Land Cover Change and Greenland

U3 AOS 1

Land Cover

‘The observed biophysical cover on the Earth’s surface’ (UNFAO)

Last Glacial Maximum Characteristics

• Around 20,000 years ago

• 8% of Earth’s surface was covered in ice, now 3% of Earth’s surface

• 25% of the Earths land was covered in ice, now 11% of the Earth’s land

• Seas levels fell by 125-130m

• Land bridges

  • Beringia (Alaska and Russia)

  • Sundalands (Indonesia)

  • Sahul (Papua New Guinea, Australia, Tasmania)

Holocene Climactic Optimum Characteristics

• Around 8,000 years ago

• Significant warming across the north of the planet

• Global temperatures up 1-2 degrees

• Up to 4 degrees at the North Pole

• Northwestern Europe warmed and forested

• Little change at low and middle latitudes

Natural Processes Influencing Land Cover Change - Milankovitch Cycle

How variations in three types of Earth orbital movement affect how much solar radiation reaches the top of Earth’s atmosphere as well as where the insolation reaches

Milankovitch Cycle Aspect 1

The shape of Earth’s orbit known as eccentricity which measures how much the shape of Earth’ s orbit departs from a perfect circle

• Earth’s orbit is most elliptic about 23% more incoming solar radiation

• Alters solar energy received impacting ice sheet growth and melt

Milankovitch Cycle Aspect 2

The angle Earth’s axis is tilted with respect to Earth’s orbital plane, know as obliquity

• A greater axial tilt makes seasons more extreme, with more solar radiation in summer when tilted towards sun and less in winter when tilted away

• Larger the tilt more periods of deglaciation melting ice sheets and glaciers

Milankovitch Cycle Aspect 3

The direction Earth’s axis of rotation is pointed, known as precession

• Axial precession makes seasonal contrasts more extreme in one hemisphere and less extreme in the other

Milankovitch Cycle Aspects in the Last Glacial Maximum

Eccentricity - More elliptic (egg-shaped), Earth further away from the sun in summer, therefore more conductive to an ice age

Tilt (obliquity) - 21.5 degrees, more upright, therefore less insolation in the Northern Hemisphere

Milankovitch Cycle Aspects in the Holocene Climactic Optimum

Eccentricity - Less elliptic (circular), therefore warmer winters and summers and more conductive to warm temperatures

Tilt (obliquity) - 24.5 degrees, more tilted, therefore more insolation in the Northern Hemisphere

Natural Processes Influencing Land Cover Change - Geophysical

Movement of the Earth’s tectonic plates influenced the distribution of the Earth’s landmasses

• Short-term - alter water flow, vegetation can adapt

• Long-term - Earthquakes can elevate or depress landmasses, steeper surface = less agriculture and residential potential

Natural Processes Influencing Land Cover Change - Geophysical Example

Mount Toba

• North-central Sumatra, Indonesia

• Some scientists maintain that it sent the planet into an ice age

• Worldwide air temperature plunged as much as 10C in the Northern Hemisphere

• 2,800 cubic km of ash and lava

Natural Processes Influencing Land Cover Change - Plant Succession

Vegetation adapting to changing climates, plants colonisation migrating to different areas

Natural Processes Influencing Land Cover Change - Fires and Pests

Fires can significantly affect vegetated land cover, preventing large areas of trees growing, promoting fire-dependent grassland and open woodlands

Natural Processes Influencing Land Cover Change - Fires and Pests Example

Australian Bushfires

• Destroyed 18 million hectares

• Ash blew to New Zealand melting as much as 30% of ice and glaciers covering greater than 2500km² for up to 3 months

Human Activity Influencing Land Cover Change - Population Dynamics

Rapid growth has led to intense pressure on land such as the need for housing production and recreation spaces

• 50-55% of people now living in towns and cities from rural spaces

• Global human population grows around 83 million annually

• Increased urbanisation and population growth → higher emissions → accelerated ice and glacier melt.

