carbon dioxide

Geosciences Column: Using volcanoes to study carbon emissions’ long-term environmental effect

Geosciences Column: Using volcanoes to study carbon emissions’ long-term environmental effect

In a world where carbon dioxide levels are rapidly rising, how do you study the long-term effect of carbon emissions?

To answer this question, some scientists have turned to Mammoth Mountain, a volcano in California that’s been releasing carbon dioxide for years. Recently, a team of researchers found that this volcanic ecosystem could give clues to how plants respond to elevated levels of carbon dioxide over long periods of time. The scientists suggest that studying carbon-emitting volcanoes could give us a deeper understanding on how climate change will influence terrestrial ecosystems through the decades. The results of their study were published last month in EGU’s open access journal Biogeosciences.

Carbon emissions reached a record high in 2018, as fossil-fuel use contributed roughly 37.1 billion tonnes of carbon dioxide to the atmosphere. Emissions are expected to increase globally if left unabated, and ecologists have been trying to better understand how this trend will impact plant ecology. One popular technique, which involves exposing environments to increased levels of carbon dioxide, has been used since the 1990s to study climate change’s impact.

The method, also known as the Free-Air Carbon dioxide Enrichment (FACE) experiment, has offered valuable insight into this matter, but can only give a short-term perspective. As a result, it’s been more challenging for scientists to study the long-term impact that emissions have on plant communities and ecosystems, according to the new study.

FACE facilities, such as the Nevada Desert FACE Facility, creates 21st century atmospheric conditions in an otherwise natural environment. Credit: National Nuclear Security Administration / Nevada Site Office via Wikimedia Commons

Carbon-emitting volcanoes, on the other hand, are often well-studied systems and have been known to emit carbon dioxide for decades to even centuries. For example, experts have been collecting data on gas emissions from Mammoth Mountain, a lava dome complex in eastern California, for almost twenty years. The volcano releases carbon dioxide at high concentrations through faults and fissures on the mountainside, subsequently leaving its forest environment exposed to the emissions. In short, the volcanic ecosystem essentially acts like a natural FACE experiment site.

“This is where long-term localized emissions from volcanic [carbon dioxide] can play a game-changing role in how to assess the long-term [carbon dioxide] effect on ecosystems,” wrote the authors in their published study. Research with longer study periods would also allow scientists to assess climate change’s effect on long-term ecosystem dynamics, including plant acclimation and species dominance shifts.

Through this exploratory study, the researchers involved sought to better understand whether the long-term ecological response to carbon-emitting volcanoes is actually representative to the ecological impact of increased atmospheric carbon dioxide.

Remotely sensed imagery acquired over Mammoth Mountain, showing (a) maps of soil CO2 flux simulated based on accumulation chamber measurements, shown overlaid on aerial RGB image, (b) above-ground biomass (c) evapotranspiration, and (d) normalized difference vegetation index (NDVI). Credit: K. Cawse-Nicholson et al.

To do so, the scientists analysed characteristics of the forest ecosystem situated on the Mammoth Mountain volcano. With the help of airborne remote-sensing tools, the team measured several ecological variables, including the forest’s canopy greenness, height and nitrogen concentrations, evapotranspiration, and biomass. Additionally they examined the carbon dioxide fluxes within actively degassing areas on Mammoth Mountain.

They used all this data to model the structure, composition, and function of the volcano’s forest, as well as model how the ecosystem changes when exposed to increased carbon emissions. Their results revealed that the carbon dioxide fluxes from Mammoth Mountain’s soil were correlated to many of the ecological variables analysed. Additionally, the researchers discovered that parts of the observed environmental impact of the volcano’s emissions were consistent with outcomes from past FACE experiments.  

Given the results, the study suggests that these kind of volcanic systems could work as natural test environments for long-term climate research. “This methodology can be applied to any site that is exposed to elevated [carbon dioxide],” the researchers wrote. Given that some plant communities have been exposed to volcanic emissions for hundreds of years, this method could help paint a more comprehensive picture of our future environment as Earth’s climate changes.

