Climate Change Greenhouse Effect, Greenhouse Gases, and Earth’s Energy Budget

Let’s Review Climate… What is climate? Climate is the average weather conditions in an area over a long period of time. Climate is different from weather…WHY? What factors determine the climate in the area ? Climate is determined by many things including latitude, wind patterns, oceanic currents and the local geography of an area. What is the most important factor in determining climate? The most important factor is distance from the equator.

Have you ever gotten into a car that has been sitting in the sun for a while with it’s windows closed? Why does this happen?

Let’s Review Solar Energy… Waves The energy from the sun travels to Earth in what form? The Electromagnetic Spectrum What is the sun’s energy called? No Does all the energy from the sun reach the Earth’s surface? some UV, visible, infra red, microwaves and radio waves What parts of the Electromagnetic Spectrum do reach the earth’s surface?

The Electromagnetic Spectrum

The Greenhouse Effect CO 2, H 2 O, CH 4 (methane) N 2 O (nitrous oxide) and even CFC’s are GHG’s(greenhouse gases) Certain gases in the atmosphere absorb OUTGOING radiation from Earth. (Earth radiates energy back into space like a hot potato) Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder (about -5ºF) – All water would be solid, no life could exist Because they warm our world like a greenhouse, these gases are referred to as greenhouse gases We NEED the Greenhouse Effect to survive

Earth’s Energy Budget 30% of incoming solar radiation is reflected back into space – Some is reflected back in space by clouds and atmosphere, Some is is reflected back in space from Earth’s surface Albedo is an object’s ability to reflect radiation – Lighter colored surfaces (snow, ice) REFLECT all colors, reflects more radiation, higher albedo – Darker-colored surfaces (blacktop, forest) ABSORB more radiation, lower albedo- GETS HOT Greenhouse gases absorb heat energy that would normally radiate back into outer space Increasing GHGs will absorb more radiation, thus average global temperatures will RISE as a result

So what are the greenhouse gases and where do they come from? Water Vapor Evaporation, transpiration, and cellular respiration water vapor alone produces somewhere between about a third and two-thirds of the greenhouse effect. Carbon Dioxide Burning fossil fuels, volcanoes, deforestation, animal respiration Methane Animal waste, biomass burning, fossil fuels, landfills, livestock, rice paddies, sewage and wetlands, fracking Nitrous Oxide Biomass burning, volcanoes, deforestation, burning of fossil fuels, microbial activity on fertilizers in the soil

Natural vs. Anthropogenic GHGs Natural: water vapor, CO2, methane, nitrous oxide Antropogenic gases are: carbon dioxide, methane, nitrous oxide, chlorinated gases Anthropogenic = Man-made

What Are the Sources of Man- Generated Greenhouse Gases?

Charles Keeling Began measuring CO2 concentrations daily on Mauna Loa in Hawaii in 1958 through retirement. Results were obvious Human activities ARE increasing CO2 in the atmosphere

Describe the trend that you notice in the graph The concentration of CO2 has steadily increased over the past 50 years

We obtain information about past CO2 levels from ice cores.

Feedback Loops (+) feedback- actions work towards INCREASING the origin event – gets amplified – Microphone screech – “Snowball” effect (-) feedback- actions work to CANCEL or NEGATE the origin event-gets diminished – Thermostat

Feedback Loops FACT: Warmer global temperatures is melting Arctic Ice, exposing darker ocean water beneath. 1)How is this event changing Earth’s albedo? 2)How does this event make warming worse?

Arctic Feedbacks

Other Climate Feedback Loops

Other climate feedback loops

Greenhouse Activity Heat lamps, beakers, construction paper, thermometers 2 minutes of heating per test, record data Test 1- inverted vs. upright beaker Test 2- white vs. black construction paper (w/ inverted beaker) Which test (1 or 2) tests albedo? Which tests GHE?