DOCSLIB.ORG

ATMS 321: Chapter 8: Past Climate Paleoclimate

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
ATMS 321: Chapter 8: Past Climate Paleoclimate ATMS 321: Chapter 8: Past Climate Paleoclimate. Stable Isotopes: Many atoms come with different numbers of neutrons, which gives them the same chemical properties, but different masses. These are called isotopes of the elements. Examples are Oxygen, which has three important stable isotopes O16, O17 and O18. Carbon has C12 and C13. Nitrogen also has stable isotopes N14 and N15. Hydrogen comes in H and D, where D is deuterium, which is hydrogen with an extra neutron, or heavy hydrogen. Oxygen, Carbon, Nitrogen and Hydrogen are important because they are important elements for molecules that move around in the climate system, either through physiochemical processes or through biological processes. Molecules with different isotopic elements within them are called isotopologues. Important molecules that can be isotopologues are water, molecular oxygen, carbon dioxide, and many biological compounds. Lets start simply with water, H2O. Water could contain two isotopes of H and three of O. The isotopic composition of water can be measured with a mass spectrometer. Suppose you drill a core into the ice in Greenland or Antarctica, or into a mountain glacier. The time that you sample will depend on the depth of the core and the rate at which ice is accumulated. Obviously you need to be in a place where the ice accumulate year upon year, and it is better if it does not melt during part of the year, as that would cause water to percolate from the top to the bottom and confuse the time signature of the isotope signature in the ice core. We would like to be able to relate depth in the core to time in the past. Why would the isotopic concentration of the ice in the core vary over time? The answer is mass fractionation. A molecule of, say, water vapor containing a heavy isotope of Oxygen or Hydrogen will have more mass than a molecule consisting of the (more common) lighter isotopes. In Brownian Motion the heavier isotopologues of water vapor will be moving a bit slower than the lighter ones. This makes it slightly more likely that the heavy molecules will condense into liquid water as the temperature decreases to induce condensation. It also makes it slightly less likely that heavy isotopologues of liquid water will evaporate, leaping from the liquid to the vapor form. This leads us to two hypotheses: First, the lighter isotopes are more likely to evaporate. Thus the water vapor in the atmosphere is likely to have a lighter isotopic concentration than the water in the ocean. As water is removed form the ocean and deposited on land in ice sheets, then the ocean should become enriched in the heavier isotopes, as these are more likely to be left behind when ocean water is evaporated. So rather than ice sheets, lets consider first the example of the isotopes in the sediment at the bottom of the ocean. This sediment is composed of many things, but much of it is organic matter or shells from organisms that lived in the ocean, died and their carcasses or shells sank to the bottom to form sediment. A big component of this bottom sediment is calcium carbonate (CaCO3), or limestone, the shells of tiny organisms that form the base of the food pyramid in the ocean. As you can see from the formula, CaCO3 contains a lot of oxygen – three molecules of oxygen, one of calcium and one of carbon. Below is a plot of the Oxygen-18 in deep sea sediment cores. It is an indicator of global volume of ice on land. Ocean Sediment Cores Because water with lighter O16 isotope of oxygen is more likely to be evaporated, when I sheets build up on land, the ocean becomes enriched in the heavier isotope O18 in and this is recorded in the shells and biomass of organisms in ocean sediment. The mixing ratio of O18 is measured as parts per thousand deviation from the value of Standard Mean Ocean Water (SMOW) 18O / 16O " 18O / 16O 18 ( )sample ( )SMOW ! O = # 1000 18O / 16O ( )SMOW http://earthobservatory.nasa.gov/Features/Paleoclimatology_SedimentCores/ Here’s a much longer record from ocean sediment cores from Lisiecki and Raymo, 2005 PaleoOceanography Ice Cores Isotopes in Ice Cores As water vapor moves from the subtropics, where most of it is evaporated, to colder latitudes to ice caps, the heavier isotopologues of water vapor condense more readily that the lighter isotopologues. Thus the water that falls on ice sheets is even lighter than the water that is evaporated from the ocean. As the temperature above the ice sheets varies with the local climate, the isotopic signature of the water will also change, such that when the climate is colder over and near the ice sheet, the water will be lighter, and vice versa. Ice cores have been drilled an analyzed over a wide range of locations, from ice cores over Greenland in which there are annual layers, but which go back only a few thousand years, to ice sheets over Antarctica that go back up to 800,000 years. Bubbles in Ice Cores Bubbles in ice cores contain atmospheric air from the time when the bubbles were sealed in the ice. This gives a record of the composition of air deep into the past. Dust and Chemicals in Ice Cores Volcanic dust, sea salt, black carbon, desert dust and other substances borne on the air are laid down on glaciers and become part of the record as snow accumulates on them. http://earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/ Luthi et al, Nature, 453, 379 Above shows a frequency spectrum of the variance of the 2.5Myr record below. Peaks at 23, 41 and 96 thousand years correspond to peaks in summer insolation from Earths orbital parameter variations. Temperature inferred from Deuterium, a smoothed temperature record from Vostok ice core, a marine O18 record indicating global ice volume and the carbon dioxide record from the Vostok core. Stable isotopes in ice cores and temperature. An example: You have a can of BBs (small spheres of metal) in a can on your bike. The can has a hole in it. Some of the BB’s are made of copper and some are made of stainless steel. Although the BBs are the same size, the stainless steel ones are slicker and denser and tend to fall out of the hole a little more easily than the copper BBs. The road is rough and the can gets shaken so that the steel and copper BBs are always well mixed up in the can. You fill the can with BBs that are half copper and half stainless steel, put the can on the back of your bike and start to ride toward Grandma’s house. The stainless steel BB’s are more likely to fall out as the copper ones. How does the proportion of steel to copper BBs change as you ride toward Grandma’s house. Let’s suppose that the number of BB’s lost per unit time depends on the number of BB’s still in the can. Then we could write that, dN dN s = ! p N c = ! p N dt s s dt c c Where Ns is the number of steel BBs and Nc is the number of copper ones. If we start out with Nso steel balls and Nco copper balls we can solve for the number of balls of each type as a function of time. Ns = Nso exp(! pst) Nc = Nco exp(! pct) Then the ratio of steel balls to copper balls is, S Nso = exp((pc ! ps )t) C Nco If the rate of loss of steel balls is greater than the loss rate of copper balls (ps > pt), then this ratio, S/C, will decrease with time. If you replace steel balls with heavy isotopes and copper balls with light isotopes and you replace time with temperature, then you have some idea why the ratio of heavy isotopes to light ones decreases as cooling causes preferential condensation of heavier isotopes, so that ice formed at colder temperatures is isotopically lighter than that formed at higher temperatures. Surface of Earth at time of last glacial maximum. Black area contours are ice sheet depth in meters. This diagram shows Temperature, non-sea-salt sulfate and non-sea-salt Calcium in 140,000-year record from Vostok Ice Core. Note that ice ages are dusty on Antarctica. This is consistent with land evidence for a drier, windier time then. .
