APES Global Climate Change

Greenhouse Effect

Infrared radiation goes back towards the atmosphere, where much of it is absorbed by greenhouse gases that radiate most of it back to the Earth. The greater the concentration of greenhouse gases, the more infrared radiation is absorbed and emitted back toward Earth

Global Warming Potential (GWP)

The contribution of each greenhouse gas to global warming depends on its warming potential. GWP is an estimate of how much a molecule of any compound can contribute to global warming over a period of 100 years compared to a molecule of carbon dioxide. CO2 has a GWP = 1

Anthropogenic

Environmental changes or processes that are caused by human activities

Positive Feedback Loop

A biological occurrence where the output of a system amplifies the system. Ex. Melted permafrost releases more greenhouse gases, increasing global warming and causing more permafrost to melt

Carbon Sequestration

An approach involving cost-effective ways of capturing CO2 from the atmosphere, from coal-burning powerplants, and from other emission sources by either storing it in agricultural soils or compressing and pumping it into abandoned oil wells or the deep ocean.

Saltwater Intrusion

Rising sea levels cause saltwater to enter groundwater supplies when groundwater is depleted by human activity.

Thermal Expansion of Water

The expansion of water as its temperature increases, contributing to rising sea levels and changes in ocean currents

Ice Cores

Ice cores have tiny trapped air bubbles of ancient air that can provide estimates of greenhouse gas concentrations, global temperatures, snowfall, and even the frequency of forest fires / volcanic eruptions at the time these bubbles of gas were trapped

Ocean Warming

The absorption of excess heat from the atmosphere due to human-caused greenhouse gas emissions, causing coral bleaching. Causes:

• Burning fossil fuels

• Deforestation

• Agriculture

• Consumption and waste

Ocean Acidification

CO2 is absorbed into the ocean and forms carbonic acid, lowering pH and altering the balance of carbonate and bicarbonate. This affects the physiology of marine animals and their ability to make shells, causing coral bleaching

Causes:

• Burning fossil fuels

• Deforestation

• Cement Production

• Agriculture

Chlorofluorocarbons

Man-made chemicals that exist as gases or liquids. These contain chlorine, fluorine, and carbon, and persist in the stratosphere. They deplete ozone by splitting oxygen atoms off ozone (O3) to form oxygen (O2)

Stratosphere

The lowest layer of Earth's atmosphere where weather occurs and we live. Contains the ozone layer

Cataracts

A clouding of the lens in the eye that can lead to a decrease in vision, caused by thinning ozone layer

Hydroflourocarbons

Replacements for CFCs that don’t contain chlorine, are less stable than CFC’s, and will break down in the troposphere

Ozone Hole

A thinning of the ozone layer, specifically over Antarctica, due to the release of chlorofluorocarbons (CFCs) and other ozone-depleting substances

Greenhouse Gas

Gases in the atmosphere that absorb infrared radiation

• Water Vapor H2O

• Carbon Dioxide CO2

• Methane CH4

• Nitrous Oxide N2O

• Ozone O3

• CFCs

What layer of the atmosphere is the “ozone layer” located?

The stratosphere

What important function does the ozone layer in the stratosphere perform for life on Earth?

Ozone has the ability to absorb ultraviolent radiation and protect life on Earth

Carbon Dioxide

CO2, caused by

• Burning of fossil fuels

• Transportation

• Deforestation

Ozone

O3, caused by

• Transportation

• Photochemical reactions

Methane

CH4, caused by

• Feedlots

• Disposing of organic matter in landfills

• Growing more rice to feed world’s growing population

Nitrous Oxide

N2O, caused by

• Agriculture

• Fertilizer use

Human and Environmental Health Effects of a Thinning Ozone Layer

• Increased UV-B

Environmental:

• Urban pollution and material damage

• Crop damage

Humans:

• Malnutrition

• Weakened immune system and skin cancer

• Acute eye defects and cataract

If the pH of a lake dropped from 8.0 to 7.0, how many times more acidic is the lake?

10 times more acidic.

10^8.0-7.0 = 10¹ = 10

If the pH of a body of water increases, is it more acidic or more basic?

Basic

If the pH of a body of water decreases, is it more acidic or more basic?

Acidic

Effects of Climate Change

• Ocean Acidification; affects formation of organisms’ shells

• Ocean warming; less dissolved oxygen

• Melting permafrost; release of greenhouse gases and decreased albedo effect

• Human Health; increased mosquitoes, heat waves, and insufficient nutrients for soil

• Extreme Weather

• Changing Vegetative Zones; as climate warms, colder plants move upward

• Rising Sea Levels; melting glaciers and sea ice cause thermal expansion

• Changes in Ocean Currents

• Salt Water Intrusion

Rank the greenhouse gases by warming potential

1. Water Vapor

   • Concentration variable with temperature

   • GWP = <1

   • 9 days atmospheric lifetime

2. Carbon Dioxide CO2

   • 390 ppm

   • GWP = 1

   • Highly variable (years to hundreds of years)

3. Methane CH4

   • 1.8 ppm

   • GWP = 25

   • 12 years

4. Nitrous Oxide N2O

   • 0.3 ppm

   • GWP = 300

   • 114 years

5. CFCs

   • 0.9 ppb

   • GWP = 1,600 to 13,000

   • 55 to >500 years

Four strategies to create a more sustainable future

1. Decrease energy for transportation

2. Decrease energy for heating/cooling

3. Decrease electricity use

4. Plant trees / use less synthetic fertilizers

Which greenhouse gas is the most abundant in the atmosphere?

CO2 is 6x more impactful than methane, nitrous oxide, and CFCs combined. Water vapor is technically more abundant, but its impact is not clearly understood and highly debated