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Seasonal biological carryover dominates northern vegetation growth

Biological cycles of a plant include many successional growth periods in which the past and the present are tightly connected. Figure shows schematic representation of the vegetation growth carryover (Source Lian et al Nat Comm 2021); image: Pixabay

The life-cycle continuity of plant growth implies that present states of vegetation growth may intrinsically affect subsequent growths, which is a type of biological memory, and can be referred to as vegetation-growth carryover (VGC). Thus, the state of ecosystems is influenced strongly by their past, and describing this carryover effect is important to accurately forecast their future behaviors. However, the processes involved in the lagged vegetation responses to precedent climate, soil, and growth conditions are highly complex and often non-linear. It should also be noted that the strength and persistence of this carryover effect on ecosystem dynamics in comparison to that of simultaneous environmental drivers are still poorly understood.

In a new study published in the journal Nature Communications authors hypothesize that the VGC has played a critical role in regulating the seasonal-to-interannual trajectory of vegetation growth. The study quantifies the impact of VGC on North Hemisphere (NH) vegetation growth with a large set of measurements, including satellite, eddy covariance (EC), and tree-ring chronologies, and compare the size of this effect against that of immediate and lagged impacts of climate change.

According to the authors, this work provides quantitative evidence that peak-to-late season vegetation productivity and greenness are primarily determined by a successful start of the growing season (via the interseasonal VGC effect), rather than by a transient or lagged response to climate. This carryover of seasonal vegetation productivity exerts strong positive impacts on seasonal vegetation growth over the Northern Hemisphere. “In particular, this VGC of early growing-season vegetation growth is even stronger than past and co-occurring climate on determining peak-to-late season vegetation growth, and is the primary contributor to the recently observed annual greening trend”, said Xu Lian and Shilong Piao from the College of Urban and Environmental Sciences, Peking University.

In order to examine whether this VGC effect operates at longer time scales of multiple years, authors performed lagged partial autocorrelations with interannual anomalies of satellite-observed NDVI and 2739 standardized tree-ring width (TRW) records. For a time lag of 1 year, a positive interannual VGC was present across northern lands, with 75.6% of vegetated areas (for NDVI) and 82.9% of the tree-ring samples (for TRW) showing positive lagged correlations. This positive interannual VGC indicates that a greener year is often followed by another greener year. When the study extended the time lags extended to 2 years, the positive correlation between current year NDVI (or TRW) and that of 2 years earlier was significant for only 14% of tree-ring samples or 5% of the total vegetated area (for NDVI). If time lags of 3 years were considered, the lagged correlation was found to be close to zero (Fig. 4a). Based on this results authors conclude that the effect of seasonal VGC persists into the subsequent year but not further.

The study also discusses process-based ecosystem models, a useful tool for predicting vegetation growth and examining the associated complex mechanisms. According to the authors, these current models greatly underestimate the VGC effect, and may therefore underestimate the CO₂ sequestration potential of northern vegetation under future warming. To better simulate biological processes related to this carryover, the study highlighted that will be necessary not only using satellite and ground measurements to refine existing parameterizations, but also using leaf-level measurements to understand the physiological mechanisms controlling VGC patterns and to incorporate new process representation in model components

“Our analyses provide new insights into how vegetation changes under global warming. The VGC effect represents a key yet often underappreciated pathway through which warmer early growing season and associated earlier plant phenology subsequently enhance plant productivity in the mid-to late growing season, which can further persist into the following year”, explains Prof. Josep Penuelas from CREAF-CSIC Barcelona while he and Prof. Shilong Piao comment between them that “their results highlight the need for improved representation of the intrinsic VGC effect in dynamic vegetation models to avoid that they greatly underestimate the VGC effect, and may therefore underestimate the CO2 sequestration potential of northern vegetation under future warming.”Reference: Lian, X., Piao, S., Chen, A., Wang, K., Li, X., Buermann, W., Huntingford, C., Penuelas, J., Xu, H., Myneni, R. 2020. Seasonal biological carryover dominates northern vegetation growth. Nature Communications (2021) 12:983. Doi: 10.1038/s41467-021-21223-2.

Aquaculture has a sustainability problem

The increasing importance of aquaculture in fish production contributes to the shortage of the critical resource phosphorus and thereby endangers food security in the long term if no counter measures are taken. This is shown by a study just published in Nature Communications of a group of Imbalance-P researchers lead by Dr. Yuanyuan Huang (CSIRO, Australia).

Phosphorus is an essential element for all forms of life on Earth. The rapid rise of human demand for food has quadrupled phosphorus inputs in form of fertilizers into the biosphere since the pre-industrial time. Due to the rapid exploitation of the finite phosphorus sources and inefficient use of P, future food security is at risk. As a consequence, the European Union has included phosphorus into the list of 20 critical raw materials which for which supply security is at risk and economic importance is high in 2014. Regulations for phosphorus fertilizer use in agricultural production has lead to improvements in the use of phosphorus, but it’s use in fishery and aquaculture has not been considered yet. This should change, as a new study shows that fish production consumes substantial amounts of phosphorus at a very low efficiency: Globally, only roughly a quarter of the phosphorus that is used to raise fish is being harvest, while the remaining is being lost potentially causing harm in nearby ecosystems (e.g. biodiversity losses). “The phosphorus that enters rivers and ocean is lost as it is difficult to be recovered. Therefore, these losses must be minimized to ensure phosphorus is available for future generations.” says co-author Dr. Daniel Goll.

Finfish, crustaceans and mollusks (hereafter generalized as fish) are becoming more and more important as a protein source in the human diet: in 2013, 17% of all animal protein consumed by mankind originated from fishery and aquaculture. Whereas captured fish satisfy their phosphorus need from naturally occurring food source (e.g. other fish, plankton), aquaculture relies on phosphorus addition in form of fish food or fertilizer to enhance plant growth (for herbivory fish) to grow fish. As the share of fish originating from aquaculture is increasing, from less than 5% in the 1950s to roughly 50% in the 2010s, the originally landwards flow of phosphorus by fishery has reversed to loss of phosphorus from land in the form of fertilizer and feed additives. On average, about 80% of the added phosphorus in aquacultures is not being harvested, which poses a sustainability issue if no measures are taken to reduce this fraction. We estimated that harvested fraction of added phosphorus in aquaculture has to more than double by the year 2050 to allow a phosphorus sustainable fish production. “Phosphorus is a non-renewable yet limited and vital nutrient for crops. We should start to think about how to recycle and reuse phosphorus in fish consumption to grow more crops, while minimise phosphorus we put into water especially for aquaculture” says Dr. Yuanyuan Huang, the leader of the study.

