Earth's Climate and Energy: Sun, Greenhouse Effect, and Milankovitch Cycles

What is the primary source of energy that heats the Earth?

The Sun

What type of energy does the Sun emit?

Electromagnetic radiation

How is wavelength defined?

The distance from the peak of one wave to the peak of the next wave.

What is the range of wavelengths that human eyes can see?

Between about 350 nanometers (purple) and 800 nanometers (red).

What type of light has wavelengths shorter than 350 nanometers?

Ultraviolet light.

What type of light has wavelengths longer than 800 nanometers?

Infrared light.

What is Albedo?

The reflectivity of an object, measured on a scale from 0 to 1.

What happens to energy that is absorbed by the Earth?

It heats the planet and is then re-emitted as infrared energy.

What is the greenhouse effect?

The process where certain gases in the atmosphere absorb and re-emit infrared radiation, warming the atmosphere and Earth.

What is Earth's Energy Budget?

The balance of energy entering and leaving Earth's systems, affecting its overall temperature.

What is the formula for Earth's Energy Budget?

Total Input - Total Output = Change in Storage.

What is the average global temperature of Earth today?

Around 15.8°C or 60.44°F.

What are climate proxies?

Preserved physical characteristics of the past that help reconstruct past climate conditions.

How can tree rings be used as climate proxies?

They reveal age and changes in local climate through their thickness.

What information can ice cores provide?

Data on temperature, atmospheric circulation, precipitation, and gas concentrations over up to 800,000 years.

What do sediment cores indicate about past climate?

They show changes in climate through different layers of sediment and can indicate past fires and vegetation.

What is the significance of the Earth's temperature changes over its 4.6 billion years of history?

It shows that global temperatures have varied significantly, impacting climate and life.

What is the average temperature of the Sun?

5,778 Kelvin.

What type of energy does Earth emit due to its cooler temperature?

Infrared energy.

What happens to some of the energy emitted by Earth?

Some escapes to space, while some is re-absorbed by greenhouse gases.

Why do some believe that current rising global temperatures are not a problem?

Because Earth has been warmer in the past, but current temperatures have not been high during human existence.

What role do greenhouse gases play in climate change?

They absorb and re-emit infrared radiation, contributing to warming.

What is the impact of more energy entering Earth's systems than leaving?

The temperature of the Earth will increase.

What is the impact of less energy entering Earth's systems than leaving?

The temperature of the Earth will decrease.

What is the relationship between Earth's Energy Budget and climate change?

Changes in the Energy Budget can lead to shifts in global temperatures and climate patterns.

What are some factors that can influence global climate?

Solar input/output and changes in Earth's Energy Budget.

What causes sunspots on the Sun?

The interaction of the Sun's strong magnetic field with its photosphere.

How often do sunspots occur?

Approximately every 11 years.

What is the maximum percentage change in the Sun's energy output between sunspot lows and highs?

Up to 0.2%.

What hypothesis explains the early Earth's warm climate?

The greenhouse gases released from volcanic outgassing.

What major change occurred in Earth's atmosphere about 1.7 billion years ago?

Ocean algae evolved and changed the atmosphere by taking in carbon dioxide and releasing oxygen.

What is 'Snowball Earth'?

A period when Earth was completely covered in ice from pole to pole due to low carbon dioxide levels.

How did volcanic eruptions affect Earth's atmosphere?

They release sulfur, ash, smoke, and dust, which can reflect light and change albedo.

What event is believed to have contributed to the extinction of the dinosaurs?

A comet impact that caused climate change, not the immediate impact itself.

What is the significance of plate tectonics in Earth's climate?

Plate tectonics influence land formation and placement, affecting temperature and climate.

What is the Vostok Ice Core and its importance?

It contains ice dating back 800,000 years, providing data on past climate and atmospheric composition.

What are Milankovitch Cycles?

Cycles of Earth's orbit and axial tilt that affect climate over periods of 12,900 to 400,000 years.

What does eccentricity measure in relation to Earth's orbit?

It measures how circular or elliptical the Earth's orbit is.

What is the current tilt of the Earth and its range over time?

