Abbott B.W.,French National Center for Scientific Research |
Abbott B.W.,University of Alaska Fairbanks |
Jones J.B.,University of Alaska Fairbanks |
Schuur E.A.G.,Northern Arizona University |
And 103 more authors.
Environmental Research Letters | Year: 2016
As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced. © 2016 IOP Publishing Ltd.
Kharuk V.I.,Siberian Federal University |
Ranson K.J.,NASA |
Im S.T.,Siberian State Aerospace University |
Petrov I.A.,Sukachev Institute of Forest
Environmental Research Letters | Year: 2015
Aim: estimation of larch (Larix gmelinii) growth response to current climate changes. Location: permafrost area within the northern part of Central Siberia (∼65.8°N, 98.5°E). Method: analysis of dendrochronological data, climate variables, drought index SPEI, GPP (gross primary production) and EVI vegetation index (both Aqua/MODIS satellite derived), and soil water content anomalies (GRACE satellite measurements of equivalent water thickness anomalies, EWTA). Results: larch tree ring width (TRW) correlated with previous year August precipitation (r = 0.63), snow accumulation (r = 0.61), soil water anomalies (r = 0.79), early summer temperatures and water vapor pressure (r = 0.73 and r = 0.69, respectively), May and June drought index (r = 0.68-0.82). There are significant positive trends of TRW since late 1980 s and GPP since the year 2000. Mean TRW increased by about 50%, which is similar to post-Little Ice Age warming. TRW correlated with GPP and EVI of larch stands (r = 0.68-0.69). Main conclusions: within the permafrost zone of central Siberia larch TRW growth is limited by early summer temperatures, available water from snowmelt, water accumulated within soil in the previous year, and permafrost thaw water. Water stress is one of the limiting factors of larch growth. Larch TRW growth and GPP increased during recent decades. © 2015 IOP Publishing Ltd.
PubMed | University of Barcelona, Siberian Federal University, University of Lleida, Pyrenean Institute of Ecology and 3 more.
Type: Journal Article | Journal: Proceedings of the National Academy of Sciences of the United States of America | