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global warming

February GeoRoundUp: the best of the Earth sciences from around the web

Comparing the TRAPPIST-1 planets

Drawing inspiration from popular stories on our social media channels, as well as  unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major story

Undoubtedly the story of the month is the discovery of a star system of seven Earth-sized planets just 40 light-years away from our own. What makes the finding so exciting is that three of the planets lie in the habitable zone. All could have oceans and atmospheres, making them good candidates to search for extraterrestrial life.

The seven Earth-sized worlds orbit the ultra-cool dwarf star, TRAPPIST-1, which has been known to astronomers for some time. As the planets passed in front of TRAPPIST-1, the star’s light output dipped. Using a combination of ground and spaced based telescopes, the changes in the light output were used to detect the planets and gather information about their size, composition and orbit, explains the press release by the European Southern Observatory.

This simple GIF by New Scientist illustrates the principle of how the remarkable planets were found (while at the same time highlighting the fact there is a mind-blowing number of exoplanets scattered throughout space!).

The ultra-cool dwarf star and its planetary system has an even cooler website, which comes complete with great posters, videos, short stories, poems and graphic novels; as well as a detailed timeline of all the years of work which took place behind the scenes and culminated in the announcement made earlier this month.

Our top pick for a science poem honouring the discovery is In Search of New Life by Sam Illingworth, a lecturer at Manchester Metropolitan University.  You can also find an audio version of the poem here.

Far into space, amongst the darkest Sea

New planets sit like marbles in a row.

We turn our eyes to find out what might be

And search for patterns in their ether’s flow;

Then try to see what else might lie below.

And as we probe how life’s rich web was spun,

Do they look back towards our distant sun?

 

What you might have missed

The discovery of a previously unknown continent below New Zealand and New Caledonia dominated headlines towards the middle of the month.

Dr. Mortimer, of GNS Science and lead author of the study, argues that “being more than 1 million square kilometers in area, and bounded by well-defined geologic and geographic limits, Zealandia [the name given to the newly discovered continent] is, by our definition, large enough to be termed a continent.”

But without an official authority which designates the existence of continents, it will be for the broader scientific community to recognise Zealandia as one. And the jury is still out, as Alex Witze finds in this Nature News & Comment article:

“Claiming that Zealandia is a continent is a bit like stamp collecting,” says Peter Cawood, a geologist at Monash University in Melbourne, Australia. “So what?”

While the (potentially) new Antipodean continent dominated headlines, you might have missed the discovery of another lost continent. Deep under the waters of the Indian Ocean, sandwiched between Madagascar and India, lie the scattered pieces of an ancient, drowned, microcontient called Mauritia. The authors of the study, published earlier this month in Nature Communications, dated zircons of up to 3 billion years old from Mauritanian volcanic rocks. Considering Mauritania is much younger, the researchers argue the zircons must have come from another, already existing continent.

Meanwhile, in the southern-most reaches of our planet, a huge iceberg is set to breakaway from the Larsen C Ice Shelf, on the northeastern coast of the Antarctic Peninsula. A large crack in the ice was spotted in natural-colour satellite imagery captured by NASA back in August 2016. Int January 2017 alone, the crack grew by more than 10 km in length and now stretches 175 km over the ice.

British Antarctic Survey (BAS) scientists recently captured footage of the huge crack. The video highlights what the calving of such a large iceberg might mean for the Larsen C ice shelf, while this Nature News and Comment story highlights how far glaciology has come since similar calving events in the 90s and 00s. Scientists now have a much better understanding of what might happen in the weeks and months to come.

Five links we liked

The EGU story

After long-awaited snowfall in January, parts of the Alps are now covered with fresh powder and happy skiers. But the Swiss side of the iconic mountain range had the driest December since record-keeping began over 150 years ago, and 2016 was the third year in a row with scarce snow over the Christmas period. A study published this month in The Cryosphere, a journal of the European Geosciences Union, shows bare Alpine slopes could be a much more common sight in the future.

The new research, by scientists based at the Institute for Snow and Avalanche Research (SLF) and at the CRYOS Laboratory at the École Polytechnique Fédérale in Switzerland, shows that the Alps could lose as much as 70% of snow cover by the end of the century. However, if humans manage to keep global warming below 2°C, the snow-cover reduction would be limited to 30% by 2100.

