Climate Change

Sun’s raditation

30% of raditation reflected back into space (albedo)

70% is absorped by earth

Short wave radiation

Inbalances between incoming and outgoing radiation cause changes in Earth’s temperature

Greenhouse effect

Shortwave radiation in from sun

Earth converts energy to longwave raditation out

Half of longwave radiation out goes can’t escape atmosphere

GHG’s in atmosphere send back longwave radiation to earth (back radiation)

Causes warming

Evapotranspiration (ET)

stores heat as latent heat

causes local cooling

releases heat into atmosphere during condensation

Drives humidity and rainfall

Redistribution and regulator of heat and moisture

Carbon geologic cycle

slow flux

weathering

carbon biological pool

fast flux

respiration

bush fires

carbon sink

stores more carbon than it releases

atmosphere

ocean

terrestrial systems

Aerosols

soot, dust, sea salt, sulfates

wide redistribution

cooling effect

Forests ability to sequester carbon

large sink

have a limit on amount they can sequestor (peaks then declines)

International Pannel on Climate Change

Assesses science related to climate change for robustness

Surface waters

interact with atmosphere

driven by wind

Latent heat

phase change without altering temperature

Sensible heat

Temperature change without changing phase

Trade winds/ correolis

East to West Along the equator

Hot air rises at equator

New air comes in from sides to replace it

causes circulation and currents

East Australian Current

controls weather on east coast of Australia

El Nino Souther Oscillation (ENSO)

Trade winds pile up water on west side of basin

3-6 year cycle

Cycles between La Nina, Neutral, and El Nino

Currently in Nuetral, heading towards El Nino

Teleconnection

Drives east Australian climate

El Nino

higher temperatures

Less Rain

Relaxed tradewinds → less water piled up → less clouds → warmer and less rain

La Nina

Lower temperatures/ More rain

Stronger tradewinds → more water piled up → more clouds → cooler and more rain

Thermohaline Circulation

Water gets cold and salty (dense) at poles and sinks

travels towards equator from displacement

Warms and rises near equator

Pushed by wind towards poles on surface

Allows ocean to take up a lot of heat

Carbon in water

cold water holds more carbon

when carbon goes into ocean → acidification

Ocean carbon ABC’s

Air-sea exchange (equilibriun exchange)

Biological production (photosynthesis, biological pump)

Carbon Circulation (in thermohaline circulation and currents)

Carbon Biological Pump

Plankton take up CO2 through photosynthesis

Die and sink to bottom of ocean

Carbon goes back up through respiration

nutrients is limiting factor

Carbon circulation in the ocean

transported through thermohaline circulation

Released at upwelling zones into atmosphere

Climate change and oceans

Increased frequency of marine heatwaves

acidification

warmer temps

Oceans take up a lot of heat and carbon produced (buffer us from climate change)

Can affect circulation processes

Marine heatwaves

extreme sea surface temperatures for long periods of times

increases evaporation

alters wind and surface ocean circulation

kills ecosystems (coral bleaching)

Economic impacts (fisheries, increasing rainfall, onshore heatwaves)

Cryosphere

Ice

high albedo (reflects energy back into space)

holds large amount of earth’s water

Sea-level rise causes

Thermal expansion of warming water (warm particles move around more and need more space)

melting ice sheets (directly adds more water and feedback loop of lower albido for additional melthing)

Plate Techtonics

movement of plates in the lithosphere

Volcanos on the boundaries

Impact climate, ocean circulation, and other cycles through distributions of continents and oceans

Volcanoes

Release CO2 (causes small amount of warming)

Cause more cooling than warming due to release of aerosols

Earths regulation of solar radiation

Ecentricity → earths orbit can be circle or eliptical

Obliquity →tilt of earth on its axis (causes seasons)

Procession → earth wobbles on axis

Records of Earth’s climate

short records → most date back to 1850’s during industrial revolution

can use climate proxies to estimate past climates

Physical proxy

Lake cores → Sediment characteristics

How much did something grow:

Tree rings → grow quicker under ideal conditions

Corals → annual layers

Chemical Proxies

Fingerprinting and isotopes

Concentrations for temperatures

Ice cores

Important in oceans

Biological Proxies

Look at temperature and depth ranges

Pollen

DNA

Fossils

Ice Cores

Can look at trapped bubbles to measure atmospheric gases (CO2)

