“The Contemporary Global Carbon Cycle and the Impact of the COVID-19 Pandemic on CO2 Emissions” with Corinne Le Quéré  (University of East Anglia, UK)


Emissions of carbon dioxide (CO2) from human activities have caused the planet to warm and have set in motion a train of changes in the natural carbon cycle. Every year, the land and ocean natural carbon reservoirs, the so-called carbon ‘sinks’, absorb 55% on average of the CO2 emissions we put in the atmosphere from burning fossil fuels, deforestation, and other activities. The carbon sinks slow down the pace of climate change, but they respond themselves to a changing climate by leaving more CO2 in the atmosphere. The latest evidence on trends in emissions and sinks of carbon of the past 60 years reveals the limits of our understanding and the challenges we face to develop a planetary monitoring system that can keep track of the rapidly changing carbon cycle. The Covid-19 pandemic generated the need to monitor global emissions daily, something that was thought impossible before. From this need has arisen an explosion of new research methods on monitoring the carbon cycle. This presentation will provide a snapshot of current understanding and capacity to untangle changes in the Earth’s vital organic element: carbon.

Corinne Le Quéré is Royal Society Research Professor of climate change science at the University of East Anglia. She conducts research on the interactions between climate change and the carbon cycle. Her research has shown that climate change and variability affects the capacity of the Earth’s natural carbon reservoirs to take up carbon dioxide emitted to the atmosphere by human activities. Corinne Le Quéré instigated and led for 13 years the annual update of the global carbon budget, an international effort to inform global climate agreements. She was author of three assessments reports by the Intergovernmental Panel on Climate Change, which was awarded the Nobel price prize in 2007, and is former Director of the Tyndall Centre for Climate Change Research. Professor Le Quéré is Chair of France’s High Council on climate, an independent experts body that advises the French Government on its responses to climate change, and member of the UK Committee on Climate Change. She was elected Fellow of the UK Royal Society in 2016 and was appointed Commander of the Order of the British Empire (CBE) in 2019 for services to climate change science.

This webinar was recorded on July 22, 2021

Spotting Hard-To-Detect Coronal Mass Ejections from the Sun

Report from ISSI Team #415 Understanding the Origins of Problem Geomagnetic Storms led by N. V. Nitta and T. Mulligan

Coronal mass ejections (CMEs) are large eruptions from the Sun that are often powerful drivers of space weather effects at Earth. Being able to predict their behaviour in interplanetary space is one of the main goals of space weather forecasting. However, there is a class of CMEs that are particularly hard to observe and, therefore, forecast. These eruptions are known as “stealth CMEs” and they were first reported by Robbrecht et al. [2009], who used the twin STEREO spacecraft (in orbit around the Sun) that were separated by ~50° in longitude to observe a clear ejection off the solar limb from one perspective, but no corresponding eruptive signatures against the solar disc from the other. The lack of indications that an eruption has occurred makes it particularly challenging to establish whether a CME is Earth-directed, especially when imagery from secondary viewpoints is not available. Nitta & Mulligan [2017] analysed a number of stealth CMEs that, in fact, caused unexpected space weather effects at Earth, also known as “problem geomagnetic storms”.

New research from Palmerio et al. [2021] aims to explore techniques that may be useful to identify and analyse eruptions that are elusive when viewed against the solar disc. The authors revisited four well-known stealth CMEs that were characterised by off-limb observations from either one or both STEREO spacecraft, enabling knowledge of their approximate source region. They first applied different image-processing techniques to these events (see example in Figure 1), noting that the most prominent changes that can be attributed to eruptive signatures are evident in long-separation difference data (where to one image is subtracted a preceding one, from e.g. 12 hours prior). Once large-scale changes in the structure of the solar corona are singled out, more refined analysis using “plain” intensity images can be applied to interpret the identified structures, and data produced with more advanced processing techniques can be used to zoom-in on the source region and inspect the eruption in deeper detail.


Figure 1. Example of different image processing techniques applied to a stealth CME that erupted on 4 February 2012. The arrows in the last column point to the faint eruptive signatures (in terms of dimmings and brightenings) found in “plain” intensity images, difference images, and images processed with the wavelet packet equalisation and multi-scale gaussian normalisation techniques. Figure from Palmerio et al. [2021].

Since the events studied were characterised by two or three simultaneous observations of the Sun and its corona, the authors also applied several geometric techniques to reconstruct the eruptions in 3D and connect them to a more-or-less defined location on the solar disc (see example in Figure 2). They concluded that the efficacy of these methods strongly depends on the propagation direction of a CME with respect to the observers and the relative spacecraft separation, since it is not unusual for CMEs to deflect in latitude and/or longitude when they are only a few solar radii away from the surface.


