OAKVILLE, Ont. - Ontario is spending almost $80 million to fight climate change by planting 50 million trees, The Canadian Press has learned.

Ontario Premier Dalton McGuinty is set to make the announcement later Monday in Oakville as part of the United Nations' Plant for the Planet: Billion Tree Campaign.

A government source says Ontario's contribution to the program is the most ambitious of any jurisdiction in North America.

The province has already planted 1.8 million trees this year and the rest are to be planted on both public and privately owned lands by 2020.

McGuinty will also announce Monday he's implementing the recommendations of Roberta Bondar, who chaired the government's review of environmental education.

The premier says a new Grade 11 course will be developed to focus on environmental issues.