What is it?
An instrument that orbits the Earth and collects a wide variety of information. The satellites in orbit today can gather information like the temperature of the atmosphere or ocean, sea level, and the amount of different gases in the atmosphere. Satellites can also take detailed pictures of the Earth's surface.
How is it used?
Scientists use temperature data and other measurements from satellites to track climate change trends. They use satellite maps to figure out how much of the Earth is covered by snow and ice at any given time.
How much information does it give scientists?
Scientists have been using satellites to learn about the Earth's climate for roughly the last 30 years. Satellites can take continuous measurements.
Weather Station
What is it?
A collection of weather monitoring tools, such as thermometers, barometers, and rain gauges, that send information to scientists about local weather conditions.
How is it used?
Scientists use the information from weather stations to track climate trends.
How much information does it give scientists?
Weather stations have been recording climate data for roughly the last 100 years. People used to record data by hand only twice a day, but newer automated instruments can report data several times each hour.
Weather Balloon
What is it?
Large balloons that launch daily from hundreds of locations around the world, carrying weather-monitoring instruments into the upper atmosphere. The instruments send data back to scientists using a radio transmitter.
How is it used?
Scientists use the data they receive from the transmitter to study the temperature of different layers of the Earth's atmosphere.
How much information does it give scientists?
Weather balloons have been used to record climate data for roughly the last 100 years. Most locations launch these balloons once or twice each day.
Ocean Buoy
What is it?
A weather station that floats on a buoy in the ocean. It records the air and water temperature, air pressure, and other measurements and then sends this information to scientists.
How is it used?
Scientists use the temperature data they receive from ocean buoys to track climate trends.
How much information does it give scientists?
Ocean buoys have been used to record climate data for roughly the last 100 years. They can take continuous measurements.
Historical Records
What are they?
Almanacs, diaries, and historical archives contain information about past temperatures and other weather data.
How are they used?
Scientists and historians use historical weather data to figure out past climate trends.
How much information do they give scientists?
It depends on the source. Most historical weather records only go back a few hundred years, but some go back for 1,000 years or more. Some records provide hourly or daily information, but others provide only monthly or yearly data.
Tree Rings
What are they?
Trees add a new layer of wood every year. When you cut across the trunk, each layer looks like a ring.
How are they used?
Scientists examine the width and chemical makeup of each tree ring to learn about past climate trends. Rings generally grow wider in warm, wet years and thinner in cold, dry years.
How much information do they give scientists?
Tree ring records can go back hundreds to thousands of years, depending on when the tree lived and how old it was. Each ring represents one year.
Coral Core
What is it?
A cross-section (slice) of coral. Like trees, corals grow by building new layers every year.
How is it used?
By studying the width, density, and chemical makeup of each layer, scientists can tell what the water temperature and other conditions were like in the past.
How much information does it give scientists?
Coral core records can go back hundreds to thousands of years. Each layer of coral represents one year.
Ice Core
What is it?
A tube of ice that scientists drill out of a glacier or an ice sheet. Ice forms in layers and sometimes traps air bubbles, pollen, and dust. Ice cores are usually a few inches wide and can be thousands of feet deep.
How is it used?
Scientists examine ice cores for many things. For example, the thickness of a layer indicates the amount of snow that fell. Scientists use trapped air bubbles to determine the levels of gases that were present in the atmosphere in the past, and they can examine the water molecules in the ice itself to get information about historical temperatures. Trapped pollen and dust also provide clues about the climate.
How much information does it give scientists?
Ice core records can go back up to 800,000 years. The top (most recent) layers of an ice core can provide information on individual seasons or years. The deeper, older layers are more compacted, and scientists have to estimate the date of each layer.
Sediment Core
What is it?
A tube of sediment (sand and mud) that scientists drill from the floor of an ocean or lake. Sediment builds up in layers over time. Rocks and fossils stuck in the sediment provide clues about past climate trends.
How is it used?
Plants and animals often prefer specific climate conditions, so the types of fossils in the sediment core can provide clues about what the climate was like in the past. Scientists can also find out what the water temperature was like in the past by studying the chemical makeup of ancient shells. Other clues about the past might come from layers of pollen, volcanic ash, or large rocks left behind by a glacier.
How much information does it give scientists?
Sediment cores can record climate data going back millions of years. Each distinct layer may represent hundreds of years or more.
Climate Model
What is it?
A computer program that uses hundreds of mathematical equations to describe how the Earth's climate system works. Scientists run these models on powerful supercomputers to see how one change—like extra greenhouse gases in the atmosphere—can affect the whole planet.
How is it used?
Scientists use models to understand how and why the Earth has changed in the past and predict what the Earth will be like in the future.
How much information does it give scientists?
Models can be used to look just a few years into the future or many years down the road.