Figure 2. Example of different geometric techniques applied to the same stealth CME shown in Figure 1, which erupted on 4 February 2012. The top row shows reconstructions applied to solar disc imagery using the tie-point technique, the middle row shows reconstructions applied to coronagraph data using the graduated cylindrical shell model, and the bottom row shows results from both methods. Figure from Palmerio et al. [2021].

The careful, multi-step analysis presented in Palmerio et al. [2021] suggests that stealth CMEs can in principle be successfully identified even if they look “invisible” at first glance, thus allowing their inclusion in space-weather forecasting models and predictions.


More information can be found here: “New method predicts ‘stealth’ solar storms before they wreak geomagnetic havoc on Earth” >>



Nitta, N. V., and Mulligan, T.: Earth-affecting Coronal Mass Ejections without Obvious Low Coronal Signatures, Solar Physics, 292:125. doi:10.1007/s11207-017-1147-7, 2017.

Palmerio, E., Nitta, N. V., Mulligan, T., Mierla, M., O’Kane, J., Richardson, I. G., Sinha, S., Srivastava, N., Yardley, S. L., and Zhukov, A. N.: Investigating remote-sensing techniques to reveal stealth coronal mass ejections, Frontiers in Astronomy and Space Sciences, 8:695966, doi:10.3389/fspas.2021.695966, 2021.

Robbrecht, E., Patsourakos, S., and Vourlidas, A.: No Trace Left Behind: STEREO Observation of a Coronal Mass Ejection without Low Coronal Signatures, The Astrophysical Journal, 701, 283–291, doi:10.1088/0004-637X/701/1/283, 2009.

“Testing the Massive Black Hole Paradigm with High Resolution Astronomy” with Reinhard Genzel (Max Planck Institute for Extraterrestrial Physics, Garching, Germany)

The discovery of the Quasars in the 1960s led to the ‘massive black hole paradigm’ in which most galaxies host massive black holes of masses between millions to billions of solar masses at their nuclei, which can become active galactic nuclei and quasars when they accrete gas and stars rapidly. I will discuss the major progress that has happened in the last decades to prove the massive black hole paradigm through ever more detailed, high resolution observations, in the center of our own Galaxy, as well as in external galaxies and even in distant quasars. In the Galactic Center such high resolution observations can also be used to test General Relativity in the regime of large masses and curvatures.
Reinhard Genzel is an infrared- and submillimetre astronomer. He and his group are also engaged in developing ground- and space-based instruments for astronomical observations. They use these to track the motions of stars at the centre of the Milky Way around Sagittarius A*, and showed that these stars are orbiting a very massive object, now known to be a black hole. Genzel and his group are also active in studies of the formation and evolution of galaxies and active galactic nuclei. Reinhard Genzel was awarded the 2020 Nobel Prize in Physics (jointly with Andrea Ghez and Roger Penrose) “for the discovery of a supermassive compact object at the centre of our galaxy”.
Genzel had studied at Freiburg University and Bonn University, finishing his PhD in 1978 at the Max Planck Institute for Radio Astronomy in Bonn. As a postdoc he worked at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; he was a Miller Fellow, then Associate Professor and in 1981 he became Full Professor in the Department of Physics at the University of California, Berkeley. In 1986, Genzel became director at the Max Planck Institute for Extraterrestrial Physics in Garching (near Munich) and in 1988 also Honorary Professor at Ludwig-Maximilians-Universität München. From 1999 to 2016, he had a joint appointment as Full Professor at the University of California, Berkeley, where he is now emeritus professor. Prior to the Nobel prize, Reinhard Genzel had received numerous awards, among them the Herschel Medal of the Royal Astronomical Society (2016), the Tycho Brahe Prize of the European Astronomical Society (2012) and the Karl Schwarzschild Medal of Astronomische Gesellschaft (2011).

This webinar was recorded on July 15, 2021

Board of Trustees appoints Prof. Dr. Roger-Maurice Bonnet as ISSI Honorary Director

ISSI Honorary Director Prof.-Dr. Roger-Maurice Bonnet

Over time, Prof. Dr. Roger-Maurice Bonnet has constantly supported the development of the International Space Science Institute (ISSI) in Bern, Switzerland. In addition, during two specific periods of time, he has played an especially important role in establishing ISSI.

First, as the director of Science of the European Space Agency (ESA), Prof. Bonnet helped Prof. Dr. Johannes Geiss in paving the way, which led to the creation of ISSI in January 1995.

