DOCSLIB.ORG

Snow, Water, Ice and Permafrost in the Arctic

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Snow, Water, Ice and Permafrost in the Arctic Snow, Water, Ice and Permafrost in the Arctic Summary for Policy-makers This Summary for Policymakers presents key findings and implications of the second SWIPA assessment, conducted from 2010 to 2016 and published in 2017. More than 90 scientists contributed to the assessment, which was peer-reviewed by 28 experts in a rigorous quality control process. More details on the SWIPA process and findings are available in the full SWIPA report, available at www.amap.no/swipa. The Snow, Water, Ice and Permafrost in the Arctic (SWIPA) assessment is a periodic update to the Arctic Climate Impact Assessment, published in 2005 by the Arctic Monitoring and Assessment Programme (AMAP), the Conservation of Arctic Flora and Fauna (CAFF), and the International Arctic Science Committee (IASC). SWIPA focuses on changes to the Arctic cryosphere (the portion of Arctic land and water that is seasonally or perennially frozen), and the implications of those changes. The first SWIPA assessment was conducted between 2008 and 2010, and was published in 2011. About the Arctic Council The Arctic Council is the leading intergovernmental forum promoting cooperation, coordination, and interaction among the Arctic States, Arctic indigenous peoples, and other Arctic inhabitants on common Arctic issues, in particular on issues of environmental protection and sustainable development in the Arctic. Established in 1996, the Arctic Council is composed of eight Member States (Canada, the Kingdom of Denmark, Finland, Iceland, Norway, the Russian Federation, Sweden, and the United States). It also includes six organizations representing Arctic indigenous peoples: the Aleut International Association, the Arctic Athabaskan Council, Gwich’in Council International, the Inuit Circumpolar Council, the Russian Association of Indigenous Peoples of the North, and the Saami Council. About AMAP AMAP, established in 1991 under the eight-country Arctic Environmental Protection Strategy, monitors and assesses the status of the Arctic region with respect to pollution and climate change. AMAP produces science- based, policy-relevant assessments and public outreach products to inform policy and decision-making processes. Since 1996, AMAP has served as one of the Arctic Council’s six working groups. 2 Photo: Søren Rysgaard Photo: Søren Key Findings Key findings of the SWIPA 2017 assessment include: The Arctic’s climate is shifting 1 to a new state Rising concentrations of greenhouse gases are driving widespread changes in the Arctic’s sensitive climate, hydrological, and ecological systems. Since 2011, downward trends have continued in sea ice thickness and extent, land ice volume, and spring snow cover extent and duration, while near-surface permafrost has continued to warm. With each additional year of data, it becomes increasingly clear that the Arctic as we know it is being replaced by a warmer, wetter, and more variable environment. This transformation has profound implications for people, resources, and ecosystems worldwide. While SWIPA 2017 includes many important new findings, summarized below, three points in particular deserve special emphasis: • The Arctic Ocean could be largely free of sea ice in summer AMAP Assessment Area as early as the late 2030s, only two decades from now. • The recent recognition of additional melt processes affecting Arctic and Antarctic glaciers, ice caps, and Climate change in the Arctic ice sheets suggests that low-end projections of global 2 has continued at a rapid pace sea-level rise made by the Intergovernmental Panel on Climate Change (IPCC) are underestimated. • Arctic temperatures are rising faster than the global average. The Arctic was warmer from 2011 to 2015 than • Changes in the Arctic may be affecting weather at any time since instrumental records began in around in mid-latitudes, even influencing the Southeast 1900, and has been warming more than twice as rapidly Asian monsoon. as the world as a whole for the past 50 years. January 2016 in the Arctic was 5°C warmer than the 1981–2010 average for the region, a full 2°C higher than the previous record set in 2008, and monthly mean temperatures in October through December 2016 were 6°C higher than THE ROLE OF ARCTIC average for these months. Sea temperatures are also GLACIERS AND ICE CAPS IN increasing, both near the surface and in deeper water. GLOBAL SEA-LEVEL RISE • The frequency of some extreme events is changing. Recent observations include a widespread decline in Scientific advances since 2011 show that while periods of extreme cold during both winter and summer, Arctic glaciers and ice caps represent only a quarter of the world’s land ice area, meltwater and increases in extreme warm periods in some areas, from these sources accounts for 35% of current such as northern Alaska and northeastern Russia in global sea-level rise. autumn and spring. 