Getty ImagesRoss Greer is running for the co-leadership of the Scottish Greens.
The party’s education and finance spokesperson announced his campaign on Thursday.
It comes after Patrick Harvie, who has led the party since 2008, announced he would stand down in April.
Scottish Green Party members elect their co-leaders every two years, with at least one to be female.
Lorna Slater, who has been the Scottish Greens co-leader since 2019, is standing again.
Green MSP Gillian Mackay also announced her bid in May.
Results of the leadership contest are expected in August.
In a campaign video published on Thursday, Greer said: “The system is rigged. The super-rich are out of control.
“They’ve caused a climate crisis and made everyone else’s lives miserable just so that they can hoard more wealth than they could spend in a thousand lifetimes.
“And the sense of hope that Scotland can be a fairer and a greener country, that’s all but disappeared.
“I think the Scottish Greens can be the party that brings that sense of hope back to our politics.”
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