Atmosphere

Climate

The average weather conditions in an area over a long period of time. Influences plant and animal life. Has effect on geological processes. Varies from place to place and time to time.

Weather

State of the atmosphere at any given time and place.

Climate system

The global geosystem that includes all the components of the Earth system and all the interactions among these components needed to determine climate on a global scale and how it changes over time.

Proxy data

Data gathered from natural recorders of climate variability such as tree rings, ice cores, and ocean-floor sediments. Indirect evidence of climate change.

Paleoclimatology

Reconstruction of past climates using proxy data.

Oxygen-16

Most common isotope of oxygen. Evaporates more readily than the other oxygen isotope.

Oxygen-18

Dense isotope of oxygen. Stays in the oceans.

Warmer period

Period when O-16/O-18 ratio drops because more O-16 is evaporated.

Glacial period

Period when O-16/O-18 ratio increases because less O-16 is evaporated.

Oxygen isotope analysis

A method of deciphering past temperatures based on precise measurement of the ratio between two isotopes of oxygen, O-16 and O-18.

Seafloor sediment Oxygen isotopes Glacial ice Fossil pollen Corals Historical data

Types of proxy data

Fossil pollen

A type of proxy data. Abundant, easily identifiable, and best preserved due to their resistant walls.

Corals

A type of proxy data. Built in warm shallow waters and form atop the hard material left behind by past corals. Density depends on climatic conditions. Have growth bands. Can serve as paleothermometer.

Paleothermometer

An indicator or proxy that can give scientists information about ancient temperatures.

Greenhouse effect

Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases. Shortwave radiation transmitted, longwave radiation absorbed by water vapor, CO2, and other trace gases. Heats the surface and prevent it from freezing.

Air

A mixture of gases surrounding the Earth.

78%

Percentage of nitrogen in the atmosphre.

21%

Percentage of oxygen in the atmosphere.

0.93%

Percentage of argon in the atmosphere.

0.0389%

Percentage of carbon dioxide in the atmosphere.

Water vapor

Constitutes 0-4% of the atmosphere. Source of clouds and precipitation. Has ability to absorb heat energy given off by the Earth as well as some solar energy.

Ozone

O3. Not uniformly concentrated in the stratosphere. Absorbs potentially harmful UV rays from the sun.

Aerosol

A type of colloid in which liquid drops or solid particles are spread throughout a gas. Can be natural or manmade. Important in the formation of clouds and fog. Can absorb or reflect solar radiation.

The atmosphere has no sharp boundary and thins out toward space.

True.

1000 millibars

Atmospheric pressure at sea level.

5.6 kilometers

Up to what altitude does 50% of the atmosphere lies?

16 kilometers

Up to what altitude does 90% of the atmosphere lies?

Troposphere Stratosphere Mesosphere Thermosphere

The layers of the atmosphere.

Troposphere

Bottom layer of the atmosphere. Temperature decreasing while ascending. Average thickness is 12km. Where weather occurs.

Tropopause

Upper limit of the troposphere. Boundary between troposphere and stratosphere.

Environmental lapse rate

As you go up, the temperature gets colder because you are moving away from source of heat (Earth).

6.5 degrees Celsius / kilometer

Normal environmental lapse rate.

Stratosphere

Second layer following the troposphere. 20-50 km thick Contains the ozone layer. Heated due to ozone absorbing UV rays.

Mesosphere

Third layer of the atmosphere following the stratosphere. Temperature decreases with height. Have surface temperature of -90 degrees Celsius.

Mesopause

Upper limit of the Mesosphere. Boundary between mesosphere and thermosphere.

Thermosphere

The uppermost layer of the atmosphere, in which temperature increases as altitude increases. Contains tiny fraction of atmosphere's mass. High temperature due to gases absorbing high-energy waves.

20x

By how much the radiation wave of the Earth is longer than the sun?

The Earth emits shortwave radiation while the sun releases longwave ones.

False.

Objects that are good absorbers of radiation are good emitters as well.

True.

The atmosphere is transparent to some wavelengths and opaque to some.

True.

Albedo

The proportion of the incident light or radiation that is reflected by a surface, typically that of a planet or moon.

50% absorbed by Earth's surface. 20% absorbed by atmospheric gases and clouds. 30% reflected back to space by clouds and reflective surfaces like snow and ice.

Distribution of the solar energy received by the Earth.

Plate tectonics Changes in eccentricity, obliquity, and precession Volcanic activity

Natural causes of climate change

1816

The Year Without a Summer that was caused by the April 1815 eruption of Mount Tambora.

0.5 degrees Celsius

Amount of global cooling that was caused by the 1991 eruption of Mount Pinatubo.

Volcanic gases combine with water in the stratosphere to form a dense cloud of sulfuric acid.

True.

Sunspots

A spot or patch appearing from time to time on the sun's surface, appearing dark by contrast with its surroundings. Best known feature of the sun. Associated with mass ejections of particles.

11 years

The number of years in the sun's cycle when there is a considerable alternating increase and decrease in the number of sunspots.

22 years

Number of years in an average solar cycle based on the fact that magnetic polarities of sunspot clusters reverse every 11 years.

During years of no sunspots, it was colder in the Northern Hemisphere and the opposite when there are abundant sunspots.

True.

Methane

Produced by anaerobic bacteria in swamps, bogs wetlands, termite guts, cattle, and mining and drilling for oil. A trace gas 20x more effective than CO2 in absorbing infrared radiation.

Nitrous oxide

Laughing gas. Has a lifetime of 150 years.

Chlorofluorocarbon

A gas used as a solvent, a propellant in aerosols, a refrigerant, and in plastic foams and fire extinguishers. Remains in the atmosphere for decades.

Methane Nitrous oxide Chlorofluorocarbon

Most common trace gases present in the atmosphere.

Climate-feedback mechanisms

Various outcomes that may result when one of this complex interactive physical system's elements is altered.

Positive-feedback mechanism

Feedback that tends to cause the level of a variable to change in the same direction as an initial change. Effect reinforces initial change.

Negative-feedback mechanism

The most common homeostatic control mechanism. The net effect is that the output of the system shuts off the original stimulus or reduces its intensity.

Sea-level rise Melting of glaciers in the Arctic and Antarctic Increase in ocean acidity

Some of the effects of global warming

Global warming

An increase in the average temperature of the earth's atmosphere (especially a sustained increase that causes climatic changes). Occurred in the geologic past; more pronounced today due to human activity