3 Sea ice is becoming more mobile as its extent and TRADITIONAL AND LOCAL thickness decrease, increasing ice-related hazards. KNOWLEDGE More open water occurs in all months of the year compared with observations reported in 2011. The SWIPA scientifi c assessment is based primarily on peer-reviewed observations, methods, and • The area and duration of snow cover are decreasing. studies, which in many cases include contributions Snow cover has continued to decline in the Arctic, with from traditional and local knowledge. However it is recognized that this approach does not necessarily its annual duration decreasing by 2–4 days per decade. capture all relevant knowledge held by Indigenous In recent years, June snow area in the North American and local communities. and Eurasian Arctic has typically been about 50% below values observed before 2000. • Permafrost warming continues. Near-surface • The decline in sea ice continues, with variation from permafrost in the High Arctic and other very cold areas year to year Sea ice thickness in the central Arctic has warmed by more than 0.5°C since 2007–2009, Ocean declined by 65% over the period 1975–2012. and the layer of the ground that thaws in summer has Sea ice extent has varied widely in recent years, but deepened in most areas where permafrost is monitored. continues a long-term downward trend. A record low minimum sea ice extent occurred in 2012 and a record • The loss of land-based ice has accelerated in recent low maximum sea ice extent occurred in 2016. decades. Since at least 1972 the Arctic has been the dominant source of global sea-level rise. Seventy percent Older ice that has survived multiple summers is rapidly of the Arctic’s contribution to sea-level rise comes from disappearing; most sea ice in the Arctic is now ‘fi rst year’ Greenland, which on average lost 375 gigatons of ice ice that grows in the autumn and winter but melts during per year—equivalent to a block of ice measuring 7.5 the spring and summer. kilometers or 4.6 miles on all sides—from 2011 to 2014. Except for the coldest northern regions of the Arctic This is close to twice the rate over the period 2003–2008. Ocean, the average number of days with sea ice cover • Freshwater storage in the Arctic Ocean has in the Arctic declined at a rate of 10–20 days per decade increased. Compared with the 1980–2000 average, the over the period 1979–2013, with some areas seeing volume of freshwater in the upper layer of the Arctic much larger declines. Warm winds during the autumn Ocean has increased by 8,000 cubic kilometers, or more of 2016 substantially delayed the formation of sea ice. than 11%. This volume equals the combined annual Sea level contribution, mm/yr 1.2 1.0 Thermal expansion Antarctic land ice 0.8 Greenland ice sheet Canadian Arctic glaciers 0.6 During the period 2004– Russian Arctic glaciers 2010, melting Arctic land ice accounted for more than U.S. Arctic (Alaskan) glaciers 1/3 of global sea-level rise, 0.4 while thermal expansion Greenland glaciers caused by warming water Scandinavian glaciers contributed another 1/3 0.2 and contributions from Other glaciers Antarctica, other glaciers and changes in terrestrial storage Terrestrial storage 0 contributed less than 1/3. 4 discharge of the Amazon and Ganges rivers, and could— • The Arctic Ocean may be ice-free sooner than if it escapes the confines of the Arctic Ocean—affect expected. Extrapolations of recent observed data circulation in the Nordic Seas and the North Atlantic. suggest a largely ice-free summer ocean by the late 2030s, which is earlier than projected by most climate . The decline in sea ice • Ecosystems are changing models. Natural variability and model limitations make thickness and extent, along with changes in the timing precise predictions impossible. of ice melt, are affecting marine ecosystems and biodiversity; changing the ranges of Arctic species; • Declines in snow and permafrost will continue. increasing the occurrence of algal blooms; leading to The duration of snow cover is projected to decrease by an changes in diet among marine mammals; and altering additional 10–20% from current levels over most of the predator-prey relationships, habitat uses, and migration Arctic by mid-century under a high emissions scenario, patterns. Terrestrial ecosystems are feeling the effects of and the area of near-surface permafrost is projected to changes in precipitation, snow cover, and the frequency decrease by around 35% under the same scenario. or severity of wildfires. The occurrence of rain-on-snow and winter thaw/refreezing events affects grazing animals • The melting of land-based ice will contribute . If increases in such as caribou, reindeer, and muskox by creating an significantly to sea-level rise greenhouse gas concentrations continue at current rates, ice barrier over lichens and mosses. While many tundra the melting of Arctic land-based ice would contribute an regions have become greener over the past 30 years, estimated 25 centimeters to sea-level rise between 2006 reflecting an increase in plant growth and productivity, and 2100.