Huang, Y., Ciais, P., Goll, D.S. et al. The shift of phosphorus transfers in global fisheries and aquaculture. Nat Commun11, 355 (2020) doi:10.1038/s41467-019-14242-7

Link to the paper: https://www.nature.com/articles/s41467-019-14242-7

Spatial variance of spring phenology depends not only on meteorology but also on climate

Leaf_pixabay_Nov2019 — In a new study in the journal Nature Communications authors study the spatial heterogeneities of leaf unfolding and its controls. Photo by: Pixabay.

Leaf unfolding (LU) determines the restart of the growing season. LU in temperate forests is driven by spring temperature, but the spatial heterogeneities of LU, and especially of its controls, have been much less studied.

In a new study published in the journal Nature Communications, authors used in situ LU observations for eight deciduous tree species to show that the two factors that control chilling (number of cold days) and heat requirement (growing degree days at LU, GDDreq) only explain 30% of the spatial variance of LU. Radiation and aridity differences among sites together explained 10% of the spatial variance of LU date, and up to 40% of the variation in GDDreq. Radiation intensity was positively correlated with GDDreq and aridity was negatively correlated with GDDreq spatial variance. Assessing the long-term spatial variance of LU and GDDreq is a first step in developing a unified framework that will allow an understanding of the multiple controls of climate on plant phenology.

“Our study provides evidence for a significant control of leaf unfolding by long-term background climatic conditions across sites, potentially representing long-term adaptation of species”, said Dr. Marc Peaucelle from CREAF-CSIC Barcelona, now in the Department of Environment of the University of Ghent. According to the authors, these findings show that at least two mechanisms influence spring phenology: i) the direct sensing of meteorological conditions during spring to optimize the restart of plant activity and ii) the long-term adjustment of bud sensitivity to spring meteorological conditions in order to cope with growing season pressures at sites.

The results presented in the study show that LU of temperate deciduous trees is adapted to local mean climate, including water and light availability, through altered sensitivity to spring temperature. This adaptation of GDDreq to background climate implies that models using constant temperature response are inherently inaccurate at local scale.

“Future research on the importance of plant phenology on ecosystem functioning should focus on space-time interactions with environmental conditions specifically to address: 1) the effects of light and aridity on bud sensitivity to temperature, and 2) the potential coordination between plant processes and phenology that could account for a co-limitation by temperature and the availability of light and water”, said Prof Josep Peñuelas from CREAF-CSIC.

Reference: Peaucelle, M., Janssens, I.A., Stocker, B.D., Descals Ferrando, A., Fu, Y.H., Molowny-Horas, R., Ciais, P., Peñuelas, J. 2019. Spatial variance of spring phenology in temperate deciduous forests is constrained by biogeographical conditions of temperature, light and aridity. Nature Communications, (2019) 10:5388. Doi: 10.1038/s41467-019-13365-1.

Does the Amazon rainforest slow down man-made climate change?

A new study published in Nature Geosciences highlights a very important feedback in the Amazon rainforest that current climate models are not considering, but may, in fact, accelerate climate change. The article was written by an international team of 27 scientists, including Daniel Goll from the Department of Geography, and lead by Katrin Fleischer from the Technical University of Munich (TUM).

Current climate change projections assume that the Amazon rainforest removes large amounts of carbon dioxide from the atmosphere storing it in biomass, thereby dampening man-made climate change. The models is used for climate change projections assume that elevated carbon dioxide concentration have a stimulating effect on plant growth. There is evidence that this fertilization effect operates in temperate forests, however, it is not clear if tropical forest respond in similar ways. To test how tropical vegetation response to elevated carbon dioxide an ecosystem-scale experiment is needed. Currently, such an experiment, the first of its kind, is being established in Brazil (AmazonFACE: https://amazonface.inpa.gov.br/), but because ecosystems respond slowly it will take many years before we will know it’s outcome. In the new study in Nature Geosciences an ensemble of state-of-the-art ecosystem models was used to simulate this experiment before-hand. The results indicate that the commonly low soil phosphorus availability in the Amazon region can lead to a much more dampened response of tropical vegetation to elevated carbon dioxide than currently assumed. This finding has still to be confirmed by the real life experiment, but it shows that current climate models which omit phosphorus effects on plant growth are likely overestimating the carbon dioxide removal by tropical forests. The findings also suggest that the Amazon forest could be even more threatened by climate change than currently thought – adding further pressure on of the most rapidly diminishing ecosystems on Earth.

You can find the paper here: https://www.nature.com/articles/s41561-019-0404-9

Technical illustration of the AmazonFACE experiment in a highly diverse, primary rainforest in Brazil.

You can find further information here:
https://www.carbonbrief.org/amazon-carbon-sink-could-be-much-less-due-to-lack-of-soil-nutrients
https://www.tum.de/nc/die-tum/aktuelles/pressemitteilungen/details/35637/

German version

Verlangsamt der Amazonas-Regenwald den vom Menschen verursachten Klimawandel?

Eine neue in Nature Geosciences veröffentlichte Studie hebt eine sehr wichtige Rueckkopplung zwischen Amazonas-Regenwald und dem Klimasystem hervor, die derzeitige Klimamodelle nicht berücksichtigen, aber die möglicherweise den Klimawandel beschleunigt. Der Artikel wurde verfasst von einem, von Katrin Fleischer von der Technischen Universität München (TUM) angefuehrtem, internationalen Team von 27 Wissenschaftlern verfasst, darunter Daniel Goll vom Institut für Geographie.

Aktuelle Klimaprojektionen gehen davon aus, dass der Amazonas-Regenwald der Atmosphäre große Mengen an Kohlendioxid entzieht und diese in Biomasse speichert, wodurch der vom Menschen verursachte Klimawandel gedämpft wird. In den dafuer genutzten Klimamodellen wird angenommen, dass eine erhöhte Kohlendioxidkonzentration sich positiv auf das Pflanzenwachstum auswirkt. Ein solcher Duengeeffekt konnte in gemäßigten Wäldern nachgewiesen werden, aber es ist nicht klar, ob er in tropischen Wäldern tatsaechlich existiert. Um zu testen, wie die tropische Vegetation auf erhöhtes Kohlendioxid reagiert, ist ein Experiment im Ökosystemmaßstab erforderlich. Derzeit wird ein solches Experiment, das erste seiner Art, in Brasilien errichtet (AmazonFACE: https://amazonface.inpa.gov.br/). Da Ökosysteme jedoch nur sehr langsam reagieren, wird es viele Jahre dauern, bis wir das Ergebnis haben. In der nun veroeffentlichten Studie wurde ein Ensemble modernster Ökosystemmodelle verwendet, um dieses Experiment vorab zu simulieren. Die Ergebnisse deuten darauf hin, dass die üblicherweise geringe Verfügbarkeit von dem Pflanzennaehrstoff Phosphor im Amazonasgebiet zu einer deutlich geringere Reaktion der tropischen Vegetation auf erhöhtes Kohlendioxid führen kann, als derzeit angenommen wird. Dieser Befund muss noch durch das reale Experiment bestätigt werden, aber es zeigt, dass aktuelle Klimamodelle, bei denen Phosphoreffekte auf das Pflanzenwachstum weggelassen werden, die Kohlendioxidentfernung durch tropische Wälder wahrscheinlich überschätzen. Die Ergebnisse deuten auch darauf hin, dass der Amazonas-Wald noch stärker vom Klimawandel bedroht sein könnte, als derzeit angenommen wird. Dies erhöht den Druck auf die am schnellsten abnehmenden Ökosysteme der Erde.

