The scientific community has been investigating the causes of climate change for decades. After thousands of studies, it came to a consensus, where it is "unequivocal that human influence has warmed the atmosphere, ocean and land since pre-industrial times." This consensus is supported by around 200 scientific organizations worldwide, The dominant role in this climate change has been played by the direct emissions of carbon dioxide from the burning of fossil fuels. Indirect CO2 emissions from land use change, and the emissions of methane, nitrous oxide and other greenhouse gases play major supporting roles.
A carbon sink is a natural or artificial process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas 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 on Earth can be, i.e. the atmosphere, oceans, soil, plants, and so forth. A carbon sink is a type of carbon pool that has the capability to take up more carbon from the atmosphere than it releases.
Effects of climate change are well documented and growing for Earth's natural environment and human societies. Changes to the climate system include an overall warming trend, changes to precipitation patterns, and more extreme weather. As the climate changes it impacts the natural environment with effects such as more intense forest fires, thawing permafrost, and desertification. These changes impact ecosystems and societies, and can become irreversible once tipping points are crossed.
Myles Robert Allen is an English climate scientist. He is Professor of Geosystem Science in the University of Oxford's School of Geography and the Environment, and head of the Atmospheric, Oceanic and Planetary Physics Department.
Land use, land-use change, and forestry (LULUCF), also referred to as Forestry and other land use (FOLU) or Agriculture, Forestry and Other Land Use (AFOLU), is defined as a "greenhouse gas inventory sector that covers emissions and removals of greenhouse gases resulting from direct human-induced land use such as settlements and commercial uses, land-use change, and forestry activities."
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices add to greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming.
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.
Atmospheric methane is the methane present in Earth's atmosphere. The concentration of atmospheric methane is increasing due to methane emissions, and is causing climate change. Methane is one of the most potent greenhouse gases. Methane's radiative forcing (RF) of climate is direct, and it is the second largest contributor to human-caused climate forcing in the historical period. Methane is a major source of water vapour in the stratosphere through oxidation; and water vapour adds about 15% to methane's radiative forcing effect. The global warming potential (GWP) for methane is about 84 in terms of its impact over a 20-year timeframe, and 28 in terms of its impact over a 100-year timeframe.
Environmental issues are disruptions in the usual function of ecosystems. Further, these issues can be caused by humans or they can be natural. These issues are considered serious when the ecosystem cannot recover in the present situation, and catastrophic if the ecosystem is projected to certainly collapse.
The environmental impact of agriculture is the effect that different farming practices have on the ecosystems around them, and how those effects can be traced back to those practices. The environmental impact of agriculture varies widely based on practices employed by farmers and by the scale of practice. Farming communities that try to reduce environmental impacts through modifying their practices will adopt sustainable agriculture practices. The negative impact of agriculture is an old issue that remains a concern even as experts design innovative means to reduce destruction and enhance eco-efficiency. Though some pastoralism is environmentally positive, modern animal agriculture practices tend to be more environmentally destructive than agricultural practices focused on fruits, vegetables and other biomass. The emissions of ammonia from cattle waste continue to raise concerns over environmental pollution.
Planetary boundaries are a framework to describe limits to the impacts of human activities on the Earth system. Beyond these limits, the environment may not be able to self-regulate anymore. This would mean the Earth system would leave the period of stability of the Holocene, in which human society developed. The framework is based on scientific evidence that human actions, especially those of industrialized societies since the Industrial Revolution, have become the main driver of global environmental change. According to the framework, "transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental-scale to planetary-scale systems."
William Lee Steffen was an American-born Australian chemist. He was the executive director of the Australian National University (ANU) Climate Change Institute and a member of the Australian Climate Commission until its dissolution in September 2013. From 1998 to 2004, he was the executive director of the International Geosphere-Biosphere Programme, a coordinating body of national environmental change organisations based in Stockholm. Steffen was one of the founding climate councillors of the Climate Council, with whom he frequently co-authored reports, and spoke in the media on issues relating to climate change and renewable energy.
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. Rockström is also chief scientist at Conservation International. He is Professor in Earth System Science at the University of Potsdam and Professor in Water Systems and Global Sustainability, Stockholm University.
The contributions of women in climate change have received increasing attention in the early 21st century. Feedback from women and the issues faced by women have been described as "imperative" by the United Nations and "critical" by the Population Reference Bureau. A report by the World Health Organization concluded that incorporating gender-based analysis would "provide more effective climate change mitigation and adaptation."
Diana Ürge-Vorsatz is a Hungarian scientist. She is a Vice-Chair of the IPCC, and professor of Environmental Sciences at Central European University. She is the Director of the Center for Climate Change and Sustainable Energy Policy. She has published widely on environmental and energy studies, primarily climate change mitigation.
Karen Ching-Yee Seto is a geographer, urbanisation and land change scientist, and Frederick C. Hixon Professor of Geography and Urbanisation Science at Yale University. She is an expert on urbanisation and sustainability, and satellite remote sensing. She was the co-lead for the chapter on urban mitigation in Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report and IPCC 5th Assessment Report. From 2014 to 2020, she was the co-editor-in-chief of the scientific journal Global Environmental Change. She is an elected member of the U.S. National Academy of Sciences (NAS), the Connecticut Academy of Science and Engineering (CASE), the American Academy of Arts and Sciences, the Council on Foreign Relations, and a fellow of the American Association for the Advancement of Science (AAAS).
Katherine Calvin is NASA's Chief Scientist and Senior Climate Advisor. In July 2023, she was elected co-chair of the Intergovernmental Panel on Climate Change (IPCC) Working Group III. As an earth scientist at the Joint Global Change Research Institute (JGCRI), she has researched human use of global resources using Earth modeling systems at JGCRI under the direction of Pacific Northwest National Laboratory (PNNL) and the University of Maryland. She has contributed to the third US National Climate Assessment as well as two special reports by the Intergovernmental Panel on Climate Change (IPCC).
Sustainable population refers to a proposed sustainable human population of Earth or a particular region of Earth, such as a nation or continent. Estimates vary widely, with estimates based on different figures ranging from 0.65 billion people to 9.8 billion, with 8 billion people being a typical estimate. Projections of population growth, evaluations of overconsumption and associated human pressures on the environment have led to some to advocate for what they consider a sustainable population. Proposed policy solutions vary, including sustainable development, female education, family planning and broad human population planning.
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.
The University of Arizona School of Geography, Development and Environment is an academic department and professional school for geographical education and urban and regional development, GIS, development practice, and environmental studies. Degrees conferred include Bachelor of Arts (BA), Bachelor of Science (BS), Master of Arts (MA), Master of Science (MS), and Doctor of Philosophy (PhD).
