G4. Climate Change

climate change

is current in a sense that it has been put under international spotlight since the start of the 21st century.

climate; klinein

• refers to a long-term weather patterns prevailing over a given area of a planet

• the term comes from a greek word ___ meaning “to slope”

klima

connoting a zone or region of the Earth as characterized by its atmospheric conditions

1. aphelion

2. perihelion

3. Earth’s axial tilt

4. precession

5. equinox

6. solstice

7. precession of the equinoxes

the elements in this interaction between the Sun and the Earth are defined as follows:

aphelion

refers to the point in the orbit of the Earth farthest from the sun

perihelion

is the point in the orbit of the Earth closest to the sun

Earth’s axial tilt

is the inclination angle of the Earth’s rotational axis in relation to a line perpendicular to its orbital plane

precession

is the change of the orientation of the rotational axis of the Eatth

equinox

refers to the time of the sun at noon is directly over the equator. it happens twice a year and causes and almost equal length of day and night

solstice

happens when the sun at noon sits above the Tropic of Cancer or Tropic of Capricorn. the summer solstice has the longest period of daylight in the year and the winter solstice has the shortest period

precession of the equinoxes

refers to the motion of the equinoxes relative to the precession of the Earth’s axis of rotation. it happens over thousand of years.

Milankovitch Parameters

the effects of the change in the radius of the Earth’s orbit, the change in the tilt of the spin of the Earth, and the wobble in the spin axis were each so small that they could not alter the amount of sunlight reaching the Earth enough to cause a phenomenon like the Ice Age

Milankovitch cycles

cause variations of up to 25 percent in the amount of incoming insolation of Earth’s mid-latitudes

1. eccentricity

2. obliquity

Milankovitch cycles

eccentricity

• the shape of the Earth’s orbit

• it measures how much the shape of Earth’s orbit departs from a perfect circle.

• is the reason why our seasons are slightly different lengths, with summers in the northern hemisphere currently about 4.5 days longer than winters

obliquity; 22.1 and 24.5; 23.5

• the angle Earth’s axis is tilted with respect to Earth’s orbital plane

• over the last million years, it has varied between _____ degrees perpendicular to Earth’s orbital plane.

• Earth’s axis is currently tilted __ degrees

Carbon Dioxide (CO₂)

Fossil fuel use is the primary source of ___. ___ can also be emitted from direct human-induced impacts on forestry and other land use, such as through deforestation, land clearing for agriculture, and degradation of soils. Likewise, land can also remove ___ from the atmosphere through reforestation, improvement of soils, and other activities.

methane (CH4)

Agricultural activities, waste management. energy use, and biomass burning all contribute to ____ emissions

nitrous oxide (N₂O)

Agricultural activities, such as fertilizer use, are the primary source of ___ emissions. Fossil fuel combustion also generates ____

fluorinated gases

Industrial processes, refrigeration, and the use of a variety of consumer products contribute to emissions of F-gases, which include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases").

1. how much gas is in the atmosphere?

2. how long do they stay in the atmosphere?

3. how strongly do they impact the atmosphere?

each gas’s effect on climate change depends on 3 factors