A carbon sink is anything, natural or otherwise, that accumulates and stores some carbon-containing chemical compound for an indefinite period and thereby removes carbon dioxide from the atmosphere. These sinks form an important part of the natural carbon cycle. An overarching term is carbon pool, which is all the places where carbon can be. A carbon sink is a type of carbon pool that has the capability to take up more carbon from the atmosphere than it releases.
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated deforestation occurs in tropical rainforests. About 31% of Earth's land surface is covered by forests at present. This is one-third less than the forest cover before the expansion of agriculture, with half of that loss occurring in the last century. Between 15 million to 18 million hectares of forest, an area the size of Bangladesh, are destroyed every year. On average 2,400 trees are cut down each minute.
The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. The carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks.
The Amazon rainforest, also called Amazon jungle or Amazonia, is a moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses 7,000,000 km2 (2,700,000 sq mi), of which 5,500,000 km2 (2,100,000 sq mi) are covered by the rainforest. This region includes territory belonging to nine nations and 3,344 formally acknowledged indigenous territories.
Climate change mitigation is action to limit climate change. This action either reduces emissions of greenhouse gases or removes those gases from the atmosphere. The recent rise in global temperature is mostly due to emissions from burning fossil fuels such as coal, oil, and natural gas. There are various ways that mitigation can reduce emissions. These are transitioning to sustainable energy sources, conserving energy, and increasing efficiency. It is possible to remove carbon dioxide from the atmosphere. This can be done by enlarging forests, restoring wetlands and using other natural and technical processes. The name for these processes is carbon sequestration. Governments and companies have pledged to reduce emissions to prevent dangerous climate change. These pledges are in line with international negotiations to limit warming.
Carbon sequestration is the process of storing carbon in a carbon pool. Carbon sequestration is a naturally occurring process but it can also be enhanced or achieved with technology, for example within carbon capture and storage projects. There are two main types of carbon sequestration: geologic and biologic.
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.
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.
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 a positive feedback cycle, as methane is itself a powerful greenhouse gas.
Carbon dioxide removal (CDR), also known as carbon removal, greenhouse gas removal (GGR) or negative emissions, is a process in which carbon dioxide gas is removed from the atmosphere by deliberate human activities and durably stored in geological, terrestrial, or ocean reservoirs, or in products. In the context of net zero greenhouse gas emissions targets, CDR is increasingly integrated into climate policy, as an element of climate change mitigation strategies. Achieving net zero emissions will require both deep cuts in emissions and the use of CDR, but CDR is not a current climate solution. In the future, CDR may be able to counterbalance emissions that are technically difficult to eliminate, such as some agricultural and industrial emissions.
Climate change feedbacks are effects of global warming that amplify or diminish the effect of forces that initially cause the warming. Positive feedbacks enhance global warming while negative feedbacks weaken it. Feedbacks are important in the understanding of climate change because they play an important part in determining the sensitivity of the climate to warming forces. Climate forcings and feedbacks together determine how much and how fast the climate changes. Large positive feedbacks can lead to tipping points—abrupt or irreversible changes in the climate system—depending upon the rate and magnitude of the climate change.
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 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.
Blue carbon is a term used in the climate change mitigation context that refers to "biologically driven carbon fluxes and storage in marine systems that are amenable to management." Most commonly, it refers to the role that tidal marshes, mangroves and seagrasses can play in carbon sequestration. Such ecosystems can contribute to climate change mitigation and also to ecosystem-based adaptation. When blue carbon ecosystems are degraded or lost they release carbon back to the atmosphere.
A peatland is a type of wetland whose soils consist of organic matter from decaying plants, forming layers of peat. Peatlands arise because of incomplete decomposition of organic matter, usually litter from vegetation, due to water-logging and subsequent anoxia. Like coral reefs, peatlands are unusual landforms that derive mostly from biological rather than physical processes, and can take on characteristic shapes and surface patterning.
David John Beerling FLSW is the Director of the Leverhulme Centre for Climate change mitigation and Sorby Professor of Natural Sciences in the Department of Animal and Plant Sciences (APS) at the University of Sheffield, UK. He is also Editor-in-Chief of the Royal Society journal Biology Letters.
Deforestation is a primary contributor to climate change, and climate change affects forests. Land use changes, especially in the form of deforestation, are the second largest anthropogenic source of atmospheric carbon dioxide emissions, after fossil fuel combustion. Greenhouse gases are emitted during combustion of forest biomass and decomposition of remaining plant material and soil carbon. Global models and national greenhouse gas inventories give similar results for deforestation emissions. As of 2019, deforestation is responsible for about 11% of global greenhouse gas emissions. Carbon emissions from tropical deforestation are accelerating. Growing forests are a carbon sink with additional potential to mitigate the effects of climate change. Some of the effects of climate change, such as more wildfires, insect outbreaks, invasive species, and storms are factors that increase deforestation.
The CO2 fertilization effect or carbon fertilization effect causes an increased rate of photosynthesis while limiting leaf transpiration in plants. Both processes result from increased levels of atmospheric carbon dioxide (CO2). The carbon fertilization effect varies depending on plant species, air and soil temperature, and availability of water and nutrients. Net primary productivity (NPP) might positively respond to the carbon fertilization effect. Although, evidence shows that enhanced rates of photosynthesis in plants due to CO2 fertilization do not directly enhance all plant growth, and thus carbon storage. The carbon fertilization effect has been reported to be the cause of 44% of gross primary productivity (GPP) increase since the 2000s. Earth System Models, Land System Models and Dynamic Global Vegetation Models are used to investigate and interpret vegetation trends related to increasing levels of atmospheric CO2. However, the ecosystem processes associated with the CO2 fertilization effect remain uncertain and therefore are challenging to model.
Yadvinder Singh Malhi is professor of Ecosystem Science at the University of Oxford and a Jackson Senior Research Fellow at Oriel College, Oxford.
This article documents events, research findings, scientific and technological advances, and human actions to measure, predict, mitigate, and adapt to the effects of global warming and climate change—during the year 2022.
This is an article of notable issues relating to the terrestrial environment of Earth in 2022. 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.
