It used to be enough to adopt a highway, recycle in the break room and install a few energy-efficient light bulbs. But businesses now must take ambitious steps if they want to be seen as sustainability leaders and join the big leagues. Consider that about two-thirds of all Fortune 500 companies now publish corporate sustainability reports. The past year has been a tough one for green businesses, though. With some financial incentives for sustainability drying up, the U.S. economy still treading water and many environmental issues getting little airtime from politicians, it\u2019s gotten harder to justify spending on sustainability. That said, smart businesses are continuing to invest in environmental sustainability. Because when you take a long-term view, these issues are just going to continue to become more critical to business success in the future. With that in mind, here are four emerging trends in sustainability likely to gain more steam in 2013: Smarter Marketing The days of broadcasting your environmental benefits to the world are pretty much over. \u201cGreen consumers\u201d are a varied bunch in terms of the reasons they buy environmentally friendly products \u2013 and eco-friendliness usually comes second to other factors. Companies are thus getting better at tying sustainability into their brand to make it just as much about the products as the green. And they\u2019re making it more fun. Take Unilever\u2019s Axe line of body products for men. The brand, which often uses suggestive marketing, recently launched its \u201cShowerpooling\u201d water conservation campaign. Besides encouraging college-age men to utilize low-flow showerheads, it also encourages fewer showers by telling them to: ". . .enjoy the company of a like-minded acquaintance." More Sharing The \u201csharing economy,\u201d is continuing to grow. People are realizing they can save money and help the environment by borrowing or renting anything from power tools to spare bedrooms to baby clothes to bicycles. Some industries might suffer. Why book a hotel room when someone with an amazing house is willing to rent it to you while they\u2019re away? In the long run, some of the actual sharing websites that are enabling this practice to grow could become powerful companies of their own, helping to promote a more sustainable future in the process.. Check out websites including Yerdle, Uniiverse, and Skillshare. \u00a0More businesses will try to break into the sharing business and more will share themselves as a way to reduce their footprint and costs. Keeping a Closer Eye on Financial Payback Early adopters of many sustainability practices and technologies jumped in because they believed in the cause. But sometimes those investments weren\u2019t the soundest from a financial perspective. They might have taken years to pay back in savings.\u00a0 But more companies are involving their CFOs in sustainability endeavors and doing elaborate payback and ROI analyses before investing in an upgrade. Sustainability is no longer a fringe activity in corporate operations; it is part of how they turn profits. Getting Serious About Data and Benchmarking Companies are tracking their sustainability progress like never before. And government officials are becoming increasingly interested in tracking businesses\u2019 sustainability practices as a way to tout achievements, as well as spurring the laggards to do more. The Institute for Market Transformation reports that cities including San Francisco, New York, Philadelphia, Seattle, Washington, D.C., and Austin, Texas have all created programs in recent years that require commercial building owners in some form to disclose energy efficiency. What do you think will be the green business trends next year? Are you planning any green initiatives at your business?