Canada needs a lot of housing – and the Liberal government is making this a priority at their cabinet retreat this week. But there are concerns that if we keep building new homes using current materials and practices, it could lead to a spike in our greenhouse gas emissions.Luigi Ferrara is the chair and CEO of the Brookfield Sustainability Institute, which looked into this issue. Today, he tells us why current building practices cause high emissions, and how homes could be built differently – and retrofitted – to become more sustainable.Questions? Comments? Ideas? Email us at thedecibel@globeandmail.com