In the Financial Post over the weekend, Lawrence Solomon celebrated the vegetable fecundity engendered by our slightly warming and more carbon-rich atmosphere.
[I]n 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.”
Lush as the planet may now be, it is as nothing compared to earlier times, when levels of CO2 and Earth temperatures were far higher. In the age of the dinosaur, for example, CO2 levels may have been five to 10 times higher than today, spurring a luxuriantly fertile planet whose plant life sated the immense animals of that era. Planet Earth is also much cooler today than during the hothouse era of the dinosaur, and cooler than it was 1,000 years ago during the Medieval Warming Period, when the Vikings colonized a verdant Greenland. Greenland lost its colonies and its farmland during the Little Ice Age that followed, and only recently started to become green again.
Anthony Watts provides the NASA images of biosphere photosynthesis.