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

New study of natural CO2 reservoirs: Carbon dioxide emissions can be safely buried underground for climate change mitigation

New study of natural CO2 reservoirs: Carbon dioxide emissions can be safely buried underground for climate change mitigation

New research shows that natural accumulations of carbon dioxide (CO2) that have been trapped underground for around 100,000 years have not significantly corroded the rocks above, suggesting that storing CO2 in reservoirs deep underground is much safer and more predictable over long periods of time than previously thought, explains Suzanne Hangx a postdoctoral researcher at the University of Utrecht.

The findings, published today in the journal Nature Communications, demonstrate the viability of a process called carbon capture and storage (CCS) as a solution to reducing carbon emissions from coal and gas-fired power stations, say researchers.

About 80% of the global carbon emissions emitted by the energy sector come from the burning of fossil fuels, which releases large volumes of CO2 into the atmosphere, contributing to climate change. With the growing global energy demand, fossil fuels are likely to continue to remain part of the energy mix. To mitigate CO2 emissions, one possible solution is to capture the carbon dioxide produced at power stations, compress it, and pump it into reservoirs in the rock more than a kilometer underground. This process is called carbon capture and storage (CCS). The CO2 must remain buried for at least 10,000 years to help alleviate the impacts of climate change.

The key component in the safety of geological storage of CO2 is an impermeable rock barrier (the ‘lid’ or caprock) over the porous rock layer (the ‘container’ or reservoir) in which the CO2 is stored in the pores – see Figure X. Although the CO2 will be injected as a dense fluid, it is still less dense than the brines originally filling the pores in the reservoir sandstones, and will rise until trapped by the relatively impermeable caprocks. One of the main concerns is that the CO2 will then slowly dissolve in the reservoir pore water, forming a slightly acidic, carbonated solution, which can only enter the caprock by diffusion through the pore water, a very slow process.

Some earlier studies, using computer simulations and laboratory experiments, have suggested that caprocks might be progressively corroded as these acidic, carbonated solutions diffuse upwards, creating weaker and more permeable layers of rock several meters thick and, in turn, jeopardizing the secure retention of the CO2.  Therefore, for the safe implementation of carbon capture and storage, it is important to accurately determine how long the CO2 pumped underground will remain securely buried. This has important implications for regulating, maintaining, and insuring future CO2 storage sites.

Schematic diagram of a storage site showing the injection of CO2 (in yellow) at a depth of more than one kilometer into a layer of porous rock (the ‘container’ or reservoir), and kept from moving upwards by a sealing layer (the ‘lid’ or caprock). Via Global CCS Institute

Schematic diagram of a storage site showing the injection of CO2 (in yellow) at a depth of more than one kilometer into a layer of porous rock (the ‘container’ or reservoir), and kept from moving upwards by a sealing layer (the ‘lid’ or caprock). Via Global CCS Institute

To understand what will happen in complex, natural systems, on much longer time-scales than can be achieved in a laboratory, a team of international researchers and industry experts traveled to the Colorado Plateau in the USA, where large natural pockets of CO2 have been safely buried underground in sedimentary rocks for over 100,000 years. The team drilled deep below the surface into one of the natural CO2 reservoirs in a drilling project sponsored by Shell, to recover samples of these rock layers and the fluids confined in the rock pores.

The team studied the corrosion of the rock by the acidic carbonated water, and how this has affected the ability of the caprock to act as an effective trap over long periods of time (thousands to millions of years). Their analysis studied the mineralogy and geochemistry of the caprock and included bombarding samples of the rock with neutrons at a facility in Germany to better understand any changes that may have occurred in the pore structure and permeability of the caprock.

They found that the CO2 had very little impact on corrosion of the caprock, with corrosion limited to a layer only 7cm thick. This is considerably less than the amount of corrosion predicted in some earlier studies, which suggested that this layer might be many metres thick. The researchers also used computer simulations, calibrated with data collected from the rock samples, to show that this layer took at least 100,000 years to form, an age consistent with how long the site is known to have contained CO2. The research demonstrates that the natural resistance of the caprock minerals to the acidic carbonated waters makes burying CO2 underground a far more predictable and secure process than previously estimated. With careful evaluation, burying carbon dioxide underground will prove safer than emitting CO2 directly to the atmosphere.

