The Premier, Paul Lennon says the target will be based in 1990 levels.
Mr Lennon has used his first speech to parliament this year to outline several other measures to deal with climate.
He says the government's car fleet will be carbon neutral by mid 2010 and State Cabinet will consider making it mandatory for major government buildings to have solar power and hot water installed.
Mr Lennon has also announced an agreement with Greening Australia to offset the government's air travel.
