Katrin Meissner | |
|---|---|
 | |
| Nationality | German, Australian |
| Alma mater | |
| Scientific career | |
| Fields | Ocean and climate change research |
| Institutions | University of New South Wales |
| Thesis | Langfristige Variabilität der thermohalinen Zirkulation in einem gekoppelten Ozean-, Meereis-, Atmosphärenmodell (1999) |
Katrin Juliane Meissner is a physical oceanographer and climate scientist known for climate models assessing the impact of abrupt climate change on terrestrial and marine biogeochemical cycling.
Meissner grew up in Berlin, Germany, where she attended the Französisches Gymnasium Berlin. [1] Meissner completed an engineering degree at the Ecole Centrale de Lille in 1995. [1] Meissner moved to the Université Pierre et Marie Curie, Paris VI, France where she investigated the predictability of the West African monsoon based on ocean-atmosphere fluxes off the coast of Senegal. [1] Meissner received her Ph.D. at the Alfred Wegener Institute for Polar and Marine Research at the Universität Bremen, Germany in 1999. [2] She developed an atmosphere model and a sea ice model and coupled both to an existing ocean model to study the long-term variability of the thermohaline circulation. [3] For this work she received the Annette Barthelt Prize for outstanding research in the field of marine science in 2000. [4]
Meissner completed a postdoc at the University of Victoria, Canada, 2000-2002 and subsequently was an Assistant Professor there in the School of Earth and Ocean Sciences from 2002 until 2009. [1] In 2009, she moved to the University of New South Wales, Sydney, Australia. [1] Her relocation from a tenure-track position in Victoria was in part due to the long term issues of reduced funding for climate change science across Canada. [5] In 2010, she was awarded an Australian Research Council Future Fellowship. [1] In 2020 she was named a Fellow of the Royal Society of New South Wales (FRSN). [6]
As of 2021, she is the Director of the Climate Change Research Centre [7] and holds an Adjunct Professor position at the University of Victoria, Canada and a courtesy position at Oregon State University. [8] She is a member of the Committee of Experts [9] for the German Excellence Strategy.
Meissner is on the steering committee for the PAGES (Past Global Changes) project [10] which coordinates and promotes climate change research. In 2015, she was one of the featured scientists in Joe Duggan's project about emotions of scientists whose work focuses on climate change. [11] This project was followed up in 2020. [12] Meissner also voiced her concerns about climate change in an episode of ABC’s Lateline in 2017 [13] and in an opinion article in the Sydney Morning Herald. [14] She is an active reviewer of "Climate Feedback" for ABC's Media Watch . [15] In June 2018, she was a co-author of a paper [16] in Nature Geoscience which posited that current model-based climate projections could be greatly underestimating the rate of warming. [17]
Meissner's primary area of research and scientific engagement centers on climate change. While at the University of Victoria, she coupled a dynamic vegetation model and a land surface scheme to an atmosphere-ocean-sea ice climate model [18] [19] and introduced several isotopic tracers into a climate model to facilitate comparison with paleoproxies in climate archives. [20]
In her research on abrupt climate change events, Meissner has developed and coupled several components to existing Earth System Climate Models which help facilitate comparison to past climate archives and incorporate complex earth processes into the models. [21] Meissner also combines climate models with palaeoclimate records to increase understanding of the basic mechanisms of climate variability and climate change, [22] particularly in the context of marine and terrestrial biogeochemical cycles, ocean circulation, and the changing chemical environment of coral reefs. [23] The work of her and her team developed model studies on rapid climate changes in Australia. [24] [25]
Cloud feedback is a type of climate change feedback that has been difficult to quantify in contemporary climate models. It can affect the magnitude of internally generated climate variability or they can affect the magnitude of climate change resulting from external radiative forcings. Cloud representations vary among global climate models, and small changes in cloud cover have a large impact on the climate.
Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae that live inside their tissue, causing the coral to turn white. The zooxanthellae are photosynthetic, and as the water temperature rises, they begin to produce reactive oxygen species. This is toxic to the coral, so the coral expels the zooxanthellae. Since the zooxanthellae produce the majority of coral colouration, the coral tissue becomes transparent, revealing the coral skeleton made of calcium carbonate. Most bleached corals appear bright white, but some are blue, yellow, or pink due to pigment proteins in the coral.
An abrupt climate change occurs when the climate system is forced to transition at a rate that is determined by the climate system energy-balance. The transition rate is more rapid than the rate of change of the external forcing, though it may include sudden forcing events such as meteorite impacts. Abrupt climate change therefore is a variation beyond the variability of a climate. Past events include the end of the Carboniferous Rainforest Collapse, Younger Dryas, Dansgaard–Oeschger events, Heinrich events and possibly also the Paleocene–Eocene Thermal Maximum. The term is also used within the context of climate change to describe sudden climate change that is detectable over the time-scale of a human lifetime, possibly as the result of feedback loops within the climate system or tipping points.
Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ocean acidification, with atmospheric carbon dioxide levels exceeding 410 ppm. CO2 from the atmosphere is absorbed by the oceans. This produces carbonic acid which dissociates into a bicarbonate ion and a hydrogen ion. The presence of free hydrogen ions lowers the pH of the ocean, increasing acidity. Marine calcifying organisms, such as mollusks and corals, are especially vulnerable because they rely on calcium carbonate to build shells and skeletons.
The Atlantic meridional overturning circulation (AMOC) is part of a global thermohaline circulation in the oceans and 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. These "limbs" are linked by regions of overturning in the Nordic and Labrador Seas and the Southern Ocean, although the extent of overturning in the Labrador Sea is disputed. The AMOC is an important component of the Earth's climate system, and is a result of both atmospheric and thermohaline drivers.
The Indian Ocean Dipole (IOD), also known as the Indian Niño, is an irregular oscillation of sea surface temperatures in which the western Indian Ocean becomes alternately warmer and then colder than the eastern part of the ocean.
Ocean heat content (OHC) is the energy absorbed and stored by oceans. To calculate the ocean heat content, it is necessary to measure ocean temperature at many different locations and depths. Integrating the areal density of ocean heat over an ocean basin or entire ocean gives the total ocean heat content. Between 1971 and 2018, the rise in ocean heat content accounted for over 90% of Earth’s excess thermal energy from global heating. The main driver of this increase was anthropogenic forcing via rising greenhouse gas emissions. By 2020, about one third of the added energy had propagated to depths below 700 meters. In 2022, the world’s oceans were again the hottest in the historical record and exceeded the previous 2021 record maximum. The four highest ocean heat observations occurred in the period 2019–2022. The North Pacific, North Atlantic, the Mediterranean, and the Southern Ocean all recorded their highest heat observations for more than sixty years. Ocean heat content and sea level rise are important indicators of climate change.
Polar amplification is the phenomenon that any change in the net radiation balance tends to produce a larger change in temperature near the poles than in the planetary average. This is commonly referred to as the ratio of polar warming to tropical warming. On a planet with an atmosphere that can restrict emission of longwave radiation to space, surface temperatures will be warmer than a simple planetary equilibrium temperature calculation would predict. Where the atmosphere or an extensive ocean is able to transport heat polewards, the poles will be warmer and equatorial regions cooler than their local net radiation balances would predict. The poles will experience the most cooling when the global-mean temperature is lower relative to a reference climate; alternatively, the poles will experience the greatest warming when the global-mean temperature is higher.
In climate science, a tipping point is a critical threshold that, when crossed, leads to large, accelerating and often irreversible changes in the climate system. If tipping points are crossed, they are likely to have severe impacts on human society and may accelerate global warming. Tipping behavior is found across the climate system, for example in ice sheets, mountain glaciers, circulation patterns in the ocean, in ecosystems, and the atmosphere. Examples of tipping points include thawing permafrost, which will release methane, a powerful greenhouse gas, or melting ice sheets and glaciers reducing Earth's albedo, which would warm the planet faster.
