In Nova’s handbook, she tells her readers that CO2 is plant food. Such a simplistic view of plant growth has been answered so many times during “skeptical” debate that I can only infer Nova is purposely trying to mislead her readers by reusing this old debunked argument once more.
As usual, Nova cherry picks out one small section of science and ignores everything else.
Nova says …
Forests grow faster too. In the last 20 years the biomass of plants on earth increased by 6%.
… and cites Nemani 2003.
The first problem for Nova is that they don’t cover the last 20 years, they cover an 18 year period from 1982 to 1999.
The second problem for Nova is that Nemani doesn’t attribute the growth to CO2. They are very specific about mentioning the many other factors that contribute to growth.
NPP [Net Primary Production] increased by more than 1% per year in Amazonia alone, which accounts for 42% of the global NPP increase between 1982 and 1999. This result cannot be explained solely by CO2 fertilization. We suggest that increases in solar radiation, owing to declining cloud cover in these predominantly radiation-limited forests, is the most likely explanation for the increased tropical NPP (28, 29).
The third problem for Nova is that by cherry picking data or science leaves you totally exposed when new data comes along. This more recent analysis of the NPP found a decrease. Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009 says …
Terrestrial net primary production (NPP) quantifies the amount of atmospheric carbon fixed by plants and accumulated as biomass. Previous studies have shown that climate constraints were relaxing with increasing temperature and solar radiation, allowing an upward trend in NPP from 1982 through 1999. The past decade (2000 to 2009) has been the warmest since instrumental measurements began, which could imply continued increases in NPP; however, our estimates suggest a reduction in the global NPP of 0.55 petagrams of carbon. Large-scale droughts have reduced regional NPP, and a drying trend in the Southern Hemisphere has decreased NPP in that area, counteracting the increased NPP over the Northern Hemisphere. A continued decline in NPP would not only weaken the terrestrial carbon sink, but it would also intensify future competition between food demand and proposed biofuel production.
Examining the full list of papers that cite Nova’s cherry picked science shows there is a wealth of knowledge on the topic, should you choose to look. Nova hopes you don’t.
Anyone with half a brain will understand that CO2 alone will not determine the growth of plants. You must consider the whole environment in order to understand the real impact.
Nova’s simplistic view doesn’t fool anyone but fools.