They can offset that by increasing support for green initiatives that also benefit the companies that implement them, like hiring remote workers. Telus, for example, cut their CO2 emissions by 20,000 tonnes in just two years by facilitating remote workers. They also cut their real estate footprint by more than a million square feet. Their goal is to have 70% of their employees working remotely, at least part-time. Meanwhile, they're enjoying a $50 million dollar reduction in lease expenses! 
http://canadiansinternet.com/mobile-virtual-commuting-telecommuting-increasing-in-canada/