Articles Collections


Oceans, Oxygen Cycle & Waterways -Specific Articles

It may appear that atmospheric oxygen fraction or ocean pH could not change by very large amounts in the near term, but there are numerous feedback loops at work in climate change and ocean chemistry change. Things can change very quickly when several amplifying loops combine into one large cycle. I don't think they can be ruled out at this time. In either case, ocean circulation, chemistry, anoxia, and temperature are all undergoing changes large enough to be disastrous to marine life at many regions and depths.


On Energy, Economy & Industry


General Climate Change and Solutions

  • The Sun Magazine:
    Before It’s Too Late
    Mary Christina Wood On Avoiding Climate Disaster
    By Mary DeMocker - February 2019
  • The New Yorker:
    How Extreme Weather Is Shrinking the Planet
    With wildfires, heat waves, and rising sea levels, large tracts of the earth are at risk of becoming uninhabitable. But the fossil-fuel industry continues its assault on the facts.
    By Bill McKibben - November 16, 2018
  • XKCD:
    Earth Temperature Timeline
    A Timeline of the Earth's Average Temperature Since the Last Ice Age Glaciation
    Mobile site version
    Randall Munroe, September 12th, 2016

Collection of Useful Concepts

  • Wikipedia:
    Dead zone (ecology)
    Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes, which causes these bodies of water to fail to support the marine life living there. Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated.
  • Wikipedia:
    Ocean Deoxygenation
    Ocean deoxygenation is the reduction of the oxygen content of the oceans due to human activities as a consequence of anthropogenic emissions of carbon dioxide and eutrophication driven excess production. It is manifest in the increasing number of coastal and estuarine hypoxic areas, or dead zones, and the expansion of oxygen minimum zones in the world's oceans. The decrease in oxygen content of the oceans has been fairly rapid and poses a threat to all aerobic marine life, as well as to people who depend on marine life for nutrition or livelihood.
  • Wikipedia:
    Climate change feedback
    Climate change feedback is important in the understanding of global warming because feedback processes may amplify or diminish the effect of each climate forcing, and so play an important part in determining the climate sensitivity and future climate state. Feedback in general is the process in which changing one quantity changes a second quantity, and the change in the second quantity in turn changes the first. Positive feedback amplifies the change in the first quantity while negative feedback reduces it.
  • Wikipedia:
    Anoxic event
    Oceanic anoxic events or anoxic events (anoxia conditions) were intervals in the Earth's past where portions of oceans became depleted in oxygen (O2) over a large geographic areas. [...] Although anoxic events have not happened for millions of years, the geological record shows that they happened many times in the past. Anoxic events coincided with several mass extinctions and may have contributed to them. These mass extinctions include some that geobiologists use as time markers in biostratigraphic dating. Many geologists believe oceanic anoxic events are strongly linked to slowing of ocean circulation, climatic warming, and elevated levels of greenhouse gases.
  • Wikipedia:
    Arctic methane emissions
    Arctic methane is much talked about, but I never hear about ancient ANTarctic deposits (yet). Arctic methane release is the release of methane from seas and soils in permafrost regions of the Arctic. While it is a long-term natural process, methane release is exacerbated by global warming. This results in negative effects, as methane is itself a powerful greenhouse gas.
  • Wikipedia:
    Greenhouse gas
    Section on Anthropogenic greenhouse gases
    A greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range. [...] Since about 1750 human activity has increased the concentration of carbon dioxide and other greenhouse gases. Measured atmospheric concentrations of carbon dioxide are currently 100 ppm higher than pre-industrial levels. Natural sources of carbon dioxide are more than 20 times greater than sources due to human activity, but over periods longer than a few years natural sources are closely balanced by natural sinks, mainly photosynthesis of carbon compounds by plants and marine plankton. As a result of this balance, the atmospheric mole fraction of carbon dioxide remained between 260 and 280 parts per million for the 10,000 years between the end of the last glacial maximum and the start of the industrial era.
  • Wikipedia:
    Great Oxidation Event
