🧊People of the Arctic Unit 7 – Climate Change in the Arctic

Arctic Climate Basics

• Arctic climate characterized by long, cold winters and short, cool summers due to its high latitude and unique geography
• Receives less solar radiation compared to lower latitudes resulting in lower temperatures and extensive ice cover
• Experiences polar night during winter months when the sun remains below the horizon and midnight sun during summer
• Permafrost, ground that remains frozen for at least two consecutive years, covers large portions of the Arctic landscape
  • Stores significant amounts of carbon in the form of frozen organic matter
  • Acts as a barrier to water drainage and influences vegetation patterns
• Sea ice plays a crucial role in regulating the Arctic climate by reflecting solar radiation (albedo effect) and insulating the ocean from the atmosphere
• Arctic amplification magnifies the effects of global climate change in the region causing temperatures to rise faster than the global average
  • Driven by positive feedback loops such as the ice-albedo feedback and increased heat absorption by the ocean

Observed Changes in the Arctic

• Arctic air temperatures have increased at more than twice the global average rate over the past few decades (Arctic amplification)
• Sea ice extent and thickness have declined rapidly with summer minimum extent decreasing by ~13% per decade since 1979
  • Older, thicker multi-year ice is being replaced by younger, thinner first-year ice
  • Sea ice loss is most pronounced in the Beaufort, Chukchi, and East Siberian Seas
• Permafrost temperatures have risen causing widespread thawing and degradation of permafrost landscapes
  • Increased active layer depth (seasonally thawed layer above permafrost) altering hydrological processes and vegetation dynamics
• Greenland ice sheet experiencing accelerated melting and mass loss contributing to global sea level rise
  • Increased surface melt, ice discharge from outlet glaciers, and submarine melting at the ice-ocean interface
• Changes in precipitation patterns with increased rainfall and more frequent rain-on-snow events affecting snow cover duration and properties
• Shifts in vegetation distribution and productivity including northward expansion of shrubs (shrubification) and greening of the tundra
• Alterations in wildlife populations and behaviors such as changes in migration patterns, breeding grounds, and food availability for species like polar bears, caribou, and migratory birds

Causes of Arctic Climate Change

• Anthropogenic greenhouse gas emissions, primarily carbon dioxide (CO2) and methane (CH4), are the main drivers of global climate change and Arctic warming
  • Burning of fossil fuels, deforestation, and land-use changes have increased atmospheric CO2 concentrations to unprecedented levels
• Black carbon (soot) from incomplete combustion of fossil fuels and biomass contributes to Arctic warming by reducing surface albedo when deposited on snow and ice
• Positive feedback loops amplify the effects of initial warming in the Arctic
  • Ice-albedo feedback: As sea ice and snow cover decrease, more solar radiation is absorbed by the darker ocean and land surfaces, further enhancing warming
  • Permafrost thaw feedback: Thawing permafrost releases stored carbon in the form of CO2 and CH4, potent greenhouse gases that contribute to additional warming
• Changes in atmospheric and oceanic circulation patterns, such as the weakening of the polar vortex and increased inflow of warm Atlantic water into the Arctic Ocean, influence regional climate
• Natural climate variability, including the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO), can modulate the effects of long-term climate change on shorter timescales
• Reduced sea ice cover allows for increased absorption of solar radiation by the ocean, leading to warmer water temperatures and delayed freeze-up in the fall

Impacts on Arctic Ecosystems

• Declining sea ice habitat threatens the survival of ice-dependent species such as polar bears, walruses, and ice seals
  • Reduced access to prey, increased energy expenditure, and potential conflicts with human activities
• Shifts in the timing and availability of sea ice alter the phenology and distribution of primary producers (algae) and zooplankton, affecting the entire marine food web
• Thawing permafrost and changes in hydrology alter soil moisture, nutrient availability, and vegetation composition
  • Expansion of shrubs and trees into tundra areas (shrubification) modifies habitat suitability for wildlife and can increase wildfire risk
• Warmer temperatures and longer growing seasons lead to greening of the tundra, increased plant productivity, and changes in plant community composition
  • Potential mismatch between plant phenology and herbivore (caribou, muskoxen) migration and breeding cycles
• Ocean acidification, caused by increased absorption of atmospheric CO2, affects the growth and survival of calcifying organisms (pteropods, mollusks) and alters marine ecosystem dynamics
• Increased freshwater input from melting glaciers and permafrost thaw alters ocean salinity, stratification, and circulation patterns, impacting nutrient distribution and primary productivity
• Invasive species and pathogens may expand their ranges into the Arctic as environmental conditions become more favorable, potentially outcompeting native species and altering ecosystem functioning

