Global Change
Lectures 1-7
2024 - 2025
Fie Thijs
2nd Bachelor Biology
,Fie Thijs 2nd Bachelor Biology 2024-2025
Table of Contents
Lecture 1 - Climate change ...................................................................................................... 2
Summary ........................................................................................................................................2
Quiz – gemaakt door AI ....................................................................................................................8
Antwoordsleutel Quiz......................................................................................................................8
Lecture 2 - Glaciers in a changing climate.................................................................................. 9
Summary ........................................................................................................................................9
Quiz – gemaakt door AI ..................................................................................................................14
Antwoordsleutel Quiz....................................................................................................................14
Lecture 3 - Land-atmosphere interactions and climate extremes in a changing climate ............... 15
Summary ......................................................................................................................................15
Quiz– gemaakt door AI...................................................................................................................20
Antwoordsleutel Quiz....................................................................................................................20
Lecture 4 - The thermohaline circulation ................................................................................. 22
Summary ......................................................................................................................................22
Quiz – gemaakt door AI ..................................................................................................................26
Antwoordsleutel Quiz....................................................................................................................26
Lecture 5 - Lakes as sentinels & archives, ice sheet dynamics & ice shelf break-up ..................... 27
Summary ......................................................................................................................................27
Quiz – gemaakt door AI ..................................................................................................................32
Antwoordsleutel Quiz....................................................................................................................32
Lecture 6 – Urbanization impacts on species, communities and ecosystem services................... 34
Summary ......................................................................................................................................34
Quiz – gemaakt door AI ..................................................................................................................40
Antwoordsleutel Quiz....................................................................................................................40
Lecture 7 - The perturbed carbon cycle as a driver of ongoing climate change ............................. 42
Summary ......................................................................................................................................42
Quiz – gemaakt door AI ..................................................................................................................54
Antwoordsleutel Quiz....................................................................................................................54
Global Change Lectures 1-7 1
,Fie Thijs 2nd Bachelor Biology 2024-2025
Lecture 1 - Climate change
Summary
SOME BASICS OF THE CLIMATE SYSTEM
Weather = atmospheric condition at a given time and place (1 characteristic)
- Air temperature, precipitation, clouds, air pressure, wind speed, atmospheric humidity, …
- Chaotic component (‘Lorenz butterfly’) = usually not be predicted more than 10 to 14 days ahead