By Olivia Trani, EGU Communications Officer


Cawse-Nicholson, K., Fisher, J. B., Famiglietti, C. A., Braverman, A., Schwandner, F. M., Lewicki, J. L., Townsend, P. A., Schimel, D. S., Pavlick, R., Bormann, K. J., Ferraz, A., Kang, E. L., Ma, P., Bogue, R. R., Youmans, T., and Pieri, D. C.: Ecosystem responses to elevated CO2 using airborne remote sensing at Mammoth Mountain, California, Biogeosciences, 15, 7403-7418,, 2018.

GeoPolicy: EGU sciences on debate at the European Parliament

GeoPolicy: EGU sciences on debate at the European Parliament

The adoption of legislation within the European Union (EU) is a complex process involving many steps. In my first blog post in this GeoPolicy series I highlighted an example of this process.

Several draft legislation pieces are currently being assessed within the European Parliament (EP) and Council of Ministers (Council) that have been influenced by EGU-related science. This blog post summarises this draft legislation and to where in the process each piece has progressed.

Much of the information for this blog post has been taken from the European Parliament Research Service (EPRS) website, which produces support documents for the EP. It is here that you can find out more information about all EU legislation currently in progress.



Post-2020 reform of the EU Emissions Trading System

The EU Emission Trading Scheme (ETS) attempts to reduce greenhouse gas emissions by buying and selling emission ‘allowances’. One allowance is equal to one tonne of carbon dioxide or gas equivalent . The video below gives a good overview of the ETS.

The total amount of allowances is capped relative to 1990 emission totals, but this cap is reduced every year by 1.74 % to incentivise industries to reduce their emissions. If companies have reduced their emissions to below this cap they can sell surplus allowances, or keep them for the next year. The price of the allowance depends on supply and demand. Industries are incentivised to invest in carbon-reducing technology if this is a cheaper alternative than buying allowances. If carbon prices are lower than alternative technologies, extra allowances can be purchased from companies who have already reduced their emissions.

This EU legislation concentrates on the 4th phase of the ETS which spans the years 2020-2028 (we are currently in the 3rd phase, 2013-2020). The major policy points are:

  • The introduction of a market stabilisation reserve where 12 % of surplus annual allowances are stored for future use;
  • The annual cap decrease will change from 1.74 % to 2.2 % to reduce emissions faster;
  • Industries will now have to account for indirect carbon leakages in their emission inventories;
  • New funds will be available to aid start-up renewable projects.

This legislation is in the early stages of the process: the EC proposal document is currently receiving feedback and suggested amendments.  National parliaments, the European Economic & Social Committee and/or the Committee of Regions must still give feedback before an edited draft can be formed.

ETS Progress Bar

Progress stage of the drafted legislation. Sourced from the ‘Emissions Trading Scheme legislation EP progress briefing’.



National emission ceilings for air pollutants

Qir Quality Exposures

Percentage of the urban population in the EU28 exposed to air pollutant concentrations above EU and WHO reference levels (2010-12). Sourced from the ‘European Environment Agency: Air quality in Europe’. 

In December 2015 the EC produced an impact assessment focusing on five different policy options to achieve the EU’s health and environment objective goals. Despite considerable improvements, the European Environment Agency (EEA) has indicated that the EU still breaks pollutant levels that are considered to result in unnacceptable risks to humands and the environment. These levels are defined by the World Health Organisation (WHO) and are based exclusively on scientific findings. EU targets are much less restrictive than those of the WHO, but these levels are still being broken, as the figure on the right shows. Health-related costs of air pollution in the EU range between €330–940 billion per year.

