Greenhouse Gases and Global Warming

Vocabulary flashcards covering key terms, atmospheric layers, solar radiation spectrum, and greenhouse gas properties based on the lecture on Greenhouse Gases and Global Warming.

Photons

Particles of light energy through which solar energy travels to Earth as electromagnetic waves across a spectrum ranging from short to long wavelengths.

Electromagnetic Spectrum

The complete range of solar radiation wavelengths and frequencies, extending from high-energy short waves such as gamma rays, X-rays, and ultraviolet to low-energy long waves like infrared, microwaves, and radio waves.

Photosynthetically Active Radiation (PhAR)

The band of visible light with wavelengths ranging from $0.40 - 0.70\,\mu m$ (specifically red light at $0.64 - 0.70\,\mu m$ and blue light at $0.44 - 0.59\,\mu m$) that green plants capture for photosynthesis.

Greenhouse Effect

The atmospheric process wherein heat-absorbing gases and water vapor trap outbound long-wave infrared radiation emitted by Earth's surface and re-radiate it back toward Earth, regulating planetary surface temperature.

Atmosphere

The thin layer of gases surrounding Earth, composed of permanent gases ($78.1\%$ nitrogen, $21\%$ oxygen, and $0.93\%$ argon) and variable trace gases divided into four distinct temperature layers.

Troposphere

The lowest layer of Earth's atmosphere containing $75\%$ of atmospheric mass and most water vapor, where weather occurs and temperature decreases with height at an average rate of $6.5\,^\circ C$ per $1{,}000\,m$.

Tropopause

The boundary layer of air that separates the troposphere below from the stratosphere above.

Stratosphere

The atmospheric layer extending from an altitude of $8 - 16\,km$ up to about $50\,km$, characterized by stable temperatures, low water vapor, high ozone concentration, and an absence of weather clouds.

Ozone Layer

A region within the stratosphere ($19 - 48\,km$ above Earth's surface) containing concentrations of up to $10\,ppm$ of ozone ($O_3$), which shields life on Earth by absorbing solar ultraviolet radiation.

Ozone Formation Cycle

The atmospheric chemical reaction in which ultraviolet rays split an oxygen molecule ($O_2$) into single oxygen atoms ($O$), which then combine with other $O_2$ molecules to create ozone ($O_3$).

Ozone Hole

A region of depleted stratospheric ozone concentration concentrated over the poles (such as the South Pole) caused by industrial chemicals releasing chlorine that breaks down ozone molecules.

Mesosphere

The coldest atmospheric layer, extending from an altitude of about $50\,km$ to $85\,km$, where air temperature decreases with height down to $-80\,^\circ C$.

Thermosphere

The outer atmospheric layer extending up to $1600\,km$, composed of highly ionized gases reaching temperatures over $1000\,^\circ C$ due to continuous absorption of high-energy solar and cosmic radiation.

Water Vapor

The most common natural greenhouse gas in the atmosphere, responsible for $60\%$ to $70\%$ of the natural greenhouse effect.

Carbon Dioxide ($CO_2$)

A major greenhouse gas circulating through the carbon cycle, whose atmospheric concentration is increasing at about $1\,ppm/yr$ primarily due to deforestation and fossil fuel combustion.

Methane ($CH_4$)

A potent greenhouse gas released in anaerobic environments (ruminant animal belches, flooded rice fields, coal mining) with a warming effect where $1$ molecule equals $25$ molecules of $CO_2$.

Nitrous Oxide ($N_2O$)

A greenhouse gas produced by fossil fuel burning, automobile exhaust, field plowing, and nitrogen fertilizer application through nitrification and denitrification pathways.

Ground-Level Ozone

Ozone ($O_3$) formed in the lower atmosphere (troposphere) that acts as a greenhouse gas and a principal component of smog, concentrated mainly around industrialized regions.

Fluorinated Compounds (CFCs)

Synthetic industrial gases used in refrigerants and aerosol sprays where $1$ molecule equals $10{,}000$ molecules of $CO_2$ in warming effect, contributing $15\%$ of the greenhouse effect and releasing chlorine that damages the ozone layer.

Annual Greenhouse Gas Emissions by Sector

The sector-wise breakdown of global greenhouse gas emissions, led by power stations ($21.3\%$), industrial processes ($16.8\%$), transportation fuels ($14.0\%$), agricultural byproducts ($12.5\%$), and fossil fuel operations ($11.3\%$).

Global Warming

The unnatural increase in Earth's surface temperature (approximately $0.6\,^\circ C$ over the last 100 years) resulting from anthropogenic greenhouse gas accumulation trapping excess heat.