Intro Environmental Issues Exam 1

How do deforestation and land-use changes contribute to greenhouse gas emissions and climate change?

Deforestation releases carbon from trees and soil, which is part of CO2, a greenhouse gas. Higher concentration of greenhouse gasses = more heat trapped and higher overall global temp

How does land use change, such as agriculture and urbanization, drive carbon release and alter climate?

Land use changes like deforestation, urbanization, and intensive agriculture drive carbon release by transforming natural carbon sinks (forests, soils) into carbon sources, increasing atmospheric greenhouse gases. Practices like intense grazing and farming can lead to soil degradation, reducing the soil's ability to store carbon and increasing soil erosion. These activities can also release other greenhouse gases, such as methane and nitrous oxide. The construction of buildings, roads, and other surfaces can change the reflectivity of the Earth's surface. Concrete and asphalt absorb more sunlight than natural landscapes, contributing to local warming effects, the production of cement for urban development is a source of carbon dioxide emissions

What are the advantages and disadvantages of thinking about GHG emissions at the per person scale vs the whole country scale?

advantages per person shows individual responsibility and whole country shows the whole country impact.

disadvantage for whole country is that if you live in a large country with many people it’ll look worse for individuals that use fewer resources, individual using fewer resources will look bad in a country that uses alot of resources.

What is species redundancy, and how does it support ecosystem stability and resilience?

species redundancy is multiple species performing similar functions within an ecosystem. the loss of one species is compensated for by the similar function of other species. Species redundancy provides ecosystem stability and resilience because the presence of multiple species performing similar functions ensures that if one species is lost or declines, another can step in and take over its ecological role, maintaining the overall function and health of the ecosystem.

Why do more diverse ecosystems tend to be more resilient to disturbances?

their greater variety of species provides redundancy, with different species capable of performing similar functions, ensuring that the ecosystem's core functions are maintained even if some species are lost during a disturbance. This also means there is a higher chance of having species with traits that can adapt to the disturbance, creating a buffer against negative impacts and allowing the ecosystem to recover more effectively

Why is species redundancy important when species are lost from an ecosystem?

species redundancy is crucial because its a "biological insurance policy" allows the ecosystem to better absorb disturbances, recover more quickly, and maintain essential processes like nutrient cycling, acting as a vital safety net against environmental changes and species loss

Why does island biodiversity (e.g., Galapagos) tend to have low redundancy?

there limited colonization, smaller habitats, and less competition lead to simplified food webs and specialized species. This makes these ecosystems fragile, as the loss of one species or niche can have cascading negative effects, due to the lack of multiple species performing the same role or function. 

What are ecosystem services, and what benefits do humans obtain from them?

the suite of benefits that ecosystems and nature provide to humanity. Provisioning services involve the production of renewable resources (example energy, transportation, national defense, food, wood, fresh water). Regulating services are those that lessen environmental change (example, climate regulation, flood prevention, erosion control, pest/disease control, water purification). Cultural (recreation, spiritual values, heritage, educational), and supporting (biological diversity maintenance, primary productivity, nutrient cycling) services

What is the difference between ecosystem services and ecosystem functions?

Ecosystem functions are the natural biophysical processes within an ecosystem, like nutrient cycling or water purification, that maintain its stability and survival, while ecosystem services are those specific functions that are directly beneficial to human well-being and provide goods or benefits to people. In essence, all ecosystem services are functions, but not all functions are services because a function must contribute to human well-being to be considered a service. 

Why are ecosystem functions like nutrient cycling and soil formation important for supporting services?

they provide the basic processes necessary for all other ecosystem services to function, such as producing food, clean air and water, and habitable environments. Nutrient cycling makes essential elements available to living organisms, while soil formation creates the fertile substrate that supports plants, crops, and habitats. Without these fundamental processes, ecosystems, and consequently the services they provide, could not be sustained

What are provisioning services? Give examples.

products obtained from ecosystems. Examples; energy, seafood, biomedial, transportation, national defense

What are regulating services? Give examples.

benefits obtained from the regulation of ecosystem processes. examples; flood prevention, climate regulation, erosion control, control of the pests and pathogens

Why is conserving biodiversity important for maintaining ecosystem services?

