Get active!

You don't have to chain yourself o a tree to be an activist. Actually, a monopole cabled to a tree-sit is WAY more effective, as it can out-reach a cherry picker. The days of chaining to things are over. Even more effective, is to lobby the politicians.
The simplest thing is to write a letter, or ring up your local member. Political lobbying is complex, but there are people who do this full-time. You can help them be more effective by convincing the pollies that the have popular support; this is where the letters and phone calls are great.
The personal is political as well. Hypocritical of me to say this while using the computer, but reducing consumption is THE most important factor in saving the planet. The fact is that we live on a finite planet, that there is a limit to the metals, oils, plastics and fuels we are consuming. Burning fossil fuels, using electricity and buying new products all contribute to polluting the world we live in. The simple things can make a difference; take your own bag to the supermarket instead of using plastic ones, grow your own veges, turn off that light. The age old saying is "REDUCE, RE-USE, RECYCLE".
Ultimately we'll live in a world where products are made from recycled materials, crops are grown organically and sustainably, we'll use renewable energy, people will be nice to each other.... well, at least we can try."

Be what you want to be
do what you want to do
your future is up to you