Podcast
Questions and Answers
What happens to the effect of warming each time CO2 doubles?
What happens to the effect of warming each time CO2 doubles?
Which gas has the largest contribution to the greenhouse effect?
Which gas has the largest contribution to the greenhouse effect?
What is the current concentration of CO2 expressed in parts per million (ppm)?
What is the current concentration of CO2 expressed in parts per million (ppm)?
How much CO2 is being released globally each year?
How much CO2 is being released globally each year?
Signup and view all the answers
Over the past century, how much have global temperatures risen?
Over the past century, how much have global temperatures risen?
Signup and view all the answers
What has been observed regarding the frequency of regional droughts and floods in recent decades?
What has been observed regarding the frequency of regional droughts and floods in recent decades?
Signup and view all the answers
Which of the following factors can bias weather station measurements?
Which of the following factors can bias weather station measurements?
Signup and view all the answers
What percentage of the atmosphere is composed of CO2?
What percentage of the atmosphere is composed of CO2?
Signup and view all the answers
What are the correct sequences of climate periods over the past 1500 years?
What are the correct sequences of climate periods over the past 1500 years?
Signup and view all the answers
What does G.I.S. stand for?
What does G.I.S. stand for?
Signup and view all the answers
What type of data does a Raster format represent within a GIS?
What type of data does a Raster format represent within a GIS?
Signup and view all the answers
What is the solar constant just outside the Earth?
What is the solar constant just outside the Earth?
Signup and view all the answers
Which gases primarily affect outgoing longwave radiation and contribute to the greenhouse effect?
Which gases primarily affect outgoing longwave radiation and contribute to the greenhouse effect?
Signup and view all the answers
What relationship is described by Earth's energy balance?
What relationship is described by Earth's energy balance?
Signup and view all the answers
What does the term 'georeferenced data' refer to?
What does the term 'georeferenced data' refer to?
Signup and view all the answers
What is the significance of the saturation effect regarding CO2 levels in the greenhouse effect?
What is the significance of the saturation effect regarding CO2 levels in the greenhouse effect?
Signup and view all the answers
What is the primary focus of Bjorn Lomborg's research regarding climate change?
What is the primary focus of Bjorn Lomborg's research regarding climate change?
Signup and view all the answers
What does IPCC stand for and what is its primary function?
What does IPCC stand for and what is its primary function?
Signup and view all the answers
What is a significant change in scenario modeling from RCPs to SSPs?
What is a significant change in scenario modeling from RCPs to SSPs?
Signup and view all the answers
Which warming scenario is currently considered the most likely by experts?
Which warming scenario is currently considered the most likely by experts?
Signup and view all the answers
What is one of the primary reasons for the revised projection of the world's peak human population?
What is one of the primary reasons for the revised projection of the world's peak human population?
Signup and view all the answers
What method is most commonly used to predict temperature and precipitation changes in climate models?
What method is most commonly used to predict temperature and precipitation changes in climate models?
Signup and view all the answers
Which of the following is a limitation associated with the SSPs?
Which of the following is a limitation associated with the SSPs?
Signup and view all the answers
How many children per woman are we currently averaging globally, according to the provided data?
How many children per woman are we currently averaging globally, according to the provided data?
Signup and view all the answers
What aspect does Grinnellian niche concept primarily focus on?
What aspect does Grinnellian niche concept primarily focus on?
Signup and view all the answers
Which of the following best describes the realized niche?
Which of the following best describes the realized niche?
Signup and view all the answers
What is niche conservatism?
What is niche conservatism?
Signup and view all the answers
In the BAM Venn diagram approach, which factor is NOT considered a component of niche?
In the BAM Venn diagram approach, which factor is NOT considered a component of niche?
Signup and view all the answers
What does the Eltonian Noise hypothesis assume about species distribution?
What does the Eltonian Noise hypothesis assume about species distribution?
Signup and view all the answers
What is the significance of Hutchinson’s duality in relation to species distribution?
What is the significance of Hutchinson’s duality in relation to species distribution?
Signup and view all the answers
Which of the following defines the potential niche?
Which of the following defines the potential niche?
Signup and view all the answers
In the context of habitats, what does the term 'Equilibrium distribution' imply?
In the context of habitats, what does the term 'Equilibrium distribution' imply?
Signup and view all the answers
What is indicated by an odd versus an even number of trophic levels?
What is indicated by an odd versus an even number of trophic levels?
Signup and view all the answers
What is the main reason for the presence of mostly uneaten plants in ecosystems, according to the Green-world hypothesis?
What is the main reason for the presence of mostly uneaten plants in ecosystems, according to the Green-world hypothesis?