Currently about 23.5°, varying between 22.1° and 24.5° over a 41,000-year cycle.

What is axial precession?

The wobble of Earth's axis caused by gravitational pull, occurring over a period of 25,800 years.

What happens to Earth's energy reception during periods of high eccentricity?

Earth receives varying amounts of solar energy at aphelion and perihelion.

How do volcanic eruptions contribute to climate change?

By releasing particulate matter that reflects sunlight, leading to cooling.

What role did algae play in changing Earth's atmosphere?

They reduced carbon dioxide levels and increased oxygen through photosynthesis.

What is the relationship between Earth's albedo and snowball Earth?

A low albedo during snowball Earth means most sunlight is reflected back into space.

What is the impact of comet and meteor dust on climate?

Dust can reflect sunlight, leading to drastic cooling.

How does the position of continents affect Earth's temperature?

Continents heat up and cool down faster than oceans, influencing climate.

What is the significance of the Milankovitch Cycles on glaciation?

They determine periods of glaciation due to changes in Earth's orbit and tilt.

What is the effect of Earth's axial tilt on seasons?

A greater tilt results in more extreme seasonal differences.

How does the gravitational pull of other planets affect Earth's orbit?

It causes changes in the shape of Earth's orbit over time.

What evidence do scientists use to study past climates?

Trapped gases in ice cores provide data on atmospheric composition and temperature.

What happens to the North Pole's direction due to precession?

It wobbles, pointing towards different stars over thousands of years.

What celestial body did stargazers note was aligned with the North Axis of the Earth around 4,000 BC?

The handle of the Big Dipper.

What effect does the tilt of the Earth have on seasonal temperatures?

It determines which hemisphere is pointed towards or away from the sun, affecting summer and winter temperatures.

When does perihelion occur?

On January 3rd.

How does the Earth's orbit affect the length of winter and summer?

The Earth takes longer to travel around the aphelion-end of the orbit, resulting in shorter winters for the hemisphere experiencing winter at perihelion.

What happens to sea levels during an ice age?

Sea levels drop dramatically due to water being stored as ice on land.

Why does the Northern Hemisphere influence global temperature more than the Southern Hemisphere?

It has more land, which heats up and cools down faster.

What is a positive feedback loop in the context of climate change?

A system where an initial cause is intensified by its effects, such as increased temperatures leading to higher CO2 levels, which further raise temperatures.

What is the difference between local climate and global climate?

Local climate refers to an area's long-term weather patterns, while global climate refers to Earth's overall temperature and precipitation patterns.

How can ice core records inform us about past climates?

They can be analyzed for trapped gases, stable isotope ratios, and pollen to infer past climate conditions up to 800,000 years ago.

What do tree rings indicate about past climates?

The thickness of tree rings can indicate fluctuations in temperature and precipitation.

What is the significance of oxygen isotope ratios in climate studies?

They provide temperature data from past climates.

What major factors can affect the climate system?

Changes in greenhouse gas concentration, solar output, distribution of continents, and Earth's orbit.

What is the relationship between sunspots and climate?

The 11-year sunspot cycle can relate to weather patterns, such as warmer winters.

How do aerosols affect Earth's climate?

They reduce incoming radiation and can have a net cooling effect on Earth's surface.

What was the impact of the K-T boundary event?

It caused a significant reduction in sunlight, stopping photosynthesis and disrupting the food chain.

What does the Milankovitch Theory explain?

It explains how variations in Earth's orbit affect climate over time.

How have human activities intensified the greenhouse effect?

By burning fossil fuels, which increases greenhouse gas concentrations in the atmosphere.

What would Earth's average temperature be without the greenhouse effect?

Around 18 degrees Celsius.

Obliquity

tilt of the earth

Eccentricity

how circular the rotation of the Earth is

Precession

When the seasons occur with sun angle

positive loop example

ice form → cold

negative loop example

increase temp → less ice

what happens to the seasons when obliquity is higher

more seasonal change

what happens to the seasons when obliquity is lower

less seasonal change

more circular eccentricity

ice forming, less variation in temp

less circular eccentricity

less ice forming, more variation in temp