At the Paris climate conference, the second and final week has begun. If we have a deal by Friday, countries will:

• Formalize their individual pledges to cut greenhouse gas emissions 
• Promise to show their work and be transparent along the way 
• Pay for poor countries to afford new energy sources 
• Schedule future meetings to “ratchet up” ambition down the road and speed up a global energy transition

Pledging an overhaul in the world’s energy economy is one thing, but following through is a different story.

Marketplace Sustainability Correspondent Scott Tong explains.