Bildunterschrift: AmazonFACE-Experiment in einem artenreichen Regenwald in Brasilien.

880 ciudades actúan de laboratorios naturales para prever la adaptación de la vegetación al cambio climático

Las zonas urbanas y sus periferias progresivamente rurales son excelentes laboratorios naturales que emulan las condiciones de temperatura y concentración de CO₂ futuras y pueden ayudar a prever cómo se adaptará la vegetación del planeta a los diferentes escenarios futuros de cambio climático. Así lo muestra una investigación internacional que ha analizado datos obtenidos vía satélite de 880 ciudades del hemisferio norte del planeta y de sus periferias.

Els punts vermells indiquen les 880 ciutats i les seves perifèries en l'hemisferi nord. Els colors de fons indiquen el tipus de vegetació: boscos perennes de fulla ampla (EBF en les seves sigles en anglès), boscos caducifolis de fulla ampla (DBF), boscos perennes de coníferes (ENF) i boscos caducifolis de coníferes (DNF).

El trabajo se acaba de publicar en la revista Nature Ecology Evolution y está codirigido por Josep Peñuelas, investigador del Consejo Superior de Investigaciones Científicas (CSIC) en el CREAF, en colaboración con el equipo del investigador Yongguang Zang, de la Universidad de Nanjing (China).

Los científicos han estudiado la actividad fotosintética de la vegetación en el hemisferio norte del planeta en función de la temperatura y la concentración de CO₂ y han obtenido los gradientes de estos tres factores, es decir, cómo se correlacionan y cómo cambian progresivamente desde cada uno de los centros urbanos hasta sus periferias. El análisis se ha realizado a partir de numerosos datos obtenidos vía satélite durante las últimas tres décadas, como la fluorescencia de clorofila inducida por luz solar, el índice de vegetación, la temperatura del aire, la temperatura del suelo, datos de precipitación y la altitud, entre otras variables.

Tal como explica Josep Peñuelas, si se toma el ejemplo de Shangai, “esta tiene una concentración de 450 ppm de CO₂ en el centro urbano, que es lo que podríamos tener de media en la atmósfera en unos 15 a 20 años. En cambio, a medida que uno se aleja del centro, las concentraciones de CO₂ van bajando a 430 ppm, 380 ppm y hasta menos de 380 ppm”.

Es decir, en el centro de muchas ciudades ya se están dando condiciones de CO₂ y temperatura más elevadas que la media y que corresponden a posibles escenarios futuros de cambio climático, explica este experto. Actualmente, la concentración media de CO₂ es de unos 400 ppm.

Los científicos han usado todos estos datos para proyectar cómo puede variar la actividad de fotosíntesis en función de diferentes escenarios climáticos desde los que contemplan incrementos de temperatura de 2,6 ºC de media hasta los que contemplan aumentos de hasta 8,5 ºC. Los resultados revelan que en todos los escenarios las hojas de la vegetación brotan antes (se adelantan una media de 5 días) y caen más tarde (unos 10 días). Además, el pico de máxima actividad fotosintética se da antes (unos 5 días antes).

En conjunto, la temporada en la que las plantas tienen vegetación y absorben CO₂ se prolonga, lo que significa que las plantas aumentan su capacidad de secuestrar CO₂, especialmente, remarca Peñuelas, “en las zonas donde hay recursos hídricos”.

Según el investigador, todo esto es una buena noticia porque significa que las plantas nos están ayudando contra el cambio climático. Pero, advierte, no es la solución porque no es en absoluto suficiente para compensar todas las emisiones que estamos generando.

Referencia científica:

Songhan Wang, Weimin Ju, Josep Peñuelas, Alessandro Cescatti, Yuyu Zhou, Yongshuo Fu, Alfredo Huete, Min Liu & Yongguang Zhang. Urban−rural gradients reveal joint control of elevated CO2 and temperature on extended photosynthetic seasons. Nature Ecology & Evolution. DOI: https://doi.org/10.1038/s41559-019-0931-1

Fuente: CSIC

Life and the five biological laws. Lessons for global change models and sustainability

forest_sunset_Pixabay_Feb2019 — In a new study in the journal Ecological complexity authors establish the five laws that rule life, arguing that biology adapts to what is available, recycles material and extracts energy from the environment while evolving to develop structures and functions optimized for their environment. Figure: Pixabay

Life on Earth is the result of evolutionary processes acting on a continuous accumulation of structural and functional information by combination and innovation in the use of matter and endo- (inside the organism) and exosomatic (outside the organism) energy and on discontinuous processes of death and destruction that recycle the materials that form structure, information and energy compounds, such as proteins, DNA and ATP, respectively.

In a new study in the journal Ecological complexity authors define five life laws for these vital processes. These processes cannot exceed natural limits of size and rates because they are constrained by space, matter and energy; biology builds on what is possible within these physicochemical limits

“Learning from the way nature deals with the accumulation of information, the limits of size and the rates at which life can acquire and expend energy and resources for maintenance, growth and competition will help us to model and manage our environmental future and sustainability”, explains Prof. Dennis Baldocchi from University of California, Berkeley.

According to this study, the five most prominent laws pertinent to life and ecology are:

The law of mass conservation (introduced by Lomonosov and Lavoisier)
The first law of thermodynamics: energy cannot be created or destroyed in an isolated system
The second law of thermodynamics, the entropy of any isolated system always increases
Information content is a power of the size of the material store with an exponent larger than one
Basic mechanisms such as natural selection, self-organization and random processes drive evolution, generating the huge complexity of organisms and ecosystems.

