演題概要

1A-PL-1000

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地球の気候と「人新世」―質量分析で解き明かす表層環境変化―

(東大大海研)
^o横山祐典

The latest report from the United Nations' Intergovernmental Panel on Climate Change (IPCC) clearly states that current global warming is caused by anthropogenic greenhouse gas emissions. The current geological era is the Holocene epoch, which began 11,700 years ago, but there has been growing debate in recent years about whether it should be defined as a new epoch called the Anthropocene. This is because geological epochs are divided when clear and distinct environmental changes are observed, and the current environment appears to be very different from the one that has been in place since 11,700 years ago. The environmental changes are not limited to surface temperature rise, but include several other areas such as ocean acidification, ecological changes both on land and in the hydrospheres, etc. To better understand these changes, highly sensitive and accurate mass spectrometers have been used to monitor trace amounts of nuclides in natural samples. These include anthropogenic radionuclides produced by atomic bomb testing in the 1950s and various isotopes released into the environment since the industrial revolution. In my group, we have been investigating current and past environmental changes at the Earth's surface. In this talk I will present these studies and provide mass spectrometry evidence that the so-called Anthropocene is distinctly different from other Holocene environmental signatures.