Climate = mean and extreme conditions of the atmosphere
- Ocean, sea ice, etc… over a longer period (e.g. 30 years)
- Statistic of the weather
Climate system = interactions with:
- Atmosphere (air)
- Cryosphere (ice)
- Hydrosphere (water)
- Biosphere (living things)
- Lithosphere (stone)
Components can make other components change = therefore change themselves
Global Change Lectures 1-7 2
,Fie Thijs 2nd Bachelor Biology 2024-2025
Radiation balance of the earth:
Incoming = outgoing
Q(1− α)= εσT4
Short wave radiation & infra-red radiation
Q Mean incoming solar radiation σ Boltzmann constant (5.67 10-8 Wm-2K-4)
at the boundary of the atmosphere (340 Wm-2) = thermal radiation that escapes to space
α Planetary albedo (0.30) T Mean global surface temperature (in K)
= fraction of solar energy that gets refracted = calculated by taking the 4th square root
ε Effective emissivity of the atmosphere (0.61) ε, σ & T Thermal radiation of the Earth
= Earth is like a black body
For current radiative fluxes T = 287.5 K = +14.8 °C
Without greenhouse effect (e = 1) T = 253.4 K = -18.6 °C
➔ All radiation escapes to space
Weaker Sun (Q: -1%) T = 286.8 K = +14.1 °C
Higher planetary albedo during the ice ages (a = 0.38) T = 279.4 K = +6.3 °C
Water vapor = important greenhouse gas, but internal to the climate system = feedback
➔ CO2 makes the atmosphere warmer = hold more water vapor = worsens climate change
CO2 2x = 15°C + 1,2°C
CO2 2x + feedback from water vapor = 15°C + 2,5°C
Global Change Lectures 1-7 3
,Fie Thijs 2nd Bachelor Biology 2024-2025
CHANGES IN HUMAN AND NATURAL DRIVERS OF CLIMATE
➔ Anthropogenic influence
CO2 Fossil fuels, cement making & deforestation
CH4 Agriculture and waste (rotting)
N2 O Fertilizers and livestock
CO2 concentrations have increase by more than 50% since pre-industrial times
- 1800 = 280 ppm
- 2024 = 424 ppm
➔ Atmospheric concentrations of CO2 have not been experienced for at least 2 million years
Human activities = natural carbon cycle out of balance = increasing atmospheric CO2 concentrations
Increase in CO2 = decrease in O2
Carbon imbalance = gap in understanding of sources and sinks
- Sources = fossil fuels & deforestation
- Sinks = atmosphere, terrestrial biosphere & ocean
Aerosols:
- Direct effect by scattering and absorbing shortwave and longwave radiation
- Indirect effect by modifying the radiative properties, amount, and lifetime of clouds
- Net cooling effect on climate (negative radiative forcing)
- Short lifetime (maximally a few years)
Global Change Lectures 1-7 4
,Fie Thijs 2nd Bachelor Biology 2024-2025
OBSERVATIONS OF CHANGES IN CLIMATE : TEMPERATURE
Last decade: global mean surface temp = comparable to temp of the Last Interglacial period (125 000 ya)
Rise of global mean surface temperature:
- Earth’s surface = warmed by 1.4°C over the period 1880 – 2024
- 2024 = warmest year so far by far; 2023 was the 2nd warmest year
- 24 of the 25 warmest years since 1880 = in the 21st century
- Total warming of almost 3°C since mid-19th century
➔ More than 2x global average
- Hockey stick graph after 1000 AD
ATTRIBUTION OF CLIMATE CHANGE
Human influence is the cause of this global warming
Observed warming = driven by greenhouse gas emissions
➔ 1/3 = masked by cooling from aerosol emissions
IMPACTS OF CLIMATE CHANGE: THE CRYOSPHERE AND SEA LEVEL
The cryosphere is mostly located in remote places, but its changes have global consequences:
- Changes in snow and ice affect the global radiation balance
➔ Affect weather and climate elsewhere, including in Europe
- Melting of land ice raises global sea level
Decrease of seasonal snow cover: Northern hemisphere snow cover is decreased by 1,1% per decade
➔ Period between 1922-2018 (April)
Decline of Arctic sea ice: lowest since at least 1850 for both annual mean and late-summer values
➔ Worldwide recession of mountain glaciers since end of 19th century
➔ Crucial as freshwater source
Global Change Lectures 1-7 5
,Fie Thijs 2nd Bachelor Biology 2024-2025
Greenland vs Antarctic ice sheet:
Greenland Antarctica
- Volume : 7.4 m sea level equivalent - Volume : 58.3 m sea level equivalent
- Maximum thickness : 3300 m - Maximum ice thickness : 4776 m
- First ice on Greenland around 7 Ma BP - First ice on Antarctica around 35 Ma BP
