polar – Cabot Institute for the Environment blog

Net Zero Oceanographic Capability: the future of marine research

Posted on December 13, 2021March 30, 2023 by janet.crompton

Image credit: Eleanor Frajka-Williams, NOC.

Our oceans are crucial in regulating global climate and are essential to life on Earth. The marine environment is being impacted severely by multiple and cumulative stressors, including pollution, ocean acidification, resource extraction, and climate change. Scientific understanding of marine systems today and in the future, and their sensitivity to these stressors, is essential if we are to manage our oceans, and achieve the United Nations Sustainable Development Goals (SDGs). However, these systems are complex – with a vast array of interacting physical, chemical, biological and sociological components – and operate on scales of microns to kilometres, and milliseconds to millennia. To address these challenges, modern marine science spans a wide range of multidisciplinary topics, including understanding the fundamental drivers of ocean circulation, ecosystem behaviour and its response to climate change, causes of and consequences of polar ice cap melt, and the impacts of ocean warming on sea level, weather and climate. Marine scientists investigate problems of societal relevance such as food security, hazards relating to sea level rise, storm surges and underwater volcanoes, and understanding the consequences of offshore development on the health of the ocean in the context of building a sustainable blue economy. With the start of the UN Decade of Ocean Science for Sustainable Development in 2021, there is a clear motivation not only for more research, but for sustainable approaches.

However, a key challenge facing all scientists in the near future is the absolute necessity to reduce and mitigate all carbon emissions, achieving ‘Net Zero’. Among many of the high-impact pledges made over recent months, UK Research and Innovation (UKRI) have promised to achieve Net Zero by 2040. UKRI is the umbrella organisation encompassing all of the UK Research Councils including the Natural Environment Research Council, which funds the National Oceanography Centre and British Antarctic Survey to operate the large-scale UK marine research infrastructure.

Whilst marine science is intrinsically linked to Net Zero objectives since the ocean is a major sink of anthropogenic carbon and excess heat, the carrying out marine research itself contributes to the problem in question: ocean-going research vessels use considerable amounts of fossil fuels. Ship-based observations allow scientists to address global challenges, to support ocean observing networks, make measurements not possible via satellite, or in remote and extreme environments. Such observations are essential to establish a thorough picture of how the ocean is changing, and the underlying processes behind the complex interweaving of physics, chemistry, biology and geology within marine systems, but can only continue into the future if the carbon footprint of sea-going research is cut dramatically.

Image credit: Eleanor Frajka-Williams, NOC.

The Net Zero Oceanographic Capability (NZOC) scoping review, led by the National Oceanography Centre but supported by researchers from around the UK, is a groundbreaking project aimed at understanding the drivers and enablers of future oceanographic research in a Net Zero world. New technologies and infrastructure – together with multidisciplinary, international approaches, and collaborations with private and public sector stakeholders – are going to be increasingly important to advance understanding of the oceans and climate, while accomplishing Net Zero. The NZOC team are building a picture of a future research ecosystem that capitalises upon emerging technologies in shipping, marine autonomous systems (MAS) sensor technology and data science. Ships will still be an essential linchpin of a new marine observing network, to gather critical information that may not be accessible using MAS, and to enable the maximum value to be extracted from datastreams collected during oceanographic expeditions. The new Net Zero approaches have the potential to not just replace existing marine research capability with one less damaging to the environment, but also to expand and extend it, with new tools available more marine observing, new avenues of research opened up, and wider accessibility. In order to achieve its potential, the development of new systems, and adaptation and improvement of existing methodologies, must be co-designed between technologists and scientists, including modellers and data scientists, as well as those engaged with sea-going observations. Investment in an equitable, diverse and inclusive marine workforce must be considered from the beginning, with engagement in skills training for existing and future marine researchers so that scientists are primed to use the new approaches afforded by a Net Zero approach to their full potential. All of these initiatives have to deliver on their promise in a co-ordinated way and in a short timeframe. Many of them will rely upon global infrastructures and international systems that must similarly adapt at pace.

Image credit: Eleanor Frajka-Williams, NOC.

Environmental and climate scientists overwhelmingly and urgently support a move towards Net Zero. However, we cannot overstate the importance of getting the transition to Net Zero right. Whilst an ever-growing number of UK marine scientists are using MAS and low carbon options, NZOC also identified a number of case studies where achieving Net Zero will limit marine science – possibly permanently – if not addressed. These include research areas where scientists need to drill into deep rock, or carry out intricate biological or geochemical experiments and measurements. Any transition to using new methods must be managed flexibly, requiring intersection between old and new technologies, due consideration to accessibility, and verification and validation by the wider scientific community.

