Geology Exam 3 - Earth Resources and Climate

Earth Resources & Energy Sources

Earth's Energy Sources

• Radiant Energy: From the Sun.

• Geothermal Energy: From Earth's internal heat.

• Gravitational Energy: Potential energy related to Earth's processes.

• Fuel Earth Processes:

  • Water Cycle

  • Plate Tectonics

  • Rock Cycle

  • Ocean Lithosphere Circulation

  • Biological Processes

Types of Energy

• Electrical

• Chemical

• Thermal

• Kinetic

• Potential

• Nuclear

• Solar

Global Energy Use

• Increasing need for energy in the past 150 years.

• Shift from wood to coal, oil, gas, wind, solar, and hydroelectric energy.

• Population growth and increased energy use are correlated.

Population Statistics & Energy Consumption

• Global Population: 8,200,000,000. Population growth leads to more demand.

• USA: 5% of world population consumes 20% of petroleum.

• China: 18% of world population consumes 15% of petroleum.

  • Overall US energy consumption is higher.

  • Per capita, US energy consumption is less per capita consumption.

• India: 1.4 billion people consume 5% of petroleum with low per capita use.

Oil and Gas Formation

• Form when source rock is buried and heat converts organic material to oil or gas.

• Temperature ranges:

  • Below 60^\,\,\text{C}: No oil formation.

  • 60^\text{o}C to 120^\text{o}C: Oil forms.

  • 120^\text{o}C to 200^\text{o}C: Natural gas forms.

  • Above 200^\text{o}C: Graphite forms.

• Oil gets trapped underground.

• Oil rises through rock due to low density, similar to water.

• If it reaches the surface, it's lost.

• Sometimes it hits a barrier and becomes trapped in reservoir rock.

  • Low permeability example: Shale.

• Oil is stored in reservoir rock.

  • High porosity. Low permeability example: Sandstone.

• Geoscientists identify oil traps and windows, and companies recover oil and gas by drilling.

Key Components of Oil Traps

• Reservoir rock (e.g., sandstone).

• Source rock (organic-rich shale).

• Petroleum.

Petroleum Production and Use

• World reserves: Middle East 63.4%; US 3.4%.

• Historically, US consumption has been greater than US production.

• In 2010, US imported 50% of its oil.

• In 2015, US imported only 25% due to fracking.

• US imports:

  • 18% from the Persian Gulf (Iran, Saudi Arabia, UAE).

  • 41% from the Western Hemisphere (Canada, Mexico, Venezuela).

• US produces 15% of global petroleum, similar to Saudi Arabia, but has 4% of global reserves.

• US has 4% of global population but consumes 22% of global petroleum.

• Petroleum use:

  • Transportation: 70%

  • Industry: 24%

• Giant oil fields produce 60% of world oil.

• Discoveries peaked 50-60 years ago and have mostly declined since.

Problems with Coal Combustion

• Acid Rain: Sulfur emissions combine with water to make sulfuric acid (H2SO4).

• Adversely impacts plants and animals.

• Erodes and weathers structures.

• Mercury depositions: Toxic mercury emissions contaminate land and water.

• Greenhouse gas emissions: 16% of US energy CO2 emission from coal burning.

• Mining Impacts:

  • Subsurface mines are prone to collapse.

  • Surface mining can fill streams and springs with waste race, degrading water quality.

  • Acid Mining: Mine drainage leads to metal contamination.

• Distribution of Coal Resource Reserves:

  • Reserves: Coal depositions that can be mined for profit.

  • Profitability depends on technology and price.

  • US has large reserves (26% of the world), but quality varies.

Petroleum and Natural Gas

• Hydrocarbon molecules.

  • Liquid forms: gasoline, motor oil, grilled oil.

  • Gas forms: natural gas (methane, ethane, propane, butane).

• Pumped from the ground.

Formation Process

• Form from marine deposits of plankton.

• Plankton mixes with sediment to form organic-rich mud, which is buried and compacted to form source rock.