- Full ice sheet by 3 Ma BP - Permanent ice sheet since 14 Ma BP
Ice sheet gains mass (snowfall) & loses mass (melting)
➔ The way in which ice is lost is not the same between Greenland and Antarctica
➔ Greenland = consistent pattern of small central thickening & larger marginal thinning
➔ Antarctica = small interior thickening & peripheral thinning in several sectors
Mass losses from West Antarctic outlet glaciers = induced by ice-shelf basal melt
➔ Locally by ice-shelf disintegration preceded by strong surface melt
➔ Mass-loss rate from Antarctic ice sheet = tripled in 2010-2019 vs 1992-1999
➔ Mass-loss rate from Greenland ice sheet = 6x in 2010-2019 vs 1992-1999
Paleoclimatic assessments from IPCC AR6:
- Global nature of glacier retreat
➔ Almost all glaciers retreating synchronously since 1950s = unprecedented in the last 2000 years
- Current Arctic sea ice coverage levels = lowest since at least 1850
➔ For both annual mean and late-summer values & for the past 1000 years for late-summer values
- Global mean sea level = risen faster since 1900 than any preceding century in the last 3000 years
➔ Will continue to rise over the 21st century = likely rise of 0.38 - 0.77 m
PROJECTIONS OF FUTURE CLIMATE CHANGE
IPCC AR6 projections:
SSP5 Fossil Fuel Intensive = Globalized world, strong economic growth
SSP3 Regional rivalry = Nationalism, low growth
SSP2 Middle of the road = Unchanged world with moderate climate policies
SSP1 Sustainability = The green road, inclusive growth, less inequality, phasing out of fossil fuels
➔ Warming by 2050 = higher than today and at least 1.5°C
➔ Only for the SSP1 scenarios the warming will stabilize below 2°C by 2100
➔ Little difference between scenarios in the near-term (2030)
General:
- Largest warming in the Arctic
- Lowest warming over the North Atlantic
- Warming larger over land than over ocean
- Future: more precipitation in tropics & polar areas (less in subtropical land areas)
Global Change Lectures 1-7 6
,Fie Thijs 2nd Bachelor Biology 2024-2025
LIMITING CLIMATE CHANGE
Cumulative carbon determines warming: peak warming = approximately proportional to total emissions
- Largely independent of the emission pathway (only the total matters)
- More emissions early = stronger reductions needed later in time
- Temp. target = max in cumulative CO2 emissions
➔ Physical and carbon cycle problem
- Allocation over time = economic and policy question
Global CO2 emissions must reach 0 to limit global warming!
Global Change Lectures 1-7 7
,Fie Thijs 2nd Bachelor Biology 2024-2025
Quiz – gemaakt door AI
1. Wat zijn de drie belangrijkste processen waardoor ijskappen massa verliezen?
2. Welke satellieten werden in de studie van Smith et al. (2020) gebruikt om veranderingen in de ijshoogte te
kwantificeren, en wat zijn de belangrijkste verschillen tussen hen?
3. Wat is het belangrijkste verschil tussen weer en klimaat volgens Huybrechts?
4. Waarom wordt waterdamp beschouwd als een feedback en niet als een forcing in het klimaatsysteem?
5. Waarom is de cryosfeer, ondanks zijn afgelegen locatie, cruciaal voor het begrip van wereldwijde
veranderingen?
6. Welke regio's van de Groenlandse ijskap vertonen de grootste massaafname, en waar neemt de massa
toe?
7. Wat is de belangrijkste oorzaak van massaverlies in de West-Antarctische ijskap volgens de bronnen?
8. Wat is het verschil in de snelheid van massaverlies tussen de Antarctische en Groenlandse ijskappen in
de periode 2010-2019 vergeleken met 1992-1999?
9. Wat is de belangrijkste factor die de opwarming van de aarde bepaalt, zelfs nadat de emissies zijn gestopt?
10. Wat is het resterende koolstofbudget om de opwarming te beperken tot 1,5°C met 50% waarschijnlijkheid,
gerekend vanaf 2024, volgens Huybrechts?
Antwoordsleutel Quiz
1. De drie belangrijkste processen waardoor ijskappen massa verliezen zijn: afsmelting aan de oppervlakte,
het afkalven van ijsbergen en het basale smelten van drijvende ijsplaten en getijdengletsjers.
2. De studie gebruikte ICESat en ICESat-2. ICESat had een grotere voetafdruk en fijnere bemonstering, terwijl
ICESat-2 een hogere bemonsteringsfrequentie, smallere voetafdruk en een zesstralen geometrie heeft
voor nauwkeurigere metingen, vooral in steile kustgebieden.