    There was a time when the atmosphere wasn't full of oxygen: The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust, or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era. Geological, isotopic, and chemical evidence suggests that biologically produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere, causing many existing species on Earth to die out. The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.
  • Wikipedia:
    Oxygen Cycle
    The oxygen cycle is the biogeochemical transitions of oxygen atoms between different oxidation states in ions, oxides, and molecules through redox reactions within and between the spheres/reservoirs of the planet Earth. The word oxygen in the literature typically refers to the most common oxygen allotrope, elemental/diatomic oxygen (O2), as it is a common product or reactant of many biogeochemical redox reactions within the cycle. Processes within the oxygen cycle are considered to be biological or geological and are evaluated as either a source (O2 production) or sink (O2 consumption).
  • Wikipedia:
    Cretaceous-Paleogene extinction event
    The Cretaceous–Paleogene (K–Pg) extinction event, also known as the Cretaceous–Tertiary (K–T) extinction, was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. As noted above (The Atlantic), many large Earth impacts did not lead to mass extinctions at the scale of this one, and this one coincided with ocean acidification, which is also begininning in our present climate crisis.
  • Wikipedia:
    Eutrophication
    Eutrophication (from Greek eutrophos, "well-nourished"), distrophication or hypertrophication, is when a body of water becomes overly enriched with minerals and nutrients which induce excessive growth of algae. This process may result in oxygen depletion of the water body. One example is an "algal bloom" or great increase of phytoplankton in a sandy body as a response to increased levels of nutrients. Eutrophication is often induced by the discharge of nitrate or phosphate-containing detergents, fertilizers, or sewage into an aquatic system.
  • Wikipedia:
    Oxygen minimum zone
    The oxygen minimum zone (OMZ), sometimes referred to as the shadow zone, is the zone in which oxygen saturation in seawater in the ocean is at its lowest. This zone occurs at depths of about 200 to 1,500 m (660–4,920 ft), depending on local circumstances. OMZs are found worldwide, typically along the western coast of continents, in areas where an interplay of physical and biological processes concurrently lower the oxygen concentration (biological processes) and restrict the water from mixing with surrounding waters (physical processes), creating a “pool” of water where oxygen concentrations fall from the normal range of 4–6 mg/l to below 2 mg/l. It is notable that a lethal decline in aqeuous dissolved oxygen is measurable in single parts per million, unlike atmospheric oxygen which is around 21% (or 210,000 parts per million) in normal conditions. It factors out this way because pure water is 1kg per liter, and seawater at the surface is 1.025 kg/l, so 4-6mg/l of oxygen is 3.90-5.85 ppm in seawater, or 4-6ppm in pure water.
  • Wikipedia:
    Atlantic meridional overturning circulation
    Section on AMOC stability
    The Atlantic meridional overturning circulation (AMOC) is the zonally-integrated component of surface and deep currents in the Atlantic Ocean. It is characterized by a northward flow of warm, salty water in the upper layers of the Atlantic, and a southward flow of colder, deep waters that are part of the thermohaline circulation. These "limbs" are linked by regions of overturning in the Nordic and Labrador Seas and the Southern Ocean. [...] Atlantic overturning is not a static feature of global circulation, but rather a sensitive function of temperature and salinity distributions as well as atmospheric forcings. Paleoceanographic reconstructions of AMOC vigour and configuration have revealed significant variations over geologic time complementing variation observed on shorter scales.
  • Wikipedia:
    Shutdown of thermohaline circulation
    A shutdown or slowdown of the thermohaline circulation is a hypothesized effect of global warming on a major ocean circulation.

    A 2015 study suggested that the Atlantic meridional overturning circulation (AMOC) has weakened by 15-20% in 200 years.
  • Wikipedia:
    Tipping points in the climate system
    A tipping point in the climate system is a threshold that, when exceeded, can lead to large changes in the state of the system. Potential tipping points have been identified in the physical climate system, in impacted ecosystems, and sometimes in both. For instance, feedback from the global carbon cycle is a driver for the transition between glacial and interglacial periods, with orbital forcing providing the initial trigger. Earth's geologic temperature record includes many more examples of geologically rapid transitions between different climate states.