-this is why landscapes are always in “inclomplete transition” and “readjustment”
5.Scales of systems: spatial and temporal
6.Temporal and spatial variability: worldwide trend does not equal local trend.
7. Instabilities in systems and “tipping points”
Earth is the “blue planet”
-Satellite imagery changed the view of scale of processes and interconnectivity
Typical Conditions on earth:
Pressure: 1atm (101kPa)
Temperature: -89 to 58C
Whether water is liquid, solid, or ice depends on Pressure and Temperature. The “triple point” is where they meet.
RETENTION TIMES (Hydro Cycle)
-Biospheric/atmospheric/river water = 1-2 week
-ice caps/glaceris = ~1000 years
-oceans and seas = ~ 4000 years
-Groundwater = ~2weeks – 18000 years
Cryosphere response and archaeology
Changes in the components of the cryosphere occur at different time scales, depending on their dynamic and thermodynamic characteristics
-frozen ground = biggest temporal range
-ice sheets longest time scale
-snow/river/lake/sea ice = shortest time scale
-glaciers and ice caps in between
Human response times= seeing is believing… though many systems are so complex that it is hard to measure the systemic changes, let alone see them.
Otzi = the prehistoric iceman, found 1991, 5200 years old
10400 year old hunting weapon found in Melting Ice Patch in 2007.. organic material is preserved in snow and ice!!
Back to the future…
1958 http://www.youtube.com/watch?v=0lgzz-L7GFg Excerpt from the educational documentary “Unchained Goddess” produced by Frank Capra for Bell Labs for their television program “The Bell Telephone Hour.”
1989 http://archives.cbc.ca/environment/climate_change/clips/14650/ The Arctic: ‘first and worst’ for global warming. CBC News 12 Oct 1989
2009 http://www.ted.com/talks/james_balog_time_lapse_proof_of_extreme_ice_loss.html Glacier talk and time- lapse photography footage by James Balog, professional photographer, July 2009.
Many complex systems have critical thresholds (tipping points) at which the system shifts abruptly from one state to another.
ie. asthma, market crashes, climate, etc
“13th tipping point” – the shift in human perception from personal denial to personal responsibility?
Natural and human influences influence direct and indirect changes in climate drivers, which impacts radiative forcing and non-initial-radiative effects, which result in climate perturbation and response, which can result in biogeochemical feedback processes.
The Keeling Curve
-Mauna Loa observatory in Hawaii
-CO2 concentrations in atmosphere have increase linearly since 1960 from ~310ppm to almost 400ppm (low variation… seasonal fluctuations very evident).
-Natural range in the last 10kyrs has been 260-280ppm.
RELATIONS OF DIF TIME SCALES OF CLIMATIC CHANGE TO CRYOSPHERIC COMPONENTS
10k-100kyrs = ice sheets
1k-10kyrs = ice caps, ice fields, large valley glaciers
100-1000yrs = small valley glaciers
10-100yrs = cirque glaciers
1-10yrs =; neves, snow fields
Ice sheet, permafrost, and sea ice changes in response to climate change
Greenland is meting at an alarming rate.
In some places, this increased meltwater results in a dramatic increase in ice flow, and related iceberg discharge.
Rates of surface elevation change derived from laster altimeter measruements at over 16000 locations on the Greenland Ice Sheet indicate rapid thinning in many regions. Mass balance is estimated to be decreasing quickly.
Antarctic shows mixed trends, with thickening in some regions and thinning in others.
Permafrost – Permafrost zones occupy up to 24% of the exposed land area of the NH.
Trends in permafrost temperatures in N Alaska over last ~25 years are increasing. There has been a general increase in permafrost temperatures in N Hem over last several decades
Sea Ice extent is decreasing rapidly
Freeze-Up and Breakup dates from norther lakes and rivers are also changing in response to climate change
Antarctic Tourism Changes
Tourism activities are epanding tremendously with the number of shipborne tourists increasing by 430% in 14 years and land-based tourists by 757% in 10 years.
Antarctic annual sea-ice extent is projected to decrease by 25% by 2100. This means easier access to the Antarctic continent by ship.
This is likely to affect not only research, which is a main activity in a continent designated as a “natural reserve devoted to peace and science”, but also commercial activities, such as tourism.
Antarctica and measuring
-98% of antarctica is ice covered
-70% of Earth’s freshwater is in teh Antarctic Ice
-91% of earth’s ice is in Antarctica
-average thickness=2.3km/ max=4.8km
*It is the highest, driest, windiest, and coldest continent
-it hasn’t rained at Canada glacier for at least 2million years
-can be down to -88C
In mid 2000, Pine Island Glacier formed a large crack in its ice shelf, which expanded 15m/day.