Load more

Recommended publications
  • Lecture 21: Glaciers and Paleoclimate Read: Chapter 15 Homework Due Thursday Nov
    Learning Objectives (LO) Lecture 21: Glaciers and Paleoclimate Read: Chapter 15 Homework due Thursday Nov. 12 What we’ll learn today:! 1. 1. Glaciers and where they occur! 2. 2. Compare depositional and erosional features of glaciers! 3. 3. Earth-Sun orbital parameters, relevance to interglacial periods ! A glacier is a river of ice. Glaciers can range in size from: 100s of m (mountain glaciers) to 100s of km (continental ice sheets) Most glaciers are 1000s to 100,000s of years old! The Snowline is the lowest elevation of a perennial (2 yrs) snow field. Glaciers can only form above the snowline, where snow does not completely melt in the summer. Requirements: Cold temperatures Polar latitudes or high elevations Sufficient snow Flat area for snow to accumulate Permafrost is permanently frozen soil beneath a seasonal active layer that supports plant life Glaciers are made of compressed, recrystallized snow. Snow buildup in the zone of accumulation flows downhill into the zone of wastage. Glacier-Covered Areas Glacier Coverage (km2) No glaciers in Australia! 160,000 glaciers total 47 countries have glaciers 94% of Earth’s ice is in Greenland and Antarctica Mountain Glaciers are Retreating Worldwide The Antarctic Ice Sheet The Greenland Ice Sheet Glaciers flow downhill through ductile (plastic) deformation & by basal sliding. Brittle deformation near the surface makes cracks, or crevasses. Antarctic ice sheet: ductile flow extends into the ocean to form an ice shelf. Wilkins Ice shelf Breakup http://www.youtube.com/watch?v=XUltAHerfpk The Greenland Ice Sheet has fewer and smaller ice shelves. Erosional Features Unique erosional landforms remain after glaciers melt.
    [Show full text]
  • Minimal Geological Methane Emissions During the Younger Dryas-Preboreal Abrupt Warming Event
    UC San Diego UC San Diego Previously Published Works Title Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event. Permalink https://escholarship.org/uc/item/1j0249ms Journal Nature, 548(7668) ISSN 0028-0836 Authors Petrenko, Vasilii V Smith, Andrew M Schaefer, Hinrich et al. Publication Date 2017-08-01 DOI 10.1038/nature23316 Peer reviewed eScholarship.org Powered by the California Digital Library University of California LETTER doi:10.1038/nature23316 Minimal geological methane emissions during the Younger Dryas–Preboreal abrupt warming event Vasilii V. Petrenko1, Andrew M. Smith2, Hinrich Schaefer3, Katja Riedel3, Edward Brook4, Daniel Baggenstos5,6, Christina Harth5, Quan Hua2, Christo Buizert4, Adrian Schilt4, Xavier Fain7, Logan Mitchell4,8, Thomas Bauska4,9, Anais Orsi5,10, Ray F. Weiss5 & Jeffrey P. Severinghaus5 Methane (CH4) is a powerful greenhouse gas and plays a key part atmosphere can only produce combined estimates of natural geological in global atmospheric chemistry. Natural geological emissions and anthropogenic fossil CH4 emissions (refs 2, 12). (fossil methane vented naturally from marine and terrestrial Polar ice contains samples of the preindustrial atmosphere and seeps and mud volcanoes) are thought to contribute around offers the opportunity to quantify geological CH4 in the absence of 52 teragrams of methane per year to the global methane source, anthropogenic fossil CH4. A recent study used a combination of revised 13 13 about 10 per cent of the total, but both bottom-up methods source δ C isotopic signatures and published ice core δ CH4 data to 1 −1 2 (measuring emissions) and top-down approaches (measuring estimate natural geological CH4 at 51 ±​ 20 Tg CH4 yr (1σ range) , atmospheric mole fractions and isotopes)2 for constraining these in agreement with the bottom-up assessment of ref.
