Climate Change

Weather vs. Climate

• The earth’s climate is dependent on the weather over a long period of time.

•Weather is what is happening now or in the near future. Weather includes: temperature, rainfall, wind & humidity.

•Climate refers to the average weather over a long period of time.

Climate Variability

•Variability is the changes that occur in daily temperature & precipitation.

•Although an area's climate is always changing, the changes do not usually occur on a time scale that's immediately detectable to us.

•Weather patterns and climate types take similar elements into account, the most important of which are:

•The temperature of the air•The humidity of the air

•The type and amount of cloudiness•Air pressure•Wind speed and direction

•Although weather and climate are different, they are very much interrelated.

•A change in one weather element often produces changes in the others and in the region's climate.

• For example, if the average temperature over a region increases significantly, it can affect the amount of cloudiness as well as the type and amount of precipitation that occur. If these changes occur over long periods of time, the average climate values for these elements will also be affected.

•Good and accurate weather records have only been recorded for the last 130 years.

•Scientists use the following techniques to find the climate of the earth’s past.

Clues in the ice –• looking for tiny air bubbles that form when greenhouse gasses are emitted

•Also looking for soot particles to indicate when forest fires happened

Clues in Sediment•Often have stored pollen grain, plant parts that grew in the past

Clues in tree rings

• All of these methods provide clues to past temperature, precipitation, and wind patterns as well as the chemical make-up of the atmosphere.

Greenhouse Gas Effect

•Greenhouses are structures that are designed to hold in heat.

Greenhouse Gas Effect

• The heat-trapping ability of a greenhouse is influenced by several factors:

1. Transparency of the greenhouse cover

2. Color of inside surfaces

3. Types of surfaces on the inside

•The earth’s atmosphere acts like an insulating blanket that is just the right thickness.

• The “blanket” is a collection of atmospheric gases called greenhouse gases that trap heat just like the glass walls of a greenhouse.

•While the earth’s temperature is dependent upon the greenhouse-like action, the amount of heating & cooling are also influenced by several factors:

1. Type of surface that the sunlight first encounter

Forests, grasslands, ocean, ice caps, deserts & cities all absorb and reflect light differently

•Sunlight falling on white glaciers will strongly reflect back into space.

• Sunlight falling on a dark desert soil is absorbed.

•Cloud cover

Greenhouses Gases

• any gas in the atmosphere capable of absorbing infrared radiation (heat) reflected from the earth’s surface

Carbon dioxide• Sources:• Burning fossil fuels• plant matter•Deforestation• volcanic eruptions

Water Vapor• Source:• Evaporation (water cycle)

Nitrous Oxide• Sources:• Fertilizer production• burning fossil fuels & wood• agricultural soil (nitrification & denitrification)

Methane• Sources:•Decomposition• livestock waste• decomposing waste in landfills

CFCs• Sources:•Manufacturing & industrial processes

Global Warming vs. Climate Change

• Global warming: trend towards increasing temperatures. 10 warmest years on record have occurred since 1990. • Global climate change: changes

in precipitation, temperatures, storm intensity. Global warming can lead to global climate change.

Proof….

• 20th century was hottest on record• Since 1861, average global

temperature has risen between 1o- 1.4o F (most of that has been since 1980)

• 16 hottest years on record have been since 1980, 10 hottest have been since 1990.

• Glaciers and sea ice are shrinking.• Sea level rising (4 to 8 inches)

1979 2003

Artic sea ice changes

Factors affecting Earth’s temps•Oceans can store heat

and CO2, but no one knows how much.• Cloud cover: can warm by trapping and releasing heat or cool by reflecting heat back to space (albedo effect)!

Factors affecting Earth’s temps

•Outdoor air pollution: aerosols can either warm or cool the atmosphere (much like clouds)

Factors affecting Earth’s temps

• Stimulate photosynthesis: more CO2 can temporarily cause higher photosynthesis. Temporary because plants will “level off” and die, releasing their CO2

Factors affecting Earth’s temps

•Methane trapped under ice is released when the ice melts.

Implications of Climate Change

Implications:

1) Plant growth changes

2) Water supply3) Diseases

4) Soil quality5) Displaced pollution6) Droughts/Floods7) Glaciers melting8) Sea levels rising

9) Warmer water temps10) Coral bleaching–Algae & coral are losing their bright colors…b/c the algae are dying from the warm temps.

10) Ocean acidity11) Migration patterns12) Food production13) Desertification–An area experiencing desert like condition… lack of water, etc.

How can we

respond?

1. Use and production of energy• Efficiency and conservation• Alternative sources – Wind, solar, hydroelectric

2. Transportation

• Efficiency of vehicle•Drive less….public transportation

3. Agriculture and Forestry• Soil and forest absorb carbon dioxide• Careful farming practices can keep soil in place to help it hold carbon.• Trees planted to replace those that are cut down.

4. Cap-and-Trade

•Government put a limit or cap on the amount of greenhouse gases that can be released by an industry.

If industry releases less than they are allowed to sell their “allowances” to another company.

5. Carbon Tax• A fee that a government changes polluters for each unit of greenhouse gases they emit.

• European countries have done this.•Downside…extra costs passed on to the consumer.

6. Carbon Offsets• Instead of reducing greenhouse gas emissions, an industry or person voluntarily pays another group or person do to so.

Example: Someone taking an airplane ride…feels guilty about the amount of greenhouse gases emitted so pays an organization to plant trees that will absorb carbon dioxide to compensate for the emissions used by the plane.

7. Carbon Sequestration•Way to capture and store carbon• Stored underground but no guarantee that is may not leak out

8. Kyoto Protocol• Is an international agreement that seeks to limit greenhouse gas emissions

The treaty is binding which means the countries that signed it MUST commit to reducing greenhouse gases.•The US did NOT sign the treaty.

9. Copenhagen Accord•Developed nations pay billions of dollars to developing nations to fund the reduction of greenhouse gases.

•Developed nations also agreed to set specific targets for emission reduction by 2020.• This is not a binding treaty & a disappointment to most nations.