The resilience of coral reefs is the biological ability of coral reefs to recover from natural and anthropogenic disturbances such as storms and bleaching episodes. Resilience refers to the ability of biological or social systems to overcome pressures and stresses by maintaining key functions through resisting or adapting to change. Reef resistance measures how well coral reefs tolerate changes in ocean chemistry, sea level, and sea surface temperature. Reef resistance and resilience are important factors in coral reef recovery from the effects of ocean acidification. Natural reef resilience can be used as a recovery model for coral reefs and an opportunity for management in marine protected areas (MPAs).
There are many effects of climate change on oceans. One of the main ones is an increase in ocean temperatures. More frequent marine heatwaves are linked to this. The rising temperature contributes to a rise in sea levels. Other effects include ocean acidification, sea ice decline, increased ocean stratification and reductions in oxygen levels. Changes to ocean currents including a weakening of the Atlantic meridional overturning circulation are another important effect. All these changes have knock-on effects which disturb marine ecosystems. The main cause of these changes is climate change due to human emissions of greenhouse gases. Carbon dioxide and methane are examples of greenhouse gases. This leads to ocean warming, because the ocean takes up most of the additional heat in the climate system. The ocean absorbs some of the extra carbon dioxide in the atmosphere. This causes the pH value of the ocean to drop. Scientists estimate that the ocean absorbs about 25% of all human-caused CO2 emissions.
The oceanic carbon cycle is composed of processes that exchange carbon between various pools within the ocean as well as between the atmosphere, Earth interior, and the seafloor. The carbon cycle is a result of many interacting forces across multiple time and space scales that circulates carbon around the planet, ensuring that carbon is available globally. The Oceanic carbon cycle is a central process to the global carbon cycle and contains both inorganic carbon and organic carbon. Part of the marine carbon cycle transforms carbon between non-living and living matter.
A marine heatwave is a period of abnormally high ocean temperatures relative to the average seasonal temperature in a particular marine region. Marine heatwaves are caused by a variety of factors, including shorter term weather phenomena such as fronts, intraseasonal events, annual, or decadal (10-year) modes like El Niño events, and longer term changes like climate change. Marine heatwaves can have biological impacts on ecosystems at individual, population, and community levels. MHWs have led to severe biodiversity changes such as coral bleaching, sea star wasting disease, harmful algal blooms, and mass mortality of benthic communities. Unlike heatwaves on land, marine heatwaves can extend for millions of square kilometers, persist for weeks to months or even years, and occur at subsurface levels.
This is an article of notable issues relating to the terrestrial environment of Earth in 2020. They relate to environmental events such as natural disasters, environmental sciences such as ecology and geoscience with a known relevance to contemporary influence of humanity on Earth, environmental law, conservation, environmentalism with major worldwide impact and environmental issues.
Jean-Pierre Gattuso is a French ocean scientist conducting research globally, from the pole to the tropics and from nearshore to the open ocean. His research addresses the biology of reef-building corals, the biogeochemistry of coastal ecosystems, and the response of marine plants, animals and ecosystems to global environmental change. He is also interested in transdisciplinary research, collaborating with social scientists to address ocean-based solutions to minimize climate change and its impacts. He is currently a CNRS Research Professor at Sorbonne University.
Joan Ann ("Joanie") Kleypas is a marine scientist known for her work on the impact of ocean acidification and climate change on coral reefs, and for advancing solutions to environmental problems caused by climate change.
Bette Otto-Bliesner is an earth scientist known for her modeling of Earth's past climate and its changes over different geological eras.
Sarah Gille is a physical oceanographer at Scripps Institution of Oceanography known for her research on the role of the Southern Ocean in the global climate system.
Galen Anile McKinley is a professor at Columbia University and the Lamont–Doherty Earth Observatory known for her work in the carbon cycle, particularly in the use of models to study the interface between the ocean and the atmosphere.
Laurie Menviel or L. Menviel; Laurie Menviel is a palaeoclimatologist, and a Scientia fellow, at the University of New South Wales, who was awarded a Dorothy Hill Medal in 2019.
| Academics | |
|---|---|
| People | |
