Climate Change
Based on the Earth system model and the molecular model, how do carbon dioxide (CO2 ) and other greenhouse gases cause Earth's atmosphere to warm?
Absorb outgoing infrared radiation. Emit outgoing infrared radiation.
How can scientists be sure that Earth is getting warmer when they are not completely certain about what is going to happen to Earth's temperature in the future?
Because of temperature data that they've measured Understanding that greenhouse gases trap heat in the atmosphere. They can be uncertain about the future because there are many things that are unknown: future levels of greenhouse gas emissions are prime unknowns.
What are some of the causes of the carbon dioxide increase over the past 50 years?
Burning of fossil fuels Removal and burning of forests.
How does carbon dioxide (CO2 ) interact with the two types of radiation (sunlight and infrared) shown in this model?
Carbon dioxide is not affected by sunlight. Infrared radiation changes direction when it hits a carbon dioxide molecule.
What is the relationship between atmospheric CO2 levels and its absorption by the ocean?
High CO2 leads to less absorption by the ocean.
Describe how changes in the amount of ice covering Earth's surface can affect Earth's temperature.
If there is more ice on Earth's surface, more of the incoming radiation is reflected into space. If the radiation is reflected into space, it can't warm the Earth, so there is a cooling of the temperature.
How does the water temperature affect the amount of carbon dioxide that can dissolve in the ocean?
Increased water temperature leads to less carbon dioxide dissolved in the ocean.
How does atmospheric carbon dioxide affect global temperature?
Increases in the temperature
What happens when infrared radiation hits the greenhouse gas molecules? How does the temperature change as a result?
It is absorbed and deflected. The greenhouse gas is excited by the radiation (it glows) The infrared radiation is re-emitted in a different direction. The temperature increases as a result.
Why is there a lag between changes in CO2 levels and temperature?
It takes time for the carbon dioxide to move between reservoirs. It takes a while for the oceans to heat up enough to release enough carbon dioxide to warm the temperature very quickly.
How can scientists look at 542 million years of temperature data (in the graph) and still be fairly confident that humans are contributing to the current warming trend?
Look at long histories of data and see trends. They match trends with what they knew was happening at the same time: volcanic eruptions, solar flares, asteroid impacts, etc. Scientists look at trends over a long periods-- periods with and without much human impact. Then compare trends to the more recent trends in which humans have put more greenhouse gases into the atmosphere. This doesn't allow them to say that humans are the only cause of global warming, It does allow them to say that humans have some effect on global warming because they've studied time periods in which there was little human activity.
In the past 50 years, where has the temperature changed the most?
Northern hemisphere, particularly in the Arctic
What happens when the sunlight hits greenhouse gas molecules?
Nothing happens to the temperature
Is the melting of Arctic ice an example of positive feedback or negative feedback?
Positive feedback
Explain how scientists can be both fairly certain that Earth is warming and still actively researching the unknown factors
Recent temperature data shows warming They don't know all of the reasons that Earth is warming There are many factors that can interact to change Earth's temperature Have to continue research to learn how all factors interact with each other to predict future warming with more accuracy
What two things can happen when energy from the Sun interacts with the ground?
Reflected back into space Absorbed by Earth's surface
How do energy packets (solar radiation and infrared radiation) interact with the clouds to cool the planet?
Solar radiation is reflected by the clouds' surface. The reflection of energy prevents addition of heat into the Earth system. Infrared radiation is sometimes reflected and sometimes passes straight through clouds. Reflection helps to keep the heat in the atmosphere Passing through allows heat to escape the Earth system.
Water is a greenhouse gas. What do you think will happen to the temperature when the amount of water vapor increases?
Temperature will increase
What happens when energy from the Sun encounters a white surface (ice or snow)?
The energy is reflected off the surface and leaves the atmosphere.
Describe a positive feedback system that affects Earth's temperature.
The feedback loop between carbon dioxide and water vapor. Increased carbon dioxide leads to higher temperatures Which leads to more water vapor Which leads to higher temperatures Which leads to more carbon dioxide coming out of the ocean Which leads to higher carbon dioxide levels Which leads to more water vapor On and on as the temperature increases
Currently, about 10% of Earth is covered with ice year-round. If this ice melts, what could happen to Earth's temperature?
The temperature could increase
What happens if you remove all of the carbon dioxide from the atmosphere?
The temperature decreases
What happens when the sunlight hits particles in the ground?
They get hotter
How can you (and scientists) tell that a model is good? What kinds of tests can you run to assess the validity of a model?
When it does a good job of replicating past scenarios. When a model can predict the past future based on some inputs, then you can have more confidence in its ability to predict future futures.
What is the relationship between water vapor and temperature?
When the temperature is high, there is more water vapor in the atmosphere.