In 2001, 7yrs of glacier outflow releaesed to the sea in a single event
Measuring and Data
-the process of measuring
-the quantities coming directly from these measurement processes
-receiving knowledge of the outisde world through the senses, or through the recording of data using scientific instruments (=measuring)
In Situ measurements/obervations
-usually obtained through direct contact with the respective subject
-may be precise, accurate and representative of site-specific location, but not necessarily of a larger region
-quantification to represent geophysical state variables and with that the state or change of processes or systems
There are currently efforts to both standardize/collect/distribute data (UN Global Observation Systems, World Meteorological Organization) as well as to centralise, catalogue, and distribute past/present data (World Data Centres, World Glacier Inventory, etc)
AWS in Antarctica
Automatic Weather Stations
First weather observations mid-late 1800s
Detailed climate observations >1950s
Palynology techniques example
1. count and identify 200 pollen grains/sample
2. Divide census into three parts
-arboreal pollen (AP)
-non-arboreal pollen (NAP)
3.express results as % of total AP at that particular depth
4. Plant assemblage at a particular horizon — pollen spectrum
5. Curves from a series of stratigraphic positions — pollen diagram
6.age dates are determined by 14C dating and cross-dating
7.History of vegetation change linked to climate, environment, and anthropological influences
MAIN: snow Extent, Thickness, and Density
Additionally: Snowpit analysis for:
-recording of snow accumulation in glacier mass balance studies
-assessment of snow variability
-assessment of spring runoff
2.record layer stratigraphy
5.record size and shape/form of snow crystals
6.record snow density
7.record snow temperature
8. record snow stability (shovel compression test)
Cosmogenic radionucleides (10Be, 36Cl, 14C) – interaction cosmic rays and atoms (solar activity and geomagnetic field)
Nitrate and Sulphate in Ice Cores
-both gradually increasing since 1900s due to coal combustion industrial revolution
-both now well above 2000 year averages
-some sulphate peaks related to volcanic eruptions
US Clean AIr Act 1972 resulted in huge decrease in sulphates
Problem with gas dating in ice is that there is mixing between layers!!
EPICA DOME C
longest continuous climate record
-Over the last 740kyr, earth experienced 8 glacial periods and 8 interglacial
-In the last 400k yrs, warm periods had temperatures similar to todays, before that, warm periods were cooler, but lasted longer
Cooling is gradual, warming can be abrupt
Concentrations of sodium, sulphate, and dust are way higher during glacial periods
Concentrations of methane, carbon dioxide, are way higher during interglacial
CH4 residence time = 10yrs
CO2 res is over 100yrs… globally well mixed
Younger Dryas and Little Ice Age
The Younger Dryas stadial, also referred to as the Big Freeze, was a geologically brief (1,300 ± 70 years) cold climate period between approximately 12,800 and 11,500 years ago (between 10,800 and 9,500 BC).
The Little Ice Age (LIA) was a period of cooling that occurred after the Medieval Warm Period. While not a true ice age, the term was introduced into scientific literature by François E. Matthes in 1939. It is conventionally defined as a period extending from the 16th to the 19th centuries
stadials and interstadials
periods of warm and cold within an interglacial
Younger Dryas was a stadial
CO2 and ice cores
Relationship b/w CO2 and Temperature is not linear!!!
CO2 max 290ppm in the last 650000 years until the most recent increase , which is unequivocally due to human activities
CO2 accounts for only ~1/3 of the total temperature increase in teh past
CO2 is amplifier of climate (dtrigger is most often orbital or ocean oscillations)
Dust and and Na Ice cores
-We get more dust during cold periods due to more wind, less vegetation, more fines available through erosion and lower sea levels.
~1400, got really cold, and sodium levels increased due to colder seas. Wiped out Vikings.
PSAs (potential source areas) for Antarctica during glacial periods are NZ, Dry Valleys, and South America
-size of source area
-volcanic eruptions (tephra)
-other chemicals and isotopes
-LGM atmospheric circulation models
10Be concentration (relative to the mean value) at South Pole is a measure of solar insolation
Thames Frost Fairs (1608-1814).. longest and coldest in 1683 (3 months)- London
THE MILANKOVITCH CYCLE
Insolation co-trigger of clmiate change at longer timescales
Precession + Obliquity + Eccentricity + Solar Forcing combine to form “Stages of Glaciation”
The cycles match gvery well to temperature in Antarctic ice cores, apart from recently the cycle has gone down, but the temperature has not.
Major findings from ice cores drilled in the Greenland and Antarctic Ice Sheets (9)
1. Close correlation b/w climate and GHG conc.
2.Ice ages are dustier, and storm tracks change
3. Some atmospheric chemistry is regional (methane)
4. Anthropogenic influences on atmosphere are global (nuke tests, emissions)
5.Some climate oscillations are global, other confined to N Hem
6.Coupling of timing and magnitude of global climate changes between the 2 hemispheres
7.Rapid and large oscillations during the last glacial period and the end of the last transition (start Holocene)
8. Climatic stability of the last 10k years contrasts with extreme climate variability through most of the rest of the last glacial
9. Last interglacial (125kyBP) was 2-5C warmer than present (orbital forcing)
Stefan-Boltzmann Law and Wien’s Displacement Law
As the temperature of an object increases, more radiation is emitted each second.
Wien’s Displacement Law
As the temperature of a body increases, so does the proportion of shorter wavelengts
From these two laws it follows that:
Sun’s radiated emission very high and mostly in the form of shortwave (SW) radiation.
Earth’s emission low and mostly longwave (LW) radiation
Net heat transport is from the tropics to the poles. Greater outgoing radiation at the poles relative to incomming.
Contribution of RF associated with anthropogenic GHG emissions: ~2.6W/m2 since 1750.