By Suzanne Hangx, Post Doctoral Researcher at the University of Utrecht

 

Reference:
Kampman, N.; Busch, A.; Bertier, P.; Snippe, J.; Hangx, S.; Pipich, V.; Di, Z.; Rother, G.; Harrington, J. F.; Evans, J. P.; Maskell, A.; Chapman, H. J.; Bickle, M. J., Observational evidence confirms modelling of the long-term integrity of CO2-reservoir caprocks. Nat Commun 2016, 7.

The research was conducted by an international consortium led by Cambridge University together with universities in Aachen (Germany) and Utrecht (Netherlands), the Jülich Centre for Neutron Science (Germany), Oak Ridge National Laboratory (USA), the British Geological Survey (UK) and Shell Global Solutions International (Netherlands). The Cambridge research into the CO2 reservoirs in Utah was funded by the Natural Environment Research Council (CRIUS consortium of Cambridge, Manchester and Leeds universities and the British Geological Survey) and the UK Department of Energy and Climate Change.

Imaggeo on Mondays: A solitary floating island

With 2014 officially named the hottest year on record, there is evidence of the effects of rising global temperatures across the globe. The solitary, shimmering iceberg in today’s Imaggeo on Mondays photograph is a reminder that one of the best places to look for evidence of change is in glaciers. Daniela Domeisen tells the story of this lonely frozen block of ancient ice.

Iceberg on Tasman glacier lake. Credit: Daniela Domeisen (distributed via imaggeo.egu.eu)

Iceberg on Tasman glacier lake. Credit: Daniela Domeisen (distributed via imaggeo.egu.eu)

The picture shows an iceberg on Tasman glacier lake in the Southern Alps of New Zealand, in the centre of Aoraki / Mount Cook National Park. The lake consists of melt water from the Tasman glacier, which calves into the lake at its far end. The glacier is one of the largest in New Zealand and flows along New Zealand’s highest peaks, Mt Tasman and Mt Cook.

As most glaciers on Earth, the glaciers in Aoraki / Mount Cook National Park are retreating at a fast pace. The lower parts of the Tasman glacier are at less than 1000m above sea level and are therefore melting especially fast. The Tasman glacier lake has formed over the past two to three decades and has in the meantime reached a length of several kilometers. It is projected to almost double in size as the glacier retreats further.

Icebergs constantly calve from the Tasman glacier into the lake and drift down the lake, driven by a weak current towards the lake’s outflow while melting in the process. The ice contained in the icebergs is several thousand years old, beautifully transparent and clean when looking at a single piece of it.

The pictured iceberg was about 10 meters wide. From its shape, and melting pattern, it is likely that it had turned to its side after calving into the lake. With some force it was possible to tip the smaller icebergs and see a shiny blue surface which had been beautifully polished by the water.

On the lake, everything was completely peaceful and quiet, except for the distant sound of a continuous rippling and trickling coming from the moraines on the sides of the lake, as pictured in the background of the photo. Stones and rocks of various sizes slid down and fell into the lake as the ice inside the moraines melted in the bright, sunny and warm January weather.

The changes which are observed in most places as a result of the changing climate are often either too slow to be observed or invisible to the naked eye. The glacier, its lake and icebergs, however, are continuously changing, and a couple of hours spent on the water give a lively impression of a quiet place where things are changing fast enough to be able to observe a notable difference between the time one enters and leaves the place. The beauty of the glacier and its lake with the glittering icebergs provide a spectacular glimpse of a transient place.

By Daniela Domeisen, Research Analyst, MarexSpectron, London

If you pre-register for the 2015 General Assembly (Vienna, 12 – 17 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

IPCC report ‘unprecedented changes’ in climate, urging policymakers to take action

“Human influence on the climate system is clear” was the key message from the report on the physical science of climate change from the Intergovernmental Panel on Climate Change (IPCC).

