Humans are fascinated by our planet’s distant past. Since human recorded history only goes back a few thousand years, we probe Earth’s “memory” in various ways to uncover its secrets. One of these methods is to hunt for traces from the past, also known as “proxies,” which help scientists understand what Earth was like long ago.
Humans are fascinated by our planet’s distant past. Since human recorded history only goes back a few thousand years, we probe Earth’s “memory” in various ways to uncover its secrets. One of these methods is to hunt for traces from the past, also known as “proxies,” which help scientists understand what Earth was like long ago.
A recent study published in PNAS describes the planet’s history by extracting previously unavailable information from ice cores from the far western Kunlun Mountains.
Ice cores are columns of ice drilled through glaciers that are located in extreme environments such as the Arctic, Antarctic, and the Third Pole, which is centered on the Tibetan Plateau.
Ice cores are amazing as they record everything in the atmosphere and freeze it in time. They are windows that unlock mysteries of the past as they record not only proxies for climatic events, such as temperature and precipitation, but they also record evidence of events that influence climate, like tephra and sulfates that come from volcanic eruptions; the cosmic nuclei chlorine 36 and beryllium 10 that indicate changes in the output of energy from the sun; and the chemistry of the air trapped in bubbles in the ice that show past composition of the Earth’s atmosphere.