a rich variety of species makes ecosystems more stable and resilient to disturbances like climate change and disease, ensuring they can continue to provide essential benefits such as clean air and water, fertile soil, pollination, carbon sequestration, and food. Without diverse species and healthy ecosystems, these fundamental services collapse, impacting human health, food security, and economic well-being

Why do fossil fuels have lower ¹³C/¹²C ratios compared to the atmosphere?

because their origin as ancient plants involved photosynthesis, a process that preferentially incorporates the lighter ¹²C over the heavier ¹³C. This enrichment of ¹²C in plants was preserved as the plants became fossilized into coal, oil, and natural gas over millions of years. When these fossil fuels are burned, the resulting CO₂ released into the atmosphere has a lower ¹³C/¹²C ratio, diluting the atmospheric CO₂ and causing the atmosphere's ¹³C/¹²C ratio to decrease over time

How has the atmospheric ¹³C/¹²C ratio changed since the Industrial Revolution, and what does this indicate about the source of rising CO₂?

Since the Industrial Revolution, the atmospheric ¹³C/¹²C ratio has decreased. This decline, known as the Suess Effect, indicates that the added CO₂ is primarily from sources like fossil fuels and land use changes, which are enriched in ¹²C due to photosynthesis

What is a temperature anomaly, and why is it used instead of absolute temperature measurements in climate science?

the temp at a specific time and place is warmer or cooler than its long-term average of reference value (usually 30 year avg). it is used because it provides a more consistent and meaningful way to understand climate variability and trends by highlighting deviations from a historical average, allowing for more accurate comparisons between different locations and longer-term trend analysis

positive anomaly means the temp was warmer than the reference value

negative anomaly means it was cooler

According to the IPCC, what is the primary cause of global warming?

human activities principally through emissions of GHGs, have unequivocally caused global warming  

How do temperature anomalies provide better insights into climate change than absolute temperature values?

temp anomalies standardize temperature data by focusing on deviations from a historical average. absolute temp are heavily influenced by local factors like elevation and urban heat islands. By minimizing these local biases, anomalies offer a consistent frame of reference for comparing temperature variations across different locations and time periods, revealing clearer and more accurate trends in global warming over larger areas.

What human activities have contributed the most to land-use change?

The primary human activity driving land-use change is agriculture, which involves clearing land for crops and livestock and is responsible for about 80% of land-use changes globally. Other major activities include deforestation, urbanization, industrialization, and the establishment of infrastructure for transportation. These activities permanently alter natural landscapes, impacting ecosystem health and contributing significantly to climate change

What is a key challenge in managing human impacts on ecosystems?

balancing economic interests with environmental concerns. This trade-off is often complicated by the inherent complexity of ecological systems, the difficulty of changing human behavior, and the need for global cooperation on issues like climate change

How does biodiversity influence ecosystem function and stability?

Biodiversity strengthens ecosystem stability by providing redundancy, resilience, and a greater capacity to maintain ecosystem services. When an ecosystem has a diverse range of species, it's more robust against disturbances like droughts, diseases, or pests, because if one species is impacted, others can fill its ecological role. A greater variety of species provides a broader range of functional traits, allowing for more efficient resource use, complete nutrient cycling, and the ability to perform specialized tasks like pest control and pollination.

How do we compare species richness and evenness between two sites (e.g., campus vs. off campus)?

species richness - number of species in a community

species evenness - commonness of species in a community

How can we represent the relationship between species richness and ecosystem function graphically, when redundancy is low? when redundancy is high?

low functional redundancy is represented by a steep, potentially exponential relationship between species richness and ecosystem function, where function declines sharply with a small loss of species, while high functional redundancy is shown by a flatter, saturating curve where function remains stable despite species loss because redundant species can compensate for each other. 

climate

long-term, average weather over a particular region

carbon sink

a forest, ocean, or other natural environment viewed in terms of its ability to absorb C02 from the atmosphere. Examples, trees which are about 50% carbon

ecosystem services

ecological characteristics, functions, or processes that directly or indirectly contribute to human wellbeing…. the benefits that people derive from functioning ecosystems

ecosystem functions

ecological processes that control the fluxes of energy, nutrients and organic matter through an environment