Effects on Indigenous Communities

• Rapid changes in sea ice extent, thickness, and seasonality disrupt traditional hunting, fishing, and transportation practices of Arctic Indigenous peoples
  • Reduced access to traditional food sources (marine mammals, fish) and increased safety risks during travel on unstable ice
• Thawing permafrost and coastal erosion threaten the stability of infrastructure, including homes, schools, and cultural sites, forcing relocation of some communities
  • Increased maintenance costs and challenges in constructing new infrastructure on unstable ground
• Changes in the distribution and abundance of culturally important species (caribou, seals, whales) impact the social, economic, and spiritual well-being of Indigenous communities
  • Disruption of traditional knowledge systems and cultural practices tied to these species
• Warmer temperatures and changing weather patterns affect the timing and success of traditional subsistence activities (hunting, fishing, gathering) and may introduce new health risks
  • Increased exposure to foodborne and waterborne illnesses, vector-borne diseases, and mental health challenges
• Increased shipping, resource extraction, and tourism in the Arctic due to reduced sea ice cover may lead to conflicts with Indigenous land use, cultural practices, and self-determination
• Adaptive capacity of Indigenous communities is influenced by factors such as access to resources, social networks, and integration of traditional knowledge with scientific understanding
  • Collaborative decision-making and co-management of resources can help build resilience and support adaptation strategies

Global Consequences

• Arctic climate change contributes to global sea level rise through increased melting of land-based ice (Greenland ice sheet, glaciers) and thermal expansion of the oceans
  • Coastal communities worldwide face increased risks of flooding, erosion, and saltwater intrusion
• Changes in Arctic sea ice and snow cover affect global atmospheric and oceanic circulation patterns, influencing weather and climate in lower latitudes
  • Potential links to more frequent and intense extreme weather events (heatwaves, droughts, floods) in mid-latitude regions
• Thawing permafrost and the release of stored carbon (CO2 and CH4) from the Arctic landscape amplify global greenhouse gas concentrations and contribute to further climate warming
  • Permafrost contains approximately twice as much carbon as the atmosphere, and its release may accelerate global climate change
• Alterations in Arctic marine ecosystems and fisheries have implications for global food security and economic activities
  • Shifts in the distribution and abundance of commercially important fish species (cod, pollock) and increased accessibility of Arctic waters for fishing fleets
• Geopolitical tensions may arise as Arctic nations and other countries seek to exploit newly accessible resources (oil, gas, minerals) and shipping routes in the region
  • Competing territorial claims, military presence, and the need for international cooperation in managing the changing Arctic environment
• The Arctic serves as a sentinel for global climate change, providing early warning signs and insights into the potential impacts and challenges facing other regions worldwide
  • Studying and understanding Arctic climate change is crucial for informing global mitigation and adaptation strategies

Adaptation and Mitigation Strategies

• Reducing global greenhouse gas emissions is essential for mitigating the long-term impacts of climate change in the Arctic and beyond
  • Transitioning to renewable energy sources, improving energy efficiency, and implementing carbon pricing mechanisms
• Enhancing the adaptive capacity of Arctic communities through investments in infrastructure, education, and health services
  • Developing climate-resilient housing, transportation, and communication systems that can withstand changing environmental conditions
• Incorporating Indigenous knowledge and local expertise into decision-making processes and adaptation planning
  • Collaborative research, monitoring, and management of Arctic resources and ecosystems
• Protecting and restoring critical habitats and biodiversity in the Arctic to enhance ecosystem resilience
  • Establishing marine protected areas, managing fisheries sustainably, and minimizing the impacts of human activities on sensitive species and habitats
• Improving early warning systems and emergency response capabilities to cope with increasing risks of natural hazards (coastal erosion, permafrost thaw, wildfires)
  • Developing community-based monitoring networks and integrating scientific data with local observations
• Supporting the diversification of Arctic economies and livelihoods to reduce vulnerability to climate-related impacts
  • Promoting sustainable tourism, renewable energy development, and value-added processing of local resources
• Strengthening international cooperation and governance frameworks to address the transboundary challenges posed by Arctic climate change
  • Implementing and enforcing agreements on climate action, biodiversity conservation, and sustainable development in the Arctic region

Future Projections and Challenges

• Climate models project continued warming of the Arctic at rates exceeding the global average, with the potential for an ice-free Arctic Ocean during summer by mid-century
  • Increased duration of the open water season and changes in the timing of sea ice formation and breakup
• Accelerated melting of the Greenland ice sheet and glaciers is expected to contribute significantly to global sea level rise, with regional variations in impacts
  • Potential for multi-meter sea level rise over the coming centuries, depending on the magnitude of future greenhouse gas emissions
• Widespread thawing of permafrost is projected to continue, with the risk of abrupt and irreversible changes in landscape stability and carbon release
  • Impacts on infrastructure, ecosystems, and global climate feedbacks, with the potential for a significant additional contribution to atmospheric greenhouse gas concentrations
• Changes in the frequency, intensity, and distribution of extreme weather events in the Arctic and beyond, affecting human safety, infrastructure, and ecosystem functioning
  • Increased likelihood of heatwaves, droughts, and wildfires in some regions, and more frequent and intense precipitation events in others
• Shifts in the distribution and productivity of marine and terrestrial species, with implications for Arctic biodiversity and the livelihoods of Indigenous communities
  • Potential for local extinctions, species invasions, and changes in ecosystem services
• Increased human activities in the Arctic, including shipping, resource extraction, and tourism, present both opportunities and challenges for sustainable development
  • Balancing economic interests with environmental protection, social equity, and the rights of Indigenous peoples
• Addressing the complex and interrelated challenges of Arctic climate change requires a holistic, interdisciplinary, and inclusive approach that engages stakeholders at all levels
  • Collaboration among scientists, policymakers, Indigenous communities, and the private sector is essential for developing effective and equitable solutions