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Why do ice cores only go back 800000 years?

Why do ice cores only go back 800000 years?

in geosciences from Princeton in 2019, explained that because ice flows and compresses over time, continual ice cores only extend back to 800,000 years ago. Gas bubbles trapped in the cores contain pristine samples of carbon dioxide, methane and other gases that serve as “snapshots” of the ancient climate.

How far do ice cores go back?

800,000 years
Current cores reach back over 800,000 years, and show 100,000-year cycles.

What do the ice cores tell us?

Ice cores can tell scientists about temperature, precipitation, atmospheric composition, volcanic activity, and even wind patterns. The thickness of each layer allows scientists to determine how much snow fell in the area during a particular year.

How do ice cores work?

The most important property of ice cores is that they are a direct archive of past atmospheric gasses. Air is trapped at the base of the firn layer, and when the compacted snow turns to ice, the air is trapped in bubbles. Older records of carbon dioxide are therefore best taken from Antarctic ice cores.

How reliable are ice cores?

Ice cores are remarkably faithful recorders of past climate, providing multiply duplicated reconstructions with small and quantifiable uncertainties.

What is the oldest ice core found?

The oldest continuous ice core records extend to 130,000 years in Greenland, and 800,000 years in Antarctica. Ice cores are typically drilled by means of either a mechanical or thermal drill.

How long is the longest ice core?

The longest ice cores collected were over 3 km (2 miles) long! Drilling into the ice allows scientists a glimpse into the climate of the past. The longest ice core record from Greenland extends back 130,000 years ago, and in 2017 an ice core dating back to 2.7 million years ago was recovered in Antarctica.

What is the longest ice core record?

The deepest ice core records come from Antarctica and Greenland, where the very deepest ice cores extend to 3 kilometers (over two miles) in depth. The oldest continuous ice core records extend to 130,000 years in Greenland, and 800,000 years in Antarctica.

How is CO2 measured in ice cores?

Scientists use air trapped in the ice to determine the CO2 levels of past climates, whereas they use the ice itself to determine temperature. But because air diffuses rapidly through the ice pack, those air bubbles are younger than the ice surrounding them.

How accurate are ice cores?

Knowledge of history, including the history of papers published in the Journal of Glaciology, shows that ice-core science is indeed reliable. The value of disciplinary journals such as the Journal of Glaciology is shown very clearly.

What is an ice core used for?

Ice cores are cylinders of ice drilled from ice sheets and glaciers. They are essentially frozen time capsules that allow scientists to reconstruct climate far into the past. Layers in ice cores correspond to years and seasons, with the youngest ice at the top and the oldest ice at the bottom of the core.

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