01.06 Global Climate Change

Which of the following factors in the geosphere affect(s) a region's climate?

A. Altitude B. Locations of mountains C. Volcanic eruptions D. All of the above Answer: D. All of the above (No one cause is responsible for all the changes in climate.)

Energy Budget

Accounts for the specific ways that heat moves into and out of the atmosphere

Goldilocks Principle

Although the term is not a proper scientific principle, scientists often use it to describe planets that have the ideal characteristics necessary to support life.

Mean

Another word for "average". To calculate the mean value of a data set, add all the values in the set and divide by the number of data points.

Ice age

Approximately 11,000 years ago, a large ice sheet covered large areas of Earth's landmasses.

Habitat loss and Extinctions: Natural, human-induced, or both?

Both: Human activities, such as deforestation, can cause habitat losses and extinctions. However, the effects of natural global climate change can also cause species to become extinct, such as the dinosaurs.

Ocean temperatures increased from 1850 to present day: Natural, human-induced, or both?

Both: Natural cycles in Earth's oceans can cause changes in ocean temperatures. Recent evidence suggests that the enhanced greenhouse effect is causing unnatural increases in ocean temperatures worldwide.

Ice Cores : Natural, human-induced, or both?

Both: Scientists extract ice cores from ice fields, such as those found in Antarctica, to get information about past climates. Trapped atmospheric gases in the ice, particles of dust, and even small organisms can be used to create a record of long-term global climate change. Estimates based on ice-core samples of the global temperature record of the past 1,000 years appear to show a rapid increase in temperatures starting around 1900, presumably from the impact of industrial activities.

Sea Level Rise: Natural, human-induced, or both?

Both: Sea levels can change slowly over time as a result of natural changes in climate. However, recent evidence also suggests an increase in sea level caused by human activities and the melting of polar ice from unnatural warming.

Coral Bleaching: Natural, human-induced, or both?

Both: Temperature changes are the primary cause of coral bleaching. Increased global temperatures caused by human activities during the last 150-plus years may be causing a dramatic increase in the death of coral communities.

Burning fossil fuels

Burning fossil fuels releases greenhouse gases such as carbon dioxide, methane, and nitrous oxides into the atmosphere.

Heat Transfer: Types

Conduction Radiation Convection

Global Climate

Each of Earth's geophysical components—the hydrosphere, geosphere, biosphere, and cryosphere—exert their influence on global climate.

Global Climate Change 2

Events such as colder ocean currents, increased cloud cover, volcanic eruptions, and reduced solar radiation all result in less heat trapped on Earth. As these events happen, Earth's temperature grows cooler; if too many of these events happen, Earth's climate may become significantly cooler. Events such as burning fossil fuels, reducing ozone in the atmosphere, melting ice caps, and deforestation all result in more heat trapped on Earth. As these events happen, Earth's temperature grows warmer; if too many of these events happen, Earth's climate may become significantly warmer.

The eruption of Iceland's Eyjafjallajökull Volcano in 2010 Natural: Natural, human-induced, or both?

Gases released from volcanic activities can increase the amount of clouds in the sky, causing more sunlight to be reflected rather than absorbed by Earth's surface. Most volcanic eruptions cause short-term changes in climate.

How would global temperatures on Earth change if the greenhouse effect were enhanced?

Global temperatures on Earth would increase.

How would global temperatures on Earth change if there were no greenhouse effect?

Global temperatures would lower with the greenhouse effect.

Geophysical

Having to do with the physical characteristics of Earth

Earth's Energy Budget

Incoming solar energy, or energy from the sun, accounts for 100% of Earth's energy. Of this incoming energy, Earth's atmosphere reflects 6%, clouds reflect 20%, and Earth's surface reflects 4%. Earth's atmosphere absorbs an additional 16% of incoming solar energy, and clouds absorb another 3%. Land and oceans absorb the remaining 51% of incoming solar energy. This energy is then gradually radiated back toward space. Conduction and rising air carries 7% of this energy away from Earth's surface, and latent heat in water vapor carries another 23% from Earth's surface to clouds and the atmosphere. Earth's atmosphere absorbs 15% of the energy radiated from Earth's surface; another 6% of this energy radiates directly back to space from Earth.

Interspersed

Inserted at intervals

Climate Interactions: Geosphere

Interactions—The Earth is constantly changing. No one cause is responsible for all the changes in climate. Details—Elevation is the vertical distance of an object above Earth's surface. Higher elevations, such as tops of mountains, can have cooler climates. Volcanic eruptions from some mountains can also release gases that cool climates for a short period of time. Changes in Earth's vegetation and changes in land surfaces over time can also change climates. The presence of mountains and other landforms can also alter air patterns, changing the climate. Keep in Mind—Factors other than incoming solar radiation contribute to climate. Even though solar energy is highest at the equator, it can snow in places near the equator, such as atop high mountains. Example—Although Mt. Kilimanjaro is located in a tropical climate zone in Africa, there is still snow on the mountaintop because of its elevation.