“Life has adapted to these ecological laws and physical limits for billions of years, and if we humans want to develop a sustainable world, we would do well to not forget them in our use of space, matter and energy. In the end, we are only another biological species among millions on Earth and are living in a very short period of Earth’s history. We should listen and learn lessons from nature that has had several billion years to evolve and get it as right as possible”, says Prof. Josep Peñuelas from CREAF-CSIC.

Reference: Peñuelas, J., Baldocchi, D. 2019. Life and the five biological laws. Lessons for global change models and sustainability. Ecological Complexity

The bioelements, the elementome and the “biogeochemical niche”

Biogeochemical niches_Elementome_2019 — Possible responses of species biogeochemical niches to long-term changes in the abiotic and biotic environmental conditions (possible evolutionary changes in the elementome of species). Authors hypothesize that each species has an optimal function related with its niche traits and thus an optimal content of the distinct bioelements. Figure: Peñuelas, J. et al. Ecology 2019.

Every living creature on Earth is made of atoms of the various bioelements (elements used by living organisms) that are harnessed in the construction of molecules, tissues, organisms and communities, as we know them. The most common bioelements are: hydrogen (H) 59%, oxygen (O) 24%, carbon (C) 11%, nitrogen (N) 4%, phosphorus (P) 1% and sulfur (S) 0.1-1% (percentages of total number of atoms in organisms), but there are other bioelements, normally present in low concentrations such as potassium (K), magnesium (Mg), iron (Fe), calcium (Ca), molybdenum (Mo), manganese (Mn) and zinc (Zn). Organisms need these bioelements in specific quantities and proportions to survive and grow.

Distinct species have different functions and life strategies, and have therefore developed distinct structures and adopted a certain combination of metabolic and physiological processes. Each species is thus also expected to have different requirements for each bioelement andbe characterized by an specific bio-elemental composition.

In a new study published in the journal Ecology authors propose that a “biogeochemical niche” can be associated with the classical ecological niche of each species. Authors show from field data examples that a biogeochemical niche is characterized by a particular elementome defined as the content of all (or at least most) bioelements. “The differences in elementome among species are a function of taxonomy and phylogenetic distance, sympatry (the bioelemental compositions should differ more among coexisting than among non-coexisting species to avoid competitive pressure), and homeostasis with a continuum between high homeostasis/low plasticity and low homeostasis/high plasticity”, explains Prof. Josep Penuelas from CREAF-CSIC Barcelona.

The biogeochemical niche hypothesis proposed in this paper has the advantage relative to other associated theoretical niche hypotheses that it can be easily characterized by actual quantification of a measurable trait: the elementome of a given organism or a community, being potentially applicable across taxa and habitats. The changes in bioelemental availability can determine genotypic selection and therefore have a feedback on ecosystem function and organization.

“Further studies are warranted to discern the ecological and evolutionary processes involved in the biogeochemical niche of all types of individuals, taxa and ecosystems. The changes of bioelements availability and use at long timescales should determine phenotypic selection and therefore also ecosystem function and organization, and, at the end, the evolution of life and the environment”, says Prof. Jordi Sardans from CREAF-CSIC.

Reference: Peñuelas, J., Fernández-Martínez, M., Ciais, P., Jou, D., Piao, S., Obersteiner, M., Vicca, S., Janssens, I.A., Sardans, J. 2019. The bioelements, the elementome and the “biogeochemical niche”. Ecology 2019.

Satellite observations reveal secrets of dry tropical forest greening

Canopy_forest_July2018 — Water stored in plant tissues is fundamental to the functioning of terrestrial ecosystems by participating in plant metabolism, nutrient and carbohydrates transport, and maintenance of the plant hydraulic system’s integrity. Photo by: Pixabay

In dry tropical forests, vegetation takes up water at the end of the wet season and stores it during the driest season of the year. This large amount of stored water enables trees to flush new leaves about one month before the next rainy season. This surprising phenomenon has been revealed for the first time using satellite observations, mainly in the African region of Miombo (around four times the surface area of France), in a study publicated in Nature Ecology and Evolution, will help researchers improve current Earth system models (which do not fully account for plant hydraulic mechanisms) and future climate change and water cycle projections in these regions of the world.

What are the relationships between plant water storage and leaf development? Are both variables closely related in time and space across the Earth’s surface? These are critical questions to improve vegetation-atmosphere feedback in Earth system models and predict ecosystem responses to climate change.

A discovery in the African tropical forest of Miombo

Using satellite observations, the study conducted by the University of Copenhagen and INRA, in collaboration with the CSIC-CREAF, CEA, CNRS, CNES and Bordeaux Science Agro, demonstrated that seasonal variations in plant water storage and leaf development are highly synchronous in boreal and temperate regions. However, more surprisingly, the researchers showed that these variations are highly asynchronous in dry tropical forests, where an increase in plant water storage precedes vegetation greening by 25 to 180 days. The study focused on the Miombo woodlands, which cover an immense surface area of more than 2.7 million square kilometres to the south of the African rainforests. Satellite observations of this region clearly show that the leaf area index (LAI) begins to increase several weeks before the rainy season begins, a clear sign of “pre-rain” green up that has already been documented in numerous studies. “The mechanisms behind this phenomenon are not yet fully understood but likely involve large construction costs to the plants, which must invest in their rooting system to access deep ground water and in their woody stems to increase their water storage capacity”, said Dr. Feng Tian from Lund University, Sweden.

The novelty comes from observations of the L-band vegetation optical depth (L-VOD) index (a crucial indicator of the plant water content dynamic) from the European Space Agency (ESA)-CNES SMOS satellite that show that vegetation in Miombo takes up water at the end of the rainy season (when transpiration losses fall) and stores it in woody tissues during most of the dry season until the emergence of new leaves a few weeks before rain starts. “This early leaf flushing has physiological and ecological advantages, reducing the time lag between the onset of the rainy season and that of photosynthetic activity”, said Prof. Rasmus Frensholt from University of Copenhagen, Denmark.

This intriguing hydraulic behaviour had previously been seen in in situ experiments of a few trees in dry tropical forests, particularly in Costa Rica. However, this new study is the first demonstrating that this is a large-scale phenomenon, visible over forested areas as large as the Miombo woodlands, as well as in the northern African woodlands and the Brazilian Cerrado.

Moreover, these physiological and hydrological processes are still not included in Earth system models. “Our results offer insights into ecosystem-scale plant water relations globally and provide a basis for an improved parameterization of eco-hydrological and Earth system models. The new L-VOD data set will be key for improving the next generation of Earth system models, leading to more robust projections of the future climate and water cycle in these regions of the world”, said Prof. Josep Peñuelas from CREAF-CSIC.

