Alison Johnstone, the city councillor who will head the Greens' top-up list in Lothians, opened the party's annual conference at Edinburgh's Napier University, claiming there had never been a more important time for Green ideas.
She hailed the election of Britain's first Green MP Caroline Lucas - who will address the conference tomorrow - as a boost for the party's Holyrood campaign.
Ms Johnstone said following the UK general election and the formation of the Conservative-Liberal Democrat coalition, political loyalties were more volatile than ever before.
She also claimed that despite predictions of a two-horse race between the SNP and Labour next May, the Greens could surpass the seven MSPs elected in 2003, "especially given how fragile Liberal Democrat votes are".
Ms Johnstone said: "It was said that the Westminster voting system would mean that Greens would never be elected to the UK Parliament. That myth has vanished now. With a proportional voting system in Scotland and real understanding among voters that Green votes count, there is no doubt in my mind that 2011 will be a big year for the Greens.
"In recent months we have seen huge surges in Green votes in Australia, Brazil and Sweden. Here in Scotland we have a strong track record to build on: investment in community-led action on climate change; fuel-bill-busting programmes of home insulation; stronger commitments on equalities, to name only a few."
Robin Harper made history at the first Scottish Parliament elections in 1999 when he was elected a list MSP for Lothians and became the UK's first Green parliamentarian. Four years later, the party got seven MSPs elected. However, in 2007, their numbers were cut to two as the close contest between Labour and the SNP squeezed the smaller parties.
Today Ms Johnstone, who will replace Mr Harper at the top of the Lothians list, said: "There has never been a more important time for Green ideas. Across the UK, we are witnessing an astonishing assault on our public services, ideology wrapped in the cloak of financial necessity. Perhaps that's predictable from Conservatives, but Liberal Democrat supporters admit to being stunned by that party's complicity. And can anyone really say that the SNP and Labour would make fundamentally different choices?
"I firmly believe that Green MSPs will be elected in increasing numbers next May, the better to help make Scotland a greener and fairer country."