Climate Interactions: Biosphere

Interactions—The biosphere includes all living things on Earth. The activities of living things can alter climate. Human beings have a significant impact on climate. Details—Excessive farming can cause areas to become deserts. The removal of trees, also known as deforestation can cause shifts in local climates, because there are no trees to protect and support animal populations. Human beings can restructure land areas, causing shifts in temperature and precipitation patterns. Human beings also influence the amount of greenhouse gases within the atmosphere, potentially altering climate. Animals and plants can suffer as a result of shifts in climate. Keep in Mind—Even small shifts in temperature can cause plants and animals to die suddenly. At the same time, other species of plants and animals may thrive and expand in population size. Example—Decreases in the amount of ice on Earth because of changes in climate have caused some animals, such as the polar bear, to lose their habitats. Some of these animals are at risk of extinction.

Climate Interactions: Cryosphere

Interactions—The cryosphere consists of all the ice on Earth's surface. Locations for ice include the tops of mountains, in glaciers, icebergs, and at Earth's poles. Details—Ice and snow can cause a shift in Earth's energy budget. The bright, white surface reflects some of the sunlight normally absorbed at Earth's surface. Keep in Mind—As ice and snow melt, the resulting runoff can cause sea levels to rise. This can cause problems such as flooding for areas near the coast. In addition, a larger volume of water requires more energy to warm. This can further affect the climate of the impacted region. Example—Solar energy is either absorbed or reflected by ice. Some solar energy is absorbed by ice, causing melting. Some energy is reflected by ice because of the bright, white surface.

Climate Interactions: Exosphere

Interactions—The exosphere is all of the parts of space outside Earth's atmosphere. The sun is a part of the exosphere and can affect climate. Changes in Earth's orbit can also change climate. Details—The intensity of solar energy from the sun depends on the angle the energy hits the Earth. Due to Earth's curvature, locations farther from the equatorial regions receive solar energy at a shallower (smaller) angle. The shallower the angle of incoming solar energy, the less radiation hits the atmosphere and the cooler the climate will be. Earth is slightly flattened at the poles and bulges at the equator, causing Earth's axis to wobble slightly. This wobble changes climate on a timescale of tens of thousands of years. Keep in Mind—Factors other than incoming solar radiation contribute to climate. Even though solar energy is highest at the equator, it can snow in places near the equator, such as atop high mountains. Example—If you were to shine a flashlight directly on the equatorial regions of a globe, you would see a small but focused pool of light. This area would heat up relatively quickly. If you were to shine another flashlight at a wider angle at the polar regions of the globe, you would see a wider, less focused pool of light. This area would not heat up as quickly or as much. In other words, the more spread out the energy, the less efficient the heat source. Therefore, the higher the latitude, the less efficiently solar radiation will heat Earth's surface.

Climate Interactions: Hydrosphere

Interactions—The hydrosphere is all the water on Earth, including oceans, lakes, rivers, streams, and groundwater. Water takes longer to heat up and cool down than land surfaces. Climates near water sources tend to be less variable because the heat held by the water evens out the shifting atmospheric temperature. Details—Circulation in the ocean creates warm and cold currents that affect the air temperature above the ocean. As the currents move, they heat or cool the air directly above the water, which in turn heats or cools the climates in areas near the water. Keep in Mind—Rises in global sea level can alter the temperature of ocean water, further changing climates. Example—The Gulf Stream current carries warm ocean water from near the equator toward Europe. Without the current, the climate of Europe would be cooler, although scientists debate how much cooler.

Global Climate: Misconception Alert

Many people use the terms climate change and global warming interchangeably. This is a mistake. Earth's climate is constantly changing, both in the short and long term. These changes result from natural processes as Earth's several spheres interact with one another. In contrast, when people speak of global warming, they are typically referring to changes in climate resulting from human activities, particularly the burning of fossil fuels such as coal, oil, and natural gas.

Ice Ages and Earth's Axial Tilt: Natural, human-induced, or both?

Natural: Changes in the tilt of Earth's axis can cause natural changes in climate as solar energy is redistributed. As a result, Earth periodically goes through cycles of warm and cold.

Enhanced greenhouse effect

Of the energy radiated from Earth's surface back toward space, 95 percent is reflected by the atmosphere back to Earth and 5 percent passes through the atmosphere into space.

No greenhouse effect

Only 10 percent of incoming solar energy is absorbed by Earth's surface and 90 percent is reflected back toward space. Of this reflected energy, 100 percent passes through Earth's atmosphere into space.

