In physical geography, tundra is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term comes from the Finnish word tunturia, meaning "treeless plain". There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra.
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.
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.
False balance, known colloquially as bothsidesism, is a media bias in which journalists present an issue as being more balanced between opposing viewpoints than the evidence supports. Journalists may present evidence and arguments out of proportion to the actual evidence for each side, or may omit information that would establish one side's claims as baseless. False balance has been cited as a cause of misinformation.
The clathrate gun hypothesis is a proposed explanation for the periods of rapid warming during the Quaternary. The hypothesis is that changes in fluxes in upper intermediate waters in the ocean caused temperature fluctuations that alternately accumulated and occasionally released methane clathrate on upper continental slopes. This would have had an immediate impact on the global temperature, as methane is a much more powerful greenhouse gas than carbon dioxide. Despite its atmospheric lifetime of around 12 years, methane's global warming potential is 72 times greater than that of carbon dioxide over 20 years, and 25 times over 100 years. It is further proposed that these warming events caused the Bond Cycles and individual interstadial events, such as the Dansgaard–Oeschger interstadials.
Michael Oppenheimer is the Albert G. Milbank Professor of Geosciences and International Affairs in the Princeton School of Public and International Affairs, the Department of Geosciences, and the High Meadows Environmental Institute at Princeton University. He is the director of the Center for Policy Research on Energy and the Environment (C-PREE) at the Princeton School of Public and International Affairs and Faculty Associate of the Atmospheric and Ocean Sciences Program and the Princeton Institute for International and Regional Studies.
There are several plausible pathways that could lead to an increased extinction risk from climate change. This is because every plant and animal species has evolved to exist within a certain ecological niche, and as climate change represents the long-term alteration of temperature and average weather patterns, it can push climatic conditions outside of the species' niche, which will ultimately render it extinct. Normally, species faced with changing conditions can either adapt in place through microevolution or move to another habitat with suitable conditions. However, the speed of recent climate change is so unprecedented, that even under "mid-range" scenarios of future warming, only 5% of current ectotherm locations are within 50 km of a place which could serve as an equally suitable habitat at the end of this century.
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.
Veerabhadran "Ram" Ramanathan is Edward A. Frieman Endowed Presidential Chair in Climate Sustainability Scripps Institution of Oceanography, University of California, San Diego. He has contributed to many areas of the atmospheric and climate sciences including developments to general circulation models, atmospheric chemistry, and radiative transfer. He has been a part of major projects such as the Indian Ocean Experiment (INDOEX) and the Earth Radiation Budget Experiment (ERBE), and is known for his contributions to the areas of climate physics, Climate Change and atmospheric aerosols research. He is now the Chair of Bending the Curve: Climate Change Solutions education project of University of California. He has received numerous awards, and is a member of the US National Academy of Sciences. He has spoken about the topic of global warming, and written that "the effect of greenhouse gases on global warming is, in my opinion, the most important environmental issue facing the world today."
The permafrost carbon cycle or Arctic carbon cycle is a sub-cycle of the larger global carbon cycle. Permafrost is defined as subsurface material that remains below 0o C for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within their frozen framework during that time. Permafrost represents a large carbon reservoir, one which was often neglected in the initial research determining global terrestrial carbon reservoirs. Since the start of the 2000s, however, far more attention has been paid to the subject, with an enormous growth both in general attention and in the scientific research output.
Johan Rockström is a Swedish scientist, internationally recognized for his work on global sustainability issues. He is joint director of the Potsdam Institute for Climate Impact Research (PIK) in Germany, together with economist Ottmar Edenhofer. He is also Professor in Earth System Science at the University of Potsdam and Professor in Water Systems and Global Sustainability, Stockholm University.
Diana Liverman is a retired Regents Professor of Geography and Development and past Director of the University of Arizona School of Geography, Development and Environment in the College of Social and Behavioral Sciences in Tucson, Arizona.
Alan Robock is an American climatologist. He is currently a Distinguished Professor in the Department of Environmental Sciences at Rutgers University, New Jersey. He advocates nuclear disarmament and, in 2010 and 2011, met with Fidel Castro during lecture trips to Cuba to discuss the dangers of nuclear weapons. Alan Robock was a 2007 IPCC author, a member of the organisation when it was awarded the Nobel Peace Prize, "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change".
Jürgen Kurths is a German physicist and mathematician. He is senior advisor in the research department Complexity Sciences of the Potsdam Institute for Climate Impact Research, a Professor of Nonlinear Dynamics at the Institute of Physics at the Humboldt University, Berlin, and a 6th-century chair for Complex Systems Biology at the Institute for Complex Systems and Mathematical Biology at Kings College, Aberdeen University (UK). His research is mainly concerned with nonlinear physics and complex systems sciences and their applications to challenging problems in Earth system, physiology, systems biology and engineering.
Climate inertia or climate change inertia is the phenomenon by which a planet's climate system shows a resistance or slowness to deviate away from a given dynamic state. It can accompany stability and other effects of feedback within complex systems, and includes the inertia exhibited by physical movements of matter and exchanges of energy. The term is a colloquialism used to encompass and loosely describe a set of interactions that extend the timescales around climate sensitivity. Inertia has been associated with the drivers of, and the responses to, climate change.
Noah S. Diffenbaugh is an American climate scientist at Stanford University, where he is the Kara J Foundation Professor of Earth System Science and Kimmelman Family Senior Fellow at the Stanford Woods Institute for the Environment, and an affiliate at the Precourt Institute for Energy. From 2015-2018, he served as editor-in-chief of the peer-review journal Geophysical Research Letters. He is known for his research on the climate system, including the effects of global warming on extreme weather and climate events such as the 2011-2017 California drought.
Abigail L. S. Swann is an Associate Professor of Atmospheric Sciences and Ecology at the University of Washington. Her research group focuses on questions that examine the interactions between plants and climate.
Anthony David Barnosky is an ecologist, geologist and biologist (paleoecology). He was Professor at the Department of Integrative Biology at UC Berkeley until his retirement. His research is concerned with the relationship between climate change and mass extinctions.
Climate change and civilizational collapse refers to a hypothetical risk of the impacts of climate change reducing global socioeconomic complexity to the point complex human society effectively ends around the world, with humanity reduced to a less developed state. This hypothetical risk is typically associated with the idea of a massive reduction of human population caused by the direct and indirect impacts of climate change, and often, it is also associated with a permanent reduction of the Earth's carrying capacity. Finally, it is sometimes suggested that a civilizational collapse caused by climate change would soon be followed by human extinction.
Jens-Christian Svenning is a Danish ecologist, biogeographer and academic. He is a Professor at the Department of Biology at Aarhus University, Denmark where he also serves as the Director of DNRF Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), established in 2023.