Human Activity Influencing Land Cover Change - Technological Change

change can happen rapidly on a larger scale - nationwide or even intentionally

Human Activity Influencing Land Cover Change - Technological Change Example

Trans-Amazonian highway (1972)

• strong spatial association between primary forest loss and the Trans-Amazonian highway

• substantial areas of the forest can be deforested easily

Human Activity Influencing Land Cover Change - Government Policies

Economic policies play a vital role

Some government policies look to try and restore land cover

Human Activity Influencing Land Cover Change - Government Policies Example

Brazil and Deforestation
1970s - military dictatorship, deforesting the Amazon funded it, Trans-Amazonian highway built to move people out, only 28% of Amazon protected

2003 - Lula Da Silva elected, he protected 47% of Amazon by 2012, created IBAMA forest police to track and fine illegal deforestation, soy and beef industry increased with effective practices

2018 - Bolsonaro elected, he reduced almost all environmental policies

Cryosphere

Locations where water is in it’s solid form, frozen into ice or snow

• Covers 20% of Earth’s surface

Glaciers

‘ a body of ice formed on land and in motion, confined by terrain; most commonly valleys’

• Generally found in alpine areas, as a result of heavy snowfalls over a sustained period of time

Natural Processes Influencing Melting Ice and Glaciers - Milankovitch Cycles

• Eccentricity: Changes in Earth’s orbit shape alter solar energy received, impacting ice sheet growth/melt.

• Obliquity: Variations in Earth’s tilt affect seasonal temperature extremes, influencing glacier stability.

Natural Processes Influencing Melting Ice and Glaciers - Oceanic Circulation Changes

Direction of ocean currents regularly change, leading to variation in climates as a result impacting the exchange of heat between oceans and the atmosphere

• La Niña: Cooler global temps → slower ice/glacier melt; increased rainfall → vegetation growth in some regions.

• El Niño: Warmer global temps → faster ice/glacier melt; droughts & fires → land cover loss.

Natural Processes Influencing Melting Ice and Glaciers - Volcanic Activity

Dust and volcanic gases in the atmosphere lead to warming and cooling in the short-term

• Mount Agung reduced temps in Bali by 0.5C

Natural Processes Influencing Melting Ice and Glaciers - Tectonic Plates

• Ocean Current Shifts: Tectonic movements influence warm water flow, increasing polar ice melt.

• Volcanic Heat: Subglacial volcanoes (e.g., Iceland) release heat, accelerating localized ice melt.

Human Activity Influencing Melting Ice and Glaciers - Altering the composition of gases in the atmosphere

From industrialisation the UN estimates that 60% of greenhouse gas emissions come from cities, despite cities only covering 2% of the Earth’s surface

• Carbon dioxide gases in March 2025 were estimated at 429ppm

Human Activity Influencing Melting Ice and Glaciers - Altering Landscapes

Significant changes in solar radiation (albedo) influenced by hard dark surfaces like cities and clearing forests for agriculture this leads to heat being retained and enhanced greenhouse gases

Human Activity Influencing Melting Ice and Glaciers - Direct addition of heat to the atmosphere

More of a local impact as burning fossil fuels as well as clearing and burning forests

• Tourism in Switzerland have been linked to declining glacier size due to development of infrastructure. Tourism is estimated to be responsible for 5% of GGGE

Greenland - Physical Characteristics

• World’s largest island

• The ice sheets have an area of approx. 1.7million square km

• Ice sheet is in a dome shape with a peak elevation of more than 3000m above sea level

• Contains 11% of the worlds freshwater

• Mass loss have been consistent for 28 years in a row

• In 1996, last year that Greenland gained ice

• Lost around 80 gigatons of ice during 2024 ending in September

Greenland - Human Characteristics

• Denmark has sovereignty

• Approx. 56,000 residents (lowest population density in world)

Greenland - Location

• Artic Ocean

• Northern Hemisphere

• Northeast of Canada

• Nuuk is Southeast of Central Greenland

• Approx. 2400km from East to West

• Approx. 4300km from North to South

Natural Processes Influencing Melting In Greenland - Cryoconite

The deposit of various minerals, generally dust and soot blown from central Asian deserts and volcanic eruptions as well as European air pollution

• Dark colour reduces albedo

• Satellite data shows margins of the ice sheet have darkened by as much as 5% per decade since 2001

• 0.6% of Southwest Greenland ice sheet is covered

Natural Processes Influencing Melting In Greenland - Glacial Algae

Phosphorus, mineral found in dust a key nutrient for algae bloom on ice sheet decreases albedo and melting

• Glacial Algae blooms are responsible for up to 13% of surface melting

• “Algal blooms can cover up to 78 percent of the bare ice surface since 2000 in the dark zone”

• Since 2000, the dark zone’s melting season has “progressively started earlier and lasted longer”

Natural Processes Influencing Melting In Greenland - Moulins (result of Glacial Algae and Cryoconite)

