To accomplish this, scientists use a variety of evidence, from tree rings to the amounts of radioactive materials in a rock.
In regions outside the tropics, trees grow more quickly during the warm summer months than during the cooler winter.
Add some rings while varying the temperature and precipitation.
Which of these factors has a stronger influence on the growth of the type of tree being modeled here? The "Show Specimen Tree" button displays a section of an "actual" tree specimen.
Even though they are not very abundant, these greenhouse gases have a major effect.
Carbon dioxide (CO2), water vapor (H2O),..Television weather forecasts in the space age routinely feature satellite views of cloud cover.
These tree ring variations will appear in all trees growing in a certain region, so scientists can match up the growth rings of living and dead trees.
Each dark band represents a winter; by counting rings it is possible to find the age of the tree (Figure 11.22).
It is the average weather pattern in a place over more than thirty years, including the variations in seasons.
To describe the regional climate..Less than 1% of the gases in Earth's atmosphere are called greenhouse gases.
The interactive diagram below demonstrates a very simple model of tree ring growth.
Select a temperature range (Normal, Cool, or Warm) and a precipitation amount (Normal, Dry, or Wet) for the coming year. The tree (which you are viewing a cross-section of the trunk of) grows one year's worth, adding a new ring.
The longest cores have helped to form a record of polar climate stretching hundreds of thousands of years back.