Marc Imhoff is an Earth scientist at Goddard Space Flight Center in Maryland. He studies human consumption of plant material – what scientists call ‘net primary production.’

Marc Imhoff: So NPP – net primary production – is essentially all the solar energy that’s been captured by plants, turned into organic matter which then we use for food and fiber. And so it’s sort of like the ‘bio-engine’ of planet Earth.

Imhoff and colleagues used satellites to measure how much plant material is created on land in a year. They compared that to U.N. data on how much food and fiber we humans use in a year – and found that we use 20% of Earth’s net primary production – that’s 20% of all new plant matter created on land each year. Other studies have estimated 50%. Imhoff says that as human population and consumption continue to increase, so does our use of solar energy from plants. He’s concerned about that.

Marc Imhoff: So I think from a biodiversity standpoint, there’s some concern about taking too much of that ‘biofuel,’ as I call it . . . that you’re impoverishing what’s left over for all the other species to survive on.

Special thanks to NASA – explore, discover, understand.

Our thanks to:
Dr. Marc L. Imhoff
ESSP Project Scientist
NASA Goddard Space Flight Center
Greenbelt, MD