There are lots of advice and messages on what to do and especially on what not to do to become more eco-friendly or to go green. With lots of imperatives one can become confused, suspicious or even downright hostile to the environmental gospel. Assuming you want to avoid this attitude but at the same time you are not willing to go lay down naked on the glacier in protest or block the airports with demonstrations etc. there are some important issues you need to think about.
In ethical decision-making we are prioritizing our values within our value systems. Some concerns are more important to us that other ones. For most of us, for example, the immediate survival of our families is more important than glacier melting. Majority feels that one needs to survive with skills and opportunities one has at present, be ethical, yes, but thinking about environment usually comes only after other ethical concerns. If environmental imperatives (such as, "do not use a car if not necessary") are directly in conflict with other imperatives we act upon (such as driving your children to specific school at the right time) and those imperatives are more important to us, then environmental concerns simply can not make it to our decision-making process that easily. We all have to face such dilemmas and there are no prescribed solutions.
Few thoughts are helpful though. We can (we need to?) see the human race as a family that collectively struggles for survival and quality of life. Several authors including Martha Nussbaum argue for global ethics and world citizenship - as world citizens we have ethical obligations to humanity as a whole. Assuming that such obligations exist, it is still true that local and immediate (family-wise, ethnic, patriotic etc.) imperatives are more concrete and easily felt than global ones. We need some ways to connect with the awareness of global human family in order to give the environmental ethical concerns - which are a part of global ethics - any higher priority (I don't mean higher priority than family concerns but higher than zero or higher than we are used to).
Letting environmental activists to make us feel guilty all the time is not a very constructive ground for making changes in becoming more eco-friendly either. It is wise to make a slow but steady progress, to gradually incorporate changes into your lifestyle. Recycling and buying saving light bulbs does not, for example, cost much sacrifice and can be easily realized. Further down the road one might think about using public transport or a bike instead of a car at times, and switching off lights and other devices in your home and in your office when actually not using them. Majority of us though, are not at the stage where we would choose more expensive and several days long train and ship travel instead of a flight on a plane (although plane emissions are by far greater than those of any other form of travel). I assume that for considering such options seriously the negative consequences of air travel would have to be much more clearly present and also directly felt by us individual travelers.
We need to be realistic and good to ourselves and at the same time gradually incorporate the eco-friendly thinking into our everyday life. The extreme positions tend not to last long. In the case of extreme environmentalist activism (like cutting the tyres of the big cars or pouring paint on them) it can do much harm and put off many people from actually taking appropriate action.