Piers Does Global Photosynthesis

I first met Piers in 1985, at a meeting in Oregon. At the time, I was fascinated by work by Jim Tucker and Inez Fung, linking the seasonal dynamics of CO₂ concentration in the atmosphere with the seasonal pattern of greening and senescence of the vegetation on the continents. My background was with photosynthesis at the leaf-scale, and this new work seemed to be defining a gas exchange system, at a planetary–scale, that seemed to call out for studies similar to what we had been doing at the leaf-scale. I was looking for a way to start on this, but I was not aware of Piers’ work before this meeting. Over the course of a couple of days in the woods of Oregon, I was to learn of his quantitative approach for using canopy radiative transport theory and satellite remote sensing to determine the flux of sunlight captured by photosynthesis – the power driving photosynthesis and transpiration. And, to top this off, there was the land surface model, SIB that he had developed to incorporate this remote sensing driven land surface into atmospheric general circulation models (GCMs). With this we could provide the all important climatic variables, light, temperature and availability of water needed to simulate photosynthesis, and the GCM offered the possibility to mix the air providing a coupling of surface fluxes with spatial and seasonal dynamics of CO₂ in the atmosphere. These were the prefect tools to begin a quantitative study of photosynthesis at the regional or global scale - and they remain so today. At the time Piers was actually more interested in the effect of the biosphere on the physical climate system, but I was able to convince him that solving photosynthesis would help with the climate problem, and we decided to collaborate. Ultimately this led to my inclusion on a team lead by Piers that was selected as one of 29 Interdisciplinary Science Investigation teams funded by NASA’s EOS program. This team, with generous, long-term funding from NASA was both exciting and amazingly productive. In this presentation I will review some of the accomplishments of Piers’ team, and in particular some observations about Piers’s leadership and creativity. I will close, with some comments on how Piers’s seminal work on global photosynthesis is still at the cutting edge today.