Unless you've been in a coma for the past three years, you've probably heard something about the real estate bubble that burst in the late 2000s. The real estate bust affects all sectors of the economy, from attorneys to home decorating, but few areas have been quite as directly affected as the construction industry. As the country -- and the world -- continues to dig its way out of the Great Recession, construction jobs and contracts remain below the peak from the boom years of 2005 and 2006. But it hasn't been all doom and gloom. Throughout the recession, one sector of the construction industry has consistently shown signs of growth: green building.

Through the darkest days of the financial collapse, green jobs have proven to be somewhat recession-proof. That's partly because green buildings and technologies make better financial sense than their energy-hogging counterparts. Although building with environmentally-friendly techniques may have started as a passion of tree-huggers and design students, the green building movement has long since entered the mainstream. It seems likely that in the coming years, there will no longer be a "green building" category, because energy- and water-efficient buildings will be the only option.

In recent years, the owners of the Empire State Building and the Willis Tower (formerly Sears Tower) have made headlines for adding green retrofits to the iconic skyscrapers. And why shouldn't they? On average, new green buildings provide their owners savings of 13.6 percent on operating costs, and green retrofits can save an average of 8.5 percent. When you're talking about a building like the Willis Tower, which has more than 4 million square feet of floor space, that can amount to some pretty serious savings. A 2009 report showed that productivity benefits from LEED-certified buildings (Leadership in Energy and Environmental Design) ranged from $230 to $450 million [source: GreenBiz.com].

Green jobs are now one of the areas of strongest growth in the construction sector. For more on what caused the construction bubble to form and how green construction weathered the storm, read on.