The Gothenburg Protocol (1999) aimed to reduce acidification, eutrophication, and ground-level ozone by setting emissions caps for sulphur dioxide, nitrogen oxides, volatile organic compounds and ammonia by 2010. This new EU legislation aims to further reduce emissions by setting new caps and larger fines for non-compliance. The European Commission estimates that implementation costs would range from €2.2 to 3.3 billion per year.

The legislation has been reviewed by impacted stakeholders and the EP advisory committee. The next stage is to discuss and amend the proposal in the EP plenary session. Once accepted, it will become the official stance of the EP. Negotiations are then continued with the Council in the trilogue before a final decision is made and the legislation is adopted.



Organic Farming Legislation

Organic farming is a political object of the EU, described as an “overall system of farm management and food production that respects natural life cycles”. Since the initial adoption in 2009,

 European Union Organic Produce Logo . Credit: (distributed via Wikimedia Commons )

European Union Organic Produce Logo . Credit: (distributed via Wikimedia Commons )

legislation has been continuously edited and expanded. The percentage area of agricultural land in the EU used for organic farming has remained at 6 % despite a steady expansion of the organic market. Currently, the EU imports organic produce to cover this gap in supply and demand.

The new legislation proposed by the European Commission (EC) has streamlined current legislation and removed historical ‘exception rules’ in order to define organic farming more rigorously. These changes include:

  • Organic farmers would no longer be able to use non-organic seed or introduce non-organic young poultry;
  • Organic farmers would be compensated if unintentional non-authorised products are found within their farms;
  • Mixed farming techniques (organic and conventional farming) would be allowed only during the conversion period from traditional to organic practices.

Market for organic foodstuffs: the top 10 countries. Sourced from the FiBL and IFOAM report ‘ORGANIC IN EUROPE: Prospects and Developments’


The figure below shows the progress of this drafted legislation: currently at the ‘trilogue’ step. This means the drafted legislation has been proposed by the EC and submitted to the Council, the EP and relevant stakeholders who have been able to give their feedback (a staggering 950 amendments were received!). Both the EP and the Council have produced their amended legislation drafts, which have been approved by their respective allocated subcommittees. Now, selected members from the EP and Council are to produce the final drafted legislation in the trilogue, which then will be voted to be adopted by the EP.

Progress stage of the drafted legislation. Sourced from Organic farming legislation EP progress briefing.

Progress stage of the drafted legislation. Sourced from the ‘organic farming legislation EP progress briefing’.


More information about the current draft legislation being considered in the European parliament can be found here.


GeoTalk: Talking about ‘ocean burps’ with James Rae

GeoTalk: Talking about ‘ocean burps’ with James Rae

Trying to understand the reasons behind the global warming of our climate is a never ending quest for scientists across the geosciences. Scientists often rely on deciphering past change to help us understand, and perhaps predict, what might happen in the future. Many will be familiar with the common saying ‘the past is the key to the future’. This is exactly what James Rae, a research fellow at the Earth & Environmental Sciences Department at the Universty of St. Andrews and this year’s recipient of the Biogeosciences Division Outstanding Young Scientists Award, has been focusing his efforts on. James’ research interest lies in understanding past climate change and he was recognised by the Biogeosciences Division after the publication of his research into ocean ‘burps’ – he and his colleagues found that changes in ocean circulation in the North Pacific caused a massive ‘burp’ of CO2 to be released from the deep ocean into the atmosphere, helping to warm the planet sufficiently to trigger the end of the ice age.

Before we get stuck into the details of your work, could you introduce yourself and tell us a little more about yourself and your career?

My name’s James Rae and I’m a geoscientist at the University of St Andrews. I actually grew up just down the road – in Edinburgh – but only just moved back to Scotland last year, after studies in Oxford, Bristol, and California. The locals tell me that the transition from LA to St Andrews shouldn’t be too tough – apparently St Andrews is “one of the sunniest places in the whole of Scotland”!