Achieving Net Zero is one of the most important societal goals over the next decade. We can not only maintain but also build on marine science capability – essential for meeting Net Zero targets – with equitable and fair strategic planning, co-design of new approaches, and by taking advantage of new opportunities that arise from emerging technologies.

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This blog is written by Cabot Institute member Dr Katharine Hendry is an Associate Professor in the School of Earth Sciences at the University of Bristol. With Contributions by Eleanor Frajka-Williams, National Oceanography Centre (NOC).

Dr Katharine Hendry

Greenland is melting: we need to worry about what’s happening on the largest island in the world

Posted on November 30, 2020April 4, 2023 by janet.crompton

Greenland is the largest island in the world and on it rests the largest ice mass in the Northern Hemisphere. If all that ice melted, the sea would rise by more than 7 metres.

But that’s not going to happen is it? Well not any time soon, but understanding how much of the ice sheet might melt over the coming century is a critical and urgent question that scientists are trying to tackle using sophisticated numerical models of how the ice sheet interacts with the rest of the climate system. The problem is that the models aren’t that good at reproducing recent observations and are limited by our poor knowledge of the detailed topography of the subglacial terrain and fjords, which the ice flows over and in to.

One way around this problem is to see how the ice sheet responded to changes in climate in the past and compare that with model projections for the future for similar changes in temperature. That is exactly what colleagues and I did in a new study now published in the journal Nature Communications.

We looked at the three largest glaciers in Greenland and used historical aerial photographs combined with measurements scientists had taken directly over the years, to reconstruct how the volume of these glaciers had changed over the period 1880 to 2012. The approach is founded on the idea that the past can help inform the future, not just in science but in all aspects of life. But just like other “classes” of history, the climate and the Earth system in future won’t be a carbon copy of the past. Nonetheless, if we figure out exactly how sensitive the ice sheet has been to temperature changes over the past century, that can provide a useful guide to how it will respond over the next century.

A man walks over grassy land with glacier in background — Greenland’s glaciers contain around 8% of the world’s fresh water.
Jonathan Bamber, Author provided

We found that the three largest glaciers were responsible for 8.1mm of sea level rise, about 15% of the whole ice sheet’s contribution. Over the period of our study the sea globally has risen by around 20cm, about the height of an A5 booklet, and of that, about a finger’s width is entirely thanks to ice melting from those three Greenland glaciers.

Melting As Usual

So what does that tell us about the future behaviour of the ice sheet? In 2013, a modelling study by Faezeh Nick and colleagues also looked at the same “big three” glaciers (Jakobshavn Isbrae in the west of the island and Helheim and Kangerlussuaq in the east) and projected how they would respond in different future climate scenarios. The most extreme of these scenarios is called RCP8.5 and assumes that economic growth will continue unabated through the 21st century, resulting in a global mean warming of about 3.7˚C above today’s temperatures (about 4.8˚C above pre-industrial or since 1850).

This scenario has sometimes been referred to as Business As Usual (BAU) and there is an active debate among climate researchers regarding how plausible RCP8.5 is. It’s interesting to note, however, that, according to a recent study from a group of US scientists it may be the most appropriate scenario up to at least 2050. Because of something called polar amplification the Arctic will likely heat up by more than double the global average, with the climate models indicating around 8.3˚C warming over Greenland in the most extreme scenario, RCP8.5.

Despite this dramatic and terrifying hike in temperature Faezeh’s modelling study projected that the “big three” would contribute between 9 and 15 mm to sea level rise by 2100, only slightly more than what we obtained from a 1.5˚C warming over the 20th century. How can that be? Our conclusion is that the models are at fault, even including the latest and most sophisticated available which are being used to assess how the whole ice sheet will respond to the next century of climate change. These models appear to have a relatively weak link between climate change and ice melt, when our results suggest it is much stronger. Projections based on these models are therefore likely to under-predict how much the ice sheet will be affected. Other lines of evidence support this conclusion.

What does all of that mean? If we do continue along that very scary RCP8.5 trajectory of increasing greenhouse gas emissions, the Greenland ice sheet is very likely to start melting at rates that we haven’t seen for at least 130,000 years, with dire consequences for sea level and the many millions of people who live in low lying coastal zones.

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This blog is written by Cabot Institute member Jonathan Bamber, Professor of Physical Geography, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Professor Jonathan Bamber

Unravelling the mysteries of the subpolar North Atlantic

Posted on March 16, 2015April 14, 2023 by janet.crompton

Why should we care about what is going on in the cold and stormy subpolar North Atlantic? I can give you at least three very good reasons:

First of all, the dynamics of this region are crucially important for modulating climatic conditions in North-Western Europe. So basically this is what keeps the UK’s weather relatively mild for its latitudes.
Secondly, deep-water is formed in the Labrador Sea and this is a key process within the global thermohaline circulation.
The transport of heat and freshwater by the Subpolar North Atlantic has an impact on global climate, marine ecosystems, hurricanes, and even on rainfall in the African Sahel, the Amazon and parts of the US.