3. Weer is de atmosferische toestand op een bepaald tijdstip en plaats, gekenmerkt door chaotische
componenten. Klimaat is de statistiek van weercondities over een langere periode, zoals 30 jaar, en omvat
interacties tussen verschillende componenten van het Aardse systeem.
4. Waterdamp is een feedback omdat de hoeveelheid ervan in de atmosfeer grotendeels wordt bepaald door
de temp; warmere lucht kan meer waterdamp bevatten, wat het broeikaseffect versterkt dat
oorspronkelijk werd veroorzaakt door andere gassen zoals CO2.
5. Veranderingen in de cryosfeer beïnvloeden de wereldwijde stralingsbalans en beïnvloeden het weer en
klimaat elders. Bovendien draagt het smelten van landijs direct bij aan de stijging van de zeespiegel, wat
wereldwijde gevolgen heeft.
6. De grootste massaafname in de Groenlandse ijskap vindt plaats langs de kustlijn, vooral in het zuidoosten
en westen langs grote uitlaatgletsjers. Massa neemt toe in de binnenlanden op hogere hoogten als gevolg
van toegenomen sneeuwaccumulatie.
7. De belangrijkste oorzaak van massaverlies in de West-Antarctische ijskap is het basale smelten van
ijsplaten, voornamelijk geïnduceerd door warm oceaanwater (gemodificeerd Circumpolair Diep Water)
dat onder de ijsplaten doordringt.
8. De massaverliessnelheid van de Antarctische ijskap is verdrievoudigd in de periode 2010-2019 vergeleken
met 1992-1999. De massaverliessnelheid van de Groenlandse ijskap is in dezelfde periode zelfs 6x.
9. Een groot deel van de klimaatverandering blijft eeuwenlang bestaan, zelfs nadat de emissies zijn gestopt.
De piek opwarming is bij benadering evenredig met de cumulatieve (totale) emissies van koolstof.
10. Vanaf 2024 is het resterende koolstofbudget om de opwarming tot 1,5°C te beperken met 50%
waarschijnlijkheid 275 GtCO2, wat overeenkomt met ongeveer 7 jaar emissies op basis van het niveau van
2019.
Global Change Lectures 1-7 8
, Fie Thijs 2nd Bachelor Biology 2024-2025
Lecture 2 - Glaciers in a changing climate
Summary
GENERAL INFORMATION AND NUMBERS
Approx. 200,000 glaciers on Earth = crucial role in planet's climate and water cycles
➔ Many glaciers worldwide are retreating at an alarming rate
Imagine: all the ice in Greenland melts = global sea levels raise by about 7 meters
➔ Antarctica holds enough ice to contribute approx. 50 meters to sea level rise
Glaciers = powerful symbols of climate change (highly sensitive to rising temperatures)
- 1911 = some parts were up to 200 meters thick
- Now = fragmented into separate sections
- Example: Rhone Glacier = lake has formed as ice continued to melt
- In 2 years = Swiss Alps experienced dramatic 10% loss in ice volume (globally about 5%)
- Over past 30 years = no glaciers that gained ice (except 1 year = outlier)
Glaciers evolve & have significant risks
➔ Catastrophic events = avalanches or icefalls (cause damage and even loss of life)
Importance for communities:
- Water supply
- Glaciers are larger in the winter, storing more ice = provide more water in the summer as they melt
- This once-reliable water source is becoming more uncertain, especially in the summer
- Risky changes in water supply that are vital for agriculture, drinking, and other essential uses.
