Today’s temperature with a simple glass thermometer We can measure it, but the thermometer appeared in the eighteenth century.

So how can we know the temperatures of thousands or even millions of years ago? How can we understand the climatic conditions of those periods?

They look at ice caps.

Ice sheets in polar regions, including Greenland, Antarctica and North America about old temperatures can provide information. The snow that falls every year forms a new layer of ice on top of the previous one.

Formed at different temperatures and unique chemical properties Because these layers are preserved, scientists can easily examine them and get an idea of ​​the temperature conditions of certain time periods.

Tree rings are another method.

The rings visible in a horizontal section cut from the trunk of a tree depend on the prevailing climatic conditions in which the tree grows. wide or narrow It can happen. Therefore, tree fossils help scientists predict changing weather conditions.

Even pollen can be controlled.

Plant pollen is very resilient and highly dependent on current weather conditions. The scarcity or abundance of assets in a particular geographic region, how warm or cold that area was in the past gives a clue.

Finally, the sediments of lakes and oceans.

Deep sediments at the bottom of water bodies such as lakes and oceans are a great source of information about ancient temperatures. The most important of these sediments are small, surface-dwelling deposits that have accumulated over millions of years. These are the layers formed by the shells of animals.

found in these sediments oxygen isotopes Scientists who study it provide information about weather conditions dating back to the age of the dinosaurs.

Of course, there are other methods, but none of them produce clear results. We can only arrive at an approximate estimate.

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