-mostly CO2 and CH4
Combined anthropogenic RF: ~2.6W/m2 since 1750
-inclued atmospheric aerosols (direct effect and cloud albedo effect)
Surface energy balance at a point
Fsol = incoming solar shortwave radiation
FIR = upwards and downward radiation flux at surface (Stefan Boltzman law)
FSE & FLE = sensible and latent heat fluxes
Fcond = conduction flux for ground/ice/snow/ocean surfaces (Fourier’s law)
Fgeo = geothermal heat flux
ENERGY BALANCE OVER POLAR TERRAIN
Closed Forest and Coastal Tundra and Thick Sea Ice: large net income in summer, small net outgoing in winter
Glacial Ablation Zone: net incoming in summer, no data for winter
Antarctic Coast: Small incoming in summer, small (about the same) outgoing in winter
Thin sea ice (winter only) net is outgoing, most incoming comes from ocean.
Properties of the Cryosphere influencing surface energy balance
SNOW AND ICE -large albedo: reflect large part of incoming energy
-store and release latent heat: affect the sasonal cycle of the surface temperature
-Good insulators – reduce the heat loss from underlying surface (land or ocean) (largest effect in winter)
Sea ice restricts heat and gas exchange between ocean and atmosphere
-When sea ice forms, only a fraction of the salt present in the ocean is trapped in the ice, the remainder is ejected towards the ocean (brine rejection)
-patterned ground – albedo and surface roughness
-melt – sea level
SNOW AND ICE
-sea ice-albedo-polynia feedback
-Melt-GHG release feedback
Heat Properties of Ice and Snow
Latent Heat of Fusion of Ice
-amount of energy required to transform ice to water at the melting point
-heat energy required to increase the temperature of a unit quantity of a material one degree (C or K)
Water Vapour (100C) = 2.08 J/gK
Water liquid (25C) = 4.18 J/gK
Ice (-10C) = 2.05 J/gK
Bedrock specific heat capacity is only ~0.2 J/gK
So what is the effect of snow/ice cover on the earth’s energy budget given the above properties?
Effect of temporal variability of Snow Cover
SNOW COVER VARIES SPATIALLY AND TEMPORALLY!
The ratio of sensible heat and latent heat energy fluxes from one medium to another
… and is related to the evaporative fraction
SNOW MEASUREMENTS Main:
Also, snow pit analysis for:
-recording of snow accumulation in glacier mass balance studies
-Firn overlain by dry snow -; rel high backscatter from interface of snow/firn layers
-Percolation or superimposed ice zone with ice lenses -; high backscatter if no active melting
-Active slush zone -; low backscatter: liquid water
-Dry ice -; low if not rough
***Sh= surface height variations
-surface is considered smooth or rough (proportional to wavelength and incident angle)
Radar can be used to detect snowline on a glacier!
Radar Error Estimates
Based on comparison with ground measurements and image comparison
Snow cover area:
Modis, AVHRR, GOES-8, etc 5-10%
Passive microwave ;1%
SAR and AMM/I large errors with point measurments, but ‘only’ 10-20mm w.e. when area averaged
Global Land Ice Measurements From Space
-GLIMS is an international consortium (26 nations)
-Primary goal: to determine the extent of the world’s glaciers and the rate at which they are changing
1)acquire a global set of multispectral, stereo satellite images of the world’s land ice near the peak or end of the melt season
2)map the global extent of land ice
3)analyze a representative selection of glaciers for length, area, ice flow, snowlines, and interannual changes in these
4)Build and populate a publicly accessible digital database of te world’s glaciers
Principal observing instrument: ASTER (aboard NASA’s Terra satellite)
-supplemented by others (LANDSAT, Ikonos, etc)
Consortium has 23 regional centers
-used mainly by GLIMS
-geomorphological and terrain changes
ASTER Global DEM (GDEM)
-released June 2009
-Free of charge for everyone
-30 m resolution world-wide coverage
Was used at James Ross and Vega Islands
-monitored a retreat of 42.4km2
-loss of ~4 glacier cover
-mostly floating ice melted
-retreat rate doubled from 75-88 to 88-01
Can calculate ice velocities, lake growth
Hester did a GLIMS study “Glacier rereat and sensitivity related project”
-Clemenceau Ice Field Group (CIG) and Chaba Icefield (CH)
-In the area, 12 of 21 glaciers have significantly accelerated retreat rate for 1985-2001
Changing landscape terminology
-Rockfall vs rockslies
-Landslides and mudslides
Glacial Lake Outburst Floods (GLOFs)
READ ABOUT ALL OF THESE FEATURES!!
Cryoturbation (cryosols or gelisols)
Ice/Frost wedge polygons
(non)sorted stone circles, polygons and stripes
-polygons can be low-centred or high-centred
Alases (large thermokarst depressions)
Palsas (frost heave of peaty ground /w ice lenses)
Pingos (hydrolaccolith: a hill of earth-covered ice)
-can be open or closed system, or collapsed (dead pingo)
**much of the paleo-process information is from studying sediments (and stratigraphy of sedimentary units), rather than from landforms
High-latitude areas on Mars and Earth both exhibit patterned ground where shallow fracturing has drawn polygons on the surface
Continuous vs Discontinuous coverage
cont: over 90% region covered
Permafrost is frozen ground
***Continuous permafrost zone coincides approximately with the 10C isotherm
Present landcover ;20%
-at LGM ~40%
Blockfields are a periglacial landform
Blockfields = felsenmeer = blockmeer= stone fields
Large, sheet-like expanses of weathered blocks (over .25m in size)
-Usually cover bedrock, though not necessarily same type of rock
-low surface gradients
-found in former arctic or alpine regions
No rock debris source (such as cliff) is seen, but the slope may rise to a ridge crest.
