NUI Galway Study Finds the Magnitude of Past Climate Change Events May have been Underestimated

A modified figure showing the underestimation of reconstructed temperatures for the last interglacial (warm) period. Photo: NUI Galway
A modified figure showing the underestimation of reconstructed temperatures for the last interglacial (warm) period. Photo: NUI Galway

A new study led by Dr Audrey Morley at NUI Galway, has found that the magnitude of past abrupt climate change events may have underestimated. If so, the impact of current climate change may be larger than expected. The study was published today (4 December 2017) in the international journal Geochemistry, Geophysics, Geosystems.

Lead author of the study, Dr Audrey Morley from the School of Geography and Archaeology at NUI Galway, said: “Abrupt climate events that occurred during the last interglacial (warm) period, ca. 125,000 years ago, have been underestimated by up to 4°Celsius. This is important because our current understanding of climate change and our predictions of future climate both rely on past examples from Earth’s climate history. Robust and quantitative methods to deduce the magnitude of abrupt climate events from the geologic record are therefore essential.”

In this new study, Dr Morley collaborated with researchers from the University of California-Santa Cruz, Rutgers University New Jersey and the University of Bergen, and studied an established geochemical tool for investigating sea surface temperatures in the past. In the modern ocean, observations have shown that marine plankton (foraminifera) will use more magnesium relative to calcium, which are elements freely available in sea water, when they form their shell in warmer waters. This allows scientists to apply this modern relationship between magnesium, calcium, and temperature to the past by measuring magnesium-to-calcium ratios (Mg/Ca) in fossilised marine plankton that are continually deposited in seafloor sediments. However, there are limitations with the Mg/Ca temperature relationship, because the scientists understanding of other processes that may influence the amount of magnesium in the shell is incomplete.

For example, higher carbon dioxide levels in seawater results in lower pH (potential of hydrogen) and lower carbonate ion concentrations. Carbonate ion is the carbon species used by foraminifera to form their calcium carbonate tests. As carbonate ion becomes less available in surrounding seawater the individual organism needs to exert more energy for calcification. Through this process more magnesium becomes incidentally incorporated than what would be predicted by temperature only. Since colder surface waters absorb more carbon dioxide than warmer waters, this leads to generally low carbonate ion concentrations in cold surface waters. Therefore, when magnesium-to-calcium values are measured on fossilised marine plankton that lived in surface waters with low carbonate ion concentrations, this relationship leads to an underestimation of reconstructed temperatures.

This study presents an innovative mathematical correction scheme that enables the carbonate ion concentration effect to be isolated from the temperature signal recorded in marine plankton (from magnesium-to-calcium ratios) via subtraction. Specifically, Dr Morley and her colleagues were able to quantify the control of low carbonate ion concentrations values on magnesium-to-calcium ratios for a specific marine plankton species (Neogloboquadrina Incompta) living in the subpolar North Atlantic Ocean, and thereby isolate the true magnesium-to-calcium temperature relationship.

Dr Morley added: “Applying the proposed correction scheme to past climate records reveals that we may have underestimated abrupt climate events by up to 4°Celsius during past interglacial (warm) periods. This is particularly important for climate records from the subpolar/polar North Atlantic region that may have experienced abrupt changes in carbonate ion concentrations linked with abrupt climate events. Correcting for low carbonate ion concentration values improves the fidelity of temperature reconstructions and allows a reassessment of the magnitude of climate events occurring during warm climates.”

Author: Marketing and Communications Office, NUI Galway

World’s biggest climate innovation summer school comes to Trinity

ourney, the world’s biggest climate innovation summer school, comes to Trinity College Dublin this week. The EU-funded climate innovation summer school is run by Climate-KIC, Europe’s largest climate innovation agency.

The 2017 Journey programme enables over 320 students and professionals from all over the world to travel to some of the best universities in Europe. For the first time, Trinity will host 40 Journey students for 11 days.

More than 240 climate-positive business ideas have been generated by over 1,200 Journey participants since 2010, with an increasing number of students successfully continuing on to Climate-KIC’s pre-incubation, accelerator and other start-up programmes.

The 40 students hosted by Trinity started their Journey in Paris at L’Ecole Polytechnique and Universite Pierre and Marie Curie. They will spend their final week at Riga Technical University in Latvia, where they will take part in a pitch competition to present a climate-positive business idea, which they will have developed during their time here.

The Journey 2017 participants interact with researchers, start-ups, government officials and large corporations, get up-to-date briefings on the latest climate change science and policy, and learn about cutting-edge adaptation and mitigation technologies and solutions.

Photo by Patrícia Cassol Pereira on Unsplash.
Photo by Patrícia Cassol Pereira on Unsplash.

The Dublin Journey

Trinity College Dublin has set up a series of expert lectures, workshops and innovation field-visits. Students will have the opportunity to learn from one of the most influential proponents of climate justice and former President of Ireland, Mary Robinson, when she kicks off the programme with an opening lecture.

While in Dublin students will learn about: innovative solutions in sustainable finance (Dublin is emerging as a global hotspot in this sector); sustainable land use; smart cities; circular economy; the cluster approach to innovation; waste management; advanced design thinking.

To prepare for the pitch competition in their final week, participants will also take part in venture creation workshops and pitch training while they are in Dublin, and learn to work in multidisciplinary and international teams to ideate and deliver a climate-related business plan.

Students will participate in workshops with Iain Stewart, Professor of Geoscience Communication at the University of Plymouth. Professor Stewart is a presenter of science programmes for the BBC — notably the BAFTA nominated Earth: The Power of the Planet. He will also give an opening speech at an ice-breaker event in the Science Gallery on Monday August 14th, 6-8 pm.

Students will also participate in a Dublin Bay Biodiversity cruise and walking tours of Dublin to learn about local solutions in smart cities, sustainable transport, and sustainable food.

Sustainable Nation is the local Climate-KIC partner for The Journey at Trinity College Dublin. Created through a 2015 merger of Ireland’s Green International Financial Services Centre (Green IFSC) and The Green Way, Sustainable Nation is leading the cleantech cluster in Ireland’s capital city. Through their collaboration with Climate-KIC UK & Ireland they are stimulating greater investment into smart innovations, new enterprises and sustainable business practices.

You can follow all Climate-KIC Journey news across Europe, including that relating to the pitch competitions for all 320 participants by keeping an eye on #climatejourney17 on Twitter.

Media Contact

Thomas Deane, Press Officer for the Faculty of Engineering, Mathematics and Science | deaneth@tcd.ie | +353 1 896 4685