放射性碳是瞭解地球過去的關鍵

 原文網址：https://www.sheffield.ac.uk/news/radiocarbon-key-understanding-earths-past

研究人員表示想要瞭解地球的氣候、磁場以及太陽活動的歷史，放射性碳的紀錄都非常重要。

在今日(2021.10.15)發表於期刊《科學》(Science)的文章中，科學家特別講解最近我們對於過去的放射性碳含量所得到的更多知識，如何讓我們更加深入地理解氣候作用、太陽活動、地球物理和碳循環。

我們必須先瞭解過去才能瞭解當下，並且預測地球的未來可能如何變化。將55000年前到今日的大氣當中有多少放射性碳的紀錄給精確地建立起來，有助於研究人員瞭解發生在地球的作用，從而讓我們更加準確地預測氣候變遷。

射性碳也告訴我們過去超級太陽風暴發生的機率――這些事件比儀器至今觀測到的還要強上幾個數量級。如果今日發生類似的風暴可能會對我們的通訊網路以及電網造成毀滅性的打擊。

這篇論文的主要作者是雪菲爾大學數學與統計學院的資深講師Tim Heaton，他說：「放射性碳最為人所知的用途，是定年過去55000年之內的許多種考古與氣候紀錄，使它們處在同一條時間線上。然而，在理解太陽、地球發電機、過去氣候以及碳循環的變化時，過往的放射性碳含量也是非常重要的。」

「最近幾年我們的技術有了革命性的進展，使得我們可以精確建立起過去的放射性碳含量記錄，結果是我們對於過去氣候事件的發生年代、太陽活動的變化、碳循環、二氧化碳含量的變動都有了全新的觀點。」

放射性碳定年法的進展讓IntCal工作小組能夠以前所未有的精準度估計過去的放射性碳含量，一直到該技術的極限(大約55000年前)為止。

去年IntCal工作小組在七年來首度重新計算了國際公認的放射性碳校正曲線，使其詳細程度達到有史以來的新高。

為了重建出新的放射性碳校正曲線，他們從年代最遠達到60000年前的物品當中測量了將近15000個樣品。從精確定年文物以至於瞭解地球和氣候系統，這條曲線在許多科學領域當中都是基礎工具。

對於地球科學和考古學來說放射性碳都很重要。政府間氣候變化專門委員會的科學家倚靠放射性碳來改進他們的模型――作為太陽的代用指標，以及要加深瞭解地球系統時的探討對象；放射性碳也是定年過去55000年之內的古氣候紀錄最常使用的時鐘。這對更加瞭解並應對未來的氣候變遷都是必須的。考古學家則利用放射性碳定年的結果來瞭解社會系統當中出現的關鍵變化，這有助於解釋現在的我們如何形成，同時對我們今日所面臨的重大挑戰提供解答。

 

Radiocarbon is key to understanding Earth’s past

Radiocarbon records are critical to understanding the history of Earth’s climate, magnetic field, and the Sun’s activity, say researchers.

In an article published today (November 5 2021) in the journal Science, scientists have highlighted how recent advances in our knowledge of past radiocarbon levels are improving our understanding of climate processes, solar activity, geophysics and the carbon cycle.

Understanding the past is essential to understanding our present and to projecting Earth's potential changes in the future. Developing an accurate record of atmospheric radiocarbon extending back 55,000 years helps researchers understand Earth's processes and consequently improve projections of climate change.

Radiocarbon also tells us about the possibility of past extreme solar storms, orders of magnitude greater than any instrumentally observed. Similar storms today would have the potential to catastrophically damage our communications networks and electricity grids.

放Dr Tim Heaton, Lead Author and Senior Lecturer from the University of Sheffield's School of Mathematics and Statistics, said: "Radiocarbon is best known as the tool by which we date and synchronise many of the various archaeological and climate records from the last 55,000 years. However, past levels of radiocarbon are also critical to understand the Sun, the geodynamo, past climate, and changes in the carbon cycle.

"Recent years have seen a revolution in our ability to construct detailed records of past radiocarbon levels, leading to new insights in the chronology of past climate events, changes in the Sun's activity, carbon cycle and fluxes in Carbon Dioxide (CO₂) levels."

Developments in radiocarbon dating have allowed the IntCal Working Group to estimate radiocarbon levels with unprecedented accuracy back to the limits of the technique ~55,000 years ago.

Last year the IntCal Working Group recalculated the internationally-agreed radiocarbon calibration curves for the first time in seven years, making them more detailed than ever before.

They used measurements from almost 15,000 samples from objects dating back as far as 60,000 years ago to create the new radiocarbon calibration curves, which are fundamental across the scientific spectrum for accurately dating artefacts, and understanding the Earth and climate systems.

Radiocarbon is vital to geoscience and archaeology. Scientists on the Intergovernmental Panel on Climate Change (IPCC) rely upon radiocarbon to improve their models -- as a proxy for the Sun, and as a target to improve their understanding of the Earth system -- and as a clock to date most paleoclimatic records over the past 55,000 years. This is essential to better understand and prepare for future changes in climate. Archaeologists use radiocarbon dating to understand pivotal changes in our societal systems that help to explain our present and answer the grand challenges we face today.

原始論文：T. J. Heaton, E. Bard, C. Bronk Ramsey, M. Butzin, P. Köhler, R. Muscheler, P. J. Reimer, L. Wacker. Radiocarbon: A key tracer for studying Earth’s dynamo, climate system, carbon cycle, and Sun. Science, 2021; 374 (6568) DOI: 10.1126/science.abd7096

引用自：University of Sheffield. "Radiocarbon is key to understanding Earth’s past."