Main circulation patterns in the North Atlantic. Orange-yellow lines are
surface, warmer currents and blue lines are deep, colder currents.

How do we know what is happening up there?

Up until now, the subpolar North Atlantic has been inadequately measured and climate models largely fail to represent its features accurately. Last week, Dr Penny Holliday from the National Oceanography Centre (Southampton) visited Bristol to give a departmental seminar in the School of Geographical Sciences, titled “Circulation and variability in the subpolar North Atlantic”. From her talk we got to know more about the importance of long-term monitoring of the circulation in the subpolar North Atlantic and about two major ongoing monitoring programmes. These are providing precious observational data that will help scientists understand more about the interannual to multidecadal variability in these regions, in order to improve the skills of our predictions.

OSNAP (Overturning in the Subpolar North Atlantic Programme) is an international programmed that started in 2014 and includes partners from USA, UK, Canada, China, France, Germany, and the Netherlands. OSNAP is designed to provide for the first time a continuous record of measurements across the entire subpolar North Atlantic, similarly to the RAPID observational system at 26°N which has been monitoring the subtropical gyre since 2004. Within UK-OSNAP, Penny is leading the observations being made in the deep western boundary current near Greenland.

Penny Holliday on the first UK-OSNAP (plus Extended Ellett
Line and RAGNARoCC) cruise in summer 2014

The Extended Ellett Line is a project led by the National Oceanography Centre (Southampton) and SAMS (The Scottish Association for Marine Science). It represents one of a small number of long-term, high-quality physical time series in the North Atlantic Ocean. This hydrographic section was started in 1975 by David Ellet, initially only in the Rockall Trough. In 1996 the section was extended up to Iceland. The expedition now runs once a year and the data collected includes physical (e.g. temperature, salinity, velocity), chemical (e.g. iron, nutrients, carbon) and biological (e.g. phytoplankton) measurements. Penny is one of the two Principal Investigators for the Extended Ellett Line.

Most recent findings

While some more time will be necessary before seeing the first results of the OSNAP project, the most recent significant discovery from the Extended Ellett Line is the importance of the episodic southward flow of the Wyville Thomson Overflow Water. Recent observations highlighted the necessity to include its contribution in the calculations of the heat transport through the Rockall Trough. In addition, after four decades of observations, it has been observed that the top layers (0-800m) of the ocean in these regions have warmed and exhibit shorter timescale variability.

Data from the 2014 cruise has also shown that temperature and salinity in 2014 were lower compared to the previous 10 years. This suggests that the North Atlantic subpolar gyre would have increased its circulation and expanded, bringing cooler and fresher water into the eastern regions.

Life at sea in the subpolar North Atlantic

The oceanographic cruises organised within these two programmes also offer the chance to several students and early career scientists to get a taste of what life at sea really means.
Penny was one of my supervisors during my MSc in Southampton, where for my research project I was analysing the results of a new simulation with a high-resolution ocean model in the North Atlantic subpolar regions (we have recently published those results). One year or so later, Penny was recruiting some extra people for one of the Extended Ellett Line cruises and she must have remembered our conversations about how I had always wanted to go on a research cruise. So there I was, ready to board the RRS James Cook as part of the physical oceanography team, sailing from Scotland to Iceland. It was such an amazing experience: I think I will be forever grateful to Penny for making my wish come true!

Myself (left) and Natalia Serpetti (right) taking sea water samples from the CTD
(conductivity-temperature-depth instrument) and looking very happy
during the Extended Ellett Line cruise in 2013.

Life at sea is actually pretty hard work and definitely not a holiday. Initial sea sickness aside, and ignoring the fact that I was waking up a 4 am every morning (yes, I had the unluckiest shift ever!), the memories that I will cherish the most are about all the things that I learnt, the awesome people I met, the breathtaking sunrises and sunsets over Iceland (at least due to the unlucky shift I got to see both of them everyday!), the pilot whales occasionally following the ship, and the power of the ocean which makes you feel so small and insignificant. Probably I will also always remember the entire night that some of us spent scooping up and sieving mud from a deep sea sledge, while listening to pretty bad club music: that was actually great fun!

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This blog is written by Cabot Institute member Alice Marzocchi, School of Geographical Sciences, at the University of Bristol. Follow Alice on Twitter @allygully.

Twitter contacts: @np_holliday @uk_osnap @osnap_updates

Read Alice’s other blog: The conference crashers! What are a geophysicist, a climate modeller, and a geochemist doing at a Social Sciences conference?