Climate change has accelerated the rate of ice loss across the continent. Scientists reveal this record by inserting hollow tubes into the mud to collect layers of sediment going back millions of years.Īn iceberg melts in the waters off Antarctica. Sediments contain a wealth of information about what was in the air and water when they fell. Pollen, particles, and dead creatures fall to the bottom of oceans and lakes each year, forming sediments. Windows on the past are also buried in lakes and oceans. Old trees and wood can tell us about conditions hundreds or even thousands of years ago. In warmer and wetter years, the rings are thicker. Each year trees grow thicker and form new rings. For example, trees store information about the climate in the place they’re rooted. How is climate change measured?Īlthough we can't look at thermometers going back thousands of years, we do have other records that help us figure out what temperatures were like in the distant past. Climate change encompasses not only rising average temperatures but also extreme weather events, shifting wildlife populations and habitats, rising seas, and a range of other impacts.Īll of these changes are emerging as humans continue to add heat-trapping greenhouse gases to the atmosphere. Scientists prefer to use “climate change” when describing the complex shifts now affecting our planet’s weather and climate systems. This trend is part of climate change, which many people consider synonymous with global warming. But by analyzing average temperatures all over the world, scientists have demonstrated an unmistakable upward trend. That doesn’t mean temperatures haven't fluctuated among regions of the globe or between seasons and times of day. Unauthorized use is prohibited.Įvidence of rising temperatures is pervasive and striking: Thermometer records kept over the past century and a half show Earth's average temperature has risen more than 1 degree Fahrenheit (0.9 degrees Celsius), and about twice that in parts of the Arctic.