This glossary of climate change is a list of definitions of terms and concepts relevant to climate change, global warming, and related topics.
The Keeling Curve is a graph of the accumulation of carbon dioxide in the Earth's atmosphere based on continuous measurements taken at the Mauna Loa Observatory on the island of Hawaii from 1958 to the present day. The curve is named for the scientist Charles David Keeling, who started the monitoring program and supervised it until his death in 2005.
The Mauna Loa Observatory (MLO) is an atmospheric baseline station on Mauna Loa, on the island of Hawaii, located in the U.S. state of Hawaii.
Charles David Keeling was an American scientist whose recording of carbon dioxide at the Mauna Loa Observatory confirmed Svante Arrhenius's proposition (1896) of the possibility of anthropogenic contribution to the greenhouse effect and global warming, by documenting the steadily rising carbon dioxide levels. The Keeling Curve measures the progressive buildup of carbon dioxide, a greenhouse gas, in the atmosphere.
Roger Randall Dougan Revelle was a scientist and scholar who was instrumental in the formative years of the University of California, San Diego and was among the early scientists to study anthropogenic global warming, as well as the movement of Earth's tectonic plates. UC San Diego's first college is named Revelle College in his honor.
Oxygen isotope ratio cycles are cyclical variations in the ratio of the abundance of oxygen with an atomic mass of 18 to the abundance of oxygen with an atomic mass of 16 present in some substances, such as polar ice or calcite in ocean core samples, measured with the isotope fractionation. The ratio is linked to ancient ocean temperature which in turn reflects ancient climate. Cycles in the ratio mirror climate changes in the geological history of Earth.
In Earth's atmosphere, carbon dioxide is a trace gas that plays an integral part in the greenhouse effect, carbon cycle, photosynthesis and oceanic carbon cycle. It is one of several greenhouse gases in the atmosphere of Earth. The current global average concentration of CO2 in the atmosphere is 421 ppm as of May 2022 (0.04%). This is an increase of 50% since the start of the Industrial Revolution, up from 280 ppm during the 10,000 years prior to the mid-18th century. The increase is due to human activity. Burning fossil fuels is the main cause of these increased CO2 concentrations and also the main cause of climate change. Other large anthropogenic sources include cement production, deforestation, and biomass burning.
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.
This is a list of climate change topics.
Ocean deoxygenation is the reduction of the oxygen content in different parts of the ocean due to human activities. It occurs firstly in coastal zones where eutrophication has driven some quite rapid declines in oxygen to very low levels. This type of ocean deoxygenation is also called "dead zones". Secondly, there is now an ongoing reduction in oxygen levels in the open ocean: naturally occurring low oxygen areas are now expanding slowly. This expansion is happening as a consequence of human caused climate change. The resulting decrease in oxygen content of the oceans poses a threat to marine life, as well as to people who depend on marine life for nutrition or livelihood. Ocean deoxygenation poses implications for ocean productivity, nutrient cycling, carbon cycling, and marine habitats.
Greenhouse gases are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. What distinguishes them from other gases is that they absorb the wavelengths of radiation that a planet emits, resulting in the greenhouse effect. The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Without greenhouse gases, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).
The history of the scientific discovery of climate change began in the early 19th century when ice ages and other natural changes in paleoclimate were first suspected and the natural greenhouse effect was first identified. In the late 19th century, scientists first argued that human emissions of greenhouse gases could change Earth's energy balance and climate. Many other theories of climate change were advanced, involving forces from volcanism to solar variation. In the 1960s, the evidence for the warming effect of carbon dioxide gas became increasingly convincing. Some scientists also pointed out that human activities that generated atmospheric aerosols could have cooling effects as well.
Marine chemistry, also known as ocean chemistry or chemical oceanography, is influenced by plate tectonics and seafloor spreading, turbidity currents, sediments, pH levels, atmospheric constituents, metamorphic activity, and ecology. The field of chemical oceanography studies the chemistry of marine environments including the influences of different variables. Marine life has adapted to the chemistries unique to Earth's oceans, and marine ecosystems are sensitive to changes in ocean chemistry.
Greenhouse gas monitoring is the direct measurement of greenhouse gas emissions and levels. There are several different methods of measuring carbon dioxide concentrations in the atmosphere, including infrared analyzing and manometry. Methane and nitrous oxide are measured by other instruments. Greenhouse gases are measured from space such as by the Orbiting Carbon Observatory and networks of ground stations such as the Integrated Carbon Observation System.
The atmospheric carbon cycle accounts for the exchange of gaseous carbon compounds, primarily carbon dioxide, between Earth's atmosphere, the oceans, and the terrestrial biosphere. It is one of the faster components of the planet's overall carbon cycle, supporting the exchange of more than 200 billion tons of carbon in and out of the atmosphere throughout the course of each year. Atmospheric concentrations of CO2 remain stable over longer timescales only when there exists a balance between these two flows. Methane, Carbon monoxide (CO), and other man-made compounds are present in smaller concentrations and are also part of the atmospheric carbon cycle.
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.
The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project is a large scale National Science Foundation funded research project based at Princeton University that started in September 2014. The project aims to increase the understanding of the Southern Ocean and the role it plays in factors such as climate, as well as educate new scientists with oceanic observation.
Heather Dawn Graven is a lecturer in Atmospheric Physics at Imperial College London. She creates mathematical models to predict how climate change will impact the carbon cycle.
Lisa Welp is a biogeochemist who utilizes stable isotopes to understand how water and carbon dioxide are exchanged between the land and atmosphere. She is a professor at Purdue University in the department of Earth, Atmosphere, and Planetary Sciences.
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.
Ralph Keeling, “The (Ralph) Keeling Curve”, Scripps Institution of Oceanography 