Signup and view all the answers
What occurs to the energy as it moves up the trophic levels, according to the rule of thumb?
What occurs to the energy as it moves up the trophic levels, according to the rule of thumb?
Signup and view all the answers
What is meant by the term 'Trophic cascade'?
What is meant by the term 'Trophic cascade'?
Signup and view all the answers
What contributes to bioaccumulation in higher trophic levels?
What contributes to bioaccumulation in higher trophic levels?
Signup and view all the answers
Which factor can reduce the sensitivity of ecosystems to changes in herbivore numbers?
Which factor can reduce the sensitivity of ecosystems to changes in herbivore numbers?
Signup and view all the answers
According to the content, which level of the trophic system is considered the first level?
According to the content, which level of the trophic system is considered the first level?
Signup and view all the answers
What did Terborgh propose regarding the role of apex predators in ecosystems?
What did Terborgh propose regarding the role of apex predators in ecosystems?
Signup and view all the answers
What impact does the number of trophic levels have on primary producers?
What impact does the number of trophic levels have on primary producers?
Signup and view all the answers
Study Notes
Climate Through Time
- There have been four distinct periods over the past 1500 years:
- Dark Ages (cold)
- Medieval Warm Period
- Little Ice Age
- Modern Warming
- The Industrial Revolution beginning around 1850 marked the start of modern warming which is the coldest 500-year period of the past 11,000 years
- The Medieval Warming Period is supported by many studies, although some argue that it was not as warm as currently believed
Geographic Information Systems (GIS)
- GIS is a system used to organize, manage, and analyze geospatial data.
- Data in GIS must be georeferenced, meaning it is tied to specific locations on the Earth using coordinates (x,y)
- GIS data models can be either Vector or Raster formats.
- Vector data represent discrete features like points, lines, or polygons.
- Raster data represent continuous values defined on a grid.
Earth's Energy Balance
- The solar constant, the amount of solar radiation received just outside Earth's atmosphere, is 1360 watts per square meter.
- About 340 watts per square meter of solar radiation reaches the top of Earth's atmosphere.
- Approximately 161 watts per square meter of solar radiation reaches the Earth's surface.
- Earth's energy balance is a delicate interplay between incoming shortwave radiation and outgoing longwave radiation.
- Clouds play a significant role in reflecting incoming radiation or absorbing outgoing radiation.
- Greenhouse gases (GHGs), such as carbon dioxide (CO2) and water vapor, primarily affect outgoing longwave radiation, trapping heat in the atmosphere.
Radiative Forcing
- Water vapor accounts for the largest portion (50%) of the greenhouse effect.
- Clouds account for the second largest portion (25%).
- CO2 accounts for the third largest portion (20%).
- Other greenhouse gases account for the remaining 5%.
- Anthropogenic radiative forcing (human-caused) is greater than recent natural variation.
- Volcanoes have a cooling effect on the atmosphere.
- Solar cycles, with their longer and shorter periods, have both warming and cooling effects but are dwarfed by the recent impact of CO2 emissions.
CO2 Levels & Emissions
- CO2 makes up a very small portion of the atmosphere (0.04%), but its influence on climate is significant due to the greenhouse effect.
- CO2 levels are measured in parts per million (ppm).
- The Keeling Curve, which monitors CO2 levels at Mauna Loa, Hawaii, shows current levels are around 420 ppm.
- The global rate of CO2 emissions is approximately 35 billion tons per year.
- Per capita CO2 emissions for Canadians are 15 tons per year, with declining emissions in recent decades for Canadians, Americans, and Europeans.
- China is experiencing rapidly increasing emissions due to its expanding industrial sector.
Recent Climate Change Observations
- Global temperatures have increased by about 1.5 degrees Celsius over the past century, with land warming faster (2 degrees Celsius) than oceans (1 degree Celsius).
- Major global changes in precipitation are not strongly supported by observations.
- The frequency of regional droughts, floods, and hurricanes remains similar to past levels.
- Weather stations may have bias in geographic distribution and local siting, leading to inaccurate temperature readings.
- The Urban Heat Island effect, where cities are warmer than rural areas, introduces a bias in temperature data.
- Studies using rural-only stations show a smaller temperature increase compared to all stations.
Climate Change and Cost-Benefit Analysis
- Bjorn Lomborg, a Danish human resource economist, argues that climate change is ranked low in terms of cost-benefit analysis due to the expensive solutions with limited overall change.
General Circulation Models (GCMs) & Projections
- GCMs are climate models used to simulate future climate scenarios.
- Regional Climate Models (RCMs) are higher resolution models focusing on specific regions.