Sea level rise:
- Need to protect coastal areas
- All 200,000 glaciers around the world were to melt = effect would be substantial
➔ potentially displacing millions of people & causing environmental and economic challenges
- On average, sea levels rise by about 4 mm per year (1 mm coming from glaciers)
- Thermal expansion contributes another 2 mm = warm water expands
- The remaining 1 mm = melting of ice sheets, primarily in Antarctica and Greenland
➔ Accelerates the rise in sea levels
Global Change Lectures 1-7 9
Lectures 1-7
2024 - 2025
Fie Thijs
2nd Bachelor Biology
,Fie Thijs 2nd Bachelor Biology 2024-2025
Table of Contents
Lecture 1 - Climate change ...................................................................................................... 2
Summary ........................................................................................................................................2
Quiz – gemaakt door AI ....................................................................................................................8
Antwoordsleutel Quiz......................................................................................................................8
Lecture 2 - Glaciers in a changing climate.................................................................................. 9
Summary ........................................................................................................................................9
Quiz – gemaakt door AI ..................................................................................................................14
Antwoordsleutel Quiz....................................................................................................................14
Lecture 3 - Land-atmosphere interactions and climate extremes in a changing climate ............... 15
Summary ......................................................................................................................................15
Quiz– gemaakt door AI...................................................................................................................20
Antwoordsleutel Quiz....................................................................................................................20
Lecture 4 - The thermohaline circulation ................................................................................. 22
Summary ......................................................................................................................................22
Quiz – gemaakt door AI ..................................................................................................................26
Antwoordsleutel Quiz....................................................................................................................26
Lecture 5 - Lakes as sentinels & archives, ice sheet dynamics & ice shelf break-up ..................... 27
Summary ......................................................................................................................................27
Quiz – gemaakt door AI ..................................................................................................................32
Antwoordsleutel Quiz....................................................................................................................32
Lecture 6 – Urbanization impacts on species, communities and ecosystem services................... 34
Summary ......................................................................................................................................34
Quiz – gemaakt door AI ..................................................................................................................40
Antwoordsleutel Quiz....................................................................................................................40
Lecture 7 - The perturbed carbon cycle as a driver of ongoing climate change ............................. 42
Summary ......................................................................................................................................42
Quiz – gemaakt door AI ..................................................................................................................54
Antwoordsleutel Quiz....................................................................................................................54
Global Change Lectures 1-7 1