    [Show full text]
  • Safeguarding the Arctic Why the U.S
    Safeguarding the Arctic Why the U.S. Must Lead in the High North By Cathleen Kelly and Miranda Peterson January 22, 2015 “As the United States assumes the Chairmanship of the Arctic Council, it is more important than ever that we have a coordinated national effort that takes advantage of our combined expertise and efforts in the Arctic region to promote our shared values and priorities.” — President Obama, Executive Order on Enhancing Coordination of National Efforts in the Arctic, January 21, 20151 While many Americans do not consider the United States to be an Arctic nation, Alaska—which constitutes 16 percent of the country’s landmass and sits on the Arctic Circle—puts the country solidly in that category.2 Consequently, it is with good reason that the United States has a seat on the Arctic Council. As Arctic warming accelerates, U.S. leadership in the High North is key not only to the public health and safety of Americans and other people in the region, but also to U.S. national security and the fate of the planet. In just three months, U.S. Secretary of State John Kerry will become chairman of the Arctic Council. The two-year position rotates among the eight Arctic nations3—Canada, Finland, Iceland, Norway, Russia, Sweden, the United States, and Denmark, including Greenland and the Faroe Islands—and is a powerful platform for shaping how the risks and opportunities of increasing commercial activity at the top of the world are managed. To ready the administration for Secretary Kerry’s turn to hold the Arctic Council gavel from 2015 to 2017, President Barack Obama recently issued an executive order to better coordinate national efforts in the Arctic.4 The executive order is the latest signal from the White House that President Obama and Secretary Kerry are focused on preparing the nation for dramatic changes in the Arctic and protecting U.S.
    [Show full text]
  • Sea Level and Climate Introduction
    Sea Level and Climate Introduction Global sea level and the Earth’s climate are closely linked. The Earth’s climate has warmed about 1°C (1.8°F) during the last 100 years. As the climate has warmed following the end of a recent cold period known as the “Little Ice Age” in the 19th century, sea level has been rising about 1 to 2 millimeters per year due to the reduction in volume of ice caps, ice fields, and mountain glaciers in addition to the thermal expansion of ocean water. If present trends continue, including an increase in global temperatures caused by increased greenhouse-gas emissions, many of the world’s mountain glaciers will disap- pear. For example, at the current rate of melting, most glaciers will be gone from Glacier National Park, Montana, by the middle of the next century (fig. 1). In Iceland, about 11 percent of the island is covered by glaciers (mostly ice caps). If warm- ing continues, Iceland’s glaciers will decrease by 40 percent by 2100 and virtually disappear by 2200. Most of the current global land ice mass is located in the Antarctic and Greenland ice sheets (table 1). Complete melt- ing of these ice sheets could lead to a sea-level rise of about 80 meters, whereas melting of all other glaciers could lead to a Figure 1. Grinnell Glacier in Glacier National Park, Montana; sea-level rise of only one-half meter. photograph by Carl H. Key, USGS, in 1981. The glacier has been retreating rapidly since the early 1900’s.