“We have come a long way since the first IPCC report was published in 1990,” a statement reiterated throughout the press conference for the release of the report. The IPCC were keen to register the significance of the work and progress made in this report – an “assessment of a string of assessments from 1990,” according to Thomas Stocker, Co-Chair for Working Group I, reporting on the physical science basis of climate change. The fourth IPCC assessment published in 2007 was the first report to state that “warming of the climate system is unequivocal” and that “most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

In the fifth report, this message is heightened. Since the 1950’s many of the changes observed and analysed in this report have been unprecedented including warming of the atmosphere and ocean, diminishing amounts of snow and ice, rising sea levels, and increases in the concentrations of greenhouse gases. With 259 lead authors citing 9200 papers in the report, two thirds of which have been published since 2007, the fifth assessment presents a strong message to policymakers across the world. Incredibly, this feat of scientific work has been approved and agreed upon by 110 governments across the world, with 1089 reviewers consisting of scientists, the public and governments from 55 of those countries offering a staggering 54,677 comments on the physical science basis report. Almost every word was commented on, disputed and discussed to come up with 18 headline messages – a first for the IPCC reports – that stated in simple language the report’s key outcomes.

“If you look at temperature, it is red” stated Stocker in a press conference, describing one of several key images from the IPCC policymaker summary.

Observed change in average surface temperature 1901-2012 from IPCC Working Group I summary for policymakers (SPM 28).

Observed change in average surface temperature 1901-2012 from IPCC Working Group I summary for policymakers (SPM 28).

This simple statement with clever wordplay not only elicits a global increase in surface temperature but also danger. Our planet is warming, and humans are the culprit. He goes on to say “…each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850…Global surface temperature change for the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900 for all RCP scenarios.” RCP stands for representative concentration pathways, four greenhouse gas concentration trajectory models used by the IPCC in its fifth report.

“In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years.” For the fifth assessment the IPCC have gone to great lengths not only to ensure consistency and reliability in scientific data and consensus, but also to outline the key points from their summary for policymakers: the use of simple language to describe the data that does not include hype or headlines but instead simple scientific language.

The report also highlights the increase in global mean sea level rise, with a key headline stating “…the rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m”.

In each of the IPCC’s four RCPs it was clear that the higher the cumulative carbon emissions, the warmer it gets.

Cumulative total anthropogenic CO2 emissions from 1870 (GtCO2 ) from IPCC Working Group I summary for policymakers (SPM 36).

Cumulative total anthropogenic CO2 emissions from 1870 (GtCO2 ) from IPCC Working Group I summary for policymakers (SPM 36).

The summary for policymakers states “…cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond”, (above), “Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2.”

Dominique Raynaud, review editor of chapter five (on palaeoclimatology) of the report and officer on the EGU Climate: Past, Present and Future Division in an interview with the EGU Educational Fellow commented on the most important aspect of this report: “For the first time the scientific community has defined a set of 4 [RCP] scenarios which represent a range of 21st century climate policies. Only one scenario suggests that the global mean temperature change for the end of the 21st century will not exceed 2°C.”

Global average surface temperature change estimated from present to 2100 (°C), from IPCC Working Group I summary for policymakers (SPM 33).

Global average surface temperature change estimated from present to 2100 (°C), from IPCC Working Group I summary for policymakers (SPM 33).

Raynaud went on to say “With this scenario, we still have a hope to keep [to the] reasonable expected warming for this century…policymakers should obviously consider such a possibly.”

In some ways, the outcomes of this report are a repetition of what the public have already been hearing: humans are influencing climate change. But what is crucial to note about this 5th assessment report is the huge consensus among scientists, public and governments about this statement.

“This is not about ideology, this is not about self-interest” was a quote from Achim Steiner, the head of the UN’s environment programme, UNEP – a comment that will resonate with many through the ‘unequivocal’ status of the report’s conclusions – and a statement that Stocker echoed later “it threatens our planet, our only home,” clearly urging policymakers across the globe to take combined action on climate change.

By Jane Robb, EGU Educational Fellow

References:

IPCC Working Group I session report for 5th Assessment Report (summary for policymakers)

IPCC 5th Assessment Report (full)

IPCC 4th Assessment Report (full)