The block in blockfields are usually angular and are often thought to be the result of ‘mechanical’ weathering processes
Blockfields sometimes survive subglacially
-can survive under cold-based ice sheets
Arctic Ecozone Classification
Arctic ecozones based on the mean temperature of the warmest month
;2C = Polar desert
2-6C = Northern Tundra
6-10C = Southern Tundra
;10C = Forest tundra to Boreal forest zone
Boreal Forest = Taiga = Swamp Forest
-Norther Boreal forest in Canada vegetation:
-Black Spruce (P. Mariana)
-White Spruce (P. glauca)
-very low biodiversity
-Black spruce adapted to slightly colder than White spruce, but not by much
Species are monitored in N America and EuroSiberia
Position of summer and winter arctic front in relation to the polar treeline/the southern boundary of the boreal forest in North America (they correlate strongly)
-polar fron in summer and winter boundaries basically outline the boreal zone
1)semipermanent, semi-continuous front b/w the deep, cold arctic air and the shallower, ess cold olar air of northern latitudes
2) Southern boundary of the Arctic air mass
Difficult to measure:
1)highest tree (or farthest North) often not found
2) Present treeline inaccurate
3) Present treeline not in equilibrium with present climate
Asymmetric response to climate forcing:
-Northward (or up-mountain) migration of treeline much more rapid than southward (down-slope) migration
Established trees might survive for a while in deteriorated climate, but new trees will not establish in such a climate
Alpine treelines were ;200m higher than at present during Hypsithermal (6-3.5kyBP)
Degradation of cryospheric landforms
Permafrost is melting
-affects infrastructure and ecosystems
-leaks water to the oceans and frees methane
*top 3m of arctic permafrost may be gone by 2100
Dried mudflows occur along slopes especially in spring, when the uppermost layer of permafrost melts;
Mudflows consist of sediment saturated with water and can have speeds ;100km/h
Bodies melting out of permafrost may contain smallpox virus (Science) as it is resilient to freezing
-is happening (look up)
Cryospheric Natural Hazards
Hazards pose a threat to human life and livelihoods and can cause damage to infrastructure and industry
*Look at hazard glacier regions map on review lecture*
-In the Himalayas, the frequency of GLOFs has increased in the 2nd half of the 20th century
-At present ; 200 lakes pose a flood hazard in Hindu Kush-Himalayan region alone
The Dig Tsho GLOF (1985) killed 5 people, destroyed the Namche small hydropower project (~US 1.5million), 30 houses, 14 bridges, and cultivated land.
The BEAT THE GLOF ACTION RUN runners gather at Imja Lake (5010m), the fastest growing glacial lake in the Himalayas
-It is growing at 74m in length annually as the glacier behind it melts away
KOLKA GLACIER DISASTER, RUSSIAN CAUCASUS
-glacial broke off and slid down valley
-caused avalanche and mudflows
-overran Karmadon village 18km downstream
-over 120 ppl killed
Some research suggests that landslides are on the increase due to climate change.
But is this also the case for rockfall and large rockslides? (See Hester’s Study)
Large Rockslides: Case Study- Tsar Mountain
-Is this rockslide typical for long-runout rockslides on glaciers?
-What are possible triggers?
-What are the effects of the rockslide on the glacier regime?
-Can climate and seismic data constrain the timing of rockslides in this region?
-What is the contribution of events like these to the overall sediment budget and denudation rates in alpine regions?
-Landsat7, ASTER, SPOT quicklooks, Astronaut photography, Airborne photography from helicopter
-4 seismic stations (Earthquake Canada)
-2 automatic snow pillow stations (BC Ministry of Environment)
-1 climate station (Environment Canada)
-field measurements on Shackleton Glacier (8km NE)
Study of Cirque glacier rockslide (2.2km long)
-fall of 311m
-length of rockslide runout depends on substrate
Rockslides on glaciers have longer runout because
-lower friction with bed?
-confined flow by valley walls and moraines?
-entrainment of snow/ice in the fockslide base: fluidization?
POSSIBLE EFFECTS OF THE ROCKSLIDE ON THE GLACIER
2)increase/decrease of sensible heat flux
3)increase in basal shear stress by increase apparent ice thickness
4)hydrological effect by sudden impact
5)alteration of the supraglacial drainage
6)snow/ice incorporation during fluidization
-sat images bracken b/w 26 Aug and 23 Sept
-weather data suggest 10-15 sept (huge precip and temperature variation)
-seismic data pinpoints it to 14 sept 2000
-for seismic data, had to differentiate b/w earthquakes and surface events
-can do this with shape of seismograph
-is similar to other rockslides on glaciers
-stress fatigue in combination with intense rain (~30mm/day) and snowmelt around freezing T co-triggered the rockslide
-caused a 0.2-0.4 m w.e./a reduction of ablation (7-12%) and had some hdrological effects on glacier
SEISMIC EVENTS -since 1985: 26 significant seismic events <40km of the cirque: none large enough to trigger rockslides
-Seismic waveforms and frequency spectra -> no unequivolcal evidence for seismic tremors caused by rockslides
Landscapes in transition
Reinterpretation of landforms, sediments and stratigraphy
Sediment exhaustion curves
The ‘paraglacial period’ is the period of readjustment from a glacial to a nonglacial condition, as fluvial, slope and aeolian systems relax towards a nonglacial state
At the scale of the Pleistocene land ice, this paraglacial period occurred between 12-6kyBP
At the smaller, alpine glacier retreat scale, we are still in the middle of it.
