Lecture

Atmospheric Composition: Understanding Key Processes and Impacts

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Description

This lecture provides a comprehensive introduction to atmospheric composition, focusing on the fundamental concepts of geochemical cycles, atmospheric lifetimes, and the role of various gases and aerosols. It begins with a recap of previous discussions on Earth's energy balance and the importance of atmospheric windows. The instructor outlines the key components of the atmosphere, including nitrogen, oxygen, and trace gases, emphasizing their sources and impacts on health and climate. The lecture delves into the dynamics of atmospheric processes, including emissions from anthropogenic and natural sources, and their interactions within the boundary layer. The significance of ozone chemistry is highlighted, along with the implications of atmospheric emissions on air quality, food security, and climate change. The instructor discusses the mass budget of the atmosphere and the importance of understanding mixing ratios and units for measuring atmospheric constituents. The lecture concludes with an overview of the global carbon and nitrogen cycles, illustrating the interconnectedness of these systems and their relevance to environmental science.

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Related concepts (32)

Biogeochemical cycle

A biogeochemical cycle, or more generally a cycle of matter, is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is transformed and cycled by living organisms and through various geological forms and reservoirs, including the atmosphere, the soil and the oceans.

Ozone

Ozone (ˈoʊzoʊn) (or trioxygen) is an inorganic molecule with the chemical formula O3. It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O2, breaking down in the lower atmosphere to O2 (dioxygen). Ozone is formed from dioxygen by the action of ultraviolet (UV) light and electrical discharges within the Earth's atmosphere. It is present in very low concentrations throughout the latter, with its highest concentration high in the ozone layer of the stratosphere, which absorbs most of the Sun's ultraviolet (UV) radiation.

Emissions trading

Emissions trading is a market-based approach to controlling pollution by providing economic incentives for reducing the emissions of pollutants. The concept is also known as cap and trade (CAT) or emissions trading scheme (ETS). Carbon emission trading for and other greenhouse gases has been introduced in China, the European Union and other countries as a key tool for climate change mitigation. Other schemes include sulfur dioxide and other pollutants.

Climate change

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 more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane.

Climate change denial

Climate change denial or global warming denial is dismissal or unwarranted doubt that contradicts the scientific consensus on climate change. Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is none. Climate change denial includes doubts to the extent of how much climate change is caused by humans, its effects on nature and human society, and the potential of adaptation to global warming by human actions.

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