APES Climate change

9.3, 9.4, 9.5, 9.6

Carbon Dioxide (CO2)

Most abundant greenhouse gas in the atmosphere. Lowest warming potential, longest residence time.

Chlorofluorocarbons (CFC’s)

Least abundant greenhouse gas in the atmosphere. Highest warming potential, second lowest residence time. Contribute to ozone depletion.

Methane (CH4)

Second most abundant greenhouse gas in the atmosphere. Second lowest warming potential, shortest residence time.

Nitrous Oxide (N2O)

Second least abundant greenhouse gas in the atmosphere. Second highest warming potential, second longest residence time.

Greenhouse effect

Sunlight hits the Earth and some is reflected or radiated back out (Earthshine). Greenhouse gases trap this heat on Earth, keeping it warm.

Water vapor

Technically a greenhouse gas, but no significant effect on climate change due to very short residence time.

Albedo

The reflectivity of a surface. 1= most reflctive, 0 = least reflective.

Clouds

Mixed effects. Low, thick ________ have High albedo and cool the surface. High, thin __________ have low albedo and heat the surface.

Earth’s Energy budget

Difference between how much energy comes in (sunlight) and is reflected back out to space.

Ice cores

Used to measure historical climate trends. Summers will appear light, winters will appear dark. 

Milankovitch Cycles

Natural fluctuations in Earth’s orbit and tilt that cause small climate changes. 

Direct impacts of climate change

Sea level rise, temperatures rise, precipitation changes

Indirect impacts of climate change

weather related mortality, infectious disease, air quality changes, crop yields, irrigation demand, forest composition, geographic forest range, forest health/productivity, water supply, water quality, competition for water, erosion of beaches, inundation of coastal lands, increased cost to protect coastal communities, loss of habitats and species, shrinking glaciers

Temperature trend

Rising over time, could be between 1 to 6 degrees by 2100

Melting glaciers

Decreases Earth’s albedo = more heat absorbed. Responsible for about 45% of sea level rise.

Melting of Greenland and Antarctic ice sheets

Decreases Earth’s albedo = more heat absorbed. Responsible for about 17% of sea level rise.

Thermal Expansion

Warm water is less dense and has more space between molecules. Responsible for about 38% of sea level rise.

Impacts of sea level rise

Displacement of coastal communities, creation of new habitats on flooded continental shelves, loss of habitat as deep communities may no longer be in the photic zone, ocean currents changing and disrupting thermohaline circulation

Disease vectors

Spreading from the tropics to the poles due to warmer global temperatures. Can change population dynamics and force migration of humans.

Atmospheric circulation changes

Warm, subtropical zone shifting poleward. Decreased differential between subtropical and pole zone leads to weakened and more variable jet stream, which causes increased weather events.

Ocean warming impacts

Loss of habitat (ex: coral bleaching), increased metabolic rate (predators deplete prey), reduced fertilization (lower population growth)

Positive feedback loop

The output of the system further stimulates the system, pushing it in a certain direction

Negative feedback loop

The output of the system regulates the system, keeping it at an equilibrium point.

Negative feedback mechanism

The output of the system will keep the system stable

Positive feedback mechanism

The output of the system will destabilize the system

Climate change mitigation

Reduce GHG emissions in electricity, buildings, transportation, food system, and manufacturing. Remove GHG from the atmosphere by planting trees or through carbon capture and sequestration.

Climate change adaptation

Move threatened populations, build seawalls or levees, crop/food substitutions, build to maximize cooling and withstand disaster, plan for disasters

Urban Heat Island effect

Due to increased paved surfaces (low albedo), lack of vegetation (which would provide high albedo and shade), and increased pollution (GHG), urban areas are usually hotter than their rural counterparts.

Solutions for urban runoff

Replace traditional pavement with permeable pavement. Plant trees, bioswales, or grass strips. The goal is to increase water infiltration.