Can use to reconstruct climates

Shows correlations between temperature and CO2

Ocean CO2-temperature feedback loop

External Forcing: solar

Warmer ocean temp → ocean solubility reduces → more CO2 released into atmosphere → higher atmospheric CO2 drives greenhouse effect → warmer ocean temp

Can add external forcing of anthropogenic warming

Can work for ocean cooling or warming

Weathering

Removes CO2 from the atmosphere when CO2 interacts with rocks

chemical and physical process

Past climates

We were in hothouse climate

Then in coolhouse climate

Now in icehouse climate → grew antarctic ice sheet

Can link past CO2 to temperature data

Current atmospheric CO2 level

430 ppm

Climate Model

Predictions of climates made of a 3D grid of Earth

Scale is important factor (global, regional, etc…)

Hard to model precipitation

Test with historical observations

Coupled Model Intercomparison Project (CMIP)

Collaboration of climate models

Latest is CMIP 6

IPCC Working Group 2 report

How climate change and risks will affect humans, ecosystems, and biodiversity

How to adapt

Human health impacts from climate change

Heat risks

Disease → malaria in mosquitos (huge killer)

Respiratory Illnesses

Heart issues

Medicine storage

Heatwaves

Mutliple days of above average heat

Frequency is increasing → driven by teleconnections

Worsened by urban heat island effects

Have highest amount of deaths from impacts

Can damage roads, agriculture, and ecosystems

Can increase fire risks and droughts

Affect human work and economy

Urban Heat Island effect

Concrete and buildings absorb heat (sensible) and reflect into environment

Less trees to convert heat into latent heat

Bushfires

Increased risk due to climate change

more intense fires during El Nino

Need to manage fuels to lessen intensity (backburning)

Many Australian species tolerate or need burning (pyrophillic)

Droughts

Meteorological droughts (months)

Agriculture droughts

Hydrological droughts (years)

Remove?

Desertification

Land degradation

Impacts biodiversity and ecosystems

Causes less rainfall

Cyclones

Increasing in intensity → higher humidity?

Occuring closer to Brisbane (poleward movement)

form over warm water

Uncertainty if frequency is increasing

Storm Surges

Increasing because of cyclones?

ADD

Wet bulb temperature

Temperature limit for human survival at 100%?

35 degrees?

No evaporative cooling

Climate change economics

Investing in climate action will offset extra costs of human health issues

Climate Risk

Risk = hazards + exposure + vulnerability

Exposure = how much will climate change around species

likelihood and consequence

8% of species at risk of going extinct

Southern Hemisphere has higher risk

Climate vulnerability

Vulnerability = exposure + sensitivity - adaptive capability

Adaptive capability → how well can spp respond

Sensitivity → can they disperse, are they restricted, high or low genetic variability

Can you afford aircon?

Vulnerability Index (VI)

Amphibians high vulnerability

Birds least vulnerable

Australia arid zones most vulnerable (hot and flat)

Maladaptation

Intended to help but does more harm than good

Sea walls increasing coastal erosion

Need to monitor

Climate Change Adaptation

Strategies to cope

Accepting what is happening and make impacts less

Climate Change Mitigation

Strategies to reduce/ prevent further climate change

Reduce carbon sources and increase sinks

Working Group 3

Have to do actions that also address non-climate issues (land use change, pollution, etc.)

Top carbon emissions

China

Highest carbon emissions per capita

Qatar

Highest emitting activities

Electricity and heat 1st

Transport 2nd

Why cities have large emissions

CO2 emitting sources

1st - coal

2nd - oil

3rd - gas

Scope 3 emissions

Emissions from up or down supply chain

Scope 4 emissions

Avoided emissions

IPCC 1.5 degree special report

net zero by 2050

need to step up actions

Project Drawdown

We don’t need to wait for new tech

We already have solutions, we just need to roll them out

Best emission mitigations

1. Wind

2. solar

3. Food waste

4. Diet

5. FIX OR COMBINE

Food and climate mitigation

Need to reduce meat consumption and increase vegestables

Beef is high emissions industry

Transport and emissions

Better bike lanes and public transport

most emissions from cars and trucks

Need electric trucks

Rail is efficient

Critical minerals

Broad category of minerals needed for green energy and new tech

needed for EV’s (batteries)

copper

lithium

cobalt

Rare earth elements

Type of critical minerals

Needed for solar pannels and wind energy

Geoengineering

Climate Engineering

Negative Emissions

CO2 Removal (CDR)

Solar Radiation Management (SRM)

