Jun 15, 2015 03:12 AM EDT
CO2 is plant food
Earth’s current atmospheric CO2 concentration is almost 390 parts per million (ppm). Adding another 300 ppm of CO2 to the air has been shown by literally thousands of experiments to greatly increase the growth or biomass production of nearly all plants. This growth stimulation occurs because CO2 is one of the two raw materials (the other being water) that are required for photosynthesis. Hence, CO2 is actually the “food” that sustains essentially all plants on the face of the earth, as well as those in the sea. And the more CO2 they “eat” (absorb from the air or water), the bigger and better they grow. (source: Plants Need CO2)
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can be later releasedto fuel the organisms’ activities (energy transformation). This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek φῶς, phōs, “light”, and σύνθεσις,synthesis, “putting together”. In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth.
Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed byproteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are held inside organelles calledchloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, producing oxygen gas. The hydrogen freed by water splitting is used in the creation of two further compounds that act as an immediate energy storage means: reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP), the “energy currency” of cells.
In plants, algae and cyanobacteria, long term energy storage in the form of sugars are produced by a subsequent sequence of light-independent reactions called the Calvin cycle, but some bacteria use different mechanisms, such as the reverse Krebs cycle. In the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate(RuBP). Using the ATP and NADPH produced by the light-dependent reactions, the resulting compounds are then reduced and removed to form further carbohydrates, such as glucose.
The first photosynthetic organisms probably evolved early in the evolutionary history of life and most likely used reducing agents such as hydrogen or hydrogen sulfide, rather than water, as sources of electrons.Cyanobacteria appeared later; the excess oxygen they produced contributed to the oxygen catastrophe,which rendered the evolution of complex life possible. Today, the average rate of energy capture by photosynthesis globally is approximately 130 terawatts, which is about three times the current power consumption of human civilization. Photosynthetic organisms also convert around 100–115 thousand million metric tonnes of carbon into biomass per year.
What are the implications of observations above 400pm? Water supply, sea level rising, increase of precipitation intensity, food production, heat waves, health threat, biodiversity collapse, etc. IPCC report consist more than 1500 pages of science-based information about causes and implications.
Existing climate changes will go faster and more extreme & unpredictable. We know about a lot of difficult and interconnected issues like ocean acidification or new type of more intensive forest fires (has already taken place in Canada, Russia, Australia) and record existing changes there.
Featured Stories, MIT | Jun 06, 2013
The Keeling Curve record from the NOAA-operated Mauna Loa Observatory shows that the atmospheric carbon dioxide concentration hovers around 400 ppm, a level not seen in more than 3 million years when sea levels were as much as 80 feet higher than today. Virtually every media outlet reported the passage of this climate milestone, but we suspect there’s more to the story. Oceans at MIT’s Genevieve Wanucha interviewed Ron Prinn, Professor of Atmospheric Science in MIT’s Department of Earth, Atmospheric and Planetary Sciences. Prinn is the Director of MIT’s Center for Global Change Science (CGCS) and Co-Director of MIT’s Joint Program on the Science and Policy of Global Change (JPSPGC). Prinn leads the Advanced Global Atmospheric Gases Experiment (AGAGE), an international project that continually measures the rates of change of the air concentrations of 50 trace gases involved in the greenhouse effect. He also works with the Integrated Global System Model, which couples economics, climate physics and chemistry, and land and ocean ecosystems, to estimate uncertainty in climate predictions and analyze proposed climate policies.