Temporal coupling between L-VOD and LAI seasonality: lag time for L-VOD to obtain the highest correlation with LAI for pixels with a clear seasonality. The black rectangle includes the Miombo woodlands. © Université de Copenhague, F. Tian

A large set of satellite observationsThis study was based on a large set of satellite observations that aim to characterise the time variations in key hydrological and vegetation parameters at the ecosystem scale. The research benefited from the new SMOS-IC data set of the vegetation index referred to as L-band vegetation optical depth, or L-VOD, retrieved from space-borne observations of the ESA-CNES SMOS satellite. This index is closely related to the vegetation water content (VWC, kg/m²) of the whole canopy layer. More specifically, along with the L-VOD (a proxy of vegetation water storage), the other variables considered in the study include leaf area index (LAI) retrieved from optical satellite observations and used to parameterise foliar phenology, terrestrial groundwater storage anomalies (TWS) retrieved from GRACE satellites, surface soil moisture, rainfall and transpiration. Surface soil moisture observations considered here were retrieved simultaneously with L-VOD from the multi-angular SMOS observations.

Seasonal water balance in the African tropical Miombo woodlands. The time series (2011-2012) of plant water storage (L-VOD), leaf area index and rainfall for a 1°×1° area (centred at 11.5°S, 18.5°E). The grey shaded rectangles indicate the dry seasons. © Université de Copenhague, F. Tian

_{When averaged at a yearly scale, the L-VOD index has been found to be closely related to global patterns of plant aboveground biomass, a feature that was used recently to quantify annual changes in sub-Saharan aboveground biomass carbon stock.For more information: http://presse.inra.fr/en/Press-releases/a-new-tool-to-monitor-the-carbon-budget-of-vegetation}

Reference

Tian, J.-P. Wigneron, P. Ciais, J. Chave, J. Ogée, J. Peñuelas, A. Ræbild, J-C Domec, X. Tong, M. Brandt, A. Mialon, N. Rodriguez-Fernandez, T. Tagesson, A. Al-Yaari, Y. Kerr, C. Chen, R. B. Myneni, W. Zhang, J. Ardö, R. Fensholt, Coupling of ecosystem-scale plant water storage and leaf phenology observed by satellite, Nature Ecology & Evolution, 13 août 2018 – https://doi.org/10.1038/s41559-018-0630-3

Species selection under long-term experimental warming and drought explained by climatic distributions

Field work sites in a Mediterranean shrubland at Garraf, Catalonia (Spain). Photo by: GEU

Global warming and reduced precipitation may trigger large-scale species losses and vegetation shifts in ecosystems around the world. However, the combined effects of temperature and precipitation are highly context-dependent. For example, both warming and decreased precipitation may increase the aridity of an already dry and warm habitat, thereby limiting plant growth. But, in cooler habitats not limited by water, warming may have positive effects on the vegetation (e.g. extending the growing season and promoting growth and reproduction) and decreasing precipitation may have little effect on plant growth.

In a new study in the journal New Phytologist authors conducted long-term (16 yr) nocturnal-warming (+0.6°C) and reduced precipitation (-20% soil moisture) experiments in a Mediterranean shrubland. Authors classified the species in the community into climatic niche groups (CNGs) using temperature and precipitation variables in order to determine community compositional change with respect to the different treatments.

“By applying a CNG approach to manipulation experiments, we provide valuable evidence that climatic niche distributions may be able to identify which species may be most vulnerable to shifts in these climate change factors either independently or in conjunction”, said Daijun Liu from CREAF-CSIC Barcelona.

This study indicates that the decline in the abundance of some climate sensitive species may be balanced by an increase in resistant species distributed in warmer or drier niches. “This was seen in our study with the delayed increase in species associated with dry climates in our drought treatment (e.g. Globularia alypum). Indeed, growing observational and experimental evidence suggests that communities are shifting towards a higher proportion of species associated with warmer climates in response to global warming”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona

“Therefore, evidence provided here from the CNG approach suggests that it may be possible to depict, on a global scale, how the magnitude of changes to either temperature and/or precipitation may affect those climate-sensitive species”, added Daijun Liu from CREAF-CSIC Barcelona.

The study findings indicate that when climatic distributions are combined with experiments, the resulting incorporation of local plant evolutionary strategies and their changing dynamics over time leads to predictable and informative shifts in community structure under independent climate change scenarios.

“We thus advocate the combined use of both manipulation experiments and the climatic niche principle to improve assessments of community responses to future climate change scenarios”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

Reference: Liu, D., Peñuelas, J., Ogaya, R., Estiarte, M., Tielbörger, K., Slowik, F., Yang, X., Bilton, M.C. 2018. Species selection under long-term experimental warming and drought explained by climatic distributions. New Phytologist (2018) 217: 1494–1506, doi: 10.1111/nph.1492

Quantifying soil moisture impacts on light use efficiency across Biomes

Agricultural droght_Pixabay_June2018 — Water availability is an important factor in limiting ecosystem productivity across much of the Earth’s surface. In the present study, authors investigate “droughts” providing an impact-oriented quantification of them. Photo by: Pixabay

Limiting water availability is a recurrent phenomenon and governs plant growth and phenology in arid, semi-arid and Mediterranean ecosystems. Moreover, in temperate, boreal and tropical ecosystems, sporadic prolonged dry periods can lead to water-limited conditions and can have far-reaching impacts on ecosystem carbon balance and structure.

In a new study in the journal New Phytologist authors investigate “agricultural droughts” characterized for having impacts on vegetation production, including seasonally recurring dry conditions.

Terrestrial primary production and carbon cycle impacts of droughts are commonly quantified using vapour pressure deficit data and remotely sensed greenness. However, soil moisture limitation is known to strongly affect plant physiology.

In this study, authors investigate light use efficiency, which means the ratio of gross primary production to absorbed light. Authors derive its fractional reduction due to soil moisture (fLUE), separated from vapour pressure deficit and greenness changes, using artificial neural networks trained on eddy covariance data, multiple soil moisture datasets and remotely sensed greenness.

“This analysis reveals substantial impacts of soil moisture alone that reduce gross primary production by up to 40% at sites located in sub-humid, semi-arid or arid regions. For sites in relatively moist climates, authors find, paradoxically, a muted fLUE response to drying soil, but reduced fLUE under wet conditions.

“We show that accounting for soil moisture effects, in addition to vapour pressure deficit, is critical for the estimation of vegetation production across the globe and to quantify drought impacts”, said Dr. Benjamin Dr. Stocker from CREAF-CSIC Barcelona.

fLUE identifies substantial drought impacts that are not captured when relying solely on vapour pressure deficit and greenness changes and, when seasonally recurring, are missed by traditional, anomaly-based drought indices. Counter to common assumptions, fLUE reductions are largest in drought-deciduous vegetation, including grasslands.

