http://www.thegwpf.org/matt-ridley-glob ... -greening/
In this lecture Myneni presented ingenious analysis of data from satellites proving that much of the vegetated area of the planet was getting greener, only a little bit was getting browner, and that overall in 30 years there had been a roughly 14% increase in green vegetation on planet Earth.
In this slide he argued that this was occurring in all vegetation types – tropical rain forests, subarctic taiga, grasslands, semi-deserts, farmland, everywhere.
What is more, Myneni argued that by various means he could calculate that about half of this greening was a direct result of rising carbon dioxide levels in the atmosphere, rather than the application of agricultural fertiliser, irrigation, warmer temperatures or increased rainfall.
Carbon dioxide, along with water, is the raw material that plants use to make carbohydrates, with the help of sunlight, so it stands to reason that raising its concentration should help plants grow.
I was startled by Myneni’s data. I knew that there had been thousands of so-called free-air concentration (FACE) experiments, in which levels of CO2 had been increased over crops or wild ecosystems to find out if it boosted their growth (it did), and that commercial greenhouse owners now routinely maintain CO2 levels in their greenhouses at more than double ambient levels – because it makes their tomatoes grow faster.
But the global effect of CO2 levels on the quantity of vegetation had not, as far as I could tell, been measured till now.
Other lines of evidence also pointed to this global greening:
the increased rate of growth of forest trees,
the increased amplitude of seasonal carbon dioxide variation measured in Hawaii and elsewhere,
photographic surveys of vegetation,
the increased growth rate of phytoplankton, marine plants and some corals, and so on.
I published an article in the Wall Street Journal in January 2013 on these various lines of evidence, including Myneni’s satellite analysis, pointing to the increase in green vegetation.