Are vertical shafts that form within glaciers, often near the edges and allow melt water to drain from the surface down to the base of the glacier, which can extend hundred meters downwards

• creates pathways for surface water to reach the base of the glacier which can lubricate the ice and accelerate its movement towards the ocean

Natural Processes Influencing Melting In Greenland - Fjords (and the calving process)

Deeper fjords allow for more surface area for warm water, hastening the undercutting process

• Out of the 226 glaciers surveyed, 74 in deep fjords accounted for nearly half of the total ice loss from Greenland between 1992 and 2017 compared to 51 glaciers in shallow fjords experienced least undercutting contributing to 15% of ice loss

• “the biggest glaciers are the most sensitive to warming, and those are ones really driving Greenland’s ice loss”

Human Activity Influencing Melting In Greenland - Climate Change

• Meltwater loss figures on average have reached about 300 gigatons per year between 1980 and 2010 with about 40% of melting episodes being extreme in recent decades

• The artic is warming at 4 times the global average rate due to greenhouse gases

• A Uni Barca study reveals that ice melting in Greenland has increased dramatically in recent decades, contributing to seas level rise and affecting global weather patterns

Human Activity Influencing Melting In Greenland - Warming Seas (Fjords)

• “In Greenland, everything got warmer at the same time: the air, the ocean surface, the depths of the ocean.”

• “Right now, the Greenland ice sheet is disappearing four times faster than in 2003 and already contributes 20% of current sea level rise”

• Between 2012–2017, Greenland’s ice melt added 0.68mm/year to sea level rise. Even with zero emissions from the 2020s, it would still raise sea levels by at least 0.27m over the next century.

Human Activity Influencing Melting In Greenland - Heat wave (2019)

• Greenland loses 12.5 billion tons of ice in a single day in Artic “heatwave”

• Experts think that a total of 197 billion tons of ice was lost

• As global temperatures have risen, extreme heat waves are now occurring at least 10 times more frequently than a century ago

Interconnection Between Natural Processes and Human Activity

• Cryoconite and Glacial Algae

• Climate Change and Warming Seas

• Cryoconite and Moulins

Impacts of Greenland’s Melting - Positive Social

• Southern Greenland's growing season extended by 3 weeks, boosting grass production for 60 sheep farmers who slaughter 23,500 sheep/lambs annually, reducing import reliance.

• Shift in marine ecosystems has led to a 14 fold increase in mackerel catches between 2011 and 2014 boosting employment in fishing related industries and promoting less reliance on imported fish

Impacts of Greenland’s Melting - Negative Social

• Due to 90% of Inuit households rely on traditional hunting and fishing as a food source with 80% of Inuit hunters report difficulty travelling on thinning ice

• 69% of Inuit Greenland and Canada’s population reported climate change is impacting their culture and traditions

• 60% of Inuit hunters have stopped using traditional travel routes due to unreliable ice conditions

Impacts of Greenland’s Melting - Positive Economic

• Greenland is estimated to hold approx. 38.5 million tonnes of rare earth minerals valued at $9.6 billion by 2026, accounting for 25% of the world’s known reserves

• Tourism contributes approx. $450 million annually to Greenland’s economy, accounting for 10% of its GDP

Impacts of Greenland’s Melting - Negative Economic

• 50% of Artic infrastructure is built on permafrost, which is rapidly thawing, The cost of adapting infrastructure is projected to be $5 billion by 2050

• Bringing in migrant workers to Greenland - London Mining US$2.35 billion iron ore project plans to bring in thousands of Chinese workers to build the mine within the next 5 years = not support for local economy

Impacts of Greenland’s Melting - Positive Environmental

• Artic Water Bank initiative, capture and transport meltwater equating to 2.5 million litres per second throughout the year to water scarce regions

  Glacial Rock Flour

• “It’s a kind of wonder material”

• silt is crushed into nano particles by the weight of the retreating ice sheets depositing roughly 1 billion tonnes of it per year

• Adding 25 tonnes of glacial rock flour per hectare increased crop yield on barley fields in Denmark by 30%

• 1 tonne of glacial rock flour can absorb 300kg of CO2

Impacts of Greenland’s Melting - Negative Environmental

• “This could lead to cooling in Europe, stronger hurricanes in North America, and disrupted monsoon patterns in Africa and Asia” - disruption of ocean currents

• The artic is warming at 4 times the global average, with temperatures increasing by 2.7C since 1971

• Greenland has contributed to 20% of global sea level rise since 2000

Spatial Technology - ICESat-2 Context

Launched in 2018 by Nasa, used by organisations such as the Norwegian Polar Institute and the United States Geological Survey (USGS)