Peak Oil

• Date at which global oil production will reach its maximum, following which oil production will decline.

• Determined by:

  • Oil reserves

  • Demand

  • Projected future demand

Glaciers and Ice Ages

Glacier Movement

• Move due to their weight and gravity, forming "rivers of ice".

Glacier Formation

• Snow accumulation in cold climates where winter snow doesn't melt away.

• Over time, layers build up, snow compacts, and pressure causes recrystallization.

Formation Locations

• Where snow persists year-round.

• High latitude (poles), e.g., Greenland, Antarctica.

• High elevation mountains, e.g., Andes, Alaska, New Zealand, Himalayas, Switzerland.

Types of Glaciers

• Continental Ice Sheets: Thick sheets of ice kilometers thick, covering large areas (>1,000 kilometers squared).

  • Movement not greatly impacted by thermal gravity.

  • Examples: Greenland, Antarctica.

• Alpine (Mountain) Glaciers: Movement controlled by topography.

  • Examples: Alaska, Andes, Himalayas.

Glaciers as Landscape Changers

• Weathering, erosion, and deposition pick up and move large volumes of rock.

• Rip rock off its outcrops.

• Rock carried in/on glaciers.

• As glaciers melt, they deposit sediment.

Consequences of Glacial Activity

• Carved out slash sharpened mountains topography.

• V-shaped valleys become U-shaped valleys.

• Mountains and peaks are sharpened.

• Example: Yosemite Valley.

• Melt water carves, polishes, and inscribes rock over which ice flows.

  • Smooth polished surfaces & linear grooves indicate ice flow direction.

Glacial Features

• Moraines: Ridges of till deposited at the edge of a glacier.

• Kettles: Circular depressions formed when ice blocks are buried and later melt.

• Drumlines: Elongated ridges of glacial till shaped by the flow of the glacier, indicating ice flow direction.

• Eskers: Ridges left by under-ice rivers.

Ice Ages

• Periods when climate is significantly colder, and continental glaciers advance and retreat.

• Glaciation (Advance):

  • Cooler climate, 7-22^\text{o}F colder.

  • Ice sheets cover continents, and sea level is lower.

• Interglacial:

  • Warmer climates (few degrees warmer than today).

  • Less ice cover with higher sea levels.

Pleistocene Ice Age

• Most recent, began 2.6 million years ago.

• Wisconsin glaciation: most recent ice advance.

  • Glaciers at max size 18,000 years ago, retreating 11,000 years ago.

  • Still technically within an ice age.

Causes of Ice Ages

• Ingredients: snow and cooler climates.

• Factors:

  • Position of Continents: Continents near poles are colder.

  • Oceanic Currents: Controlled by the distribution of continents, impacting climate and snowfall.

    • Europe is 8-17^\text{o}F colder without the Gulf Stream.

    • Separation of Atlantic from South America and Australia influences circulation.

  • Lower CO2 Concentrations: In the atmosphere. Higher CO2 leads to increased Earth temperatures and lower favoring ice age.

  • Milankovitch Cycles: Changes in Earth's orbit, tilt, and spin affect solar radiation distribution.

Global Climate Change

• Earth controls on climate.

Climate Definition

• Average weather condition in an area over time.

• Climate ≠ Weather; Climate ≠ One event

• Climate is a determinant of climate, not equal to temperature alone.

Climate Change Impacts

• Global sea level changes.

• Distribution of climate belts and growing zones shifts.

• Global weather patterns (rainfall, hot and cold streams) altered.

• Hurricane intensity changes.

• Global ocean pH changes.

• Earth's climate is dynamic and always changing.

Understanding Climate Controls & Temperature

• Earth's energy budget is crucial.

• Balances incoming and outgoing energy (radiation).

Radiation Energy

• Electromagnetic waves emitted or reflected by objects, classified based on wavelength.

• Sun emits different kinds of radiation/energy -- light, electromagnetic radiation.

Incoming Radiation

• Solar energy (sunlight).

• Earth primarily receives short wavelength radiation (visible and ultraviolet).

