Transcript Document
Ecosystems Primary Source: IPCC WG-2 Chapter 4 - Ecosystems, their properties, goods and services (Plus parts of WG-2 Chapters 9-16) (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Ecosystem From WG-2 Chapter 4: “a dynamic complex of plant, animal and micro-organism communities, and the nonliving environment, interacting as a functional unit” “strong interactions between components within their boundaries and weak interactions across boundaries” (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Ecosystem Goods & Services - 1 Supporting services • Primary and secondary production • Biodiversity Provisioning services • Food • Fibre • Medicinal and cosmetic products (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Ecosystem Goods & Services - 2 Regulating services • Carbon sequestration • Climate and water regulation • Buffering natural hazards (e.g., floods) • Water and air purification • Disease and pest regulation Cultural services • Human spiritual & aesthetic appreciation (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Major Ecosystems: Areas and Carbon Stocks Transformed by land use (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Key Issues - Resilience Resilience disturbance tolerated before shifting to a different state (e.g., forest prairie) - also: ability to adapt naturally Expectation that ecosystems will tolerate some level of climate change and persist - Speed of (“stable”) transient responses? (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Key Issues - Other Human Pressures Extractive use of goods Increased degradation of natural habitats Increased fragmentation of natural habitats Climate change can amplify these pressures (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Key Issues - Critical Thresholds Exceding critical threshold positive feedbacks novel states, poorly understood “Climate future and direct human pressures ‘virtually certain’ to be unprecedented vs. past 100s millenia” (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Key Issues - Time Lags Time needed for broad-scale biospheric responses or shifts in geographical ranges: poorly understood E.G.: • centuries for vegetation • millennia for soil formation Further understanding needed: How do ecosystems respond to continuously changing conditions (esp. on human time scales)? (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Key Issues - Species Extinctions Global extinction is a critical issue: Biodiversity is “very likely” linked to ecosystem functioning and maintenance of ecosystem services. What extinctions are critical for ecosystem functioning? How do they reduce societal options for adaptation? (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Example: “Hot Spots” in Australia & New Zealand Criteria: large impacts, low adaptive capacity, substantial population, economically important, substantial exposed infrastructure, and subject to other major stresses (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Example: Europe’s Key Vulnerabilities Colors: Main biogeographic regions (EEA, 2004) Criteria: large impacts, low adaptive capacity, substantial population, economically important, substantial exposed infrastructure, and subject to other major stresses (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Example: Europe - Change in Species Richness (Amphibians and Reptiles) Criteria: large impacts, low adaptive capacity, substantial population, economically important, substantial exposed infrastructure, and subject to other major stresses Richness Green (Using HadCM3, A1F1 Scenario) Richness Purple (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Latin America: Deforestation Predicted 2000-2100 Deforestation Areas Latin America GHG emissions = ~ 4% of global total ( ~ 50% from land-use change) Up to 40% loss of mammalian habitats by 2050. Important driver: soybean planting [38 Mha (2003/04) 59 Mha (2019/20)] (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) North America: Forest Fires Effect of projected precipitation and (precipitation - evaporation) changes? Other stresses (e.g., pests)? (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) North America: Bud Burst Effect on other parts of ecosystem (e.g., pollinating insects)? (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Arctic: Ecosystem Changes Dynamic vegetation model driven by HadCM2 (2090-2100) (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Coral Bleaching Threats from pollution, development, fishing, sediments, nutrients Low: Blue High: Red Stresses include: • Increased ocean acidity (pH) • Stronger storms • Over-fishing • Pollution • Cycles such as ENSO & Warmer SST (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Future Coral Bleaching Stresses: • Increased ocean acidity (pH): No current link • Stronger storms: Possible in future • Others: over-fishing, pollution, cycles such as ENSO • Warmer SST: T > ~ 1 ˚C above summer max. for 4+ weeks - expulsion of symbiotic zooxanthellae - fast-growing, bleaching-resistant genera dominate recovery Challenge for projections: How much does coral adapt? (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Coral Bleaching Events vs. SST (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Projected Risks vs. T Not Included: Effects of over-harvesting, pollution, land-use change, habitat fragmentation (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16) Ecosystems END (Mt/Ag/EnSc/EnSt 404/504 - Global Change) Ecosystems (from IPCC WG-2, Chapters 4,9-16)