“Our results indicate that local hydrological conditions are important for understanding drought impacts on vegetation production, highlighting the necessity to account for soil moisture limitation in terrestrial primary production data products, especially for drought-related assessments”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

Reference: Stocker, B.D., Zscheischler, J., Keenan, T.F., Prentice, I.C., Peñuelas, J., Seneviratne, S.I. 2018. Quantifying soil moisture impacts on light use efficiency across biomes. New Phytologist (2018) 218: 1430–1449. doi: 10.1111/nph.15123. doi: 10.1111/nph.15123

Afforestation neutralizes soil pH

Afforestation is a type of land use change project primarily designated for wood production, soil and water conservation, increasing carbon storage and mitigating climate change. This study shows that afforestation changes, moreover, soil pH, that is a key soil variable. Photo by: Pixabay

Soil pH, which measures the acidity or alkalinity of soils, is associated with many soil properties such as hydrolysis equilibrium of ions, microbial communities, and organic matter contents. Soil pH regulates soil biogeochemical processes and has cascading effects on terrestrial ecosystem structure and functions.

Afforestation has been widely adopted to increase terrestrial carbon sequestration and enhance water and soil preservation. However, the effect of afforestation on soil pH is still poorly understood and inconclusive.

In a new study in the journal Nature Communications scientists investigate the afforestation-caused soil pH changes with pairwise samplings from 549 afforested and 148 control plots in northern China, across different tree species and soil pH gradient.

Authors find significant soil pH neutralization by afforestation—afforestation lowers pH in relatively alkaline soils but raises pH in relatively acid soils. The soil pH thresholds (TpH), the point when afforestation changes from increasing to decreasing soil pH, are species-specific, ranging from 5.5 (Pinus koraiensis) to 7.3 (Populus spp.) with a mean of 6.3.

The study provides improved understandings on how afforestation impacts soil pH across a broad range of soil types and afforestation tree species, which is critical for developing climate change mitigation strategies and ecological sustainability plans.

“Our study indicates that afforestation has the potential to alleviate soil acidification caused by enhanced acidic deposition with the appropriate selection of tree species and thus could further increase ecosystem productivity and carbon sequestration”, said Dr. Songbai Hong from Sino-French Institute for Earth System Science, Peking University.

“Our findings indicate that afforestation can modify soil pH if tree species and initial pH are properly matched, which may potentially improve soil fertility and promote ecosystem productivity”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

According to the authors, further field studies are still needed to determine best tree species for afforestation according to soil properties, water availability and climate suitability, and designated ecosystem and socioeconomic goals.

Journal Reference: Hong, S., Piao, s., Chen, A., Liu, Y., Liu, L., Peng, S., Sardans, J., Sun, Y., Peñuelas, J., Zeng, H. 2017. Afforestation neutralizes soil pH. Nature Communications, (2018) 9:520. doi: 10.1038/s41467-018-02970-1.

The large mean body size of mammalian herbivores explains the productivity paradox during the last glacial maximum

Bison_pixabay_Jan2018 — Mammalian herbivores live in major terrestrial ecosystems on Earth. During the past decades, our understanding has increased about the important role of large mammalian herbivores (body mass >10 kg) in controlling vegetation structure and carbon and nutrient flows within ecosystems. Photo by: Pixabay

Large herbivores are a major agent in ecosystems, influencing vegetation structure and carbon and nutrient flows (shattering woody vegetation and consuming large amounts of foliage). Despite the non-negligible ecological impacts of large herbivores, most of the current DGVMs, or land surface models that include a dynamic vegetation module, lack explicit representation of large herbivores and their interactions with vegetation.

During the last glacial period, the steppe-tundra ecosystem prevailed on the unglaciated northern lands, hosting a high diversity and density of megafaunal herbivores. The apparent discrepancy between the late Pleistocene dry and cold climates and the abundant herbivorous fossil fauna found in the mammoth steppe biome has provoked long-standing debates, termed as “productivity paradox” by some paleontologists.

In a new study in the journal Nature Ecology and -Evolution scientists, aiming to address the productivity paradox, incorporated a grazing module in the ORCHIDEE-MICT DGVM model. “This grazing module is based on physiological and demographic equations for wild large grazers, describing grass forage intake and metabolic rates dependent on body size, and demographic parameters describing the reproduction and mortality rates of large grazers”, explained Dr. Dan Zhu from the Laboratoire des Sciences du Climat et de l’Environnement, LSCE CEA CNRS UVSQ, France.

In the study authors also extended the modelling domain to the globe for two distinct periods, present-day and the last glacial maximum (ca. 21 ka BP). The present-day results of potential grazer biomass, combined with an empirical land use map, infer a reduction of wild grazer biomass by 79-93% due to anthropogenic land replacement over natural grasslands.

For the last glacial maximum, authors find that the larger mean body size of mammalian herbivores than today is the crucial clue to explain the productivity paradox, due to a more efficient exploitation of grass production by grazers with a larger-body size. Evidences from fossil and extant mammal species have shown a long-term trend towards increasing body size in mammals throughout the Cenozoic, this indicates selective advantages of larger body sizes, such as larger guts of herbivores that allow microbes to break down low-quality plant materials, and higher tolerance to coldness and starvation. “Our results show quantitatively the importance of body size to explain the productivity paradox, as a larger-body size enables grazers to live on the mammoth steppe in substantial densities during the LGM, despite colder temperatures and shorter growing seasons than today”, said Dr. Philippe Ciais from the Laboratoire des Sciences du Climat et de l’Environnement, LSCE CEA CNRS UVSQ, France.

For the authors large herbivores might have fundamentally modified Pleistocene ecosystems; therefore, “to bring them into large-scale land surface models would help us better understand the intricate interactions among climate, plants and animals that shaped the biosphere”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

Journal Reference: Zhu, D., CIiais, P., Chang, J., Krinner, G., Peng, S., Viovy, N., Peñuelas, J., Zimov, S. 2018. The large mean body size of mammalian herbivores explains the productivity paradox during the last glacial maximum. Nature Ecology & Evolution

Mapping local and global variability in plant trait distributions

: Specific leaf area (SLA), and dry mass-based concentrations of leaf nitrogen (Nm) and phosphorus (Pm) are used in this study to better capture the response of the land surface component of the Earth System to environmental change. Image: Butler, E.E., et al. 2017. Proceedings of the National Academy of Sciences

Our ability to understand and predict the response of ecosystems to a changing environment depends on quantifying vegetation functional diversity. However, representing this diversity at the global scale is challenging. Typically, in Earth Systems Models, characterization of plant diversity has been limited to grouping related species into Plant Functional Types (PFTs), with all trait variation in a PFT collapsed into a single mean value that is applied globally.