Second, as the successor of Prof. Geiss as Executive Director of ISSI, from 2003 till 2012, Prof. Bonnet has expanded ISSI scientific interests and developed the tools by which ISSI now engages a global scientific audience.

Acknowledging his pivotal role and expressing deep gratitude for his steady and effective support and leadership that has made ISSI a beacon in space science, the ISSI Board of Trustees presents Prof. Roger-Maurice Bonnet with the title of Honorary Director of the International Space Science Institute, effective as of June 1, 2021.

With this award, the Board of Trustees wishes to highlight Prof. Bonnet’s essential role, both in the past and today, as a true ambassador of ISSI to the international scientific community.

The ISSI Board of Trustees


A Word form the ISSI Executive Director

Dear friends of ISSI,

Dear visitors of our web site,

As we proceed into the summer infection rates are pleasingly low although the Delta variant of the virus is causing concern. Activities at ISSI are picking up for September onwards with team meetings and the planned workshop on “Venus: Evolution Through Time”. We at ISSI certainly hope that the increasing number of vaccinations will keep Delta at bay and allow activities to continue in the fall and winter. 

Here at the institute things are evolving with significant changes in the staff and the directorate now and ahead of us! Look for spotlights in due time as we say farewell and welcome our new members or old friends in new responsibilities:

First of all, let me report that at its last meeting the ISSI Board of Trustees has awarded Prof. Roger-Maurice Bonnet with the ISSI honorary directorship for life. Prof Bonnet thus follows in the footsteps of ISSI’s founding father Prof. Johannes Geiss. The board thus acknowledges the “pivotal role and expressing deep gratitude for his steady and effective support and leadership that has made ISSI a beacon in space science.” The ISSI staff and directors congratulate Prof. Bonnet on this highly-deserved honor. Prof. Bonnet is in our Spotlight this week!

By the end of the month, Prof. Ruedi von Steiger will retire from his positions at the University of Bern and at ISSI and will be followed by Prof. Maurizio Falanga. Maurizio, known to many of you as our Science Program Manager will be followed as of September 15th by Dr. Mark Sargent. He is a lecturer in Astronomy at the University of Sussex board and presently on sabbatical leave visiting with the University of Geneve

ISSI is deeply thankful to Ruedi von Steiger who has served the institute right from the beginning. His continued service has fundamentally helped to make ISSI what it is today. We will honor Ruedi on July 29th at 17:00 CDT with a special issue of the weekly Game Changers Seminar.

Finally, the ISSI board of Trustees at its last meeting decided to offer the position of ISSI Earth Science director to Prof. Michael Rast. Prof.  Rast will join the ISSI directorate as of Jan 1st, 2022 and will follow in the footsteps of Prof. Anny Cazenave. Prof. Rast is known to ISSI since the beginning of the Earth Science program at the institute having served as ex-officio member of the ISSI Science Committee.

Stay safe and I hope to see you all back in person at ISSI sometime soon!

Tilman Spohn

ISSI executive Director

“(Almost) 50 Years of Coronal Heating” with Joan Schmelz (USRA, USA)

The actual source of coronal heating may be one of the longest standing unsolved mysteries in all of astrophysics, but it is only in recent years that observations have begun making significant contributions. Coronal loops, their structure and sub-structure, their temperature and density details, and their evolution with time, may hold the key to solving this mystery. A loop had always been thought of as a simple magnetic flux tube, where each position along the loop is characterized by a single temperature and density. Recent results, however, including loops with unexpectedly high densities, ultra-long lifetimes, and multithermal cross-field temperatures, were not consistent with results expected from steady uniform heating models. A loop, however, may be a tangle of magnetic strands, like the structures revealed by the High-resolution Coronal Imager. Hi-C observed magnetic braids untwisting and reconnecting, dispersing enough energy to heat the surrounding plasma. The hot (T > 5 MK) plasma observed in most active regions also provides a key observation. The existence of multithermal, cooling loops and hot active region plasma do not yet prove that one particular mechanism heats the corona, but these results do provide observational constraints that all viable coronal heating models will need to explain.

