قالب وردپرس درنا توس
Home / Science / Scientists have discovered that melting icebergs is the key to the ice age

Scientists have discovered that melting icebergs is the key to the ice age



iceberg

Credit: PNG/CC0 public domain

Scientists claim to have discovered the “missing link” in the process leading to the Ice Age on Earth.

The research team at Cardiff University said the melting iceberg in Antarctica is the key, and it triggered a series of chain reactions that plunged the earth into a long-term low temperature.

The survey results were published today in nature An international consortium of scientists from universities around the world.

It has long been known that the cycle of the ice age is accelerated by periodically changing the earth’s solar orbit, which subsequently changes the amount of solar radiation reaching the earth’s surface.

However, so far, it is still a mystery how small changes in solar energy can trigger such drastic changes in the Earth’s climate.

In their research, the research team proposed that when the earth revolves around the sun in the correct orbit, the Antarctic icebergs begin to gradually melt away from the Antarctic, transferring large amounts of fresh water from the Southern Ocean to the Atlantic Ocean.

As the Southern Ocean became saltier and the North Atlantic became fresher, large-scale ocean circulation patterns began to change dramatically.2 And reduce the so-called greenhouse effect.

In turn, this pushed the earth into an ice age.

As part of the research, the scientists used a variety of techniques to reconstruct past weather conditions, including identifying tiny fragments of Antarctic rocks that have fallen into the sea from melting icebergs.

The rock fragments were obtained from sediments recovered by the International Ocean Discovery Program (IODP) Expedition 361

. It has a history of more than 1.6 million years and is one of the oldest detailed archives of Antarctic icebergs.

Studies have found that these sediments, known as “ice raft wrecks,” seem to have been causing changes in the deep-sea circulation, which are reconstructed by the chemical action of tiny deep-sea fossils called foraminifera.

The team also used a new climate model simulation to test its hypothesis and found that icebergs can move large amounts of fresh water.

Lead author Aidan Starr of Cardiff University’s School of Earth and Environmental Sciences said: “We were surprised to find that this lead-lag relationship existed at the beginning of every ice age in the past 1.6 million years. It is speculated that , The Southern Ocean and Antarctica play a leading role in the global climate, but it is very exciting to see this so clearly in the geological evidence.”

Professor Ian Hall, the chief scientist and co-author of the IODP expedition research from the School of Earth and Environmental Sciences, said: “Our findings provide a missing link between Antarctica and the Southern Ocean’s response to the natural environment. Climate system The rhythm is related to our orbit around the sun.”

In the past three million years, the earth has often fallen into ice ages, but it is currently in a period of rising interglacial temperatures.

However, the global temperature rises due to man-made carbon dioxide2 Researchers believe that the natural rhythm of the ice age cycle may be disturbed because the South Ocean may become too warm and the Antarctic icebergs cannot go far enough to trigger the changes in ocean circulation required for the development of the ice age.

Professor Hall believes that these results can be used to understand how our climate will respond to man-made climate change in the future.

“Similarly, since we have observed an increase in mass loss caused by iceberg activities in the Antarctic continent and the Southern Ocean, which is due to the current warming caused by human greenhouse gas emissions, our research emphasizes the importance of understanding iceberg trajectories and melting patterns for the development of Antarctica. Importance. The strongest prediction of their future impact on ocean circulation and climate.”

Professor Grant Bigg, a professor in the Department of Geography at the University of Sheffield, simulated the iceberg model. He said: “The groundbreaking modeling of icebergs in the climate model is important for identifying and supporting ice cream fragments that affect the melting of Antarctic iceberg The hypothesis is crucial. It led to the eruption of the glacial cycle.”


New research redefines understanding of where icebergs injected meltwater into the Southern Ocean


More information:
During the Pleistocene glaciers, Antarctic icebergs reorganized the ocean cycle, nature (2021). DOI: 10.1038/s41586-020-03094-7, www.nature.com/articles/s41586-020-03094-7

Provided by Cardiff University



Citation: Scientists discovered (January 13, 2021) that melting icebergs is the key to the formation of the ice age. This is from https://phys.org/news/2021-01-icebergs-key-sequence- on January 13, 2021. retrieved by ice-age.html.

This document is protected by copyright. Except for any fair transactions for private learning or research purposes, no content may be copied without written permission. The content is for reference only.




Source link