In a new study in the journal Proceedings of the National Academy of Sciences authors created fine-grained global maps of plant trait distributions that can be applied to Earth System Models by using the largest global plant trait database and state of the art Bayesian modeling. “Here, we use an updated version of the largest global database of plant traits coupled with modern Bayesian spatial statistical modeling techniques to capture local and global variability in plant traits. This combination allows the representation of trait variation both within pixels on a gridded land surface as well as across global environmental gradients”, said Dr. Butler from Department of Forest Resources, University of Minnesota.

Focusing on a set of plant traits closely coupled to photosynthesis and foliar respiration – specific leaf area (SLA), and dry mass-based concentrations of leaf nitrogen (Nm) and phosphorus (Pm), authors characterize how traits vary within and among over 50,000 ~ 50 × 50 km cells across the entire vegetated land surface. “The importance of these traits (SLA, Nm, Pm) and the more advanced representation of functional diversity developed here may be used to better capture the response of the land surface component of the Earth System to environmental change”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

This endeavor advances prior trait mapping by generating global maps that preserve variability across scales by using modern Bayesian spatial statistical modeling in combination with a database over three times larger than previous analyses. “Our maps reveal that the most diverse grid cells possess trait variability close to the range of global PFT means”, said Dr. Butler from Department of Forest Resources, University of Minnesota.

Journal Reference: Butler, E.E., Datta, A., Flores-Moreno, H., Chen, M., Wythers, K.R., Fazayeli, F., Banerjee, A., Atkin, O.K., Kattge, J., Amiaud, B., Blonder, B., Boenisch, G., Bond-Lamberty, B., Brown, K.A., Byun, C., Campetella, G., Cerabolini, B.E.L., Cornelissen, J.H.C., Craine, J.M., Craven, D., de Vries, F.T., Díaz, S., Domingues, T., Forey, E., Gonzalez, A., Gross, N., Han, W., Hattingh, W.N., Hickler, T., Jansen, S., Kramer, K., Kraft, N.J.B., Kurokawa, H., Laughlin, D.C., Meir, P., Minden, V., Niinemets, Ü., Onoda, Y., Peñuelas, J., Read, Q., Valladares Ros, F., Sack, L., Schamp, B., Soudzilovskaia, N.A., Spasojevic, M.J., Sosinski, E., Thornton, P., van Bodegom, P.M., Williams, M., Wirth, C., Reich, P.B.. 2017. Mapping local and global variability in plant trait distributions. Proceedings of the National Academy of Sciences.

Atmospheric deposition, CO2, and change in the land carbon sink

Fum_bosc_Marcos_Agost2017 — The reduction in acidic deposition of nitrogen and Sulphur should lead to a slow recovery of forests to a pre-acid deposition state. Photo by Pixabay

Human activities result in increasing atmospheric concentrations of CO₂ that affects the terrestrial biosphere in multiple ways: warming the climate, increasing photosynthesis (CO₂ fertilization), decreasing transpiration by stimulating stomatal closure and changing the stoichiometry of carbon, nitrogen and phosphorus (C:N:P) in ecosystem carbon pools. Concentrations of atmospheric carbon dioxide (CO₂) have continued to increase whereas, due to air-quality policies, atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades.

Terrestrial ecosystems are key components of the global carbon cycle, as indicated by the fact that, since the 1960s, they have been sequestering an average of about 30% of the annual anthropogenic CO₂ emitted into the atmosphere.

In a new study in the journal Scientific Reports authors used time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models to end up finding that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011.

In this study, authors test the hypothesis that gross primary production, ecosystem respiration and the net C-sink strength (net land-atmosphere CO₂ flux) or net ecosystem production (NEP), have accelerated during the last two decades because of the increased atmospheric CO₂ concentrations and temperature, and because of the recovery from high loads of S deposition in Europe and North America. “We expected these deposition reductions to have modulated the biogeochemical effects of rising CO₂” added Dr. Marcos Fernández-Martínez from CREAF-CSIC Barcelona

Statistical models indicated that increasing atmospheric CO₂ was the most important factor driving the increasing strength of carbon sinks in these forests. Authors also found that the reduction of sulphur deposition in Europe and the USA led to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, the study shows that trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. “Our findings support the hypothesis of a general CO₂-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona

“Our results show the need to include the effects of changing atmospheric composition, beyond CO₂, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling”, said Dr. Fernández-Martínez from CREAF-CSIC Barcelona

This study was funded by the European Research Council Synergy grant ERC-2013-SyG-610028, the Spanish Government project CGL2016-79835-P and the Catalan Government grant FI-2013

Journal Reference: Fernández-Martínez, M., Vicca, S., Janssens, I.A., Ciais, P., Obersteiner, M., Bartrons, M., Sardans, J., Verger, A., Canadell, J.G., Chevallier, F., Wang, X., Bernhofer, C., Curtis, P.S., Gianelle, D., Grünwald, T., Heinesch, B., Ibrom, A., Knohl, A., Laurila, T., Law, B.E., Limousin, J.M., Longdoz, B., Loustau, D., Mammarella, I., Matteucci, G., Monson, R.K., Montagnani, L., Moors, E.J., Munger, J.W., Papale, D., Piao, S.L., Peñuelas, J. 2017. Atmospheric deposition, CO2, and change in the land carbon sink. Scientific Reports 7, 9632.

β-Ocimene, a Key Floral and Foliar Volatile Involved in Multiple Interactions between Plants and Other Organisms

Farre_Armengol_PR_agost2017 — Plants generally synthesize and emit species-specific floral volatile organic compounds (VOCs) mixtures to attract pollinators by mixing several of these common VOCs. Photo by Pexels

More than 1700 volatile organic compounds (VOCs) have been identified in the floral scents of flowering plants. These VOCs are not equally distributed across the phylogeny of flowering plants, so that the commonness and predominance of these compounds in floral scents varies widely among species. Common floral VOCs have a widespread phylogenetic distribution, which means that they are present in the floral scents of many species from different plant families. Instead, less common floral VOCs are only present in plants that are pollinated by specific pollinator groups with specific innate preferences for those VOCs.

β-Ocimene is a very common plant volatile released in important amounts from the leaves and flowers of many plant species. This acyclic monoterpene can play several biological functions in plants, by potentially affecting floral visitors and also by mediating defensive responses to herbivory.

In a new study in the journal Molecules authors indicated that the ubiquity and high relative abundance of β-ocimene in the floral scents of species from most plant families and from different pollination syndromes (ranging from generalism to specialism) strongly suggest that this terpenoid may play an important role in the attraction of pollinators to flowers.

