (LEED) certification programme. LEED is the most well known of a number of green building certifications, such as the Energy Star programme administered by the Environmental Protection Agency (EPA).

Gifford has argued that the LEED programme allows builders to create computer models showing energy savings by comparing a proposed project to an imagined similar project and noting an improvement between the two. In 2012, a New York federal judge dismissed a lawsuit brought by Gifford against the USGBC.

Projects do not have caps on them, Gifford said, but only need to show various environmental factors have been considered. “There’s no limit to how much energy a building can use and still be LEED-rated,” he said.

The new report defines green building as focusing on the categories of “energy efficiency, water efficiency, resource efficiency, responsible site management and improved indoor air quality”, to the exclusion of projects that only address one or only a few of these categories.

Helene Gotthelf, a project manager at Colorado State University’s Institute for the Built Environment, teaches LEED classes and said although it has flaws, the programme does lead to more environmentally-friendly building practices by requiring consideration of multiple issues related to sustainability. “It brings together a diverse group of stakeholders, which is not necessarily the industry norm,” she said.

The LEED requirements can also be used by some builders as a simple checklist they need to complete in exchange for a gold, silver or platinum plaque or certificate, leading to a “mechanistic view” of a project, instead of the intended “ecological or worldview”, Gotthelf said.

A 2014 report by McGraw Hill Construction also forecasted large growth in green building. That reported predicted that by 2018, 84% of firms building new homes will be building 15% of them to be green. It defined green building as construction that is sensitive to site placement, resources use and indoor air quality, among other factors.

The American Institute of Architects predicts an overall increase in construction in the remainder of 2015 and 2016. It forecasts nonresidential building spending to reach nearly $360bn in 2015 and $390bn in 2016, still 10% lower than it was in 2008.