I got into geosciences through a love of the outdoors and outdoor sports – mountain biking, surfing, snowboarding, climbing – and though most of my work is now in a super clean lab, I still try to get out in the Scottish Highlands whenever possible.

My career to date has focussed on using geochemistry to reconstruct past environmental change. This means I make measurements of the chemistry of things like shells, fossils, rocks, and ice, which often reflect aspects of the environment they formed in. So by making a series of these measurements on fossil shells back through time we can see how the environment changed in the past. My specialty is using boron in tiny fossil shells, called foraminifera, to reconstruct past CO2 change.

So, ocean ‘burps’? During EGU 2015, you received the Biogeosciences Division Outstanding Young Scientists Award for your study of this unusual phenomenon. Can you tell us more about those?

One of the most interesting things about the ice ages of the last few million years is that they seem to be punctuated with really dramatic rapid climate change. The most recent examples of this are at the end of the last ice age – between about 20 and 10 thousand years ago – where we see intervals of rapid CO2 rise recorded in ice cores. The only place where you can quickly get enough carbon to drive these CO2 changes is the deep ocean. During ice ages we think CO2 gets hidden away beneath the waves, at water depths of 2000 – 5000m, and because the Pacific is so big it’s likely that a lot of this CO2 is stored down there. Other scientists had suggested that this CO2 remerged at the end of the last ice age in the ocean round Antarctica. However my research shows that it could also “burp” out in the North Pacific.

Schematic of how James use boron isotope measurements in foraminifera to reconstruct pH and CO2. Credit: James Rae

Schematic of how James use boron isotope measurements in foraminifera to reconstruct pH and CO2. Credit: James Rae

And how exactly did the release of CO2 in these ‘burps’ affect the climate of the ice age?

Our Pacific “burp” happens right at the beginning of the end of the last ice age – it coincides with the first CO2 rise that heralds the start of the deglaciation. It’s possible that the warming associated with the CO2 “burp” helped push the earth out of it’s ice age, though we need to do more work to test this. But even aside from the CO2, the change in circulation that drove this event had a big influence on local climate. Although most of the Northern Hemisphere is really cold at this time the North Pacific is actually quite warm, which I think is a result of this unusual circulation state.

So, the Northern Hemisphere was very cold at this time; can you describe a little more what the Earth might have looked at during this time and how the local climate of the North Pacific might have been different?

At the end of the last ice age massive ice sheets still covered much of North America and Northern Europe. Over St Andrews the ice was around a kilometre thick. Then, at the beginning of the last deglaciation, in an interval called Heinrich Stadial 1, the ice sheets round the North Atlantic start collapsing. This flooded the North Atlantic Ocean with fresh water and reduced the Atlantic overturning circulation that currently provides heat to this region. As a result much of the Northern Hemisphere got colder. However the climate in the North Pacific does something very different. Likely in response to the big cooling in the North Atlantic, there was a large change in the position of major rain belts, like the Westerly storm track and East Asian Monsoon, and we think this acted to make the North Pacific more salty. This led to a more vigorous overturning circulation in the Pacific, a regional warming, and a burp of CO2 release from the deep sea.

What is the next step, if you like, in order to better understand ocean ‘burps’?

At the moment our key evidence for the North Pacific burp comes from a single sediment core. To test the idea we really need to make more measurements from other cores in this region. Our main evidence for ocean CO2 change also currently comes from records from the deep ocean. One of my PhD students is currently making new records to test how much CO2 made it up from the deep to the surface ocean, and from there to the atmosphere. Finally, with collaborators in Switzerland and the US we’re also testing the physical driving mechanisms of this circulation change using state of the art climate models.

(L) An ocean cruise on which the sediment cores used in the study are collected. (R) Benthic foraminifera - James uses these to make measurements of the chemistry of these to reconstruct past climate change. Credit: James Rae

(L) An ocean cruise on which the sediment cores used in the study are collected. (R) Benthic foraminifera – James uses these to make measurements of the chemistry of these to reconstruct past climate change. Credit: James Rae

You’ve enjoyed success as a researcher, not least your 2015 EGU Award. As an early career researcher, do you have any words of advice for masters and PhD students who are hoping to pursue a career as a scientist in the Earth sciences?

