Presentation on theme: "Created by Laura Marschke, Southwest Early College"— Presentation transcript:
1 Created by Laura Marschke, Southwest Early College Black CarbonCreated by Laura Marschke, Southwest Early College
2 Different Forms of Elements Elements are always pure, but do not always look the sameExample: carbondiamondgraphite
3 Forms of carbon, cont.BLACK CARBONcarbon nanotubes
4 What is carbon? An element (number 6) 6 protonsSixth-most abundant element in the universeTypical formsSootGraphiteDiamondFullerenesEssential for lifeHas 15 isotopes (varieties)Approximately ten million compounds contain carbonCommon compoundsCarbon dioxide - CO2Methane - CH4Vinegar - CH3COOH
5 What is black carbon? A product from incomplete combustion (burning) SootParticles thousands of times smaller than the width of a human hairCan travel long distances on air currentsFalls out of the air in 7-10 days due to rain, etc“Short-lived climate forcing”Causes warming
6 Where does black carbon come from? Top producersEast AsiaSouth AmericaWestern AfricaTop sector (area/branch)Biomass burningResidential – biofuelTransport - road
7 Where is black carbon?A) Global distribution of black carbon emissions (tons/year)B) Estimated global radiative forcing due to black carbon (W/m2)
8 Why should we care about black carbon? Contributes to climate change (warming) in two waysAbsorbing sunlight and heating air around itFalling on snow or ice, decreasing reflectivity, and increasing meltingBC absorbs heat a million times more than CO2Contributes to regional heatingDisrupts rainfall patternsReducing black carbon output could slow warming by 0.1 – 0.2 oCENVIRONMENT
9 Why should we care about black carbon? Reductions would prevent 2.4 million premature deaths worldwideParticulate emissions from diesel exhaust (major source of BC) are linked to lung and heart disease, as well as cancerHEALTH
10 Feedback Loops Positive Feedback Negative Feedback Reaction enhances original stimulus“Runaway effect”Promotes instability and changeNegative FeedbackReaction negates original stimulusWhether too high, or too low, negative feedback brings it back to a set pointPromotes stability and constancy
11 Albedo and Arctic Climate Which snow will melt faster? Why?What is going to happen in this situation?
13 Albedo Low albedo High albedo Albedo: the fraction of incoming radiation (light) that is reflected by a surfaceScale from 0 – 1 (0% - 100%)Low albedoHigh albedoReflects sunlight wellAbsorbs sunlight wellIceForestsSnowOceansSandSoil
14 Arctic Sea Ice What happens to incoming sunlight in each case? What does this mean in terms of the snow-albedo feedback loop?
15 Snow-Albedo Feedback Loop these loops show the same type of change (positive feedback) in two different ways
16 Black Carbon in the Arctic Black carbon falls on snow and ice Albedo decreases More sunlight is absorbed Melting increasesIs this a positive or negative feedback loop?
18 What can be done?Replace traditional cook and heat stoves in developing countries with clean-burning biomass stoves or alternate energy sourcesInstall filters on diesel vehiclesCreate tighter restrictions on diesel vehiclesEliminate open field burning of agricultural waste
19 How well do changes work? Rate of decline = – = .33 g BC/kg diesel2003 – per yearRegulations were implemented in California to reduce emissionsThe black dots are the average black carbon emission over time
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