,Fie Thijs 2nd Bachelor Biology 2024-2025
Lecture 1 - Climate change
Summary
SOME BASICS OF THE CLIMATE SYSTEM
Weather = atmospheric condition at a given time and place (1 characteristic)
- Air temperature, precipitation, clouds, air pressure, wind speed, atmospheric humidity, …
- Chaotic component (‘Lorenz butterfly’) = usually not be predicted more than 10 to 14 days ahead
Climate = mean and extreme conditions of the atmosphere
- Ocean, sea ice, etc… over a longer period (e.g. 30 years)
- Statistic of the weather
Climate system = interactions with:
- Atmosphere (air)
- Cryosphere (ice)
- Hydrosphere (water)
- Biosphere (living things)
- Lithosphere (stone)
Components can make other components change = therefore change themselves
Global Change Lectures 1-7 2
,Fie Thijs 2nd Bachelor Biology 2024-2025
Radiation balance of the earth:
Incoming = outgoing
Q(1− α)= εσT4
Short wave radiation & infra-red radiation
Q Mean incoming solar radiation σ Boltzmann constant (5.67 10-8 Wm-2K-4)
at the boundary of the atmosphere (340 Wm-2) = thermal radiation that escapes to space
α Planetary albedo (0.30) T Mean global surface temperature (in K)
= fraction of solar energy that gets refracted = calculated by taking the 4th square root
ε Effective emissivity of the atmosphere (0.61) ε, σ & T Thermal radiation of the Earth
= Earth is like a black body
For current radiative fluxes T = 287.5 K = +14.8 °C
Without greenhouse effect (e = 1) T = 253.4 K = -18.6 °C
➔ All radiation escapes to space
Weaker Sun (Q: -1%) T = 286.8 K = +14.1 °C
Higher planetary albedo during the ice ages (a = 0.38) T = 279.4 K = +6.3 °C
Water vapor = important greenhouse gas, but internal to the climate system = feedback
➔ CO2 makes the atmosphere warmer = hold more water vapor = worsens climate change
CO2 2x = 15°C + 1,2°C
CO2 2x + feedback from water vapor = 15°C + 2,5°C
Global Change Lectures 1-7 3
,Fie Thijs 2nd Bachelor Biology 2024-2025
CHANGES IN HUMAN AND NATURAL DRIVERS OF CLIMATE
➔ Anthropogenic influence
CO2 Fossil fuels, cement making & deforestation
CH4 Agriculture and waste (rotting)
N2 O Fertilizers and livestock
CO2 concentrations have increase by more than 50% since pre-industrial times
- 1800 = 280 ppm
- 2024 = 424 ppm
➔ Atmospheric concentrations of CO2 have not been experienced for at least 2 million years
Human activities = natural carbon cycle out of balance = increasing atmospheric CO2 concentrations
Increase in CO2 = decrease in O2
Carbon imbalance = gap in understanding of sources and sinks
- Sources = fossil fuels & deforestation
- Sinks = atmosphere, terrestrial biosphere & ocean
Aerosols:
- Direct effect by scattering and absorbing shortwave and longwave radiation
- Indirect effect by modifying the radiative properties, amount, and lifetime of clouds
- Net cooling effect on climate (negative radiative forcing)
- Short lifetime (maximally a few years)
Global Change Lectures 1-7 4
,Fie Thijs 2nd Bachelor Biology 2024-2025
OBSERVATIONS OF CHANGES IN CLIMATE : TEMPERATURE
Last decade: global mean surface temp = comparable to temp of the Last Interglacial period (125 000 ya)
Rise of global mean surface temperature:
- Earth’s surface = warmed by 1.4°C over the period 1880 – 2024
- 2024 = warmest year so far by far; 2023 was the 2nd warmest year
- 24 of the 25 warmest years since 1880 = in the 21st century
- Total warming of almost 3°C since mid-19th century
➔ More than 2x global average
- Hockey stick graph after 1000 AD
ATTRIBUTION OF CLIMATE CHANGE
Human influence is the cause of this global warming
Observed warming = driven by greenhouse gas emissions
➔ 1/3 = masked by cooling from aerosol emissions
IMPACTS OF CLIMATE CHANGE: THE CRYOSPHERE AND SEA LEVEL
The cryosphere is mostly located in remote places, but its changes have global consequences:
- Changes in snow and ice affect the global radiation balance
➔ Affect weather and climate elsewhere, including in Europe
- Melting of land ice raises global sea level
Decrease of seasonal snow cover: Northern hemisphere snow cover is decreased by 1,1% per decade
➔ Period between 1922-2018 (April)
Decline of Arctic sea ice: lowest since at least 1850 for both annual mean and late-summer values
➔ Worldwide recession of mountain glaciers since end of 19th century
➔ Crucial as freshwater source
Global Change Lectures 1-7 5
,Fie Thijs 2nd Bachelor Biology 2024-2025
Greenland vs Antarctic ice sheet:
Greenland Antarctica
