Katrin Meissner | |
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| 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]
Coral bleaching is the process when corals become white due to loss of symbiotic algae and photosynthetic pigments. This loss of pigment can be caused by 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.
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 422 ppm. CO2 from the atmosphere is absorbed by the oceans. This chemical reaction 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 the main ocean current system in the Atlantic Ocean. It is a component of Earth's ocean circulation system and plays an important role in the climate system. The AMOC includes Atlantic currents at the surface and at great depths that are driven by changes in weather, temperature and salinity. Those currents comprise half of the global thermohaline circulation that includes the flow of major ocean currents, the other half being the Southern Ocean overturning circulation.
Ocean heat content (OHC) or ocean heat uptake (OHU) 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 a change in enthalpic energy over an ocean basin or entire ocean gives the total ocean heat uptake. Between 1971 and 2018, the rise in ocean heat content accounted for over 90% of Earth's excess energy from global heating. The main driver of this increase was caused by humans via their rising greenhouse gas emissions. By 2020, about one third of the added energy had propagated to depths below 700 meters.
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. Thawing permafrost is a threat multiplier because it holds roughly twice as much carbon as the amount currently circulating in the atmosphere.
Climate change feedbacks are natural processes that impact how much global temperatures will increase for a given amount of greenhouse gas emissions. Positive feedbacks amplify global warming while negative feedbacks diminish it. Feedbacks influence both the amount of greenhouse gases in the atmosphere and the amount of temperature change that happens in response. While emissions are the forcing that causes climate change, feedbacks combine to control climate sensitivity to that forcing.
Human activities have substantial impact on coral reefs, contributing to their worldwide decline. Damaging activities encompass coral mining, pollution, overfishing, blast fishing, as well as the excavation of canals and access points to islands and bays. Additional threats comprise disease, destructive fishing practices, and the warming of oceans.[2] Furthermore, the ocean's function as a carbon dioxide sink, alterations in the atmosphere, ultraviolet light, ocean acidification, viral infections, the repercussions of dust storms transporting agents to distant reefs, pollutants, and algal blooms represent some of the factors exerting influence on coral reefs. Importantly, the jeopardy faced by coral reefs extends far beyond coastal regions. The ramifications of climate change, notably global warming, induce an elevation in ocean temperatures that triggers coral bleaching—a potentially lethal phenomenon for coral ecosystems.
Maureen E. Raymo is an American paleoclimatologist and marine geologist. She is the Co-Founding Dean Emerita of the Columbia Climate School and the G. Unger Vetlesen Professor of Earth & Environmental Sciences at Columbia University. From 2011 to 2022, she was also Director of Lamont-Doherty Earth Observatory's (LDEO) Core Repository and, until 2024, was the Founding Director of the LDEO Hudson River Field Station. From 2020 to 2023, she was first Interim Director then Director of Lamont-Doherty Earth Observatory, the first climate scientist and first female scientist to head the institution.
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).
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.
Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.
A marine heatwave is a period of abnormally high sea water temperatures compared to the typical temperatures in the past for a particular season and region. Marine heatwaves are caused by a variety of drivers. These include shorter term weather events such as fronts, intraseasonal events, annual, and decadal (10-year) modes like El Niño events, and human-caused climate change. Marine heatwaves affect ecosystems in the oceans. For example, marine heatwaves can lead 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 over vast areas, 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.
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