Environmental Studies Exam 12

What is the Anthropocene and when did it start?

A proposed new geological era in which the key characteristic of natural systems is human forcing —., humans are now the dominant driver of change in Earth's systems. It started during the Great Collision (1750-200)

What is the I = P*A*T Model and what do the terms in the equation mean?

I = Envrionmental Impact

P= Population

A = Affluence Per Person

T = Technology (Impact of Tech Used)

Countries Used in Example of I=PAT and there comparisons?

USA = Population growth is low, but high levels of Affluence and per capita foot print

China = Large total foot print, but much lower footprint per capita

Sweden : Smaller Population with a low (T) and (A), well developed country as well.

Nature as a model for sustainability is:

Nature systems have sustained life for 3.8 billion years using principle human systems. It should emulate:

Reliance on renewable solar energy

Population control

Nutrient Cycling

Biodiversity

What is TFR (Total Fertility Rate) and the factors influencing it?

 The average number of children born to women in a population. The factors that influence it are child labor (economic value of children), cost of raising children, infant mortality rate, and opportunities for women (education, employment, family planning access).

What are the factors leading to our exponential increase in population?

Unprecedented human population growth, economic growth, resource consumption, and globalization, enabled by improved food production, medicine/health, and sanitation.

What is the demographic transition model?

Predictable changes in birth rate, death rate, and population growth as societies industrialize

What is stage 1 in the DTM?

Preindustrial: High birth rate AND high death rate (compensating for high infant mortality) → population grows very slowly.

What is stage 2 in the DTM?

Death rate drops sharply (better food production/health) while birth rate stays high → population grows rapidly.

What is Stage 3 of DTM

Birth rate drops too (better food, health, education) → population growth slows.

What is Stage 4 of DTM?

Birth rate ≈ or below death rate → growth levels off, then can decline (negative growth).

Where are developed vs developing countries located in the DTM?

Developed countries (e.g., Germany, Bulgaria, Russia, Japan, Italy, Greece) are generally in Stage 3/4 (slow, stable, or declining growth); developing countries (e.g., Guatemala, Nigeria, Saudi Arabia) are more often in Stage 2 (rapid growth).

What is population momentum?

 population continues to grow for a period even after fertility drops to replacement level, because of the existing age structure

What is population age structures?

Age-structure diagrams (pyramids) show the distribution of a population across pre-reproductive (0–14), reproductive (15–44), and post-reproductive (45–85+) age classes

What does rapid expansion look like on a pyramid? Which countries fit this?

Wide base. Guatemala, Nigeria, Saudi Arabia

What does declining expansion look like on a pyrmid? which countries fit this?

Narrower base than the middle. Germany, Russia, Bulgaria

Factors of Bongaat’s population projection and factors that influence it?

Making family planning services and birth control available. Improving the economic, social, and legal status of women. The three causes of continued growth identified in his model: (1) unwanted fertility, (2) high desired family size, (3) population momentum.

History of the discovery of the greenhouse effect? Year discovered, person discovered by? ·      who relationship of CO2?

Joseph Fourier first described the concept in 1824.

Svante Arrhenius was first to discuss the relationship of CO2 and warming, in 1896

Shortwave Radiation is:

Incoming solar radiation which is absorbed by the earths surface and the rest is reflected back to space by cloud and surface albedo.

Longwave radiation is:

The energy radiated from the surface which is trapped by GHG and warming the earth.

What fraction of solar radiation is absorbed by earth and what is reflected?

2/3 is absorbed and 1/3 is reflected

What percent of the lower atmosphere does GHG’s make up

~1%

What are the most common GHG’s

Methane, carbon dioxide, nitrous oxide

What has the highest global warming potential?

Sulfar hexaflouride = 23,900

What has the lowest global warming potential?

Carbon Dioxide

In terms of CO2 equivalents what do we emit the most of?

CO2

What is the Keeling Curve and seasonal changes in atmospheric CO2

The Keeling Curve is the long-term record of atmospheric CO2 concentration showing both the steady overall increase and the season sawtooth pattern. CO₂ dips in Northern Hemisphere summer (more photosynthesis/uptake by land plants) and rises in winter (less photosynthesis, more respiration/decomposition), because most of Earth's landmass (and plant biomass) is in the Northern Hemisphere.

What does main carbon sinks mean (sequestration?)

Compartments that absorb more carbon than they release: Oceans, Forests, wetlands, soil

What is the pre-industrial CO2 Concentration?

~280ppm

What is the current atmospheric CO2 concentration?

~428ppm

Who is the largest annual CO2 emissions producer?

China

Who is the largest per-capita CO2 emissions producer?

United States

Who is the largest cumulative CO2 producer?

United States

Greenhouse gas emissions by sector — energy vs. agriculture

The global energy sector produces about 76.7% of greenhouse gas emissions worldwide, making it by far the largest source compared to agriculture, which accounts for roughly 10% to 12.3% globally

Predicted climate changes (temp, precipitation, extreme events)

1. Temperature: IPCC predicts a 1.5–4.5°C (2.7–8.1°F) increase by 2100.

2. Precipitation: Warming "revs up" the hydrologic cycle → generally wetter at high latitudes, drier at mid-latitudes (and in parts of the subtropics/tropics); larger % changes seen at higher levels of warming (1.5°C vs. 2°C vs. 4°C scenarios).

