William Happer, physicist, Princeton University, USA, W A Wijngaarden, physicist, York University, Canada: William Happer's view is that human emissions likely dominate the increase of atmospheric CO2 over the past century. There is enormous complexity of CO2 in the atmosphere, the land and the oceans. One has to wonder if four coupled linear equations are too simple with respect to reality. He thinks that growing CO2 levels are a great benefit to life on Earth and to humanity.