Load more

Recommended publications
  • U.S. National Black Carbon and Methane Emissions a Report to the Arctic Council
    U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL AUGUST 2015 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL AUGUST 2015 TABLE OF CONTENTS EXECUTIVE SUMMARY. 1 ABOUT THIS REPORT. 1 SUMMARY OF CURRENT BLACK CARBON EMISSIONS AND FUTURE PROJECTIONS . 2 SUMMARY OF CURRENT METHANE EMISSIONS AND FUTURE PROJECTIONS. 4 SUMMARY OF NATIONAL MITIGATION ACTIONS BY POLLUTANT AND SECTOR . 6 BLACK CARBON . .6 METHANE . 11 HIGHLIGHTS OF BEST PRACTICES AND LESSONS LEARNED FOR KEY SECTORS . .16 TRANSPORT/MOBILE . 16 OPEN BIOMASS BURNING (INCLUDING WILDFIRES) . 16 RESIDENTIAL/DOMESTIC . .17 OIL & NATURAL GAS. .17 OTHER . 17 PROJECTS RELEVANT FOR THE ARCTIC. .18 ARCTIC AIR QUALITY IMPACT ASSESSMENT MODELING. 18 BLACK CARBON DEPOSITION ON U.S. SNOW PACK . .18 EMISSIONS AND TRANSPORT FROM AGRICULTURAL BURNING AND FOREST FIRES . .18 MEASUREMENT OF BLACK CARBON AND METHANE IN THE ARCTIC. .18 MEASUREMENT OF MARITIME BLACK CARBON EMISSIONS AND DIESEL FUEL ALTERNATIVES. .18 REDUCTION OF BLACK CARBON IN THE RUSSIAN ARCTIC. .19 VALDAY CLUSTER UPGRADE FOR BLACK CARBON REDUCTION IN THE REPUBLIC OF KARELIA, RUSSIAN FEDERATION. 19 AVIATION CLIMATE CHANGE RESEARCH INITIATIVE. .20 TRACKING SOURCES OF BLACK CARBON IN THE ARCTIC . 20 OTHER INFORMATION. .20 APPENDIX 1: U.S. BLACK CARBON EMISSIONS . .22 APPENDIX 2: U.S. METHANE EMISSIONS (MMT CO2E), 1990–2013 . 24 EXECUTIVE SUMMARY U.S. black carbon emissions are declining and additional reductions are expected, largely through strategies to reduce the emissions from mobile diesel engines that account for roughly 40 percent of the U.S. total. A number of fine particulate matter (PM2.5) control strategies have proven successful in reducing black carbon emissions from mobile sources.
    [Show full text]
  • Climate Effects of Black Carbon Aerosols in China and India Surabi Menon, Et Al
    Climate Effects of Black Carbon Aerosols in China and India Surabi Menon, et al. Science 297, 2250 (2002); DOI: 10.1126/science.1075159 The following resources related to this article are available online at www.sciencemag.org (this information is current as of October 3, 2008 ): Updated information and services, including high-resolution figures, can be found in the online version of this article at: http://www.sciencemag.org/cgi/content/full/297/5590/2250 Supporting Online Material can be found at: http://www.sciencemag.org/cgi/content/full/297/5590/2250/DC1 A list of selected additional articles on the Science Web sites related to this article can be found at: http://www.sciencemag.org/cgi/content/full/297/5590/2250#related-content This article cites 23 articles, 3 of which can be accessed for free: http://www.sciencemag.org/cgi/content/full/297/5590/2250#otherarticles on October 3, 2008 This article has been cited by 251 article(s) on the ISI Web of Science. This article has been cited by 8 articles hosted by HighWire Press; see: http://www.sciencemag.org/cgi/content/full/297/5590/2250#otherarticles This article appears in the following subject collections: Atmospheric Science http://www.sciencemag.org/cgi/collection/atmos www.sciencemag.org Information about obtaining reprints of this article or about obtaining permission to reproduce this article in whole or in part can be found at: http://www.sciencemag.org/about/permissions.dtl Downloaded from Science (print ISSN 0036-8075; online ISSN 1095-9203) is published weekly, except the last week in December, by the American Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005.
