It wasn't that long ago that the news of my career choice would be met with an incredulous or (at best) bemused reaction. Family and friends would attempt to hide their disbelief or disapproval behind tightlipped smiles -- with little success.

Why would a young attorney eschew the six-figure salary and prestige of a legal job for the unsteady and undefined world of sustainability? The decision was simply baffling.

Let's just say I had a hunch, three years ago. A premonition that what began as a somewhat superficial movement to put a green spin on the status quo would evolve into something more substantive, meaningful and complex.

In 2006, Thomas Friedman's celebrated "tipping point," much of the work being performed by our burgeoning industry was trial and error. Now, in the dawn of a new decade, sustainability professionals have many real accomplishments to celebrate -- and many, many more challenges ahead.

There is no precedent to rely on in the world of sustainability. The key to success is not in relying on the past, but in anticipating and responding to future trends. I've been fortunate to have the opportunity to collaborate with smart, tireless people who shared a similar hunch and the same passion for motivating change. Following are our combined predictions for 2010:

The Trickle-Down Effect

Sustainability shows no signs of decelerating this year. Instead, green business practices will infiltrate an even broader segment of the market. Big companies (and not just Walmart) wield a big stick and are starting to pull their suppliers, vendors and partners along. No longer just a hot-button issue for the Fortune 500, sustainability will trickle down to smaller businesses, particularly mid-sized companies.

Those companies are at somewhat of a disadvantage, because the world of sustainability is much more dense and sprawling than when the early corporate adopters first blazed the trail.  That complexity can be paralyzing, so progress may be slow. Small to mid-sized companies will need help wading through the clutter to identify programs that make sense for their business and culture.

Sustainability Also Expands in Concentric Circles

In addition to reaching more businesses, a broader employee base at larger companies will start to see evidence of sustainable policies and practices in their daily work life.  Until now, responsibility for environmental stewardship has typically been limited to an executive team or an employee green team. Very few companies have actual departments devoted to sustainability. 

In fact, sustainability has often been the responsibility of one individual, the sustainability director. That person is usually overwhelmed with a global sphere of responsibility and no budget, team, or clear role within the company. He or she is often pulled from another section of the company and may even have to keep their "day job," which results in a lot of late nights and early mornings. Fortunately, companies are starting to figure this out (and I get fewer e-mails from sustainability directors at 4 a.m.!)