Land-atmosphere research for global sustainability

iLEAPS (Integrated Land Ecosystem – Atmosphere Processes Study) is an international research programme focussing on the land-atmosphere interface. The iLEAPS International Project Office (IPO) is hosted by our Division since the start, and for the past 8 years, iLEAPS has tried to advance multidisciplinary research on land-atmosphere interactions in an international setting. Now, the IPO consists of Tanja Suni, Alla Borisova, and 10% of Magdalena Brus.

The first phase of iLEAPS (2004 – 2014) has been a time of awareness-raising and establishing a united community of land-atmosphere scientists. Science conferences held in Helsinki (2003), Boulder (2006), Melbourne (2009), and Garmisch-Partenkirchen (2011) brought to light the importance of land-atmosphere processes and feedbacks in the Earth System, and a number of publications have shown the crucial role of the terrestrial ecosystems as regulators of climate and emphasised both the long-term net impacts of aerosols on clouds and precipitation. Furthermore, the iLEAPS community has drawn attention to the importance of realistic land-use representation in land surface modelling and to that of other feedback processes and regional characteristics in current climate models and recommended actions to improve them.

Human influence has always been an important part of iLEAPS science but in Phase II (2014-2024), iLEAPS will move further towards bridging the gap between socioeconomics and natural sciences to shed light on research questions advancing global sustainability. Phase II will see the foundation of new types of research groups such as the Pan-Eurasian Experiment (PEEX) that will include large-scale, long-term, coordinated observations and modelling in the Pan Eurasian region, especially to cover ground base, airborne and satellite observations together with global and regional models to find out different forcing and feedback mechanisms in the changing climate, taking into account the simultaneous societal and cultural change. PEEX is coordinated by the iLEAPS-Eurasia Office, run by  Hanna Lappalainen and Tuukka Petäjä.

Engineering the climate can only buy time

Governments are failing to act on climate change, and greenhouse gas emissions are increasing with accelerated speed. Joonas Merikanto is studying another route to mitigate climate change, climate engineering, of which there are two main types: some methods remove carbon dioxide from the atmosphere (carbon dioxide removal), whereas others reflect sunlight back to space (radiation management).

Carbon dioxide removal methods are slow and cumbersome. Planting new forests is an option but there really isn’t enough land and, since forest is usually darker than open land, the consequences on albedo could be adverse. Fertilising certain seaweeds is another option but it would have unpredictable consequences to marine ecosystems. Engineered carbon capture would also be possible, but appears to be extremely costly compared to emissions cuts, and involves storage problems.

The reflectivity of the atmosphere could be increased by  spraying aerosol particles in the sky, where they would become seeds for new clouds or directly reflect solar radiation. Aerosols could quickly cool the planet with relative little costs. According to Joonas, this method, too, entails severe risks and unknowns. Making clouds whiter could mix up rain patterns, and particles injected in the stratosphere could turn the sky from blue to grey and possibly increase ozone layer destruction. Termination of aerosol cooling in a world with increased carbon dioxide concentrations would be problematic, as it would quickly heat the planet to temperatures above the starting point. Therefore, aerosols offer no long-term solution to climate change.

At the moment, nobody really engineers climate although some countries like China have large scale rain enhancement projects. International legislation should be developed quickly, so that individual countries wouldn’t cool the climate without consideration of consequences outside their borders. “Climate engineering is not a magical remedy. It can only be a short-term solution that would buy us time to prevent environmental crises. No matter how much we engineer the climate artificially, we still need to cut down our emissions”, Joonas says. “However, a cooler Earth that suffers from side effects of climate engineering could still be a better place to live than a severely heated planet”, he concludes.

Summary of original article (in Finnish) “Pilvi Peitoksi”, Yliopisto 10/2012, page 25.

Russell et al. (2012), Ecosystem Impacts of Geoengineering: A Review for Developing a Science Plan, AMBIO, 41(4):350-69.

Photo of Hyytiälä by Juho Aalto.

A new role for forests in atmospheric oxidation

It is commonly known that forests emit volatile organic compounds (VOC) that participate in atmospheric chemistry and, when oxidised in the atmosphere, also form new aerosol particles. Ozone, the hydroxyl radical (OH) and the nitrate radical (NO3) are generally considered to be the dominant oxidants that initiate the removal of trace gases, including pollutants, from the atmosphere. But now a new finding by Lee Mauldin IIIMikko Sipilä, Pauli Paasonen, Tuukka Petäjä, Theo Kurtén, Veli-Matti Kerminen, Markku Kulmala and their collaborators suggests that forests also participate in the production of atmospherically relevant oxidants. In a recent Nature article, the group presented atmospheric observations from Hyytiälä supported by laboratory experiments and theoretical considerations that identified another compound, probably a stabilized Criegee intermediate (a carbonyl oxide with two freeradical sites) or its derivative, which has a significant capacity to oxidize sulphur dioxide and potentially other trace gases. This compound probably enhances the reactivity of the atmosphere, particularly with regard to the production of sulphuric acid, and consequently atmospheric aerosol formation. The oxidation chemistry of this compound seems to be tightly linked to the presence of alkenes of biogenic origin. Michael Boy and his group tested this idea for Hyytiälä and Hohenpeissenberg in Boy et al (2012)Photo of Hyytiälä by Juho Aalto.

Mauldin III et al (2012) A new atmospherically relevant oxidant of sulphur dioxide, Nature 488, 193–196

Online measurement of volatile organics in Hyytiälä


Taina Ruuskanen has been working on measuring biosphere-atmosphere exchange of volatile organic compounds (VOC) for years. Originally, emissions were measured in little chambers with just one twig of a tree inside; but because VOCs participate in many chemical processes in the atmosphere and, especially, make tiny aerosol particles grow to climatically important sizes and into cloud droplets, it soon became evident that a more continuous and comprehensive observation technique is necessary. During her post-doc at the University of Innsbruck in Austria Taina worked with instrument manufacturers trying to get a new device, PTR-ToF (Proton Transfer Reaction  – Time of Flight mass spectrometer) function online with an eddy covariance system. This would allow the instantaneous and continuous observation of VOC fluxes between vegetation and the atmosphere. Taina and her group have spent the last year trying to
 make the measurement work in Hyytiälä, and this autumn they finally got good results. “Our preliminary results show that the flux method really works and I’m exited to dig out seasonal changes in the forest-atmosphere exchange of organic compounds from our one-year dataset!”, Taina says.


Ruuskanen et al., 2011, . Top: PTR-ToF in Hyytiälä for the first time; photo by Simon Schallhart. Bottom: Taina Ruuskanen in pensive mode.


From the sphere of land and atmosphere

Welcome to our Division’s blog! Ideas for a joint blog for our Division of Atmospheric Sciences, our Centres of Excellence, and our regional activitiesin China, India, South America and many other places have been thrown around for a long time and now we finally got it started. The aim of this blog is to help increase the information flow among our diverse groups in a way that is accessible to everyone and doesn’t take as much time as seminars; to tie our work into the bigger picture (sustainable development, climate change, global environmental change, human dimension); and to offer a forum for discussing any interesting topics we happen to think of.Anyone in our extended group is welcome to write to this blog on their research, travels, crazy ideas or other thoughts. Group supervisors/members are especially welcome to introduce their work and their people with a couple of photos and a paragraph from time to time to keep the whole Division and CoEs in the loop on what they are doing. The floor is yours!