THECARBONCYCLEANDGLOBALWARMINGTeacherWeb：teacherweb碳循环和全球变暖课件

1、THE CARBON CYCLE AND GLOBAL WARMING1第1页，共17页。CARBON4TH most abundant element on EarthEssential for life- all organic (living) compounds are composed of carbonFound in various forms:Carbon dioxide (gas)Limestone (solid)WoodPlasticDiamondsGraphiteFossil fuels2第2页，共17页。CARBON CYCLEMovement of carbon be

2、tween the atmosphere, oceans, biosphere, and geosphereDivided into two components:Geological carbon cycleBiological carbon cycle3第3页，共17页。GEOLOGICAL CARBON CYCLECarbonic acid combines with minerals on the earths surface forming carbonates (weathering)Carbonates erode from the surface into the ocean

3、and settle on the ocean floorSinks into the earth, heats up, and eventually rises up as carbon dioxide into the atmosphere* OCCURS OVER MILLIONS OF YEARS4第4页，共17页。GEOLOGICAL CARBON CYCLECarbon dioxide diffuses into the ocean forming bicarbonates or calcium carbonate (used to make shells and other bo

4、dy parts by organisms such as coral and brachiopod shells)These organisms die and their shells and body parts become carbonate-rich depositsAfter a long period of time, these deposits become sedimentary rocks, coal, or oil5第5页，共17页。BIOLOGICAL CARBON CYCLEThe movement of carbon through the processes

5、of photosynthesis and cellular respirationAlso, the consumption of living matter by other organismsThe amount of carbon cycled through annually is a 1,000 times greater than the geological carbon cycle component6第6页，共17页。PHOTOSYNTHESISAutotrophs take in carbon dioxide, water, and sunlight to produce

6、 sugars and oxygenChemical Formula:6CO2 + 6H2O + light energy C6H12O6 + 6 O27第7页，共17页。CELLULAR RESPIRATIONCarbon dioxide is released back into the atmosphere by breaking down sugar during cellular respirationChemical Formula:C6H12O6 + 6O2 6CO2 + 6H2O + energy8第8页，共17页。RELEASE OF CARBON DIOXIDECO2 is

7、 also released into the atmosphere by:Decaying dead matterForest firesVolcanoesBurning of fossil fuels (coal, oil, gas)9第9页，共17页。10第10页，共17页。HUMAN IMPACTSince the onset of the industrial revolution, burning of fossil fuels and deforestation have lead to increase of atmospheric CO2There is strong evi

8、dence that supports the idea that these activities increase the atmospheres ability to hold in heat (greenhouse effect) and is resulting in a climate change (global warming)11第11页，共17页。GREENHOUSE EFFECTGreenhouse effect: process by which carbon dioxide and other gases in the atmosphere absorb infrar

9、ed radiation from the sun, forming a “heat blanket” around the EarthSome sunlight is reflected and other is trapped as heat to warm the EarthEnhanced greenhouse effect: caused from an increase of carbon dioxide, methane, and nitrous oxides from human activities into the air which traps more heat and

10、 raises the temperatures of the Earths surface12第12页，共17页。CLIMATE CHANGEGlobal Warming: an average increase in the Earths temperature, which in turn causes changes in climate. A warmer Earth may lead to changes inrainfall patternsA rise in sea levelA wide range of impacts on plants, wildlife, and hu

11、mansWhen most scientists talk about the issue of climate change, their concern is about global warming caused by human activities. 13第13页，共17页。GLOBAL WARMING DEBATEPOSITION 1Human pollution is the causeCarbon dioxide released into the atmosphere has increased by 30% in the last 200 yearsOver the las

12、t 100 years, temperatures have increased slowly due to an increase in greenhouse gases (CFCs, nitrous oxides, methane, and carbon dioxide)POSITION 2Natural patterns and fluctuationsNothing to do with human activitiesCarbon dioxide usage is hard to measure (ex. plant absorption)Temperatures have incr

13、eased and decreased in the past14第14页，共17页。15第15页，共17页。READ AND RESPONDEven with a dramatic cut in global greenhouse emmisions, most scientists predict a temperature rice of about 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 affec