- Volume : 7.4 m sea level equivalent - Volume : 58.3 m sea level equivalent
- Maximum thickness : 3300 m - Maximum ice thickness : 4776 m
- First ice on Greenland around 7 Ma BP - First ice on Antarctica around 35 Ma BP
- Full ice sheet by 3 Ma BP - Permanent ice sheet since 14 Ma BP
Ice sheet gains mass (snowfall) & loses mass (melting)
➔ The way in which ice is lost is not the same between Greenland and Antarctica
➔ Greenland = consistent pattern of small central thickening & larger marginal thinning
➔ Antarctica = small interior thickening & peripheral thinning in several sectors
Mass losses from West Antarctic outlet glaciers = induced by ice-shelf basal melt
➔ Locally by ice-shelf disintegration preceded by strong surface melt
➔ Mass-loss rate from Antarctic ice sheet = tripled in 2010-2019 vs 1992-1999
➔ Mass-loss rate from Greenland ice sheet = 6x in 2010-2019 vs 1992-1999
Paleoclimatic assessments from IPCC AR6:
- Global nature of glacier retreat
➔ Almost all glaciers retreating synchronously since 1950s = unprecedented in the last 2000 years
- Current Arctic sea ice coverage levels = lowest since at least 1850
➔ For both annual mean and late-summer values & for the past 1000 years for late-summer values
- Global mean sea level = risen faster since 1900 than any preceding century in the last 3000 years
➔ Will continue to rise over the 21st century = likely rise of 0.38 - 0.77 m
PROJECTIONS OF FUTURE CLIMATE CHANGE
IPCC AR6 projections:
SSP5 Fossil Fuel Intensive = Globalized world, strong economic growth
SSP3 Regional rivalry = Nationalism, low growth
SSP2 Middle of the road = Unchanged world with moderate climate policies
SSP1 Sustainability = The green road, inclusive growth, less inequality, phasing out of fossil fuels
➔ Warming by 2050 = higher than today and at least 1.5°C
➔ Only for the SSP1 scenarios the warming will stabilize below 2°C by 2100
➔ Little difference between scenarios in the near-term (2030)
General:
- Largest warming in the Arctic
- Lowest warming over the North Atlantic
- Warming larger over land than over ocean
- Future: more precipitation in tropics & polar areas (less in subtropical land areas)
Global Change Lectures 1-7 6
,Fie Thijs 2nd Bachelor Biology 2024-2025
LIMITING CLIMATE CHANGE
Cumulative carbon determines warming: peak warming = approximately proportional to total emissions
- Largely independent of the emission pathway (only the total matters)
- More emissions early = stronger reductions needed later in time
- Temp. target = max in cumulative CO2 emissions
➔ Physical and carbon cycle problem
- Allocation over time = economic and policy question
Global CO2 emissions must reach 0 to limit global warming!
Global Change Lectures 1-7 7
,Fie Thijs 2nd Bachelor Biology 2024-2025
Quiz – gemaakt door AI
1. Wat zijn de drie belangrijkste processen waardoor ijskappen massa verliezen?
2. Welke satellieten werden in de studie van Smith et al. (2020) gebruikt om veranderingen in de ijshoogte te
kwantificeren, en wat zijn de belangrijkste verschillen tussen hen?
3. Wat is het belangrijkste verschil tussen weer en klimaat volgens Huybrechts?
4. Waarom wordt waterdamp beschouwd als een feedback en niet als een forcing in het klimaatsysteem?
5. Waarom is de cryosfeer, ondanks zijn afgelegen locatie, cruciaal voor het begrip van wereldwijde
veranderingen?
6. Welke regio's van de Groenlandse ijskap vertonen de grootste massaafname, en waar neemt de massa
toe?
7. Wat is de belangrijkste oorzaak van massaverlies in de West-Antarctische ijskap volgens de bronnen?
8. Wat is het verschil in de snelheid van massaverlies tussen de Antarctische en Groenlandse ijskappen in
de periode 2010-2019 vergeleken met 1992-1999?
9. Wat is de belangrijkste factor die de opwarming van de aarde bepaalt, zelfs nadat de emissies zijn gestopt?
10. Wat is het resterende koolstofbudget om de opwarming te beperken tot 1,5°C met 50% waarschijnlijkheid,
gerekend vanaf 2024, volgens Huybrechts?
Antwoordsleutel Quiz
1. De drie belangrijkste processen waardoor ijskappen massa verliezen zijn: afsmelting aan de oppervlakte,
het afkalven van ijsbergen en het basale smelten van drijvende ijsplaten en getijdengletsjers.
2. De studie gebruikte ICESat en ICESat-2. ICESat had een grotere voetafdruk en fijnere bemonstering, terwijl
ICESat-2 een hogere bemonsteringsfrequentie, smallere voetafdruk en een zesstralen geometrie heeft
voor nauwkeurigere metingen, vooral in steile kustgebieden.
