global climate change 3rd unit

What is this image showing about major river deltas?

• major rivers like ganges, yangtze, pearl river, mississippi, nile and mekong have super high population density at their deltas

• deltas are 1% of earths area but hold 5% of the earths population

• deltas are sinking faster than sea levels are rising due to weight and messing with sediment deposits

• extreme subsidence, vulnerable to extreme weather events, urbanization ruins soils

What is this showing

it is showing were the most extreme risk is for each delta, south east asia is low lying and is going to go under,

this image goes with the nightime light one, the highest populatin densisites are at deltas that are the most vulnerable

deltas

• Low elevation coastal zones 

• So vulnerable

  • Accelerated sea level rise, subsidence (human induced), sediment deficit, adverse human impacts 

    • Human induced: ground water extraction 

• Coastal Louisiana can be seen as the canary in the coal mine within this context, what happened here has global significance 

  • We have lower land than other places so it is happening here

when are deltas sustainable?

• Need a lot of sediment to offset delta plain loss 

• Circles are delta size and it maximum sediment available v sediment needed to elevate delta plain by 100 years

• In any large deltas there is a deficit

• If on upper left or on line its 1-1 or better so the delta is fine

what is this showing? What is the temperature?

• the prediction of sea level rise for 3 degrees celsius brings the coast line to baton rouge

• we are the example

what is this showing?

• over the past 100 years Current rates of loss football fields for every one hundred minutes

• New delta lobes are green

• yellow is predicted land loss, red is already lost, green is predicted gain

• so much of it is wet land loss which ecological goods and services are valued at 200,0000 dollars ha-1 yr-1

What are these projections?

a. relative sea level rise projections through 2100

• maximum at red predicts 1.4 meters a year when adding 8mm/yr of subsidence

• projected yellow area is with 5mm/yr

• minimum is 0.5 meters at 3mm/yr

• and the sea level rise without local subsidence, would be worse for louisiana

b. is regional map showing how bad it will be

c. is the potential loss of land

• pink is the accelerating scnario 3-4 mm/yr loisiana will lose 15,000 km2 by 2100

• stable is green 1mm/yr is still 7,500 km yr

basically LA going under

what is this showing about wetlands? non climatic cause

• there is extreme wetland loss from canals dissecting delta plain

  • saltwater intrusion, river can’t move back and forth

  • Widen over time and entire areas are lost

  • 15,000 km of canals for oil and gas and artificial levees shut down sediment deposits

  • 45 square kilometers per year

what is this showing

• swamp turned to marsh

• loss of carbon sequestration peat is lost, no carbon sink

• can’t bounce back

• much more vulnerable to storms

the front is with action, the back is without action. Coastal Master Plan does what for us?

What is this new subsidence map showing us?

• 9 mm/yr subsidence but varies by location which is much higher than other papers

  • implies different parts of the shoreline need more help

  • levees big cause

  • combines gps data, and rods in sediments below surface of the water measures land elevation because looks at land motions because tide gauges have too many influences

Relative sea level rise rate need what three components, what is it saying

• the combination of shallow subsidence, deep subsidence (gps), and sea level rise (satellite allimetry, 2 mm/yr)

• regional variance: mississippi delta has a higher rslr driven by sedment compaction and subsidence compare to chenier plain

• graph on right shows that 80% of the locations that were studied have a median rslr of 9mm/yr

• huge amount mississippi delta is going to experience extreme rates of 20 mm/yr way higher than global average

• low tidal range in the gulf of mexico makes la really vulnerable since we are really low

relative sea level rise ad sediment acretian (sediment build up on wetlands), vulnerability

• green is ok, accretian surplus

• blue bad accretan deficit

• grey is the buffer zone where 1:1 accrtian matches sea level rise

• 35% of of the coastal ecosystem cores are in accretian deifcit

• 50% of mississippi in deficit, and western chenier and eastern chenier plane

Relative sea level curve figure, three axis for the mississippi delta only

• High early on and then it slowed down, because ice sheets especially great lakes dotted line

• Solid line is the derivative 

• Then see what the marshes did and see if they could keep up, based on sediment core which abrupt marsh just flooded so it was able to persist for a little but couldn't and turned to open water so we should be scared 

• SLIP: sea level posistion green markers, from peat compaction free basal marsh peat

  • show that sea levels were much lower 8,000 years ago

• tipping point done tbh

what is this?

• 355 boreholes for paleo-marsh analysis

what are the 15 sedimentary logs showing RSLR

• shows the transitions from a wetland paleosol to basal holocen facies

• Move to right and see blue stuff showing drowning of the marshes

• Takes awhile to kick in, gradual drowning 

• Easily going to get in to rapid drowning for us based on the cm rise waterm, terrestial plants cant keep up, total loss of coastal wetland system

• Turned in to compact bars in a rectangle to show sites which remain  fully terrestrial to when they drown which it is a 3mm year there is an abrupt shift, three or higher game over, right at Katrina we hit the 3mm, we've crossed the threshold 

• open water sediment is compact and dead compared to peat

what is this showing? (threshold effect)

• the threshold effect is a clear tipping point at 3.00 mm or higher where sites are drowned

