This includes a fundamental reorientation and restructuring of national and international institutions to move to effective Earth-system governance.

UNESCO: Providing scientific leadership towards Rio+20

"This requires fundamental reorientation and restructuring of national and international institutions toward more effective Earth system governance and planetary stewardship, " they write.

BBC: Gear change on road to Rio?

This bare, sandy earth then becomes an effective rain trap - with no vegetation, water cannot be lost through transpiration (the evaporation of water from plants).

BBC: Termites 'engineer fairy circles'

St Therese said she intended to use her time in heaven to do good on Earth, and she was considered to be an effective bridge to God.

BBC: Saint's remains arrive for tour

If scientists detected a major asteroid headed for Earth now, it would take at least five years to develop an effective defense system to either alter its course or possibly destroy it, no matter how much money was spent, according to Holdren and Bolden.

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