So far, we've been having a look at the problems, and I've explained why I'm not fully satisfied with the way in which, and the extent to which, they're currently being addressed. In case you share this assessment of the situation and are wondering what can be done about it, here are some of my preliminary answers. They may change with time, and yours may be different, but maybe they can provide a strating point for your own thoughts.
I see two basic possible approaches which I'd like to label "bottom-up" and "top-down". Bottom-up would mean individual people getting informed, stepping up, taking action, and leading with a good example. Top-down would mean national governments or even supranational bodies like the European Union or the United Nations laying down rules which are binding for everybody.
Which way, now, is the right one? I, personally, think that we need both. The charm of bottom-up is the preservation of personal liberty, and the fact that individuals are free to think ahead and act more swiftly and radically than a government that needs to find a democratic consensus first. A growing group of frontrunners can influence opinions, create trends, and, by the choice of which products they demand for, increase supply of sustainable goods and services, and initiate a positive self-reinforcing process. The downside is that people have their desires and irrationalities that may limit the extent to which voluntary measures can go. For instance, I don't have a car, and that works pretty well for me - usually I can get to where I want to be by bike or public transportation, and in the few cases when I can't, I usually find someone who gives me a ride. On the other hand, I thoroughly enjoy travelling, and if that involves taking a plane, so be it. I know that flights aren't particularly eco-friendly (even if I compensate my CO2 emissions with a donation at www.atmosfair.de, the fuel is still gone for good afterwards). But I decided at a young age, long before ever hearing of Peak Oil and the like, that one thing I want to get out of this life is seeing the world, and I don't think I'll completely give up travelling while I can afford it.
And that's where top-down comes into play. If a measure makes sense and is necessary (admittetly it's not always easy to figure out whether or not this is the case), but not everybody will do it voluntarily, politics can make the rules and "force people to their own good". If, say, kerosene taxes went up, I wouldn't be thrilled to be paying more for my plane ticket, but I would accept it, knowing that it's for a good reason and that the restriction applies to everybody (well, at least everybody living in the same jurisdiction as me, assuming that not all nations will pass the same law at the same time). The downside is that in a democratic pluralistic society, governments continuously have to try and find a consensus - which is good in the sense that everybody gets a chance to have their interests considered, but bad if it means that necessary actions don't get taken because some powerful interest group manages to prevent that. (Let me concede again that I acknowledge the problem that there is no infallible authority that can tell us for sure what is "right" and "necessary".)
So, what can be your role in this? On the bottom-up side, think about your lifestyle, and which changes you might make to it in order to save energy and lower your negative impact on the environment. If you're German, the book "Welt retten für Einsteiger" and its associated website may provide a starting point for you. (A hint - try thinking quantitatively about how much good the various suggestions in there would do, and give "sustainability" the preference over "lifestyle". That is, if you're wondering whether you should devote your time to better thermally insulating your house, or to picking the most eco-friendly wine, go for the first option.) Also, spread the word, and become a multiplier by talking to friends, family and colleagues, and help reaching a critical mass of people who are aware of the problems at hand. Finally, if you happen to be endowed with a good dose of entrepreneurial spirit and starting capital, why not kick off a company that specializes in eco-friendly goods and services? Companies are important actors in our world and have possibilities that private individuals and even governments don't have. So, why not do some good with them? (The restriction here being, of course, that with a company you have to be profitable, and what's ecologically sensible doesn't necessarily have to be profitable [yet]).
On the top-down side, unless you happen to be in a position of power, your influence will necessarily be more indirect. The point I want to make is that if you think politicians aren't doing enough, you don't have to sit in silence and complain that "they up there do what they want anyway", but that democracy gives you the right to participate. You can write to your Member of Parliament / House of Representatives / Bundestag /whatever. If he doesn't read your letter personally, someone of his staff will, and, if your point is good, hopefully pass your concern on. (By the way, a neat way to ask questions to members of Bundestag in public is offered by the website www.abgeordnetenwatch.de ). You can join a political party, if you find one that accomodates your views and beliefs. You can participate in the public discussion by writing a letter to your favourite newspaper. And, last but not least, in an election year like 2009 is for Germany, you can cast your vote. Find out the political parties' positions on the topics that concern you, and make sustainability a key factor in your voting decision.
Most importantly, however: get started. I've tried to indicate a few possibilities; whatever you end up doing, the most important thing is to do the first step. Even if you're starting small, it'll be better than nothing. If you have made it reading up to here, then now is the time to make the first step of you own.
If you do, then there's hope.