- The Intergovernmental Panel on Climate Change (IPCC) is a UN group that produces reports on climate change and potential adaptations/mitigations. The report is now in its sixth iteration - Assessment Report 6 (AR6).
- IPCC develops standardized frameworks for GCMs and incorporates them into scenarios that simulate human population growth and energy transitions.
- The old version of scenarios, Representative Concentration Pathways (RCPs), has been replaced by Shared Socioeconomic Pathways (SSPs).
- SSPs are categorized based on the level of radiative forcing (warming) in watts per square meter, ranging from 1.9 to 8.5.
- Most SSPs suggest a moderate warming scenario (2.6 to 4.5 w/m2) is most likely, resulting in 1.8 to 2.7 degrees Celsius warming by 2100.
- Ensemble models, which average the results of multiple models, reduce uncertainty in climate projections.
- A key limitation in SSPs is predicting long-term trends in human population and energy transitions.
- Current projections suggest a peak human population slightly over 10 billion, a decline from earlier estimates.
- The decline in peak population is attributed to decreasing fertility rates.
Niche
- The term niche describes species' ecological roles, habitat requirements, and interactions within an environment.
- There are multiple interpretations of niche.
- Grinnellian niche: Focuses on the ecological role or habitat needs of a species.
- Eltonian niche: Describes the species' place in the biotic environment, especially its trophic level (e.g., predator, herbivore).
- Hutchinsonian niche: Considers multiple dimensions of the environment in which a species persists.
- Hutchinson's niche can be subdivided further.
- Fundamental niche: All possible conditions a species can persist in (including conditions not observed on Earth).
- Potential niche: The place where a species would thrive in the absence of biotic factors and dispersal limitations.
- Realized niche: The environment actually occupied by the species, considering interactions with other species.
- Niche conservatism refers to the retention of ecological traits over time (such as habitat preferences) and is essential for climate change risk assessments for species.
- The BAM (Biotic, Abiotic, Movement) Venn diagram approach categorizes niches into three components: Biotic interactions, Abiotic factors, and Movement ability. It can be applied under different conditions.
- Equilibrium distribution: Occurs when there are no movement limitations, meaning a species is at equilibrium with its climate and location.
- Non-equilibrium distribution: Occurs when there are limitations on movement or migration, meaning species aren't fully at equilibrium with their climate and location.
- The Eltonian Noise hypothesis assumes that the biotic and abiotic factors in an environment are at equilibrium, meaning species are at equilibrium with the environment and there are no movement limitations. Many models for species distribution and climate change assume this.
- Hutchinson's duality highlights the difference between environment space (E-space) and geographic space (G-space). These two spaces are not reciprocal, meaning one geographic location can support multiple environments, while one environment can occur across various geographic locations which can explain why species distributions are not always at equilibrium with the climate, why there are invasive species.
Trophic Levels & Cascades
- Trophic levels represent feeding levels in an ecosystem:
- Primary producers (1st level): Plants, algae, etc., which convert sunlight into energy.
- Primary consumers (2nd level): Herbivores that eat primary producers.
- Apex predators (higher levels): Top predators that feed on other consumers.
- The "rule of thumb" states that only about 10% of energy is transferred from one trophic level to the next.
- This energy loss leads to bioaccumulation of toxins at higher trophic levels as organisms consume prey containing toxins.
- The Green-world hypothesis attempts to explain why there is an abundance of uneaten plants (suggesting a lack of herbivore pressure).
- The explanation lies in the control of herbivores by apex predators, resulting in greater plant abundance.
- Terborgh tested this hypothesis by observing trophic cascades in Panama and Venezuela, suggesting a "top-down" perspective, with apex predators having a significant influence on the ecosystem.
- Schmitz further tested this theory in a food web involving plants, grasshoppers, and spiders.
- The removal of top predators often leads to a trophic cascade, where significant changes occur throughout the food web, including disruptions to lower trophic levels.
- The Yellowstone National Park wolf reintroduction is perhaps the most well-known example of a trophic cascade.
- While a top-down perspective is common in ecosystems, it is not the only factor influencing trophic dynamics. Plant defenses, such as thorns and chemical deterrents, can also limit herbivory.
- The number of trophic levels in an ecosystem plays a significant role in influencing the abundance of primary producers.
- Even trophic levels often lead to greater herbivore abundance and lower plant abundance, while odd trophic levels lead to reduced herbivore abundance and greater plant abundance.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore significant climate periods over the last 1500 years including the Dark Ages, Medieval Warm Period, and Modern Warming. This quiz also covers the basics of Geographic Information Systems (GIS) including data types and georeferencing. Test your knowledge on these critical environmental topics.