    [Show full text]
  • Aerosols, Their Direct and Indirect Effects
    5 Aerosols, their Direct and Indirect Effects Co-ordinating Lead Author J.E. Penner Lead Authors M. Andreae, H. Annegarn, L. Barrie, J. Feichter, D. Hegg, A. Jayaraman, R. Leaitch, D. Murphy, J. Nganga, G. Pitari Contributing Authors A. Ackerman, P. Adams, P. Austin, R. Boers, O. Boucher, M. Chin, C. Chuang, B. Collins, W. Cooke, P. DeMott, Y. Feng, H. Fischer, I. Fung, S. Ghan, P. Ginoux, S.-L. Gong, A. Guenther, M. Herzog, A. Higurashi, Y. Kaufman, A. Kettle, J. Kiehl, D. Koch, G. Lammel, C. Land, U. Lohmann, S. Madronich, E. Mancini, M. Mishchenko, T. Nakajima, P. Quinn, P. Rasch, D.L. Roberts, D. Savoie, S. Schwartz, J. Seinfeld, B. Soden, D. Tanré, K. Taylor, I. Tegen, X. Tie, G. Vali, R. Van Dingenen, M. van Weele, Y. Zhang Review Editors B. Nyenzi, J. Prospero Contents Executive Summary 291 5.4.1 Summary of Current Model Capabilities 313 5.4.1.1 Comparison of large-scale sulphate 5.1 Introduction 293 models (COSAM) 313 5.1.1 Advances since the Second Assessment 5.4.1.2 The IPCC model comparison Report 293 workshop: sulphate, organic carbon, 5.1.2 Aerosol Properties Relevant to Radiative black carbon, dust, and sea salt 314 Forcing 293 5.4.1.3 Comparison of modelled and observed aerosol concentrations 314 5.2 Sources and Production Mechanisms of 5.4.1.4 Comparison of modelled and satellite- Atmospheric Aerosols 295 derived aerosol optical depth 318 5.2.1 Introduction 295 5.4.2 Overall Uncertainty in Direct Forcing 5.2.2 Primary and Secondary Sources of Aerosols 296 Estimates 322 5.2.2.1 Soil dust 296 5.4.3 Modelling the Indirect
    [Show full text]
  • Black Carbon-Induced Snow Albedo Reduction Over the Tibetan Plateau
    Atmos. Chem. Phys., 18, 11507–11527, 2018 https://doi.org/10.5194/acp-18-11507-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Black carbon-induced snow albedo reduction over the Tibetan Plateau: uncertainties from snow grain shape and aerosol–snow mixing state based on an updated SNICAR model Cenlin He1,2, Mark G. Flanner3, Fei Chen2,4, Michael Barlage2, Kuo-Nan Liou5, Shichang Kang6,7, Jing Ming8, and Yun Qian9 1Advanced Study Program, National Center for Atmospheric Research, Boulder, CO, USA 2Research Applications Laboratory, National Center for Atmospheric Research, Boulder, CO, USA 3Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA 4State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China 5Joint Institute for Regional Earth System Science and Engineering, and Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA 6State key laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China 7CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, China 8Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany 9Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA Correspondence: Cenlin He ([email protected]) Received: 12 May 2018 – Discussion started: 22 May 2018 Revised: 31 July 2018 – Accepted: 4 August 2018 – Published: 15 August 2018 Abstract. We implement a set of new parameterizations into regional and seasonal variations, with higher values in the the widely used Snow, Ice, and Aerosol Radiative (SNICAR) non-monsoon season and low altitudes.
    [Show full text]
  • Black Carbon and Methane in the Norwegian Barents Region Black Carbon and Methane in the Norwegian Barents Region | M276
    REPORT M-276 | 2014 Black carbon and methane in the Norwegian Barents region Black carbon and methane in the Norwegian Barents region | M276 COLOPHON Executive institution The Norwegian Environment Agency Project manager for the contractor Contact person in the Norwegian Environment Agency Ingrid Lillehagen, The Ministry of Climate and Solrun Figenschau Skjellum Environment, section for polar affairs and the High North M-no Year Pages Contract number M-276 2014 15 Publisher The project is funded by The Norwegian Environment Agency The Norwegian Environment Agency Author(s) Maria Malene Kvalevåg, Vigdis Vestreng and Nina Holmengen Title – Norwegian and English Black carbon and methane in the Norwegian Barents Region Svart karbon og metan i den norske Barentsregionen Summary – sammendrag In 2011, land based emissions of black carbon and methane in the Norwegian Barents region were 400 tons and 23 700 tons, respectively. The largest emissions of black carbon originate from the transport sector and wood combustion in residential heating. For methane, the largest contributors to emissions are the agricultural sector and landfills. Different measures to reduce emissions from black carbon and methane can be implemented. Retrofitting of diesel particulate filters on light and heavy vehicles, tractors and construction machines will reduce black carbon emitted from the transport sector. Measures to reduce black carbon from residential heating are to accelerate the introduction of wood stoves with cleaner burning, improve burning techniques and inspect and maintain the wood stoves that are already in use. In the agricultural sector, methane emissions from food production can be reduced by using manure or food waste as raw material to biogas production.
