Caroline Lucas is aiming to become the Green's first MP
Green Party leader Caroline Lucas has accused the government of a "political crime" in failing to properly address the issues of climate change.
At her party's conference in Brighton, she said plans to expand Heathrow Airport and for a new generation of coal-fired power stations must end.
She also called for reform of party funding, the voting system and of the House of Lords.
Ms Lucas, one of two British Green MEPs, hopes to become a Westminster MP.
She will stand in the Brighton Pavilion constituency at the general election - where the Greens took 22% of the vote in 2005.
'Politics with passion'
The party was "up to the task" of the "formidable challenges" it faced to get its first MPs at the election - expected next spring - she said in her speech.
It could offer an agenda-setting "politics with a passion", she said and voters had a choice between continuing with "growing inequality and cynicism as drift towards environmental catastrophe" which offered a "politics built on fairness".
Our government's inaction is nothing less than a political crime
Caroline Lucas Green Party
The Greens have 123 councillors and two London Assembly members and gained 8.7% of the vote in Britain in June's European elections, up from 6.2% in 2004.
The party says the fact it polled 1.3m votes in the June election shows it can win support, even during a recession when environmental issues can slip down the political agenda.
In her speech she said the "current level of ambition" on tackling climate change would not deliver the scale of emission cuts needed, nor sufficient financial resources to help poorer countries adjust.
She called for "an end to airport expansion, to plans for a fleet of new coal-fired power stations".
"We demand massive investment in energy efficiency, renewable energies, public transport, green jobs.
"And we demand that when the government signs up to new emissions targets, that they are honest about it, that they undertake domestic cuts here at home, not try to outsource it or offset it in poorer countries."
Green leader recalls poll successes
She praised grassroots protests but said that had to be matched by political leadership.
The mainstream parties "pretended that they have the problem under control" through measures like low energy light bulbs and loft insulation, she said but actually thought major change would involve too much "sacrifice".
But she argued that moving to a "post-carbon world" could create jobs, an equal society and a way of life "with the potential to be far more fulfilling than the turbo-charged consumerism which is being peddled by other politicians today."
"That's why we say our government's inaction is nothing less than a political crime."
Ms Lucas also said the Greens had warned of the "lethal cocktail" of liberalisation and deregulation before the recession and had "sounded the alarm" about the housing market, privatisation of health and education and about hedge funds.
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