Wednesday, May 15, 2013

New paper finds a large CO2 fertilization effect greening the globe since 1982

A paper published today in Geophysical Research Letters finds that CO2 fertilization has increased green foliage cover across warm, arid environments by a remarkable 11% due to the 14% increase in CO2 over the past 28 years [1982-2010]. According to the authors, "the [CO2] fertilisation effect is now a significant land surface process" and satellite observations show even greater [11%] greening of these environments than was theoretically predicted [5-10%]. 

CO2 fertilisation has increased maximum foliage cover across the globe's warm, arid environments

Randall J. Donohue et al 

Abstract: Satellite observations reveal a greening of the globe over recent decades. The role in this greening of the ‘CO2 fertilization’ effect – the enhancement of photosynthesis due to rising CO2 levels – is yet to be established. The direct CO2 effect on vegetation should be most clearly expressed in warm, arid environments where water is the dominant limit to vegetation growth. Using gas exchange theory, we predict that the 14% increase in atmospheric CO2 (1982–2010) led to a 5 to 10% increase in green foliage cover in warm, arid environments. Satellite observations, analysed to remove the effect of variations in rainfall, show that cover across these environments has increased by 11%. Our results confirm that the anticipated CO2 fertilization effect is occurring alongside ongoing anthropogenic perturbations to the carbon cycle and that the fertilisation effect is now a significant land surface process.

Related: Distinguished physicist Dr. William Happer: 'The conventional wisdom about carbon dioxide is that it is a dangerous pollutant. That's simply not the case'



  2. see also this paper finding 6% increase in net primary production