Geomorphological and System theories
Hutton (1880s): geological cycle
Church (1970s): paraglacial
Hewitt (1990s): landscapes of transition
Brunsden (1990): system stability
Holling: relisience (1973) & Panarchy (2002)
Diamond’s (2005) collapse of societies
Landscape System stability and sensitivity
Hutton’s rock cycle (decay of continents to the sea and then to uplift again) = Uniformitarianism
-landscape changes are through punctuated equilibrium…
Is equilibrium a state of stability or conservation???
stability: the temporal behaviour of a landscape over time
sensitivity: is the susceptibility of landforms to change
Phillips (2009) framework for the assessment of geomorphic changes and responses based on 4Rs
-Response (reaction and relaxation times)
-Resistance (relative to the drivers of change)
-Resilience (this is how well you maintain a self-organizing capacity? -> recovery ability, based on dynamical stability)
-Recursion (positive and/or negative feedbacks
resilience = capacity to dal with change and contiue to develop. Ecosystem resilience, social resilience, etc.
Holling’s panarchy cycle incorporates collapse and creative reorganisation as two of the NORMAL stages of an adaptive cycle
2-Phase Adaptive Cycle
Phase 1: expansion and prosperity with growth and accumulation of capital and wealth. Though changes may be slow, the effects can become substantial as they gradually accumulate.
Phase 2: “back-loop” characterized by creative destruction and reorganization, potentially suddenly. Period of low predictability (potential for surprises). Suddenevents (eg. forest fire), can unexpectedly and sometimes irreversibly “flip” an ecosystem or economy into a qualitatively different state by triggering the release of biomass, capital and wealth.
2-phase wehre resources are less widely available
3- release or creative destruction phase
4-reorganization and restructuring
Adaption = reaction to drivers and constraints
***Panarchy works at different scales and over dif time frames
***Watch video on Buzz Holling, father of resilience theory (http://stockholmresilience.org
Panarchy and Sustainability
*Panarchy makes ‘sustainability not a static condition that need to be preserved for future generations
Tradition ‘sustainability’ ignores transcience, transitional states and collapse as normal environmental characteristics
Pattern of punctuated change is the norm.
PANARCHY/ADAPTIVE CYCLE PROPERTIES
(sustainability can be seen as the collective strength of the above)
Diamond’s Societal Collapse Model
Identifies 5 factors that can contribute to the decline and collapse of civilization:
1)environmental damage and population growth
3) hostile neighbors
4)widespread trade partners
5)failure to solve societal problems
Must increase resilience to avoid collapse.
How do we promote the adaptive capacity of resource users? (increase resilience of local people?)
Prof Terry Chapin (UAF): plant physiology and Arctic ecosystem ecology, and resilience of social-ecological systems
Tipping points in a system are the critical threshold of a level of change in a (sub) system after which changes will proceed under their own momentum: like a run-away system.
Sometimes the changes after the tipping point are accelerated or step-wise.
Many of earth’s potential anthropogenic tipping points are related to the cryosphere
Potential Global Warming Triggers:
-Arctic Summer Sa Ice (1-2C)
-Greenland Ice Sheet (1-2C)
-Boreal Forest (2-3C)
-West Antarctic Ice Sheet (3-4C)
-Amazon Rainforest (3-4C)
Biodiversity has already hit a tipping point.
Another one has too (read on review)
-Climate change is over halfway there
-ocean acidification and P-cycle are getting there too.
-see Terry Chapin (1:41) video
What are consequences of climate change in the Arctic?
-Rapidity of changes
-Large scale environmental effects
Ice and Biome Distribution/ Peopling of the New World
-degrade rapidly by hydrolysis on exposure to light, air, soil
-small amounts can be detected in food and drinking water
-slowly phased out in scientific equipment
-asia currently 50% of emissions
-pipes, fillings, paint
-many contaiminants accumulate in fatty tissue
Some good news!
US clean air act (1972 and 1996) and world-wide ban phasing out of leaded gasoline/petroleum.
-decrease in nitrate, and later in Pb concentrations
LOTS OF BAD
-game sea birds, particularly eider, contain high concentrations of lead (but this is because the use of ‘lead shot’ in hunting the birds
-human blood lead concentration is higher with the more sea birds consumed.
Radioactive ice cores found and can accurately date nuclear testing, chernobyl, and the testing ban.
Russian underground nuclear explosions (71-88) occurred in the norht quite often.
There were 43 underground explosions in Novaya Zemlyabefore 1991.
There is a great amount of radioactive material in the world. The potential exists for climate change to mobilize it.
EFFECTS -acute radiation Syndrome (death due to high doses)
-damaged DNA (less resilience)
-etc. etc. etc.
-can skip steps
PROJECT CHARIOT (58-62)
US Atmoic Energy Commission proposal to detonate a string of underground nuclear devices at Cape Thompson on the N Slope of Alska
Inupiat vilage of Point Hope -; hunting grounds in the area…
Prediction of Pollution Effects
Heat and salt content are important factors affecting
1)the functioning of polar ecosystems
2)the rates of substance flows
3)the stratification of the water, internal waves, circulation patterns, sea ice distribution
In order to predict and make timely decisions after teh appearance of undesirable trends or extreme environmental situations, it is necessary to understand enviornmental processes, and construct models of abiotic and biotic relationships.
