Plants absorb 1/4 of human emitted CO2 each year. Trees and forests do this through photosynthesis, storing carbon in wood and leaves, and returning it to the soil through their roots. While still shrinking in the tropics, forests are expanding in the Northern hemisphere, often through reforestation programs. We discuss with forest ecologists Dr. Sarah Keubbing and Dr. William Anderegg.

The arctic provides 10% of the world's oil and 25% of our gas -- but new production may be overly expensive and environmentally risky. So arctic nations are looking to hydro, wind, nuclear and solar for electricity -- while facing melting sea ice and permafrost. With Mark Myers, from the US Arctic Research Commission, and Sergey Vakulenko from Gazprom Neft, Russia's 3rd largest oil company.

Many now embrace nuclear energy as a low-carbon, always-on, domestic energy source. If the US wants to build more, we'd need to overcome budget and schedule overruns, complicated permitting, a stagnated industry and broken supply chain. Sama Bilbao y Leon, Director of the World Nuclear Association, and Adam Stein, Director of Nuclear Energy Innovation at Breakthrough Institute, offer solutions.