Global Climate Change 1

Over time, Earth cycles between periods of warm and cold. Scientists are not certain why these natural changes in global climate happen, but a number of factors beyond human control cause them. Today, scientists are concerned about an imbalance in Earth's energy budget as a result of human activities. These activities cause unnatural climate changes by disturbing Earth's energy budget. The changes are causing a rise in global temperatures. Even a small change in global temperatures could have dramatic, potentially devastating consequences because such a change affects all of Earth. *** (Changes in Earth's energy budget can shift climates from warm to cold, from cold to warm, and everything in between. ) (Even slight increases and decreases can be devastating to the different parts of Earth, including life.)

How does the hydrosphere influence climate?

Places near bodies of water have less climate variation.

How does the angle of incoming solar radiation from the exosphere affect the climate of an area?

Places that experience a wider angle are closer to the equator and have a warmer climate.

How does deforestation most likely affect the biosphere?

Plants and animals lose their habitats.

Calculating Mean Temperature

Slide 1: Below are the high temperatures in Climateville over a period of seven days: We are going to calculate the mean high temperature in Climateville. Day 1: 25℃ Day 2: 27℃ Day 3: 24℃ Day 4: 23℃ Day 5: 29℃ Day 6: 27℃ Day 7: 26℃ Slide 2-Mean: Let's first find the mean of the numbers. Remember, the mean is the average of the high temperatures recorded in Climateville during the time period in question—in this case, seven days. Slide 3-Mean: The first step is to add up the numbers. 25 + 27 + 24 + 23 + 29 + 27 + 26 = 181. Slide 4-Mean: The second step is to divide by the total number of measurements. In this case, this is the total number of days: 7. Slide 5-Mean: The answer is 181 ÷ 7 = 25.9. Slide 6-Mean: Climateville's mean temperature for the past 7 days is 25.9℃.

Earth's Greenhouse Effect

Solar radiation enters Earth's atmosphere and is reflected back toward space. Some of this radiation escapes into space, and some of this radiation is reflected back toward Earth. Over time, the heat reflected back toward Earth gradually warms the planet. Gases in the atmosphere—including water vapor, carbon dioxide, methane, nitrous oxide, and ozone—trap heat in the atmosphere. Changes in the composition of the atmosphere can cause changes in the amount of heat on Earth. Changes in the amount of heat on Earth can have significant consequences for Earth's climate. Earth's climate has changed many times throughout the planet's history. The greenhouse effect begins with solar radiation entering the atmosphere. Earth's atmosphere reflects approximately 26 percent of the sun's heat back into space before it can reach Earth's surface. The rest of the heat is trapped inside the atmosphere temporarily. Changes in the composition of the atmosphere can affect how much heat is reflected back into space or trapped in the atmosphere.

Heat Transfer

Solar radiation reaches Earth, warming its surface, and moves around the planet through heat transfer. The gases that make up Earth's atmosphere trap this heat near the surface and prevent the heat from being lost into space. This process keeps the planet warm.

Climatologist

Studies past weather records to determine patterns that may be helpful in predicting long-term future events. (They may study changes in ocean currents or shifts in global temperatures.) (They may also study global warming, ancient climate changes, and more.)

Equatorial Regions

The areas of Earth closet to the equator, or 0 degrees latitude.

Deforestation

The clearance of forests by logging and/or burning.

Elevation

The height above a fixed reference point.

Greenhouse Effect

The result of certain gases in Earth's atmosphere, such as carbon dioxide and methane, which cause the atmosphere to retain more heat than would otherwise be the case ( Life on Earth would not be possible without this)

Earth's primary source of energy

The sun

Climatology

The systematic study of climate.

Producing an energy budget

The three types of heat transfer work within Earth's atmosphere, geosphere, cryosphere, and hydrosphere. Together, the heat transfer within and among these geophysical realms produces an energy budget.

Conduction

The transfer of heat between two substances that are in direct contact with each other.

Convection

The transfer of heat in liquids or gasses. This transfer creates currents that move heat.

Radiation

The transfer of heat through electromagnetic waves.

Gases in the atmosphere that trap heat in the atmosphere

Water vapor, carbon dioxide, methane, nitrous oxide, and ozone

How does the cryosphere influence climate?

- Ice can reflect the the sun's rays, causing cooler temperatures - Ice can absorb incoming solar radiation, warming the climate - Ice can melt and run into bodies of water, increasing the amount of energy required to warm them

Analyzing Climate

- Weather systems change over time and space; therefore, climate changes accordingly. - To determine an area's climate, scientists record weather data such as temperature, rainfall, and cloud cover each day for many years. - The scientists then calculate the averages of these daily conditions; the result provides a snapshot of an area's climate.

Natural greenhouse effect

30 percent of incoming solar energy is reflected by Earth's atmosphere, 20 percent is reflected by clouds, and 50 percent is absorbed by Earth's surface and gradually radiated back toward space. Of this radiated energy, 80 percent is reflected by the atmosphere back to Earth and 20 percent passes through the atmosphere into space.

Ice sheet

A large sheet of ice that covers an extended area

Global warming

A rapid increase in overall global temperatures caused by human activities combined with natural changes in climate.