THE CARBON CYCLE

What Is Carbon? An element The basis of life on earth Found in rocks, oceans, atmosphere

CARBON An element 4TH most abundant element on Earth The basis of life on earth Essential for life- all organic (living) compounds are composed of carbon Found in lots of places: Rocks, oceans, atmosphere Found in various forms: Carbon dioxide (gas) Limestone (solid) Wood Plastic Diamonds Graphite Fossil fuels

Organic Carbon Hydrocarbons: CH4 Carbohydrate: CH2O

Inorganic carbon Carbon Dioxide: CO2 Calcium Carbonate: CaCO3 Mandale Limestone Quarry

Carbon reservoirs Parts of the Earth system where carbon is stored is called carbon reservoirs

Carbon reservoirs The atmosphere. The biosphere (include fresh water systems and non-living organic material, such as soil carbon). The oceans ( including dissolved inorganic carbon and living and non-living marine biota). The lithosphere (sediments, Earth core including fossil fuels).

Carbon Cycle The same carbon atoms are used repeatedly on earth. They cycle between the earth and the atmosphere.

CARBON CYCLE Movement of carbon between the atmosphere, oceans, biosphere, and geosphere Divided into two components: Geological carbon cycle Biological carbon cycle

GEOLOGICAL CARBON CYCLE Carbonic acid combines with minerals on the earth’s surface forming carbonates (weathering) Carbonates erode from the surface into the ocean and settle on the ocean floor Sinks into the earth, heats up, and eventually rises up as carbon dioxide into the atmosphere * OCCURS OVER MILLIONS OF YEARS

GEOLOGICAL CARBON CYCLE Carbon dioxide diffuses into the ocean forming bicarbonates or calcium carbonate (used to make shells and other body parts by organisms such as coral and brachiopod shells) These organisms die and their shells and body parts become carbonate-rich deposits After a long period of time, these deposits become sedimentary rocks, coal, or oil

Carbon in Oceans Additional carbon is stored in the ocean. Many animals pull carbon from water to use in shells, etc. Animals die and carbon substances are deposited at the bottom of the ocean. Oceans contain earth’s largest store of carbon.

BIOLOGICAL CARBON CYCLE The movement of carbon through the processes of photosynthesis and cellular respiration Also, the consumption of living matter by other organisms The amount of carbon cycled through annually is a 1,000 times greater than the geological carbon cycle component

Carbon is taken from the atmosphere in several ways Photosynthesis. The oceans when the seawater becomes cooler, more CO2 dissolve and become carbonic acid. In the upper ocean areas organisms convert reduced carbon to tissues, or carbonates.

Plants Use Carbon Dioxide Plants pull carbon dioxide from the atmosphere and use it to make food = photosynthesis. The carbon becomes part of the plant (stored food).

6CO2 + 6H2O + light energy → C6H12O6 + 6 O2 PHOTOSYNTHESIS Autotrophs take in carbon dioxide, water, and sunlight to produce sugars and oxygen Chemical Formula: 6CO2 + 6H2O + light energy → C6H12O6 + 6 O2

Animals Eat Plants When organisms eat plants, they take in the carbon and some of it becomes part of their own bodies.

CELLULAR RESPIRATION C6H12O6 + 6O2 → 6CO2 + 6H2O + energy Carbon dioxide is released back into the atmosphere by breaking down sugar during cellular respiration Chemical Formula: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

Plants and Animal Die When plants and animals die, most of their bodies are decomposed and carbon atoms are returned to the atmosphere. Some are not decomposed fully and end up in deposits underground (oil, coal, etc.).

Carbon is released into the atmosphere in several ways Respiration by plants and animals. Decay of animal and plant matter. Combustion of organic material Production of cement. The ocean releases CO2 into the atmosphere. Volcanic eruptions and metamorphism Through the respiration performed by plants and animals. Through the decay of animal and plant matter. Through combustion of organic material which oxidizes the carbon it contains. Production of cement. At the surface of the oceans where the water becomes warmer, dissolved carbon dioxide is released back into the atmosphere. Volcanic eruptions and metamorphism release gases into the atmosphere.

