How do we know what the climate was like before recorded history? How can we predict what it will do next? To help understand Earth’s past and predict future climate change, scientists have developed sophisticated computer models that incorporate detailed mathematical descriptions of the atmosphere, oceans, land, and ice.
Use our climate modeling interactive to see how scientists peer into the past and predict the future.
This video explains the basics of climate modeling.
Scientists compare today’s climate with that of the distant past using proxy data from tree rings, ice cores, and other indicators. These data collections offer indirect evidence of temperature and other climate properties from before instrumental measurements became available.
Taken together, proxy data show that the past few decades were warmer than any other comparable period during at least the last 400 years, and possibly the last 1,000 years or longer.
Scientists use measurements of tree ring samples collected from numerous locations to reconstruct climate condition trends for the last two millennia and beyond. Wider rings correlate to increased temperature and precipitation.
Samples of ice offer clues about the Earth’s atmosphere and temperatures from the ancient past. Scientists analyze bubbles trapped in the ice to determine the concentration of greenhouse gases that were in the air when the bubbles were formed.
Corals that grow in shallow tropical and subtropical waters often have growth rings similar to those seen in trees on land. The density and width of coral growth bands—and the chemicals they contain—provide information about the temperature and salinity of the oceans over time.
Records from Instruments
People have been measuring and recording air temperature for more than 250 years in some locations. These temperature records, especially data from observing stations put in place in the mid-nineteenth century, provide data to estimate average temperatures.
Additional Resources from the National Academies
The materials in the Koshland Science Museum’s Earth Lab exhibit are based on reports of the National Research Council and works of the U.S. government and have been vetted for scientific accuracy by a panel of expert advisors.