Joan Schmelz is the director of the NASA Postdoctoral Program at Universities Space Research Association (USRA). She was the Associate Director for Science and Public Outreach at SOFIA, the Stratospheric Observatory for Infrared Astronomy (2018-19), and the deputy director of the Arecibo Observatory in Puerto Rico (2015-18). She was a program officer for the National Science Foundation’s Division of Astronomical Sciences (2013-15) and a professor at University of Memphis for over 20 years. Her research involves observations of solar coronal loops and developing constraints for coronal heating models. Schmelz has published papers on a variety of astronomical topics including magnetic fields, gas dynamics, and physical properties in stars, galaxies, interstellar matter, and the Sun using data from ground- and space-based telescopes at (almost) every band of the spectrum. She is the chair of USRA’s Diversity, Equity, and Inclusion Committee, a former Vice President of the American Astronomical Society, and a former chair of the Committee on the Status of Women in Astronomy. She won a teaching award from Rensselaer Polytechnic Institute, a service award from Gallaudet University, and a research award from the University of Memphis. She gives talks and writes articles on topics such as unconscious bias, stereotype threat, and the gender gap. She was honored in 2015 as one of Nature’s top ten people who made a difference in science for her work fighting sexual harassment.

This webinar was recorded on July 8, 2021


Moving Langmuir Waves and the Most Intense Radio Sources in the Sky

Report from the ISSI Team #408  Low Frequency Imaging Spectroscopy with LOFAR – New Look at Non-Thermal Processes in the Outer Corona led by E. Kontar

The combination of kinetic simulations with LOFAR telescope observations published  in a paper in Nature Astronomy shows that the fine structures are caused by the moving intense clumps of Langmuir waves in a turbulent medium.

The Sun routinely produces energetic electrons in its outer atmosphere that subsequently travel through interplanetary space. These electron beams generate Langmuir waves in the background plasma, producing type III radio bursts that are the brightest radio sources in the sky (Suzuki & Dulk, 1985).

These solar radio bursts also provide a unique opportunity to understand particle acceleration and transport which is important for our prediction of extreme space weather events near the Earth. However, the formation and motion of type III fine frequency structures is a puzzle but is commonly believed to be related to plasma turbulence in the solar corona and solar wind. 

Recent work by Reid & Kontar, Nature Astronomy, combines a theoretical framework with kinetic simulations and high-resolution radio type III observations using the Low Frequency Array and quantitatively demonstrates that the fine structures are caused by the moving intense clumps of Langmuir waves in a turbulent medium. These results show how type III fine structure can be used to remotely analyse the intensity and spectrum of compressive density fluctuations, and can infer ambient temperatures in astrophysical plasma, both significantly expanding the current diagnostic potential of solar radio emission.

Image shows dynamic spectra (left) and associated radio contours of solar type III radio bursts observed by LOFAR (right).  The LOFAR contours at 75% of the peak flux of the type III bursts going from 40 MHz to 30 MHz in the colour sequence white-blue-green-yellow-red. The LOFAR beam contour at 75% for 30 MHz is shown in the top left corner in white. The background is the Sun in EUV at 171 Angstroms observed by AIA. Image from Reid & Kontar, Nature Astronomy, 2021.


Suzuki, S. & Dulk, G. A. Bursts of Type III and Type V 289–332 (Cambridge Univ. Press, 1985)

Reid, H.A.S., Kontar, E.P. Fine structure of type III solar radio bursts from Langmuir wave motion in turbulent plasma. Nat. Astron. (2021). https://doi.org/10.1038/s41550-021-01370-8

“Age and Formation of the Moon” with Thorsten Kleine (Münster University, Germany)

The Moon has been Earth’s steady companion ever since about 4.4 billion years ago. The age of the Moon and just how it formed is still a matter of intense scientific debate and research. Soon after the return of the first Apollo lunar samples, early hypotheses of the formation of the Moon (co-accretion, fission, and capture) have mostly been discarded in favor of the giant impact model, whereby a collision between a Mars-sized body with proto-Earth led to vaporization of the outer rock layers, expansion of the vapor cloud, and, ultimately, cooling and accretion of a comparatively iron-poor planetary body in orbit around Earth. Geophysical evidence for a small iron core and petrological evidence for an early lunar magma ocean lend credibility to the hypotheses. The giant impact model also predicts that the Moon consists predominantly of impactor mantle material. This implies that the Moon should be isotopically distinct from Earth, but isotope data for lunar samples have convincingly shown that it is not. This “lunar isotopic crisis” has led to the development of a new generation of giant impact models, in which the Moon either formed mostly from Earth’s mantle or isotopically equilibrated with the Earth after the giant impact. However, whether or not these models can account for the high degree of isotopic homogeneity of the Earth and Moon remains a matter of debate. 