    [Show full text]
  • Saving the Arctic the Urgent Need to Cut Black Carbon Emissions and Slow Climate Change
    AP PHOTO/IAN JOUGHIN PHOTO/IAN AP Saving the Arctic The Urgent Need to Cut Black Carbon Emissions and Slow Climate Change By Rebecca Lefton and Cathleen Kelly August 2014 WWW.AMERICANPROGRESS.ORG Saving the Arctic The Urgent Need to Cut Black Carbon Emissions and Slow Climate Change By Rebecca Lefton and Cathleen Kelly August 2014 Contents 1 Introduction and summary 3 Where does black carbon come from? 6 Future black carbon emissions in the Arctic 9 Why cutting black carbon outside the Arctic matters 13 Recommendations 19 Conclusion 20 Appendix 24 Endnotes Introduction and summary The Arctic is warming at a rate twice as fast as the rest of the world, in part because of the harsh effects of black carbon pollution on the region, which is made up mostly of snow and ice.1 Black carbon—one of the main components of soot—is a deadly and widespread air pollutant and a potent driver of climate change, espe- cially in the near term and on a regional basis. In colder, icier regions such as the Arctic, it peppers the Arctic snow with heat-absorbing black particles, increasing the amount of heat absorbed and rapidly accelerating local warming. This accel- eration exposes darker ground or water, causing snow and ice melt and lowering the amount of heat reflected away from the Earth.2 Combating climate change requires immediate and long-term cuts in heat-trap- ping carbon pollution, or CO2, around the globe. But reducing carbon pollution alone will not be enough to avoid the worst effects of a rapidly warming Arctic— slashing black carbon emissions near the Arctic and globally must also be part of the solution.
    [Show full text]
  • Black Carbon's Properties and Role in the Environment
    Sustainability 2010, 2, 294-320; doi:10.3390/su2010294 OPEN ACCESS sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Review Black Carbon’s Properties and Role in the Environment: A Comprehensive Review Gyami Shrestha 1,*, Samuel J. Traina 1 and Christopher W. Swanston 2 1 Environmental Systems Program, Sierra Nevada Research Institute, University of California- Merced, 5200 N. Lake Road, Merced, CA 95343, USA; E-Mail: [email protected] 2 Northern Institute of Applied Carbon Science, Climate, Fire, & Carbon Cycle Science Research, Northern Research Station, USDA Forest Service, 410 MacInnes Drive, Houghton, MI 49931, USA; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]. Received: 13 November 2009 / Accepted: 7 January 2010 / Published: 15 January 2010 Abstract: Produced from incomplete combustion of biomass and fossil fuel in the absence of oxygen, black carbon (BC) is the collective term for a range of carbonaceous substances encompassing partly charred plant residues to highly graphitized soot. Depending on its form, condition of origin and storage (from the atmosphere to the geosphere), and surrounding environmental conditions, BC can influence the environment at local, regional and global scales in different ways. In this paper, we review and synthesize recent findings and discussions on the nature of these different forms of BC and their impacts, particularly in relation to pollution and climate change. We start by describing the different types of BCs and their mechanisms of formation. To elucidate their pollutant sorption properties, we present some models involving polycyclic aromatic hydrocarbons and organic carbon. Subsequently, we discuss the stability of BC in the environment, summarizing the results of studies that showed a lack of chemical degradation of BC in soil and those that exposed BC to severe oxidative reactions to degrade it.
