Professor Timothy J Heaton

Profile

I am an interdisciplinary academic working at the intersection of statistics and the environmental sciences. Originally trained as a methodological statistician, I became interdisciplinary through my involvement with the International Radiocarbon Calibration (INTCAL) Working Group which began in 2009.

All radiocarbon dates must be calibrated before they can be interpreted. The INTCAL group provide the internationally-ratified standards for this calibration. Our research helps to create the ultimate clock by which we study our past – allowing us to explain our present, and accurately predict/mitigate our future.

This is essential to designing climate and environment policy: providing a critical underpinning to the Intergovernmental Panel on Climate Change (IPCC), a better understanding of the Earth and climate system, and insight into societal responses to environmental change.

My environmental science research has been publicised internationally, including in Scientific American, Science, and Nature. I have generated Research Excellence Framework (REF) impact case studies in 2014 and 2021, and I have been lead author on invited/comissioned reviews of my field in the journal Nature (giving a perspective on extreme solar storms and exact dating using radiocarbon) and in the journal Science (looking at radiocarbon’s use as a key tracer to study the Earth system and carbon cycle).

Research interests

I became an academic because I like learning about new things. Through INTCAL, I am lucky to work with an international team of academics from a wide spectrum of disciplines – including geoscientists, archaeologists, geochemists, oceanographers, physicists and modellers. I never expected to work across these subjects when I began studying mathematics as an undergraduate. I am particularly interested in applied statistics research, bringing together expert teams and knowledge from a wide range of fields, and demonstrating the benefits that a statistician’s perspective can bring to interdisciplinary projects.

Radiocarbon dating is the most frequently-used dating technique to study the past 55,000 years and is vital to fields such as archaeology and geoscience to date everything from the oldest modern human bones to historic climate patterns. Archaeologists can use the calendar dates that INTCAL provide to help make decisions about restoring historic monuments or to study the demise of the Neanderthals, while geoscientists on the Intergovernmental Panel on Climate Change (IPCC) rely upon our work to find out about what the climate was like in the past to better understand and prepare for future changes.

Radiocarbon dating was first developed in 1949. It depends upon two isotopes of carbon called stable ¹²C and radioactive ¹⁴C. While a plant or animal is alive it takes in new carbon, so has the same ratio of these isotopes as its surroundings at the time. But once an organism dies it stops taking in new carbon, the stable ¹²C remains but the ¹⁴C decays at a known rate. By measuring the ratio of ¹⁴C to ¹²C left in an object the date of its death can be estimated. If the level of atmospheric ¹⁴C were constant, this would be easy. However, it has fluctuated significantly throughout history.

To date organisms precisely, scientists need a reliable historical record of ¹⁴C variation over time to accurately transform radiocarbon measurements into calendar ages. INTCAL provides this link. We develop three internationally-agreed curves dependent upon where the object to be dated is found: IntCal20 for the Northern Hemisphere, SHCal20 for the Southern Hemisphere, and Marine20 for the world’s surface oceans. I work on all of these curves. You can find a podcast (interviewing myself and my colleague Edouard Bard) where we discuss our work at:

https://www.science.org/content/podcast/folate-debate-and-rewriting-radiocarbon-curve.

• Next-generation Radiocarbon Calibration: Incorporating information on calibration curve covariance
• Obtaining robust "dates-as-data" inference from the calibration of multiple radiocarbon determinations
• Robust Identification of Changepoints in Population Size via Radiocarbon Dating

Qualifications

• PhD (2005)
• Part III Mathematics (2001)
• BA Mathematics (2000)

Professional memberships

• IntCal Working Group (Radiocarbon Calibration)