Ecosystem Pollution and Arctic Foodwebs
Ecosystems have 4 basic components:
1)the abiotic environment
2) producers (autotrophs)
3) consumers (heterotrophs)
Energy cycles through them
trophic level the position that an organism occupies in a food chain
-what an organism eats and what eats the organism
*Marine food webs have more tropihc levels than terrestrial food webs
The Tundra Biome
-Productivty very low
-Recovery from any distrubance is very slow as tundra is a very delicate and fragile biome
Timescale of ecological processes in relation to natural disturbances in the Arctic…. NO FAST RESPONSES
How do Contaminants get concentrated in Cold Environments?
-ie. all of the contaminant moves from air to water: increased concentration in water
-removal of solvent by a variety of processes
-can lead to “fugacity amplification” (fugacity reflects the tendency of a substance to prefer one phase (liquid, solid, or gas)
-Read about this, and look at diagram (lec9p5)
-organism absorbs toxic substance at a greater rate than that at which the substance is lost
-within a trophic level
-increase in concentration of a toxic substance in a food chain resulting from a)persistence (slow degradation), b)food chain energetics, or c) low rate of internal degradation/excretion (often due to water-inslubility)
Arctic pollution and glacier melt
DDT levels in the Adelie penguin have been unchanged since the 1970s, despite an 80% reduction in global DDT use (has been banned in N hemisphere)
1-4kg of DDT are released into coastal waters annually along the W Antarctic Ice sheet from glacial meltwater
Glacier melt a probable source for DDT pollution of Antarctic marine systems
MELTING ALPINE GLACIERS: POPs Released
-relevant release of POPs from melting Alpine glaciers
-input fluxes from the high-alpine lake Oberaar into the lake sediment
EFFECTS of both biomagnification and solvent depletion in glacial stream in the Italian Alps
-peak in July possibly from solvent depletion (rain and melting of snow)
-Glaciers and snow are temporary sinks for atmospherically transported pollutants
Bioaccumulation ; Biomagnification
Causal link b/w POPs and adverse health in top predators
-hormone, immune and reproductive systems
Many indigenous populations in the Arctic have poorer health than the national averages = combination of western food, lifestyle choices and polluted food.
-cardiovascular, reproductive, hormone, neurological, metabolic and immune systems
Traditional food remains important for social, cultural, nutritional, economic and spiritual reasons.
SMOKE FROM FIRES
-reddish-brown smog (mostly N of 60N)
-Sulfuric acid, nitrogen and organic aerosols formed in the air from the combination of naturally occurring chemicals and pollutant sulfur dioxide or hydrocarbon gases.
Aerosols smal enough to float in the air, but large enough to reflect sunlight, and cause haze.
Arctic haze also carries a mes of airborne toxic contaminants, heavy metals, and industrial organic compounts
It is seasonal. Peaks in late winter and spring and is most severe when stable, high pressure systems produce clear, calm weather. Removed by wind or rain. This rain is often acid rain.
WHY does it form over the arctic region???
Arctic haze is the result of the ‘trapping’ of air masses in Arctic Dome (or cold air) that sits over the N Pole region. The Arctic Dome is confined by the Arctic front, which is the boundary between polar and arctic air masses and lies to the north of the Polar Front (boundary of polar and warmer air masses).
The Arctic Front is discontinuous and wavy and depends on the temperature contrast between two air masses. It is particularly prominent during summer in N Eurasia.
Arctic haze can appear in distinct ‘bands’ or ‘layers’ at different heights because warm dirty air is forced upward. These bands can be 10-1000m thick and can extend over 20-200km. Within the bands, visibility can sometimes be just a few km.
-smelter complexes in Siberia (largest source of sulfur dioxide emissions within Arctic region is at Norilsk)
NAmerica contributes most ozone, Europe contributes most sulfate, black carbon. CO is mostly equal for all sources.
SOURCE REGION SENSITIVITY
Sensitivities show strong seasonality…
1) surface sensitivities typically maximize during boreal winter for European and during spring for E Asian and N American emissions
2)Mid-tropospheric sensitivities nearly always maximize during spring or summer for all regions
3)Deposition of black carbon (BC) onto Grenland is most sensitive to N American emissions.
Exxon Valdez (1989)
Exxon Valdez ran aground on a well-known reef and spilled 11million gallons of crude oil
-one of the largest spills in US history and one of the largest ecological disasters
-one of very few oil disasters in Arctic regions
Timeline for recovery depends on substrate:
-bedrock shorelines in wave zone :weeks
-exposed sandy beaches: months
-marshes and salt flats: years to decades
Oil in sediments (sand/silt/clay) will remain there fore years/decades.
Prince William Sound has made a remarkable recovery from a severe injury, but it remains an ecosystem in transition, 20yrs later:
-26000 gallons Valdez oil still in Alaska’s sand/soil
-Deeply penetrated oil still leaches from a few beaches
-in some areas, intertidal animals (mussels) are still contaminated by oil
-some rocky sites that were stripped of heavy plant cover by high-pressure, hot-water cleaning remain mostly bare rock.