Do what you really enjoy. This feeds in to everything else you do; it means you’ll work hard and carefully in lab, find the reading interesting, and be able to present your work effectively to your colleagues. We do science because we love it, so it’s really important to find topics within your field that you love working on. I think it’s also helpful to find skills to be a specialist in and be known for, but then to try to apply these broadly to big picture questions in geosciences.

Imaggeo on Mondays: How sea urchins can help mitigate climate change

This week’s Imaggeo on Mondays stars the humble sea urchin – a creature suffering from the effects of climate change, but one that could also provide a way to sequester some of the CO2 responsible…

Carbon dioxide and water react to form carbonic acid – a mixture of bicarbonate and hydrogen ions. Sea urchins bag the bicarbonate to grow bigger, stronger shells, or ‘tests’, but without a catalyst, this reaction happens fairly slowly. In fact, because the reaction is reversible, the hydrogen ions and bicarbonate can recombine, rendering the bicarbonate unavailable for the urchin. Not ideal.

To help themselves on their way to adulthood, larval urchins use trace nutrients from the water as catalysts for carbonate uptake. Catalysts to molecules are like bars are to people – interaction is much more likely to occur.

This image shows a sea urchin long past the end of its life cycle, but back when it was a little nipper, it was quite an amazing creature! (Credit: Natalia Rudaya, distributed via

This image shows a sea urchin long past the end of its life cycle, but back when it was a little nipper, it was quite an amazing creature! (Credit: Natalia Rudaya, distributed via

By building nickel into their tests, urchins can speed up the conversion of carbon in the water to carbon for growth because the nickel, like any catalyst, provides a site for the reaction to occur.

This fantastic feature of sea urchins is now being mimicked in a pilot process that uses nickel to help capture carbon from the atmosphere and store it as stony sediment.

The application was a chance discovery. Physicist Lidija Šiller, while working on a carbon capture project at Newcastle University, was also investigating how sea urchins convert CO2 to calcium carbonate. “When we analysed the surface of the urchin larvae we found a high concentration of Nickel on their exoskeleton. Taking Nickel nanoparticles which have a large surface area, we added them to our carbonic acid test and the result was the complete removal of CO2,” Šiller explains in a press release for the study.

The carbon capture process used to use an enzyme to speed up the conversion carbon dioxide into calcium carbonate, but the enzyme is only active for a short time and it rapidly fails under acidic conditions. To speed up the process, and prevent enzyme wastage, the scientists took a leaf from the urchin’s book. Nickel nanoparticles can used to catalyse the conversion of atmospheric CO2 into carbonate. What’s more, the nanoparticles are magnetic, so can be removed from the mixture and reused in another round of carbon capture.

While urchins themselves aren’t the key to climate mitigation, the urchin-inspired process has great potential. Watch this space!

By Sara Mynott, EGU Communications Officer


Gaurav A. Bhaduri, Lidija Šiller. Nickel nanoparticles catalyse reversible hydration of carbon dioxide for mineralization carbon capture and storage. Catalysis Science & Technology, 3, 1234-1239, 2013.

The EGU’s open access geoscience image repository has a new and improved home at! We’ve redesigned the website to give the database a more modern, image-based layout and have implemented a fully responsive page design. This means the new website adapts to the visitor’s screen size and looks good whether you’re using a smartphone, tablet or laptop.

Photos uploaded to Imaggeo are licensed under Creative Commons, meaning they can be used by scientists, the public, and even the press, provided the original author is credited. Further, you can now choose how you would like to licence your work. Users can also connect to Imaggeo through their social media accounts too! Find out more about the relaunch on the EGU website.