They are a joke in the sense that they will only ever be an annoying 3rd party. But they are dead serious in the sense that a large chunk of liberal democrats agree 100% with their policies. Excessive non-violence, Environmentalism (the pseudo-religion), LGBT rights to the extreme, wealth redistribution, etc., etc....It's a paradise for the most liberal of special snowflakes.
I'm a moderate Republican, and I care deeply about our planet. It's the only one we ever get, and the repairs are often costly. At the same time, though, elevating the earth to a deity-like position (as awe-inspiring as it is at times) is too far in the opposite direction. It causes them to forget that their policies to save the earth often times kill the most vulnerable of the human race. The ban on DDT killed millions through Malaria, clean energy isn't mature enough to fully supply an industrialized nation (without exceptional capital costs), and their ban on nutrition-enhanced GMO staples like Golden Rice will keep the poorest of the world's inhabitants at arm's length.
I agree we shouldn't pollute, and that companies/individuals who do should be prosecuted. While human activity does have some impact on global warming, it is a speck in the geological timescale. We are absolutely nowhere near the warmest this planet has ever been, not by a long shot.
Yeah, I just made up that word. But it does describe the whole "green" thing. It is nothing more than a fad, I can tell you that. It makes me laugh that so many people think that environmentalism is a real philosophy that will stick around, nope it will go the way of the dodo.
Think about fascism, or communism: First it was weird, then it was fashionable, then it was globally recognized, then it climaxed as it proved destructive, then it faded out and became unfashionable. The environmental policies are in the middle of the "globally recognized" phase, I just hope that I'm not impacted in 15 or 25 years when we reach phase 4.
The Green Party is an organization for the minorities. They make sure the people are heard instead of only the ginormous corporations. They appeal to the people on all sorts of issues. http://www.gp.org/the-real-difference
They are trying to and have made a big difference in making sure that everyone is equally represented and heard. While I may not agree with all of their standpoints, I appreciate what they are doing to help those not fully heard.
I am a university student and I know of many people who are voting green based on the ideological policies which the party throws out. I decided to read their manifesto and the first thing I thought was "wow, they really don't have a clue about the real world". The society they propose is some sort of socialist utopia which sounds fantastic but the reality is it cannot and will not exist in our lifetimes. I believe the main reason it wouldn't work is down to the irresponsibility and laziness of the general public. If every member of the public wanted to contribute to a fair society and was willing to put in the required effort then I genuinely believe that this ideal society is achievable in a time frame of 50-100 years. Unfortunately due to bad parenting and teaching many people have grown up to become lazy and irresponsible and because of the drain on resources they create, it would be impossible to fund all of the public services the Green party wish to run.
In summary, they are not a joke but they are incredibly naive.
The Green party seems to actually want to be taken seriously, so I kind of doubt that they are joking per say. Maybe some think it's 'laughable' for some reason, but no, they have a website and everything, all kinds of propaganda, and that takes effort, most people would not put that kind of effort into a joke.