    [Show full text]
  • BLACK CARBON RESEAR RESEARC CH and FUTURE STRATEGIES Reducing Emissions, Improving Hhumanuman Health and Taking Action on Climate Changec Hange
    BLACK CARBON RESEAR RESEARC CH AND FUTURE STRATEGIES Reducing emissions, improving hhumanuman health and taking action on climate changec hange Introduction Black carbon is the sooty black material emitted from gas and diesel engines, coal-fired power plants, and other sources that burn fossil fuel. It comprises a significant portion of particulate matter or PM, which is an air pollutant. Black carbon is a global environmental problem that has negative implications for both human health and our climate. Inhalation of black carbon is associated with health problems including respiratory and cardiovascular disease, cancer, and even birth defects. And because of its ability to absorb light as heat, it also contributes to climate change. For example, as black carbon warms the air, rapid changes in patterns of Diesel exhaust black carbon particle (500 nm). Photo byb y NASA. rain and clouds can occur. Nine EPA STAR Research grants, • Measueasurringing black carbon’s mass totaling more than $6.6 million, and if othero ther particles adhere to This absorption quality also impacts were announced in October 2011 to black carbonc arbon polar ice. As black carbon deposits eight universities to research black • Evaluvaluaating ting low-cost and palm- in the Arctic, the particles cover the carbon. The grantees will further sized blackb lack carbon instruments snow and ice, decreasing the Earth’s research the pollutant’s emission that mmaay y give a wider range of ability to reflect the warming rays of sources and its impacts on climate measumeasurrements. ements. the sun, while absorbing heat and change and health. hastening melt. New black carbonc arbon measurement Measurement Research methods hahavvee been tested in This broad and complex role of EPA scientists are working to laboratory aanndd field studies using airborne black carbon is now under improve ways to measure black EPA’s GeoGeosspatialpatial Measurement of intense study by the EPA.
    [Show full text]
  • Climate Change Regulatory Authority Beyond the Clean Air Act
    Jul y 2012 RFF DP 12-39 Climate Change Regulatory Authority beyond the Clean Air Act Peter Anderson, with Nathan Richardson 1616 P St. NW Washington, DC 20036 202-328-5000 www.rff.org DISCUSSION PAPER Climate Change Regulatory Authority beyond the Clean Air Act Peter Anderson, with Nathan Richardson Abstract While the U.S. Environmental Protection Agency (EPA) is in the process of regulating greenhouse gas (GHG) emissions under its Clean Air Act (CAA) authority, Congress has considered several different bills that would preempt CAA regulation of GHGs and replace it with a comprehensive national climate policy. Policymakers should be aware that there are other existing federal statutes granting GHG regulatory authority, and new legislation would likely preempt them as well. This paper surveys these other statutes in order to highlight existing federal authority that might be given up with the passage of a new comprehensive bill. It explores the possibility of direct regulation of GHGs under the Clean Water Act (CWA), along with federal authority to block projects that contribute to climate change under the National Environmental Policy Act (NEPA) and conservation statutes such as the Endangered Species Act (ESA). Newer statutes like the Energy Independence and Security Act (EISA) mandate narrower regulation, but they are also considered here. Key Words: Clean Air Act, GHGs, emissions, climate change, regulatory authority © 2012 Resources for the Future. All rights reserved. No portion of this paper may be reproduced without permission of the authors. Discussion papers are research materials circulated by their authors for purposes of information and discussion. They have not necessarily undergone formal peer review.
    [Show full text]
  • Arctic Black Carbon: Policy Issues and Options
    Arctic Black Carbon: Policy Issues and Options Presentation at the ICCT Workshop Marine Black Carbon Emissions: Measuring and Controlling BC from Marine Engines Vancouver, BC, Canada – 7-8 September 2016 Thomas L. Brewer Senior Fellow, ICTSD Visiting Scholar, MIT Brewer - ICCT Vancouver 7-8 Sept 2016 1 Analytic Agenda Climate change science and impacts Industry technologies Government policies and practices and institutions Brewer - ICCT Vancouver 7-8 Sept 2016 2 Outline of Comments Problems Arctic warming Black carbon depositions Shipping emissions Solutions Industry technologies and practices Existing government policies and institutions Arctic Black Carbon (ABC) agreement proposal Brewer - ICCT Vancouver 7-8 Sept 2016 3 ARCTIC WARMING Processes and Effects Ocean Acidification Greenland Ice Melt* Sea Level Rise N. Atl.Thermohaline Circ. Temp Jet Stream Shift N. Hemisphere Weather Permafrost Thaw * Methane Leakage Sea Ice Melt * Sea Routes/Shipping *“Arctic Amplification” feedback loops tic Brewer - ICCT AVancouverA 7-8 Sept 2016 4 Greenland Cumulative Ice Sheet Loss, Mass Source: www.polarportal.dk 26 August 2016 Brewer - ICCT Vancouver 7-8 Sept 2016 5 Greenland Ice Sheet Melt, Surface, 2016 Monthly Source: www.nsidc.org August 2016 Brewer - ICCT Vancouver 7-8 Sept 2016 6 Arctic Sea Ice Volume, 1979-2016, Monthly Brewer - ICCT Vancouver 7-8 Sept 2016 7 BC Depositions in Arctic Region (Sources: AMAP, 2015; and …) Effects • “Arctic Amplification” – snow & ice albedo reduction • BC has a greater warming impact than carbon dioxide • Impact of BC emissions per unit is 5 times greater for within-region emissions than for outside-region • Mitigating BC emissions is necessary to prevent Arctic/Global catastrophe.