    [Show full text]
  • Calving Processes and the Dynamics of Calving Glaciers ⁎ Douglas I
    Earth-Science Reviews 82 (2007) 143–179 www.elsevier.com/locate/earscirev Calving processes and the dynamics of calving glaciers ⁎ Douglas I. Benn a,b, , Charles R. Warren a, Ruth H. Mottram a a School of Geography and Geosciences, University of St Andrews, KY16 9AL, UK b The University Centre in Svalbard, PO Box 156, N-9171 Longyearbyen, Norway Received 26 October 2006; accepted 13 February 2007 Available online 27 February 2007 Abstract Calving of icebergs is an important component of mass loss from the polar ice sheets and glaciers in many parts of the world. Calving rates can increase dramatically in response to increases in velocity and/or retreat of the glacier margin, with important implications for sea level change. Despite their importance, calving and related dynamic processes are poorly represented in the current generation of ice sheet models. This is largely because understanding the ‘calving problem’ involves several other long-standing problems in glaciology, combined with the difficulties and dangers of field data collection. In this paper, we systematically review different aspects of the calving problem, and outline a new framework for representing calving processes in ice sheet models. We define a hierarchy of calving processes, to distinguish those that exert a fundamental control on the position of the ice margin from more localised processes responsible for individual calving events. The first-order control on calving is the strain rate arising from spatial variations in velocity (particularly sliding speed), which determines the location and depth of surface crevasses. Superimposed on this first-order process are second-order processes that can further erode the ice margin.
    [Show full text]
  • GSA TODAY • Southeastern Section Meeting, P
    Vol. 5, No. 1 January 1995 INSIDE • 1995 GeoVentures, p. 4 • Environmental Education, p. 9 GSA TODAY • Southeastern Section Meeting, p. 15 A Publication of the Geological Society of America • North-Central–South-Central Section Meeting, p. 18 Stability or Instability of Antarctic Ice Sheets During Warm Climates of the Pliocene? James P. Kennett Marine Science Institute and Department of Geological Sciences, University of California Santa Barbara, CA 93106 David A. Hodell Department of Geology, University of Florida, Gainesville, FL 32611 ABSTRACT to the south from warmer, less nutrient- rich Subantarctic surface water. Up- During the Pliocene between welling of deep water in the circum- ~5 and 3 Ma, polar ice sheets were Antarctic links the mean chemical restricted to Antarctica, and climate composition of ocean deep water with was at times significantly warmer the atmosphere through gas exchange than now. Debate on whether the (Toggweiler and Sarmiento, 1985). Antarctic ice sheets and climate sys- The evolution of the Antarctic cryo- tem withstood this warmth with sphere-ocean system has profoundly relatively little change (stability influenced global climate, sea-level his- hypothesis) or whether much of the tory, Earth’s heat budget, atmospheric ice sheet disappeared (deglaciation composition and circulation, thermo- hypothesis) is ongoing. Paleoclimatic haline circulation, and the develop- data from high-latitude deep-sea sed- ment of Antarctic biota. iments strongly support the stability Given current concern about possi- hypothesis. Oxygen isotopic data ble global greenhouse warming, under- indicate that average sea-surface standing the history of the Antarctic temperatures in the Southern Ocean ocean-cryosphere system is important could not have increased by more for assessing future response of the Figure 1.
