University of Illinois Professor Stephen Long discusses his talk at the recent U.N. Climate Summit in Paris about the need to improve agricultural productivity, and his own work to develop more plants with more efficient photosynthesis.

Guest: Stephen Pyne.

So far this year, more than four and a half million acres of land have been affected by large fires. This morning on Focus we're joined by Professor Stephen Pyne to talk about the ways nature and human activity both contribute to the increased risk of large, intense fires, as well as some of the controversy surrounding the prevention and fighting of wildfires.

Guest: Stephen Schneider.

According to the National Academy of Sciences, the surface temperature of the Earth has risen by about a degree in the last 100 years. Many scientists argue that most of the warming over the last 50 years is due to human activity. Others say we don't have enough data to draw that conclusion. This morning on Focus, we're joined by Stanford biologist Stephen Schneider to explore the question of whether climate change is too uncertain for policy.