Air

The composition of our air determines many things: how much of the sun's radiation is held in, warming the earth; our ability to breathe; the growth rate of plants; and more. As an invisible component of our systems, air holds special challenges for scientific study, yet its qualities are crucial to the existence of life on Earth. To explore what scientists investigate when they study air and how they do it, take a look at some key questions and clips.

Greenhouse Gases

How much carbon is human activity adding to the atmosphere?

play Mike Apps :
Can planting trees counter our carbon out-put ?

Human Interactions/Societal Needs

How do scientists monitor global change?

play Pam Matson :
What does the biosphere breathing look like?

Climate of the Past

What is the climate record of the Holocene and recent past?

play Peter Cox :
Who was Charles David Keeling, and was he nuts?

Air /e(ə)r/ 1. The invisible mix of gases surrounding the planet which make up its atmosphere and enable life on Earth.

Image Credit: NASA Earth Observatory

United States Global Change Research Program Definition of Air

Air

Definition The particles and the concentrations of the particles in the protective envelope surrounding the Earth.

Summary The composition of the atmosphere - its gases and particles - plays a critical role in connecting human welfare with global and regional changes because the atmosphere links all of the principal components of the Earth system. The atmosphere interacts with the oceans, land, terrestrial and marine plants and animals, and the frozen regions. Because of these linkages, the atmosphere is a conduit of change. Emissions from natural sources and human activities enter the atmosphere at the surface and are transported to other geographical locations and often higher altitudes. Some emissions undergo chemical transformation or removal while in the atmosphere or interact with cloud formation and precipitation. Some natural events and human activities that change atmospheric composition also change the Earth's radiative (energy) balance. Subsequent responses to changes in atmospheric composition by the stratospheric ozone layer, the climate system, and regional chemical composition (air quality), create multiple environmental effects that can influence human health and natural systems.

Research Questions 1. What are the climate-relevant chemical, microphysical, and optical properties, and spatial and temporal distributions, of human-caused and naturally occurring aerosols? 2. What are the atmospheric sources and sinks of the greenhouse gases other than CO2 and the implications for the Earth's energy balance? 3. What are the effects of regional pollution on the global atmosphere and the effects of global climate and chemical change on regional air quality and atmospheric chemical inputs to ecosystems? 4. What are the characteristics of the recovery of the stratospheric ozone layer in response to declining abundances of ozone-depleting gases and increasing abundances of greenhouse gases? 5. What are the couplings and feedback mechanisms among climate change, air pollution, and ozone layer depletion, and their relationship to the health of humans and ecosystems?

Source: Climate Change Science Program, and The Subcommittee Global Change Research. "Our Changing Planet: The U.S. Climate Change Science Program for Fiscal Year 2006." Washington: Climate Change Science Program Office, 2006.

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Air

How much carbon is human activity adding to the atmosphere?

How do scientists monitor global change?

What is the climate record of the Holocene and recent past?

Air