    [Show full text]
  • Comparison of Remote Sensing Extraction Methods for Glacier Firn Line- Considering Urumqi Glacier No.1 As the Experimental Area
    E3S Web of Conferences 218, 04024 (2020) https://doi.org/10.1051/e3sconf/202021804024 ISEESE 2020 Comparison of remote sensing extraction methods for glacier firn line- considering Urumqi Glacier No.1 as the experimental area YANJUN ZHAO1, JUN ZHAO1, XIAOYING YUE2and YANQIANG WANG1 1College of Geography and Environmental Science, Northwest Normal University, Lanzhou, China 2State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources/Tien Shan Glaciological Station, Chinese Academy of Sciences, Lanzhou, China Abstract. In mid-latitude glaciers, the altitude of the snowline at the end of the ablating season can be used to indicate the equilibrium line, which can be used as an approximation for it. In this paper, Urumqi Glacier No.1 was selected as the experimental area while Landsat TM/ETM+/OLI images were used to analyze and compare the accuracy as well as applicability of the visual interpretation, Normalized Difference Snow Index, single-band threshold and albedo remote sensing inversion methods for the extraction of the firn lines. The results show that the visual interpretation and the albedo remote sensing inversion methods have strong adaptability, alonger with the high accuracy of the extracted firn line while it is followed by the Normalized Difference Snow Index and the single-band threshold methods. In the year with extremely negative mass balance, the altitude deviation of the firn line extracted by different methods is increased. Except for the years with extremely negative mass balance, the altitude of the firn line at the end of the ablating season has a good indication for the altitude of the balance line.
    [Show full text]
  • Glacier (And Ice Sheet) Mass Balance
    Glacier (and ice sheet) Mass Balance The long-term average position of the highest (late summer) firn line ! is termed the Equilibrium Line Altitude (ELA) Firn is old snow How an ice sheet works (roughly): Accumulation zone ablation zone ice land ocean • Net accumulation creates surface slope Why is the NH insolation important for global ice• sheetSurface advance slope causes (Milankovitch ice to flow towards theory)? edges • Accumulation (and mass flow) is balanced by ablation and/or calving Why focus on summertime? Ice sheets are very sensitive to Normal summertime temperatures! • Ice sheet has parabolic shape. • line represents melt zone • small warming increases melt zone (horizontal area) a lot because of shape! Slightly warmer Influence of shape Warmer climate freezing line Normal freezing line ground Furthermore temperature has a powerful influence on melting rate Temperature and Ice Mass Balance Summer Temperature main factor determining ice growth e.g., a warming will Expand ablation area, lengthen melt season, increase the melt rate, and increase proportion of precip falling as rain It may also bring more precip to the region Since ablation rate increases rapidly with increasing temperature – Summer melting controls ice sheet fate* – Orbital timescales - Summer insolation must control ice sheet growth *Not true for Antarctica in near term though, where it ʼs too cold to melt much at surface Temperature and Ice Mass Balance Rule of thumb is that 1C warming causes an additional 1m of melt (see slope of ablation curve at right)
    [Show full text]
  • A Globally Complete Inventory of Glaciers
    Journal of Glaciology, Vol. 60, No. 221, 2014 doi: 10.3189/2014JoG13J176 537 The Randolph Glacier Inventory: a globally complete inventory of glaciers W. Tad PFEFFER,1 Anthony A. ARENDT,2 Andrew BLISS,2 Tobias BOLCH,3,4 J. Graham COGLEY,5 Alex S. GARDNER,6 Jon-Ove HAGEN,7 Regine HOCK,2,8 Georg KASER,9 Christian KIENHOLZ,2 Evan S. MILES,10 Geir MOHOLDT,11 Nico MOÈ LG,3 Frank PAUL,3 Valentina RADICÂ ,12 Philipp RASTNER,3 Bruce H. RAUP,13 Justin RICH,2 Martin J. SHARP,14 THE RANDOLPH CONSORTIUM15 1Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA 2Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA 3Department of Geography, University of ZuÈrich, ZuÈrich, Switzerland 4Institute for Cartography, Technische UniversitaÈt Dresden, Dresden, Germany 5Department of Geography, Trent University, Peterborough, Ontario, Canada E-mail: [email protected] 6Graduate School of Geography, Clark University, Worcester, MA, USA 7Department of Geosciences, University of Oslo, Oslo, Norway 8Department of Earth Sciences, Uppsala University, Uppsala, Sweden 9Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria 10Scott Polar Research Institute, University of Cambridge, Cambridge, UK 11Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA 12Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada 13National Snow and Ice Data Center, University of Colorado, Boulder, CO, USA 14Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada 15A complete list of Consortium authors is in the Appendix ABSTRACT. The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance.