3. Extreme events: Increased intensity and damage, with possible increased frequency (hurricanes, tornadoes, floods, droughts, wildfires); heavy downpour frequency in the U.S. has increased ~20% since 1958.

4. Polar amplification - Poles warm up faster than the rest of the planet. Less ice = less heat reflection.

Key anthropogenic carbon cycle alterations

• Deforestation — loss of large C sinks, CO₂ to atmosphere ("triple whammy")

• Combustion of fossil fuels (electricity, automobiles) — CO₂ to atmosphere

• Cattle farming — significant CH₄ emissions

Key climate change positive feedback loops

• Peatland: warmer/drier conditions increase decomposition of organic matter in peat soils and increase peat fires → more CO₂/CH₄ released.

• Forest fires: more frequent/larger fires (average U.S. wildfire size has increased) release stored carbon as CO₂.

• Warmer ocean water: reduces the ocean's capacity to absorb/dissolve CO₂, leaving more CO₂ in the atmosphere.

Climate-change-related human activities that are positive feedback loops

Arctic ice-free summers: opens the Arctic to commercialization (energy production, shipping) → more GHG emissions.

Air conditioning (AC): as it gets hotter, AC demand rises (especially in developing/hot regions); AC coolants (HFCs) have GWP far greater than CO₂ → more warming → more AC demand.

Climate refugees: catastrophic events and long-term impacts (desertification, sea level rise) displace people (~24 million/year from weather disasters; an estimated 143 million by 2050 from desertification/sea level rise, mainly sub-Saharan Africa, South Asia, Latin America) → displaced populations need new land, often leading to more land conversion/deforestation and further emissions.

Polar amplification — causes & consequences

• Cause: Loss of sea ice/snow reduces surface albedo in polar regions (ice-albedo feedback), so polar regions absorb more solar energy and warm disproportionately.

• Consequence: Polar regions warm to a greater degree than equatorial regions, accelerating ice melt, permafrost thaw, sea level rise, and disruption of the temperature gradient between the poles and equator (which in turn affects the jet stream — see below).

Climate change & jet stream – why/how is it changing and impacts on weather patterns?

Why is it changing? Melting polar ice reduces that temperature differential (polar amplification), which slows the jet stream and makes its loops deeper/wavier.

How is it changing? Impacts: southern areas can experience colder-than-normal weather, northern areas warmer-than-normal weather, and because the jet stream moves more slowly, these unusual weather patterns persist longer (e.g., record snow dumped in one area).

Factors changing the intensity of hurricanes

Warm air holds more moisture, warmer ocean water, rising sea levels.

Different impacts of sea level rise on coastal vs. island communities

• Island communities (e.g., Kiribati, ~3 m above sea level): among the first climate refugees; saltwater intrusion — movement of saline water into freshwater aquifers — causes loss of potable drinking water and farmland.

• Coastal (and high-elevation) communities: growing danger from glacial lake outburst floods in mountain regions (e.g., Himalayas/Everest area); desertification turning productive land to dust in other regions; generally, coastal groundwater depletion + sea level rise = worse saltwater intrusion, and coastal groundwater depletion/dams + subsidence + sea level rise = far worse flooding of coastal cities.

Developing countries – more deaths – why?

 This is generally attributed to fewer resources for early warning systems, weaker infrastructure/building codes, less capacity for evacuation and emergency response, and greater reliance on climate-sensitive subsistence activities (agriculture).

Developed countries — more economic damage - why?

because developed nations have far more expensive infrastructure, property, and insured assets at risk, even though fewer people die relative to developing countries.

Ecological consequences of climate change?

Extinction risk, species distribution shifts to escape heat, cold blooded animals reaching adulthood at smaller size.

Changes in disease and disease vectors due to climate change?

• Warming expands suitable habitat for disease vectors (and changing rainfall can too).

• Shortens generation time for insect vectors, and shortens pathogen incubation periods within vectors.

• Increases vector population sizes.

• Disasters damage water/sewer infrastructure → more waterborne disease.

• Climate refugee crises can create unsanitary/crowded conditions.

• Food/water stress lowers human immunity, increasing disease susceptibility.

Steffen et al base information?

Using atmospheric CO2 as a simple tracking indicator, the authors argue humanity has shifted from a species whose environmental footprint was local and reversible to one whose combined economic and technological power now rivals — and increasingly overwhelms — the natural forces that have shaped Earth's climate and biosphere for millions of years. They frame the next few decades as a critical tipping point for how this story unfolds.

Odum 1998 key points?

Ecology offers a body of hard-won lessons about growth, energy, organization, change, behavior, and diversity that apply directly to human affairs — but humans have largely ignored them, and doing so is driving us toward the kind of "boom-and-bust" collapse ecosystems naturally avoid.

Nichols et al key points?

Global sea levels have been rising through the 20th century and this rise is very likely to accelerate through the 21st century due to global warming — but exactly how much remains highly uncertain, and that uncertainty is centered mainly on how the Greenland and West Antarctic ice sheets will behave.