Since the industrial revolution the concentration of atmospheric CO2 has increased. This potent greenhouse gas is already causing demonstrable climate change. Important insights into exactly how the climate will change in the future in response to increased greenhouse emissions can be gained from looking into the past to those time periods that were warmer than today.
1. What is the sensitivity of the climate system to CO2 forcing? – how hot will it get in the future?
2. What is the relationship between CO2, ice-volume and sea level? – how high will sea level rise as the major ice sheets melt in the future?
How do we do it?
We use cutting edge analytical techniques to measure the chemical and boron isotopic composition of the calcium carbonate shells of single celled organisms called foraminifera.
These animals lived in the ancient ocean and their shells now make up deep ocean sediments. Such sediments represent a continuous archive of ancient climate that stretches back continuously for up to 65 million years.
From the chemical and isotopic signals locked up in the shells of these animals we can reconstruct ocean pH (and hence atmospheric CO2 ), ice volume (and hence sea-level) and water temperature (and hence climate).
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