Carbon Dioxide Removal (CDR)

Aforestation → planting more trees

Carbon Capture → pump Co2 into rocks

Minerals → weathering

Biochar → burn to stabilise CO2

Direct Carbon Capture → expensive

Marine Carbon Dioxide Removal (CDR)

seaweed farming

Alkalisation → allows ocean to absorb more CO2

Solar Radiation Management (SRM)

Reduce solar radiation (heat) hitting Earth

Doesn’t reduce CO2

Pumping aerosols into atmosphere

Seaspray to brighten clouds (increase albido)

Effects of Species redistribution from climate change

Ecosystem structure, function, conservation

Human well-being

Governance challenges

Climate Feedback

Thermal Performance Curve

Tolerance range for which a species can survive

Maximum to minimum ciritical temperatures

Optimal temperature is best for performance

Climate change impact on species distribution

Species will move polewards or up elevations to reach cooler temperatures

Complications of species distribution and climate change

Endotherms vs exotherms →exotherms moving faster

Species have complex life cycles → dif vulnerabilities in each stage

Effects of extremes → heatwaves

Refugia → buffers

Evolution → individuals have dif max critical temps leads to evolution

Refugia

Where species can escape form climate change threats

Protect from heat, fire, invasives and disease

Topographic, hydrological, and paleo refugias

found in places with variations in microclimates, rugged, wet, mountainous, non-sunfaceing slopes, gores, valleys

Why marine species redistrution is faster

They can move easier → less obstacles

They don’t have refugia → more pressure to move

Precipitation and Climate Change

Less patterns than heat

Phenological mismatch

Misalignment of life history events between two species

Due to spring becoming earlier → warm temps earlier in year

Plants bud earlier → catepillars come earlier → birds too late to arrive to eat them

Flowers and pollinators

Trophic cascades → mismatch happens overtime

Linear change in condition

State proportional to driver

Non-linear change in condition

State disproportionate to change in driver

Small change can cause big change in state

S Shaped change in condition

Hit threshold (critical transmission), go straight down the line

can’t go back to original line

Some changes are not easily reversible

Don’t want to cross threshold

Threshold

Variable at which flip in state occurs

Histerisis

Forward transition and back transition not the same

Self-reinforcing feedbacks now maintain current state

Recovery Requires much more effort

Has tipping point (critical transition)

Ice cap → ice thickness has threshold (less albido and lower sheet to warmer air feedbacks)

Rainforest → rainforest or savannah (less forest, less moisture recycling, less rainfall, less forest) pulled to savannah state

Seagrass→ sea grass binds sediment, stops erosion, less sediment, more light in water, more seagrass :) OR sediment in water→ light blocked → less seagrass :(

Histerisis Resillience

Deepening a cup makes env more resilliant

Warmer climate means less deforestation to flip rainfores to savannah

Humans can stop deforestation even if warming is already locked in

Shade Trees in Agriculture

Mitigation (absorb CO2)

Adaptation (shading/ cooling crops)

Can help store more carbon in system

Biodiversity benefit

Can reduce yeild

Avoided emissions

would have happened without management intervention

deforestation →preventing logging

replacing fossil fuels

Negative Emissions

Actively removing CO2 from atmosphere and storing elsewhere

Planting more trees

carbon capture

Largest mitigation actions

reforestation → cleared in past and now replanting

avoided forest conservation → avoided emissions

Natural Forest Management

Non-intensive management for wood production

Extending rotation length → more storage

Negative emissions

Biochar

production of charcoal

locks away carbon

improves soil health

Nutrient Management

Nitrous oxide in fertiliser

Reducing fertiliser use/ improving application

Coastal restoration

Blue carbon

Wetlands are dense in carbon

Avoided emissions?

mangroves

Peat restoration

Peat is basically carbon?

Avoiding peatland conversion to agriculture

Restoring/rewetting peatland → wet peatlands can’t release CO2

Natural Climate Solutions

Can mitigate half of what is needed

Co-benefits (habitat, erosion control, water quality, etc)

Non-climate solutions good too, just depends on circumstance (we need both)

Downsides can be limit of available land to replant, monoculture replantings

30 by 30

Protect 30% of the Earth’s land and oceans by 2030

risk quantity over quality for protected area

Protected Area

Protect species and their habitat

Can become a cage not a fortress with climate change

Most vulnerable protected areas

Small

Low elevation

Flat land

Temperate Zone