Planetary Bio-Production Increases Due to CO2
by Lawrence Solomon, Financial Post, June 07, 2008
Planet Earth is on a roll! GPP is way up. NPP is way up. To the surprise of those who have been bearish on the planet, the data shows global production has been steadily climbing to record levels, ones not seen since these measurements began.
GPP is Gross Primary Production, a measure of the daily output of the global biosphere — the amount of new plant matter on land. NPP is Net Primary Production, an annual tally of the globe’s production. Biomass is booming. The planet is the greenest it’s been in decades, perhaps in centuries.
Until the 1980s, ecologists had no way to systematically track growth in plant matter in every corner of the Earth — the best they could do was analyze small plots of one-tenth of a hectare or less. The notion of continuously tracking global production to discover the true state of the globe’s biota was not even considered.
Then, in the 1980s, ecologists realized that satellites could track production, and enlisted NASA to collect the data. For the first time, ecologists did not need to rely on rough estimates or anecdotal evidence of the health of the ecology: They could objectively measure the land’s output and soon did — on a daily basis and down to the last kilometre.
The results surprised Steven Running of the University of Montana and Ramakrishna Nemani of NASA, scientists involved in analyzing the NASA data. They found that over a period of almost two decades, the Earth as a whole became more bountiful by a whopping 6.2%. About 25% of the Earth’s vegetated landmass — almost 110 million square kilometres — enjoyed significant increases and only 7% showed significant declines. When the satellite data zooms in, it finds that each square metre of land, on average, now produces almost 500 grams of greenery per year.
Why the increase? Their 2004 study, and other more recent ones, point to the warming of the planet and the presence of CO2, a gas indispensable to plant life. CO2 is nature’s fertilizer, bathing the biota with its life-giving nutrients. Plants take the carbon from CO2 to bulk themselves up — carbon is the building block of life — and release the oxygen, which along with the plants, then sustain animal life. As summarized in a report last month, released along with a petition signed by 32,000 U. S. scientists who vouched for the benefits of CO2: “Higher CO2 enables plants to grow faster and larger and to live in drier climates. Plants provide food for animals, which are thereby also enhanced. The extent and diversity of plant and animal life have both increased substantially during the past half-century.” … [more]