-Rich clam beds that suffered high mortalities from oil and extensive beach cleaning have not repopulated to previous levels
Pollution in Chernobyl, Rockies, and Tibet
RECENT CLIMATE EXTREMES ALTER ALPINE LAKE ECOSYSTEMS
-Alpine lake ecosystems responsive to interannual variation in climate, based on long-term limnological and meteorological data from the Canadian Rockies
In 2000s, rel to 1990s, in years with colder winters, higher snowfall, later snowmelt, shorter ice-free seasons, and drier summers, alpine lakes:
1)became clearer, warmer, and mixed to deeper depths
2)became more dilute and nutrient poor (leading to declines in total phytoplankton biomass)
3)had increased concentrations of dissolved organic carbon (stimulating the appearance of small mixotrophic algal species, partially offsetting the decline in autotrophic phytoplankton biomass)
-1 of 15 worst places to live
-1986, home to over 14k residents, now is uninhabited due to contamination
-worldwide spinach, mushrooms, lichen, caribou
-one of 15 as well
-a soot-covered mining town in the Peruvian Andes
-99% of the children who live here have blood levels over acceptable limits for lead poisoning, which can be directly attributed to an American-owned smelter that has been polluting the city since 1922.
Mining operations in Tibet have been booming since the arrival of the Qinghai-Tibet rail line in 2006, bringing wealth to local governments and mine owners.
Little benefit to local Tibetan farmers and nomads who say the mines scar mountains they consider sacred and kill the yaks and sheep they need in order to make a living
Protests against China’s billion-dollar mining industry are rising.
Precautionary Principle, Future threats, and Arctic Charter
In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.
Conclusions of the ALDE Conference on Arctic Governance (2008)
-Borders and jurisdiction are not seen as the main obstacles for Arctic governance
-environmenta changes and risks from human activity are the most important challenges
-inerconnectedness of the arctic ecysystems should have implications for its governance
-the regime in the Antarctic cannot be transferred to the Arctic; the two polar regions are totally different from each other in so many perspectives
-existing treaties must be ratified, implemented and strengthened
-at the moment it is not politically and legally feasible for a broad, binding legal regime at a regional Arctic scale (yet there is need for strategic coordination)
-there are limitations in teh functionality of the Arctic council (scientific agenda), limiting the possibilities of acting as a strategic coordinating body
-International collaboration, including nations outside the arctic, where most pollution is originating from, through partnership and stewardship.
How Animals Survive in Cold Regions
David Attenborough: The Frozen Seas
Reduce area:volume ratio
Fat or Blubber
Fur/Feathers – not such good insulators in water unless coated, not great in wind
-antifreeze in blood (frogs)
-vascular counter-current heat exchanger (fish)
-birds, butterflies, caribou, lemmings, narwhals and whales
Movement to keep ice open (warmer and can breathe)
-ducks, whales, seals
Fattening up for winter!
Rain on Snow Events
In October 2003, a severe ROS event killed ~20 000 musk-oxen on Banks Island, westermost island in the Canadian Arctic
The event reduced the isolated herd by 25% and significantly affected the people dependent on the herd’s well-being
ROS induced water and ice layers facilitate a) the growth of toxic fungi 2) significantly warm the soil surface under thick snowpack and 3) the hard snow crust deters large grazing mamals (musk oxen and caribou)
ROS events are defined as a minimum of 3mm of rain falling on a minimum of 5mm of snow w.e. (~5cm snow)
Increased frequency of ROS events in much of northwestern NA: habitat for several types of caribou.
-quantitative analysis of plants/animals: mean shift towards earlier spring of 2.3 days per decade
-qualitative analysis of 677spp 62% showed trends towards spring advancement
B)RANGE BOUNDARY SHIFTS
99 spp of birds, butterflies and alpine herbs
-Range limits of spp have moved on average 6.1 km/decade N
-significantly in direction predicted by climate change
C)COMMUNITY SPP DIST/ABUNDANCE
Qual. anal. ~900spp
-neither support nor refute a climate change signal
-will be important for predictive biological models to eventualy determine what proportion of these are truly stable systems
Range Distribution Shifts
-New spp have colonized previously ‘cool’ regions
-Some arctic spp have contracted in range size
-over past 40 yrs, max range shifts vary from 200km (butterflies) to 1000km (marine copepods)
-Difference b/w polar and temperate spp
Polar: stable or decline
Temperate: increased in abundance and/or epanded distributions.
A changing landscape: investigating a warming climate
Also find and watch movie on Svalbard Global Seed Vault
Periglacial processes characerise regions with cold climates
-periglacial used to describe proceses and features in areas adjacent to modern ice sheets
A periglacial environment is difficult to define..
-stones shaped and polished by wind abrasion
-aeolian transported sand is dominant factor
Created by sand moving in the saltation zone
Can be 3- or 4-siders
Produced on surfaces nearly perpendicular to wind direction
-small depressions eroded into surface
-best developed on steep surfaces facing prevailing wind
-begin and grow from points of weakness
-what are some possible points of weakness?
-grow from pits
-extend across the rock surface linearly on surface facing wind
-aligned parallel to strongest wind direction
-most reliable type for determining wind direction
-Larger scale ventifact
Wind eroded ridge that is elongated parallel to prevailing wind (typically 2-3 times longer than they are wide)
-usually less than 10m high
Can extend for kilometres
Stoss side is blunt and steep
Common in regions underlain by relatively soft rocks
HOW are ventifacts important?