3. Weer is de atmosferische toestand op een bepaald tijdstip en plaats, gekenmerkt door chaotische
componenten. Klimaat is de statistiek van weercondities over een langere periode, zoals 30 jaar, en omvat
interacties tussen verschillende componenten van het Aardse systeem.
4. Waterdamp is een feedback omdat de hoeveelheid ervan in de atmosfeer grotendeels wordt bepaald door
de temp; warmere lucht kan meer waterdamp bevatten, wat het broeikaseffect versterkt dat
oorspronkelijk werd veroorzaakt door andere gassen zoals CO2.
5. Veranderingen in de cryosfeer beïnvloeden de wereldwijde stralingsbalans en beïnvloeden het weer en
klimaat elders. Bovendien draagt het smelten van landijs direct bij aan de stijging van de zeespiegel, wat
wereldwijde gevolgen heeft.
6. De grootste massaafname in de Groenlandse ijskap vindt plaats langs de kustlijn, vooral in het zuidoosten
en westen langs grote uitlaatgletsjers. Massa neemt toe in de binnenlanden op hogere hoogten als gevolg
van toegenomen sneeuwaccumulatie.
7. De belangrijkste oorzaak van massaverlies in de West-Antarctische ijskap is het basale smelten van
ijsplaten, voornamelijk geïnduceerd door warm oceaanwater (gemodificeerd Circumpolair Diep Water)
dat onder de ijsplaten doordringt.
8. De massaverliessnelheid van de Antarctische ijskap is verdrievoudigd in de periode 2010-2019 vergeleken
met 1992-1999. De massaverliessnelheid van de Groenlandse ijskap is in dezelfde periode zelfs 6x.
9. Een groot deel van de klimaatverandering blijft eeuwenlang bestaan, zelfs nadat de emissies zijn gestopt.
De piek opwarming is bij benadering evenredig met de cumulatieve (totale) emissies van koolstof.
10. Vanaf 2024 is het resterende koolstofbudget om de opwarming tot 1,5°C te beperken met 50%
waarschijnlijkheid 275 GtCO2, wat overeenkomt met ongeveer 7 jaar emissies op basis van het niveau van
2019.
Global Change Lectures 1-7 8
, Fie Thijs 2nd Bachelor Biology 2024-2025
Lecture 2 - Glaciers in a changing climate
Summary
GENERAL INFORMATION AND NUMBERS
Approx. 200,000 glaciers on Earth = crucial role in planet's climate and water cycles
➔ Many glaciers worldwide are retreating at an alarming rate
Imagine: all the ice in Greenland melts = global sea levels raise by about 7 meters
➔ Antarctica holds enough ice to contribute approx. 50 meters to sea level rise
Glaciers = powerful symbols of climate change (highly sensitive to rising temperatures)
- 1911 = some parts were up to 200 meters thick
- Now = fragmented into separate sections
- Example: Rhone Glacier = lake has formed as ice continued to melt
- In 2 years = Swiss Alps experienced dramatic 10% loss in ice volume (globally about 5%)
- Over past 30 years = no glaciers that gained ice (except 1 year = outlier)
Glaciers evolve & have significant risks
➔ Catastrophic events = avalanches or icefalls (cause damage and even loss of life)
Importance for communities:
- Water supply
- Glaciers are larger in the winter, storing more ice = provide more water in the summer as they melt
- This once-reliable water source is becoming more uncertain, especially in the summer
- Risky changes in water supply that are vital for agriculture, drinking, and other essential uses.
Sea level rise:
- Need to protect coastal areas
- All 200,000 glaciers around the world were to melt = effect would be substantial
➔ potentially displacing millions of people & causing environmental and economic challenges
- On average, sea levels rise by about 4 mm per year (1 mm coming from glaciers)
- Thermal expansion contributes another 2 mm = warm water expands
- The remaining 1 mm = melting of ice sheets, primarily in Antarctica and Greenland
➔ Accelerates the rise in sea levels
Global Change Lectures 1-7 9