In this study authors compiled abundant evidence from published studies that supports β-ocimene as a generalist attractant of a wide spectrum of pollinators. They found no studies testing behavioural responses of pollinators to β-ocimene, that could directly demonstrate or deny the function of β-ocimene in pollinator attraction; but “several case studies support that the emissions of β-ocimene in flowers of different species follow marked temporal and spatial patterns of emission, which are typical from floral volatile organic compound (VOC) emissions that are involved in pollinator attraction”, said Dr. Gerard Farré-Armengol from CREAF-CSIC Barcelona, now in the University of Salzburg.

Furthermore, important β-ocimene emissions are induced from vegetative plant tissues after herbivory in many species, which have relevant functions in the establishment of tritrophic interactions. Authors thus conclude that β-ocimene is a key plant volatile with multiple relevant functions in plants, depending on the organ and the time of emission.

Experimental behavioural studies on pure β-ocimene conducted with pollinating insects will be necessary to prove the assumptions made here. “In view of the presented indirect evidences, we strongly encourage the inclusion of β-ocimene alone or in combination with other floral volatiles in coupled gas chromatography electroantennographic detection (GC-EAD) analyses and behavioural tests when conducting future studies in order to provide a solid experimental proof for the assumptions made in the study”, said Prof. Josep Peñuelas from CREAF-CSIC Barcelona.

This study was funded by the European Research Council Synergy grant ERC-2013-SyG-610028, the Spanish Government project CGL2016-79835-P and the Catalan Government grant FI-2013

Journal Reference: Farré-Armengol, G., Filella, I., Llusià, J., Peñuelas, J. 2017. β-Ocimene, a Key Floral and Foliar Volatile Involved in Multiple Interactions between Plants and Other Organisms. Molecules 2017, 22, 1148; doi: 10.3390/molecules22071148.

Next 10 years critical for achieving climate change goals

Carbon dioxide (CO₂) and other greenhouse gases in the atmosphere can be reduce in two ways — by cutting our emissions, or by removing it from the atmosphere, for example through plants, the ocean, and soil.

In a new study, published in the journal Nature Communications, researchers from the International Institute for Applied Systems Analysis (IIASA) used a global model of the carbon system that accounts for carbon release and uptake through both natural and anthropogenic activities.

“The study shows that the combined energy and land-use system should deliver zero net anthropogenic emissions well before 2040 in order to assure the attainability of a 1.5°C target by 2100,” says IIASA Ecosystems Services and Management Program Director Michael Obersteiner, a study coauthor.

According to the study, fossil fuel consumption would likely need to be reduced to less than 25% of the global energy supply by 2100, compared to 95% today. At the same time, land use change, such as deforestation, must be decreased. This would lead to a 42% decrease in cumulative emissions by the end of the century compared to a business as usual scenario.

“This study gives a broad accounting of the carbon dioxide in our atmosphere, where it comes from and where it goes. We take into account not just emissions from fossil fuels, but also agriculture, land use, food production, bioenergy, and carbon uptake by natural ecosystems,” explains World Bank consultant Brian Walsh, who led the study while working as an IIASA researcher.

The compares four different scenarios for future energy development, with a range of mixtures of renewable and fossil energy. In a “high-renewable” scenario where wind, solar, and bioenergy increase by around 5% a year, net emissions could peak by 2022, the study shows. Yet without substantial negative emissions technologies, that pathway would still lead to a global average temperature rise of 2.5°C, missing the Paris Agreement target.

Walsh notes that the high-renewable energy scenario is ambitious, but not impossible — global production of renewable energy grew 2.6% between 2013 and 2014, according to the IEA. In contrast, the study finds that continued reliance on fossil fuels (with growth rates of renewables between 2% and 3% per year), would cause carbon emissions to peak only at the end of the century, causing an estimated 3.5°C global temperature rise by 2100.

The authors note that not only the mix of energy matters, but also the overall amount of energy consumed. The study also included ranges for high energy consumption and low energy consumption.

The study adds to a large body of IIASA research on climate mitigation policy and the chances of achieving targets.

“Earlier work on mitigation strategies by IIASA has shown the importance of demand-side measures, including efficiency, conservation, and behavioral change. Success in these areas may explain the difference between reaching 1.5C instead of 2C,” says IIASA Energy Program Director Keywan Riahi, who also contributed to the new work.

A new model

The study is one of the first published results from the newly developed FeliX model, a system dynamics model of social, economic, and environmental earth systems and their interdependencies. The model is freely available for download and use at http://www.felixmodel.com/.

“Compared to other climate and integrated assessment models, the FeliX model is less detailed, but it provides a unique systemic view of the whole carbon cycle, which is vital to our understanding of future climate change and energy,” says IIASA Ecosystem Services and Management Program Director.

This study received support from the European Research Council Synergy grant ERC-2013-SyG-610028

Reference:

Brian Walsh, Philippe Ciais, Ivan A. Janssens, Josep Peñuelas, Keywan Riahi, Felicjan Rydzak, Detlef P. van Vuuren, Michael Obersteiner. Pathways for balancing CO2 emissions and sinks. Nature Communications, 2017; 8: 14856 DOI: 10.1038/NCOMMS14856

Científics alerten a la revista Scientific Reports de l’extensa acumulació de contaminants orgànics a la vegetació arreu del planeta

Un article publicat a la revista Scientific Reports alerta d’una extensa acumulació de contaminants orgànics a la vegetació arreu del planeta. L’article ha recollit, analitzat i comparat les dades de 79 estudis sobre aquesta matèria publicats entre 1979 i 2015, més de la meitat dels quals incloïen resultats d’àrees rurals i remotes.

El treball l’ha elaborat la doctora en Biologia i professora de la Universitat de Vic – Universitat Central de Catalunya Mireia Bartrons, juntament amb Jordi Catalan i Josep Peñuelas, ambdós investigadors membres del CREAF, el centre públic de recerca en ecologia terrestre i anàlisi del territori que genera coneixement i metodologies per a la conservació, la gestió i l’adaptació del medi natural al canvi global.

See more at: http://www.uvic.cat/cient%C3%ADfics-alerten-la-revista-scientific-reports-de-l%E2%80%99extensa-acumulaci%C3%B3-de-contaminants-org%C3%A0nics-la#sthash.urpo4Pl8.dpuf

See more at: http://www.uvic.cat/

IMBALANCE-P article on how ocean acidification will impact marine life

A new analysis by Ligia Azevedo from IIASA and collaborators provides a holistic assessment of the impacts of climate change and ocean acidification on marine organisms including coral, shellfish, sea urchins, and other calcifying species. Please, find more detailed information here.