The analyses of lunar samples not only provide clues to how but also when the Moon formed. Although the giant impact cannot be dated directly, the age of the Moon can be determined by dating the solidification of the lunar magma ocean. Yet, there is debate about how the ages of the distinct crystallization products of the magma ocean can be tied to the age of the Moon. The most recent results provide a Moon formation age of 4.425 ± 0.025 billion years, which is remarkably similar to the combined hafnium-tungsten and uranium-lead age for core formation on Earth. This suggests that the Moon-forming impact triggered the last major core formation event on Earth, as predicted in the giant impact model. 

Thorsten Kleine is a professor for Planetology at the University of Münster, Germany. He is a member of the North-Rhine Westphalian Academy of Sciences, Humanities and Arts, a fellow of the Meteoritical Society, recipient of the F.W. Clarke Award of the Geochemical Society, of the Victor Moritz Goldschmidt Award of the German Mineralogical Society, and of the Nier Prize of the Meteoritical Society. Thorsten Kleine specializes in isotopic studies of meteorites, lunar, martian and terrestrial rocks. His work is highly cited and is supported by an ERC Consolidator Grant. Since 2020 he is speaker of the DFG-funded collaborative research center “Late Accretion onto the Terrestrial Planets”, which investigates the late growth history of the Earth and Moon.

This webinar was recorded on July 1, 2021

Reading Terrestrial Planet Evolution in Isotopes and Element Measurements

Volume 80 in the Space Sciences Series of ISSI

This volume takes an interdisciplinary approach to the evolution of terrestrial planets, addressing the topic from the perspectives of planetary sciences, geochemistry, geophysics and biology, and solar and astrophysics.
The review papers analyze the chemical, isotopic and elemental evolution of the early Solar System, with specific emphasis on Venus, Earth, and Mars. They discuss how these factors contribute to our understanding of accretion timescales, volatile delivery, the origin of the Moon and the evolution of atmospheres and water inventories of terrestrial planets. Also explored are plate tectonic formation, the origin of nitrogen atmospheres and the prospects for exoplanet habitability.The papers are forward-looking as well, considering the importance of future space missions for understanding terrestrial planet evolution in the Solar System and beyond. Overall, this volume shall be useful for academic and professional audiences across a range of scientific disciplines.

This volume is based on an interdisciplinary international Workshop organised by Europlanet and ISSI, which took place at ISSI, in Bern (Switzerland) during October 22 and 26, 2018 where about 48 leading scientists discussed the issues presented here.

The papers are edited by H. Lammer, B. Marty, A. Zerkle, M. Blanc, H. O’Neill, T. Kleine

This volume is co-published in Space Science Reviews in the Topical Collection “Reading Terrestrial Planet Evolution in Isotopes and Element Measurements” (Partial Open Access) >>

Hard Cover Book >>


“Weather Disasters in a Changing Climate” with Stephen Belcher (MET Office, Exeter, UK)

Weather and climate extremes such as heatwaves, heavy rainfall, drought, wind storms, flooding and wildfires have huge socio-economic and environmental costs. And climate change is already driving changes in weather extremes. Since the Paris Agreement in December 2015 there is a focus on the transition to net zero emissions, in order to limit the damage from climate change. Nevertheless, we are committed to further changes on the climate system, and so there remains a need to understand the impacts of further changes to the climate and to build resilience. As a result, the focus of climate science research at centres such as the Met Office has shifted to reflect these changing drivers: moving from proving that climate change is happening, to understanding the nature of the change and helping design solutions. This presentation will survey some of the inspirational new work that is being done to rise to this enormous challenge, including new observations, new modelling for projections, and new partnerships that are needed to move to building solutions.

Stephen Belcher obtained his PhD in fluid dynamics from the University of Cambridge (UK) in 1990 and has subsequently published over 100 peer-reviewed papers on the fluid dynamics of atmospheric and oceanic turbulence. Having completed his PhD he became a research fellow at Stanford and Cambridge Universities. In 1994 he moved to the Department of Meteorology at the University of Reading (UK), where he served as Head of the School of Mathematical and Physical Sciences between 2007 and 2010.  In 2010 he became the Joint Met Office Chair in Weather Systems. This role gave him a taster of working closely with the Met Office, and in 2012 he joined the Met Office as Director of the Met Office Hadley Centre (UK).Stephen led the evolution of the Met Office Hadley Centre to focus on climate science and services: motivated by the need to provide governments, industry and society with actionable advice, i.e. ‘climate services’. He was a driving force behind the initiation of the Newton Fund Climate Science for Service Partnership China (CSSP China), in which scientists from both China and the UK are now working together to develop fundamental climate science and climate services.

This webinar was recorded on June 24, 2021