Unit 9 Global Change Notes

Global Change

The wide range of physical, ecological, and socio-economic alterations that affect Earth as a system. Global Change is caused by the changing/warming of our climate due to the greenhouse effect and ozone depletion

Climate Change

Shifts in global or regional climate patterns attributed to increased atmospheric greenhouse gases. Differs from global warming as it refers only to the Earth's rising surface temperature, while climate change includes warming and the “side effects” of warming—like melting glaciers, heavier rainstorms, or more frequent droughts.

Ozone Depletion

the thinning of the ozone layer in Earth's stratosphere due to the release of certain chemicals like CFCs and halons. This thinning allows more harmful ultraviolet (UV) radiation from the sun to reach the Earth's surface.

• Ex. the ozone hole located over the South Pole (Antartica)

Human Causes of Global Change

1. Burning fossil fuels for transport, industry and electricity

2. Agriculture through deforestation, machinery emissions, and methane from cattle

3. Growing human population which causes agriculture and fossil fuel combustion to increase

Key Molecules/GHG’s

Carbon dioxide (CO2), methane (CH4), water vapor (H2O), Chlorofluorocarbons (CFCs) and nitrous oxide (NOx)

• trap heat in the atmosphere and contribute to global warming.

Environment Effects of Global Change

rising temperatures, altered precipitation patterns, sea level rise, ocean acidification, and disruptions to ecosystems and biodiversit

Environment Effects of Ozone Depletion

increased UV radiation reaching the Earth's surface, leading to damage to ecosystems.

• damaged plant stomata = decreased photosynthesis

Health Effects of Global Change

increased risks from extreme weather events, altered disease transmission patterns, and changes in air and water quality

• respiratory problems due to poor air quality, heat-related illnesses, and food and water security issues.

  • asthma, respiratory illness, heat strokes

• disease vector habitat changes, leading them to move farther north/south, away from equator

  • Zika, West Nile, Malaria, bird flu, Lyme disease, etc.

Health Effects of Ozone Depletion

increased UV exposure leading to higher rates of skin cancer, cataracts, and weakened immune responses.

Global Warming Potential (GWP)

the measure of how much a greenhouse gas traps heat in the atmosphere over a specific time period, relative to carbon dioxide (CO2)

Criteria GHG’s GWP ranked

1. Chlorofluorocarbons (CFCs) = (13,000)

2. nitrous oxide = (300)

3. methane = (25)

4. Carbon = (1)

5. water vapor = between -0.001 and +0.0005

What is a way we can determine the current CO2 levels in the atmosphere?

Ice cores are long cylinders of ice drilled from glaciers or polar ice sheets that provide valuable information about past climate conditions. They contain layers that represent different time periods and preserve atmospheric gases trapped within them.

Greenhouse Effect

The process by which certain gases in Earth's atmosphere trap heat, preventing it from escaping into space and thereby warming the planet.

Chlorofluorocarbons (CFCs)

A family of organic compounds whose properties make them ideal for use in refrigeration, air-conditioning, and aerosols; cause ozone depletion

How do CFCs and HCFCs destroy ozone?

chlorine atoms contained in the compounds are highly reactive; they interact with Ozone (O3) by stripping off one Oxygen molecule, leaving behind O2.

How can ozone depletion be mitigated (reduced)?

by replacing ozone-depleting chemicals with substitutes that do not deplete the ozone layer such as Hydrofluorocarbons (HCFs)

Even though HCFs do not deplete the ozone-layer, they are still an environmental concern because they…

have a high Global Warming Potential and are thousands of times more powerful as a greenhouse gas than carbon dioxide

Albedo Effect

the measure of how much sunlight is reflected by a surface compared to how much is absorbed. It plays a crucial role in the climate system and the greenhouse effect, as surfaces with high albedo (like ice and snow) reflect more sunlight, helping to cool the Earth, while darker surfaces (like forests and oceans) absorb more heat, contributing to warming.

what are some examples of ways ocean warming can affect marine species?

loss of habitat, and metabolic and reproductive changes; may displace some species and cause them to migrate in new patterns

coral bleaching

caused by increased ocean temperatures; causes algae within corals to die and the corals bleach white; some corals recover and some die

what are some ways humans can mitigate the impact of loss of biodiversity?

creating protected areas, use of habitat corridors, promoting sustainable land use practices and restoring lost habitat

habitat corridors

protected strips of land that allow the migration of organisms from one wilderness area to another