Ocean acidification is the ongoing decrease in the pH of the Earth‘s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. Seawater is slightly basic (meaning pH > 7), and the process in question is a shift towards pH-neutral conditions rather than a transition to acidic conditions (pH < 7). Ocean alkalinity is not changed by the process, or may increase over long time periods due to carbonate dissolution. An estimated 30–40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes. To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion, thus increasing ocean acidity (H+ ion concentration). Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14, representing an increase of almost 30% in H+ion concentration in the world’s oceans. Earth System Models project that within the last decade ocean acidity exceeded historical analogs and in combination with other ocean biogeochemical changes could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean.
Increasing acidity is thought to have a range of potentially harmful consequences for marine organisms, such as depressing metabolic rates and immune responses in some organisms, and causing coral bleaching. By increasing the presence of free hydrogen ions, each molecule of carbonic acid that forms in the oceans ultimately results in the conversion of two carbonate ions into bicarbonate ions. This net decrease in the amount of carbonate ions available makes it more difficult for marine calcifying organisms, such as coral and some plankton, to form biogenic calcium carbonate, and such structures become vulnerable to dissolution. Ongoing acidification of the oceans threatens food chains connected with the oceans. As members of theInterAcademy Panel, 105 science academies have issued a statement on ocean acidification recommending that by 2050, global CO2emissions be reduced by at least 50% compared to the 1990 level.
While ongoing ocean acidification is anthropogenic in origin, it has occurred previously in Earth’s history. The most notable example is the Paleocene-Eocene Thermal Maximum (PETM), which occurred approximately 56 million years ago. For reasons that are currently uncertain, massive amounts of carbon entered the ocean and atmosphere, and led to the dissolution of carbonate sediments in all ocean basins.
Climate deniers try to distort or obfuscate the evidence about the changing atmosphere, and it’s not always easy to give overwhelmingly conclusive data that would convince them. In some cases the data are tricky to analyze, or do not have well-documented long-term histories necessary to answer every concern about whether recent weather events are truly unprecedented. The atmospheric system is very complicated, with many different processes operating on short-term, medium-term, and long-term time scales, and not all of it is as well understood as we would like. Thus, the arguments over changes in earth’s atmosphere often reach an impasse.
Not so for the oceans. Although oceans are an even larger system than the atmosphere, we understand them much better. More importantly, we have an excellent long-term record of how the oceans have changed over millions of years from thousands of deep-sea cores, and from the paleontological record of marine fossils that goes back over 700 million years. And unlike the atmospheres, oceans change very slowly over time, since the thermal inertia of water makes the seas very resistant to change except on long-term time scales. In addition, most ocean currents move slowly compared to atmospheric currents. So no matter what you want to make of the data showing atmospheric change, the changes in the oceans are more alarming, since oceans require immense stimuli to cause such change.
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.
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.
Scientists at the Large Hadron Collider may have just discovered a new fundamental particle that could change the way we look at the universe. Is this Dark Energy? A giant Neutrino? The big brother of the Higgs Boson? Or could it be the mysterious Graviton?
Science, Technology, Engineering and Mathematics (STEM, previously SMET) is an acronym that refers to the academic disciplines of science[note 1], technology, engineeringand mathematics. The term is typically used when addressing education policy and curriculum choices in schools to improve competitiveness in science and technology development. It has implications for workforce development, national security concerns and immigration policy. Education emphasizing STEM disciplines is considered to be more beneficial to the student than the previous generation of education standards that emphasizes broad “core” disciplines and social skills instead.
The acronym arose in common use shortly after an interagency meeting on science education held at the US National Science Foundation chaired by the then NSF director Rita Colwell. A director from the Office of Science division of Workforce Development for Teachers and Scientists, Dr. Peter Faletra, suggested the change from the older acronym SMET to STEM. Dr. Colwell, expressing some dislike for the older acronym, responded by suggesting NSF to institute the change. One of the first NSF projects to use the acronym was STEMTEC, the Science, Technology, Engineering and Math Teacher Education Collaborative at the University of Massachusetts Amherst, which was funded in 1997.
At the end of the month, world governments will convene at the UN COP21 conference in Paris for the next round of binding emission commitments aimed at restricting global warming to no more than two degrees by the end of the century.
When it comes to agreeing potentially tougher targets, both policymakers and members of the public will now be armed with the COP21 climate change calculator, developed by the Climate-KIC, the EU’s main climate innovation research centre, in collaboration with Imperial College, London and FT.com.
Using data on the emission reduction pledges made to date and scientific forecasts on future warming, it aims to inform the public and policymakers on the impact a variety of choices by individual countries would have on overall global warming.