• compared to global sea level rise current rate is 4.5 mm/yr

• non linear response of marsh to rae of sea level rise

• in some cases they can keep up but not really anymore

coastal ecosystem, global warming and RSLR

• a-d spatial distribution of relative sea level rise rates for different global mean temperature warming scenarios 1.5c -4.0c above pre industrial

• e-g proportion of coastal ecosystem tidal marshes, mangroces, corla reefs that are projected to experience rslr rate greater than 7mm yr-1 at various levles of global mean warming

• global warming that exceeds 2c will lead to decline of critical coastal and marine ecosystems

what is this showing about land area changes

• this was the plan for the barataria bay and breton sound levee breaches for sediment deposits

• was canceled

• diversions like this mimic natural delta building processes but they have to contend with accelerating sea level rise

climate impacts

• never occur in isolation and must be viewed within the broader context of environmental degradation

• coastal louisiana provides and excellent example of an already severely wounded landscape that now faces the onslaught of accelerated sea-level rise

hydrological cycle changes at different rcps climate impacts

• rhine river levee ex

• changes to the hydrological cycle are reflected by a more intense precipitation regime in most of the world but drought in other parts

• river floods are already on the rise and will continue to do so there impact is the result of a combination of hydrologic changes and increased population densities and economic activites in flood plains

• coastal storms especially tropical cyclones constitute another threat, most of the issue is from the storm surges rather than wind

hurricane katrina storm surge

• harrison county hit the hardest

• Tracks eye of the storm goes straight up to the right of nola

• Storm surge was the highest in harrison mississippi people who stayed there did not survive

• similarly when hurricane florence and harvey stalled they dumped so muc rain

Cyclone patterns

• On equator no cyclones lowest latitudes

• Start in africa cross the atlantic

• The requirement for the storms to be strong is really warm waters

• Higher latitude ferrel cell with westerlies that move in opposite direction

• Why is there nothing 

• West coast africa upwelling makes cold water so no hurricanes

• Amount might not change but their intensity is increasing

• Their impact increase because rising sea levels make coastal areas vulnerable regardless of storm climate changes

  • Disproportional population increase in low elevation coastal zone, economic reasons global trend

climate impacts cylcones

• tropical cyclones are particularly deadly and costly there is concern how they will be in warming world

• frequency may not change but intensity is

• the impact of tropical cyclones increase with rising sea levels making coastal areas more vulnerable regardless if storms change

• disproportional population increase in low elevation coastal zones

water witdrawal in cubic kilometer 1900-2000

• agriculture dominant driver of global water usage, more than all other human uses combined

• agricultural, municipal, industrial and resevoir storage

various climate change impacts on water resources and infrastructure

freshwater lens decline: in small island nations sea level rise projected to reduce the thickness of freshwater lenses significantly by 2040

water supply riss: streamflow decrease threaten water satidfaction and salmon habitats while groundwater recharge is expected to drop sharply in 2050

infrastructure and energy: hydropower potential is predicted to decrease by over 25% by 2070s and flooding in areas like bangladesh will increase 2c

pathogen risk: wil increase beaces heavy rains in areas with out good water supply and sanitation

groundwater footprints

• sustainability indicators where its the withdrawal of local regions groundwater compared to natural reservoir, also the area needed to dilute pollutants

  • usually 3.5

  • over exploited in upper ganges, northern china, central valley

  • Gf/Aa > 1 : unsustainable

  • Gf/Aa » 1: when people are mining water and refilled by past climatic events

  • but there are a lot thats not over that

  • increasing heavily in areas that are facing drought

what is the effect of global climate change on food production

climate change may have some beneficial impacts in some area since precipiation may increase in some places

climate impact on biopshere

• extreme and expresses itself in multiple ways

• extinction occurs when habitats disappears altogether or becomes small/ fragmented to support the species concerned, 20-30% of species so far assesed are at increasingly high risk of extinction

• biome migration along with the migration of individual species occurs both latitudinally and altitudinally it is often hampered by other human-caused barriers

• species vulnerability graph, species with movement speed falling below a specific climate velocity line are unlikely to keep up with warming without human intervention

  • trees and herbaceous plants are lowest movement making them vulnerable to even moderate climate change

  • split hoofed and carnivorous mammals show the highest mobility with many capable of exceeding 100 km/decade

  • rcp8.5 is way higher than any animal can keep up with

realtionship between climate (temperature and precipitation) and the biomass of three tree species: Arolla pine, norway spruce, and common beech

ecological niches, certain

• arolla pine: cooler direr environmnets in 0-4C and precipitation below 1000 mm/yr

• norway spruce: occupies a mid-range niche and prefers high to moderate precipitation >1000 mm/yr and temperatures 0-8C

• common beech: dominates in warmer, wetter conditions highest biomass occurs at temperature 6C precipitation levels exceeding 1000 mm/yr

projected artic conditions, what is happening with plants

• loss of tundra and polar desert, expected to shrink and be overtaken by grasslands and forests

• ice reduction the white ice region at the pole shows a significant decrease in the projected map compared to the current map

• biome migration along with the migration of individual species occurs both latitudinally and altitudinally it is often hampered by toehr human caused barriers

ocean acidification

presents an immense threat to a wide range of marine species and ecosystems notably coral reefs