|A composite image of the Western hemisphere of the Earth. Credit: NASA|
An international team of 32 authors from 24 institutions in eight countries has just published a study titled “Greening of the Earth and its Drivers” in the journal Nature Climate Change showing significant greening of a quarter to one-half of the Earth’s vegetated lands using data from the NASA-MODIS and NOAA-AVHRR satellite sensors of the past 33 years. The greening represents an increase in leaves on plants and trees. Green leaves produce sugars using energy in the sunlight to mix carbon dioxide (CO2) drawn in from the air with water and nutrients pumped in from the ground. These sugars are the source of food, fiber and fuel for life on Earth. More sugars are produced when there is more CO2 in the air, and this is called CO2 fertilization.
The beneficial aspect of CO2 fertilization in promoting plant growth has been used by contrarians, notably Lord Ridley (hereditary peer in the UK House of Lords) and Mr. Rupert Murdoch (owner of several news outlets), to argue against cuts in carbon emissions to mitigate climate change, similar to those agreed at the 21st Conference of Parties (COP) meeting in Paris last year under the UN Framework on Climate Change (UNFCCC). “The fallacy of the contrarian argument is two-fold. First, the many negative aspects of climate change.
The ‘negative’ aspects:
1. Global warming – Try some global cooling, watch crops fail, mass poverty ensue and disease run rife. The BBC would have you believe that the Black Death was the cause of climate change in the 14th century. “Europe’s “Little Ice Age” may have been triggered by the 14th Century Black Death plague, according to a new study.” Apart from the fact that that the cooling led to crop failure, starvation and therefore increase in disease, not the other way round.
2. Rising sea levels – “The United Kingdom regularly experiences tidal ranges up to 15 metres.” I think we can handle between 2.6 and 2.9 millimetres sea level rise per year. If anyone wants to discuss the Maldives and Kiribati, by all means.
3. Melting glaciers and sea ice – Is this really an issue? For more than a century the Swiss have appreciated the retreat of glaciers and have no wish to see whole valleys buried again. “The Morteratsch Glacier in Switzerland has had one of the longest periods of scientific study with yearly measurements of the glacier’s length commencing in 1878. The overall retreat from 1878 to 1998 has been 2 km (1.2 mi) with a mean annual retreat rate of approximately 17 m (56 ft) per year.” Needless to say that man-made global warming only started late in the 20th century. As for melting sea ice, I’m not sure how that contributes to sea level rise . . .
4. More severe tropical storms – From the NOAA Sept 2015. “It is premature to conclude that human activities–and particularly greenhouse gas emissions that cause global warming–have already had a detectable impact on Atlantic hurricane or global tropical cyclone activity. That said, human activities may have already caused changes that are not yet detectable due to the small magnitude of the changes or observational limitations, or are model-estimated changes with considerable uncertainty (e.g., aerosol effects).” So not true.
Let’s look at the second fallacy.
Second, studies have shown that plants acclimatize, or adjust, to rising CO2 concentration and the fertilization effect diminishes over time,” says co-author Dr. Philippe Ciais, Associate Director of the Laboratory of Climate and Environmental Sciences, Gif-suvYvette, France and Contributing Lead Author of the Carbon Chapter for the recent IPCC Assessment Report 5.
Studies? I can’t find any justification for the above claim. Here is the Canadian Min Ag on ‘Carbon Dioxide in Greenhouses’.
The benefits of carbon dioxide supplementation on plant growth and production within the greenhouse environment have been well understood for many years.
Carbon dioxide (CO2) is an essential component of photosynthesis (also called carbon assimilation). Photosynthesis is a chemical process that uses light energy to convert CO2 and water into sugars in green plants. These sugars are then used for growth within the plant, through respiration. The difference between the rate of photosynthesis and the rate of respiration is the basis for dry-matter accumulation (growth) in the plant. In greenhouse production the aim of all growers is to increase dry-matter content and economically optimize crop yield. CO2 increases productivity through improved plant growth and vigour. Some ways in which productivity is increased by CO2 include earlier flowering, higher fruit yields, reduced bud abortion in roses, improved stem strength and flower size. Growers should regard CO2 as a nutrient.
So not all doom and gloom then.