Spatial Technology - ICESat-2 Aim

To identify why and how much cryosphere is changing by measuring aspects such as ice sheet mass balance

Spatial Technology - ICESat-2 How it works

• Uses ATLAS sends pulses of 10,000 green laser light in 6 parallel tracks towards the Earth’s surface

• Measures ice sheet thickness, changes in surface elevation and glacier movement and melt rates

• The satellite uses remote sensing to monitor and detect the physical characteristics of an area by measuring its reflected and emitted radiation at a distance

Spatial Technology - ICESat-2 Effectiveness

• Helping scientists year round to identify seasonal changes in ice thickness, detects regional variations in melting and measure ice loss due to climate change with sub-centimeter accuracy

• Shows long-term trends in ice loss, effect of warming temperatures on glaciers and how meltwater affects sea level rise

Spatial Technology - ICESat-2 Strengths

• Enables scientists to measure the thickness of the ice sheet with a precision of less than 2.5cm

• The data is freely available worldwide. It can inform policies such as the Paris Agreement and UNFCCC to study polar regions

• “As ice sheet mass loss is a key contributor to global sea level rise, this is incredibly useful for scientific community and policymakers”

Spatial Technology - ICESat-2 Limitations

• Expensive, approx. $1.1 billion

• The required accuracy of 5cm is limited to areas with a slope less than 1 degree, excluding steep areas

• Data is only available to users 30-45 days after satellite observation for final standard data = not providing real time data

Responses to Melting - World Glacier Monitoring Service (WGMS) Context

In 1986 the World Glacier Monitoring Service started to maintain and continue the collection of information on glacier changes

Responses to Melting - World Glacier Monitoring Service (WGMS) Success

• Global Ice Loss Evidence: Over a century of data, including the WGMS 2015 survey of 442 glaciers, showing 90% are in decline.

• Standardized Data: Consistent length, area, volume, and mass measurements across 40+ countries, enabling annual tracking.

• Strong Global Support: Funded by Swiss Government, MeteoSwiss, University of Zurich, and the UN.

Responses to Melting - World Glacier Monitoring Service (WGMS) Limitations

• Data Bias: Small glaciers and tropical regions (e.g., Africa) are underrepresented, with most monitoring in Europe and North America were infrastructure is developed

• Limited Coverage: Of 200,000 glaciers, only 492 (0.25%) have long-term mass balance data, leaving major gaps in comprehensive data

• Policy Dependency: Despite clear evidence of glacier melt, global governments must act to drive change.

Responses to Melting - World Glacier Monitoring Service (WGMS) Effectiveness of Impacts

Impacts it addresses: identifying rate of melting globally, interconnection between glacial loss and sea level rise

Impacts it doesn’t addresses: significant gap in their data, fails to identify and assess key impacts in underrepresented regions

Responses to Melting - Development of Climate Farming and Glacial Rock Flour Context

• 2013: Greenland’s government commissioned a study on expanding agriculture as the island warms.

• 2017: Greenland Agricultural Initiative (GRAIN) launched to boost research and sector growth.

• 2021: Professor Minik Rosing (Uni of Copenhagen) highlighted 1 billion tonnes of Glacial Rock Flour (GRF) produced each year as a potential soil enhancer.

Responses to Melting - Development of Climate Farming and Glacial Rock Flour Success

• Future Growth: "I expect a lot of development in farming sheep and agriculture due to global warming. It may become an important supplement to our economy."

• Food Independence: Hoegh estimates Greenland could supply 50% of its food needs, reducing reliance on costly Danish imports.

• Crop Expansion: Potato production in Southern Greenland doubled from 2008 to 2012, reaching 100+ tonnes.

Responses to Melting - Development of Climate Farming and Glacial Rock Flour Limitations

• Glacial Melt Reliance: GRF extraction depends on melting glaciers, raising sustainability concerns.

• Ecosystem Disruption: Dredging in glacial river deltas may harm local environments.

• High Transport Emissions: Shipping GRF from remote areas could offset its climate benefits.

Responses to Melting - Development of Climate Farming and Glacial Rock Flour Effectiveness of Impacts

• Increase revenue allows for less reliance on Denmark’s $550 million funding

• Less reliance on agricultural imports

• Job opportunities for Inuit’s in agriculture, reduce mental health rates associated with the economy

• Shift towards more farming based practices as it addresses the economic impacts of melting