    [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]
  • Climate Change and Southern Ocean Resilience
    No.No. 52 5 l l JuneMay 20202021 POLARKENNAN PERSPECTIVES CABLE Adélie penguins on top of an ice flow near the Antarctic Peninsula. © Jo Crebbin/Shutterstock Climate Change and Southern Ocean Resilience REPORT FROM AN INTERDISCIPLINARY SCIENTIFIC WORKSHOP, MARCH 30, 2021 Andrea Capurroi, Florence Colleoniii, Rachel Downeyiii, Evgeny Pakhomoviv, Ricardo Rourav, Anne Christiansonvi i. Boston University Frederick S. Pardee Center for the Study of the Longer-Range Future ii. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale Antarctic and Southern Ocean Coalition iii. Australian National University iv. University of British Columbia v. Antarctic and Southern Ocean Coalition vi. The Pew Charitable Trusts CONTENTS I. INTRODUCTION BY EVAN T. BLOOM 3 II. EXECUTIVE SUMMARY 5 III. CLIMATE CHANGE AND SOUTHERN OCEAN RESILIENCE 7 A. CLIMATE CHANGE AND THE SOUTHERN OCEAN 7 B. CONNECTION OF REGIONAL SOUTHERN OCEAN PROCESS TO GLOBAL SYSTEMS 9 C. UNDERSTANDING PROCESS CHANGES IN THE SOUTHERN OCEAN 10 D. ANTARCTIC GOVERNANCE AND DECISION MAKING 15 E. CONCLUSION 18 F. REFERENCES 19 POLAR PERSPECTIVES 2 No. 5 l June 2021 I. INTRODUCTION BY EVAN T. BLOOM vii Fig 1: Southern Ocean regions proposed for protection A network of MPAs could allow for conservation of distinct areas, each representing unique ecosystems As the world prepares for the Glasgow Climate Change Conference in November 2021, there is considerable focus on the Southern Ocean. The international community has come to realize that the polar regions hold many of the keys to unlocking our understanding of climate-related phenomena - and thus polar science will influence policy decisions on which our collective futures depend.
    [Show full text]
  • Evaluation of a New Snow Albedo Scheme for the Greenland Ice Sheet in the Regional Climate Model RACMO2 Christiaan T
    https://doi.org/10.5194/tc-2020-118 Preprint. Discussion started: 2 June 2020 c Author(s) 2020. CC BY 4.0 License. Evaluation of a new snow albedo scheme for the Greenland ice sheet in the regional climate model RACMO2 Christiaan T. van Dalum1, Willem Jan van de Berg1, Stef Lhermitte2, and Michiel R. van den Broeke1 1Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, The Netherlands 2Department of Geoscience & Remote Sensing, Delft University of Technology, Delft, The Netherlands Correspondence: Christiaan van Dalum ([email protected]) Abstract. Snow and ice albedo schemes in present day climate models often lack a sophisticated radiation penetration scheme and do not explicitly include spectral albedo variations. In this study, we evaluate a new snow albedo scheme in the regional climate model RACMO2 for the Greenland ice sheet, version 2.3p3, that includes these processes. The new albedo scheme uses the two-stream radiative transfer in snow model TARTES and the spectral-to-narrowband albedo module SNOWBAL, 5 version 1.2. Additionally, the bare ice albedo parameterization has been updated. The snow and ice broadband and narrow- band albedo output of the updated version of RACMO2 is evaluated using PROMICE and K-transect in-situ data and MODIS remote-sensing observations. Generally, the modeled narrowband and broadband albedo is in very good agreement with satel- lite observations, leading to a negligible domain-averaged broadband albedo bias smaller than 0.001 for the interior. Some discrepancies are, however, observed close to the ice margin. Compared to the previous model version, RACMO2.3p2, the 10 broadband albedo is considerably higher in the bare ice zone during the ablation season, as atmospheric conditions now alter the bare ice broadband albedo.
    [Show full text]