RELEASE OF CARBON DIOXIDE CO2 is also released into the atmosphere by: Burning of fossil fuels (coal, oil, gas) Forest fires Volcanoes Decaying dead things

Carbon Slowly Returns to Atmosphere Carbon in rocks and underground deposits is released very slowly into the atmosphere. This process takes many years.

Human Impact Fossil fuels release carbon stores very slowly Burning anything releases more carbon into atmosphere — especially fossil fuels Increased carbon dioxide in atmosphere increases global warming Fewer plants mean less CO2 removed from atmosphere

HUMAN IMPACT Since the onset of the industrial revolution, burning of fossil fuels and deforestation have lead to increase of atmospheric CO2 There is strong evidence that supports the idea that these activities increase the atmosphere’s ability to hold in heat (greenhouse effect) and is resulting in a climate change (global warming)

GREENHOUSE EFFECT Greenhouse effect: process by which carbon dioxide and other gases in the atmosphere absorb infrared radiation from the sun, forming a “heat blanket” around the Earth Some sunlight is reflected and other is trapped as heat to warm the Earth Enhanced greenhouse effect: caused from an increase of carbon dioxide, methane, and nitrous oxides from human activities into the air which traps more heat and raises the temperatures of the Earth’s surface

Variations of the Earth’s surface temperature for the past 1,000 years SPM 1b

Variations of the Earth’s surface temperature for the past 140 years SPM 1a

Fossil Fuels

Fossil Fuels In the past, fossil fuels were a dead end for the carbon cycle. Petroleum and Coal are the main fossil fuels Humans are now burning fossil fuels at alarmingly high rates, releasing excess carbon that used to be in the ground into the atmosphere.

Deforestation Deforestation increases the amount of carbon dioxide in the atmosphere: • Removing plants decreases the rate of photosynthesis • The removed trees are often burnt • Waste plant material can be left to rot • The cleared land is often used to farm animals like cattle, increasing the rate of respiration • Increased industrial activity increases the use of fossil fuels

Global Warming Global Warming: an average increase in the Earth's temperature, which in turn causes changes in climate. A warmer Earth will lead to changes in rainfall patterns A rise in sea level A wide range of impacts on plants, wildlife, and humans When scientists talk about the issue of climate change, their concern is about global warming caused by human activities. (called anthropogenic)

GLOBAL WARMING DEBATE POSITION 1 99% of scientists Human pollution is the cause (anthropogenic causes) Carbon dioxide levels in the atmosphere has increased by 30% in the last 200 years Over the last 100 years, temperatures have increased slowly due to an increase in greenhouse gases (CFC’s, nitrous oxides, methane, and carbon dioxide) POSITION 2 Half of people who aren’t scientists Natural patterns and fluctuations (Milankovitch Cycles) Nothing to do with human activities Carbon dioxide usage is hard to measure (ex. plant absorption) Temperatures have increased and decreased in the past

What is your carbon footprint? A carbon footprint is the amount of carbon emitted into the atmosphere by your personal, day-to-day activities. Examples: Type of car you drive, how far you drive your car, how much electricity you use (electricity primarily comes from burning coal), where the food you buy is grown and airplane flights. Why do we care?? GLOBAL WARMING

Things you can do to reduce your carbon footprint Promote plant life, especially trees Buy a fuel efficient vehicle Purchase locally grown food Reduce electricity use Reduce how far/much you drive Take less airplane trips Reduce, Reuse, Recycle!

What We Need to Do Burn less, especially fossil fuels Promote plant life, especially trees

READ AND RESPOND Even with a dramatic cut in global greenhouse emmisions, scientists predict a temperature rise of at least 2C (4.4F) over the next century. Think about your daily routines, how would your life be different if it were two degrees warmer? Think about the foods and products that you consume throughout the year, how would a 2 degree increase affect their availability? Think about the community in which you live, how would a 2 degree increase in the average global temperatures affect jobs, businesses, and industry in your community?