    [Show full text]
  • Can Black Carbon in Snow Be Detected by Remote Sensing? Stephen G
    JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES, VOL. 118, 779–786, doi:10.1029/2012JD018476, 2013 Can black carbon in snow be detected by remote sensing? Stephen G. Warren1 Received 11 July 2012; revised 29 November 2012; accepted 30 November 2012; published 30 January 2013. [1] In remote areas of the Northern Hemisphere, typical mixing ratios of black carbon (BC) in snow are 3–30 ng/g. In cold fine-grained snow these BC amounts can reduce the broadband albedo by 0–1% and the visible-wavelength albedo by 0–2%, representing significant climatic forcings. In melting snow the reductions are larger, 0–3% and 1–6%, respectively. Surface albedos inferred from satellite measurements have typical errors of a few percent, so a signal of reduced albedo will be difficult to detect. The inference of albedo from a nadir radiance measurement can be biased low because of undetected thin clouds or blowing snow altering the angular reflectance pattern. But even if the albedo could be measured perfectly from satellite, its attribution would be ambiguous because of the vertical variation of snow grain size, absorbing aerosol in the atmosphere above the snow, and especially because of subpixel heterogeneity of the thin and patchy snow cover of the Arctic and many other treeless regions. The spectral signature of thin snow resembles that of BC in snow. For these reasons, attempts to use satellite remote sensing to estimate the BC content of snow, or the reduction of albedo by BC, are unlikely to be successful, except in highly polluted industrial regions. Citation: Warren, S. G.
    [Show full text]
  • Special Edition: Understanding Methane's Potential to Amplify Or
    A Publication of the Climate Institute | Protecting the balance between climate and life on Earth Special Edition: Understanding Methane’s Potential to Amplify or Reduce Arctic Climate Change CLIMATE INSTITUTE Summer 2015 Volume 27, No. 1 Climate Alert A MESSAGE FROM THE CHIEF SCIENTIST Methane—the Other Carbon-Containing Greenhouse Gas Commentary by we first need to find an alternative nations would by now be well along Michael MacCracken means for securing the services that in cutting their emissions. Unfortu- fossil energy has been providing and nately, that has not been the case. In With good reason, more, given the continuing growth in the search for emissions pathways significant attention the global population. that could contribute to a near-term is being devoted to The global average temperature is slowing of the overall greenhouse sharply cutting emis- now up about 0.9°C over its prein- warming influence, we now have to sions of carbon diox- dustrial average and projected to rise go back and separate out the distinct ide (CO2). In general, emissions result further with the onset of the strong roles and lifetimes of each individual from combustion of coal, oil, and nat- El Niño that appears to be emerging. greenhouse gas and type of warming ural gas (together, fossil fuels) to pro- Furthermore, the rate of sea level or cooling aerosol. Continuing to use vide energy and, somewhat less im- rise is accelerating due both to addi- the hundred-year Global Warming portantly, from clearing of land for tional melting of the Greenland and Potential (GWP-100) would be ob- agriculture, wood products, and com- Antarctic ice sheets and greater up- scuring potentially effective policy munities.
    [Show full text]