I’ve blogged before about evolving consumer attitudes on “green” products, and the telltale signs that “green fatigue” may be setting in with at least some people.

And now we have survey results that lend additional support to this observation. Harris Interactive conducted an online survey of ~2,350 U.S. adults in November, 2010 – one which is done annually by the polling firm. A comparison between the 2010 and 2009 survey results suggests that fewer Americans are engaging in various green behaviors in their daily lives.

While the year-on-year differences may be slight, the overall trend in participation is down. To illustrate, here are the comparative percentages of respondents who report that they “always” or “often” engage in certain “green” activities:

 Turning off lights when leaving a room: 81% (versus 83% in 2009)
 Making an effort to use less water: 57% (vs. 60%)
 Purchasing locally grown produce: 33% (vs. 39%)
 Purchasing locally manufactured products: 23% (vs. 26%)

Are there any areas where the trend is up rather than down? Actually, no. But Harris did find one area of stability: The same percentage of respondents in both years reported “always” or “often” engaging in recycling activities (68%).

What about other environmental activities? Again, the trend lines aren’t going in green’s favor:

 Purchased energy-efficient appliances (e.g., Energy Star): 30% (versus 36% in 2009)
 Donated or recycled electronic devices or parts: 32% (vs. 41%)
 Switched from bottled water to filtered tap water: 23% (vs. 29%)
 Purchased a more fuel-efficient car or hybrid vehicle: 8% (vs. 13%)

In fact, only one of the nearly 20 activities that were surveyed by Harris showed a positive “green” trend for 2010 versus the year prior — and that was switching to paperless statements for personal financial accounts.

Big whoop.

In trying to understand what is causing the change in behavior, it’s too simplistic to cite the economic recession. After all, 2010 was a less challenging year on that front compared to 2009, when the economy was really in the dumper.

For clues, we might turn to several other consumer research studies. The 2010 Green Gauge® Study conducted by GfK Roper gives us some possible reasons. That study concluded that there’s a sense of “green fatigue” among U.S. consumers. Clear majorities believe that green products are “too expensive” … while one–third of the people surveyed believe that green products “don’t work as well” as the alternatives.

But a more startling statistic from the GfK Roper study is that nearly 40% of the people surveyed feel that “green products aren’t really better for the environment.”

That shows a pretty skeptical public! And what about the issue of truth in advertising? The newest Green Gap Trend Tracker survey from Cone, just released this month, found that well over half of the ~1,035 adults surveyed do not trust the “green” claims made by products and brands.

Interestingly, even with so much of the consumer participation trending down rather than up, these surveys also found that more people today actually consider themselves to be environmentalists or green/environmentally aware.

So, consumers see themselves as green-friendly … but it’s all in how someone defines the term. As it turns out, it’s a murky definition that has people all over the map when it comes to the actual behavior.