What does the word temperature measure?
How hot or cold something is.
What is the main topic of the article?
How scientists know that Earth is warming.
What two places do scientists collect temperature readings from?
Satellites and climate monitoring stations.
What is the central idea of the article?
Scientists use temperature records, satellites, and ice cores to show that Earth is warming rapidly.
Name one greenhouse gas mentioned in the article.
Carbon dioxide or methane.
What is a glacier?
A large mass of ice that forms from layers of snow over time.
Since about what year have scientists had reliable temperature records from weather stations?
1880
What are ice cores?
Long tubes of ice that scientists drill out of glaciers.
Why do scientists need to study ice cores instead of relying only on weather records?
Detailed weather records only go back to about 1880, but ice cores provide information about much earlier climates.
What human activity adds more greenhouse gases to the atmosphere?
Burning fossil fuels such as coal, oil, and gas.
What are fossil fuels?
Fuels such as coal, oil, and natural gas.
What technology did scientists begin using in the 1960s to help measure Earth's temperature?
Satellites.
Why do scientists study layers of ice?
Each layer contains clues about Earth's climate in the past.
Why does the author explain that Earth has experienced ice ages in the past?
To show that Earth's climate has changed naturally before, but today's warming is happening much faster.
What happens when greenhouse gases trap more heat near Earth's surface?
Earth's temperature increases.
What are greenhouse gases?
Gases in the atmosphere that trap heat near Earth's surface.
What do satellites measure to help scientists calculate temperatures?
Radiation given off by oxygen in Earth's atmosphere.
What two elements do scientists study in ice cores to learn about past temperatures?
Oxygen and hydrogen.
What can you infer about the importance of studying Earth's past temperatures?
Understanding past temperatures helps scientists compare natural climate changes with today's rapid warming.
Why did greenhouse gas levels begin increasing during the Industrial Revolution?
People began burning large amounts of fossil fuels for manufacturing and transportation.
What are isotopes, according to the article?
Different forms of the same element that vary in weight.
According to the article, about how many years of climate information can glaciers and ice sheets preserve?
About one million years.
How can scientists use isotopes in ice cores to figure out past temperatures?
Different amounts of heavy and light isotopes provide clues about whether the climate was warmer or cooler.
What is the author's main purpose in writing this article?
To explain the scientific methods and evidence that show Earth is warming at an unusually fast rate.
According to the article, how does the rate of warming during the past century compare with warming periods in Earth's past?
Earth's temperature has been rising roughly 10 times faster than during earlier warming periods described in the article.