-provide useful information about periglacial wind conditions both past and present
-former wind conditions are useful for reconstructing periglacial environments
Surface is only one or two stone layers thick
Fine sediment under stones
Removal of finer sediments from the surface
This causes deflation
Once finer sediment is removed and only rocks are exposed, wind threshold cannot continue to erode
Common in aluvial fans and unsorted deposits
Occurs under very windy conditions
How is it periglacial?
-alluvial fans from glacial outwash
-katabatic winds next to a glacier
-rocks in the pavement can be ventifacts
-ventifacts help determine wind regime of past
-wind regime can help reconstruct past climates
Wind deposited sediment
Loess deposits blanket the landscape
over 50% silt, 5-30% clay, and 5-10% fine sand
-porosity less than 50%
-sudden collapsibility when saturated
-forms nearly vertical exposures
-cold climate periglacial sediment deposits
-originates from flood plains, (ie outwash from glacial streams)
-silt and clay is transported by the wind as dust, it is called loess when it is deposited
-thus, loess does not necessarily indicate a periglacial enviornment due to aeolian trasportation
Thick loess sheets of central Europe, Russia, and China were deposited in glacial periods.
Warmer climatic conditions allow organic layers (Paleosols) to form on the loess deposits
-paleosols can be carbon dated
-can reconstruct past climatic conditions
-Thus, loess deposits are archives of past climatic conditions and environmental changes
Assymetrical mounds of sand that migrate by aeolian erosion
Contains: backslope, crest, slipface
What are requirements for periglacial sand dunes?
-lack of veg
-climate (arid, semi-arid)
How are they periglacial?
Sediment supply originates from glacio-fluvial and glacio-lacustrine sediment from glacial outwash and melt water
-katabatic winds drive the formation of the dunes
Barchan dunes vs Parabolic dunes
-ridges of sand with steep stoss face
-barchan dunes transform into transverse dunes if the sediment supply increases
-form parallel to prevailing wind irections
-wider and steeper at upwind end
-form in areas with limited sand supply
Commonalites (ventifacts, loess, desert pavement, and sand dunes)
All rely on :
Each landform occurs in a transitioning landscape relative to periglacial environments
-ventifacts occur in areas with unsorted deposits and katabatic winds from glacier
loess originates from outwash of glacial streams. Deposits indicate glacial and interglacial periods.
Desert pavement is common in alluvial fans and unsorted deposits. Kat winds from the adj glacier.
Dunes are supplied by glacial outwash sediment … again katabatic winds.
Measuring the Cryosphere
The cryosphere is the most sensitive to changes in climate of all environmental systems at the earth surface…
..relatively few measurements because of geographical remoteness, large scale, extreme conditions, extreme variability, and the long time-scale of some cryospheric processes.
Review- Cryosphere components and trends
Sea ice, ince 1978, has decreased in extent by about 2.1% per decade (slope of -9)
Northern lakes are experiences earlier freeze and later breakup dates.
Mean lengths in global glacier tongues are all decreasing (small variability).
Snow, river/lake/sea ice: day to month
Glaciers/Ice caps: months to centuries
Frozen ground: days to millennia
Ice sheet margins: months
ice shelves: years
ice sheets: millennia
Relevance of Tayler’s presentation
Landscapes in transition!
Regions where glacier hazards are currently problematic
BC: moraine dammed lake outbursts following recesion
N Andes/Cascades: outburst floods from glacier topped volcanoes
Peruvian Andes: Moraine dammed lake outbursts following glacier recession
Iceland: outburst floods from subglacier volcanic eruptions
European Alps: ice avalanches
-GLOFs from recession
Caucasus mtns: Rock/ice avalanches
Tien Shan Mountains: Glacier dammed lake outburst following glacier advances
Large fluctuations in energy/size of sediment
Angular, large boulders
PARAGLACIAL SEDIMENT REWORKING
-The paraglacial period of enhanced sediment yield commences at deglaciation and terminates when sediment yield is indistinguishable from the ‘gological norm’ resulting from primary denudation of the land surface by subaerial processes.
**review this graph (in review)
At commencement of deglaciation, sediment yield increases a little bit then gradually goes down and levels off
That which is attributed to glaciation is the entrainment of paraglacial rock-slope debris.
Geological norm consists of debris input from valley walls and subglacial abrasion and quarrying
Also study paraglacial exhaustion curves (next slide)
Some tipping points…
Boreal Forest DIe Back..
Melt of Greenland Ice Sheet
Arctic Sea Ice Loss
Instability of West Antarctic Ice Sheet
Atlantic Deep water Formation
Changes in ENSO Amplitude/Frequency
West African Monsoon Shift
Indian Monsoon chaotic multistability
Climate change induced ozone hole
Tipping points of chemical polution and atmospheric aerosol loading have not yet been quantified…
Already past tipping points for biodiversity loss and Nitrogen cycle (biogeochemical flow boundary)
Do all the tasks!!!
Data exploration task (google earth) prob testable..
Taught us to:
1)understand presented phenomena
2)think about the wider implications
Hocky stick graph
Comparison of NH temperature proxies with model simulations over the past 1000 years, and T record extension to 2000 years using long proxy temp data series
Climate denial with Peter Sinclain (crock of the week)