Contrary to the fact that attitudes usually precede behaviors, numerous sustainability attitudes are stable or have declined slightly since NMI first started measuring them in 2002, while many sustainability behaviors are climbing - in some cases rapidly.
Attitudes on the decline include overall caring about the environment, sustainable agriculture, renewable power, and socially responsible business. The declines are modest on a year-on-year basis, but the trend is consistent. On the other hand, many behaviors are on a steady uptick, including taking bags to the store, avoiding brands whose values consumers don't agree with, and many related to transportation, including use of public transit, carpooling, etc.
There are explanations for both the trend in attitudes and behaviors. First, with respect to attitudes, there has been so much attention paid to sustainability by companies and government that some consumers think that with all the discussion, something must have been improved.
At the same time, it is so much easier to be green now than ever before... leading retailers sell not just organic food, but organic clothes! An American carmaker has an electric car on the market this fall (admittedly not for the first time)! We can dispose of batteries at local retailers! And on and on… The ease in being green these days brings consumers into the green marketplace and lifestyle, even though they may not be avid environmentalists.
In the end, it's the behavior that really matters. So, while the softening attitudes are important to recognize and understand, they are outweighed by the much stronger trends in behavior.