Outgoing Radiation

• Heat that Earth radiates off to space.

• Warmed objects give off heat in the form of infrared radiation (large wavelength).

Factors Affecting Incoming and Outgoing Radiation

• Greenhouse Effect: Increases outgoing radiation by preventing heat from escaping.

How Greenhouse Effect Works

• Incoming radiation (solar energy) heats Earth's surface and atmosphere.

• Earth's surface and atmosphere radiate infrared radiation.

• Greenhouse gases in the atmosphere trap outgoing infrared radiation and prevent heat from escaping to space.

Major Greenhouse Gases

• Carbon dioxide (CO_2)

• Methane (CH_4)

• Sulfuric dioxide (SO_2)

• Water vapor (H_2O)

• Ozone (O_3)

• CFCs (Chlorofluorocarbons)

• Greenhouse effect is a natural process. Without naturally occuring gases, Earth would be 60^\text{o}F colder, and water would be frozen.

Changes in Solar Energy Reflection

• Weather reflects sunlight.

• Dust in the atmosphere.

• Tiny particles, solids or liquids.

• Clouds & reflective ground (snow or ice).

Changes in Solar Output

• Sun brightens and dims in an 11-year cycle.

• Climate and solar output minimums compared to other controls on climate.

Predictable Changes in Earths Orbit and Rotation

• Change in orbit of Earth around the Sun.

• Change in tilt of Earth rotation.

• Change in wobbles (Milankovitch Cycles).

Other Factors Controlling Climate

• Atmosphere and ocean circulation transfer heat around the planet, strongly influencing major climate zones.

• Position of continents affected by central position plate tectonic.

• Volcanic emissions can cause warming by adding greenhouse gases and cooling by emitting ash. Volcanic emit gas greenhouse gas cause warming, volcanic emit ash cause cooling.

• Chemical weathering uses carbonic acid in the formation of limestone and other carbon-rich rocks and lock away cO_2. Example, coal, oil, and natural gas.

Understanding Climate Change

• Paleoclimatology: Study of past climates.

• Addresses:

  1. What processes induce climate change.

  2. How chronic is climate change.

  3. How much do these processes contribute to climate change.

Studying Past Climates

• Direct Measures: Measure temperature, precipitation, CO_2.

• Proxy Measures: Indirect data that provide climate information.

Examples of Proxy Data

• Tree rings (0-1100 years).

• Ice cores (0-800,000 years).

• Geologic records (millions of years): rock types.

• Fossils.

Learning from Studying Climate

• Global temperature are rising, 10 warmest years from 2010 onward.

• 2024- warmest year.

• Temperatures in the last 100 years have increased by 1.6°F.

• Global Sea level is rising, having risen 8 inches since 1900's, affects 40% of US population near sea level.

Causes

• Greenland plus authentic ice sheets melted water explosion due to increase in temperature.

• NASA estimates 50,000 glaciers have melted since January.

• CO_2 is rising. Varies naturally (180-300 ppm) as seen in glacier ice bubbles plus direct measurement. Concentrations now highest in millions of years.

• 2025 = 427 ppm CO_2.

• 15 million years ago: Earth was 5-10°F warmer, sea level 75-120 feet higher, and Greenland was ice-free.

• High CO_2 concentration from fossil fuel consumption.

• CO_2 rose exponentially following the industrial revolution.

• Pre-industrial CO_2 was 280 ppm.

• Human release of CO_2 is 100 times more than volcanoes.

• Volcanoes release some amount of CO_2, global but also emit ash as the state of Florida, Michigan, and Iowa.

• CO_2 plus temperature linked in ice core data.

Natural Causes of Climate Change

• Warm ocean circulation, volcanic circular, plus dust gas, change in earth orbit, tilt and wobbles (Milankovitch cycles).

• Natural causes can't explain temperature trends.

• Can only be explained by Greenland gas emission.

• Change in CO_2 cycle linked to change that amplified cooling plus warming.

• Earth system science example gas distribution of release from oceans amplifies cooling plus warming trends.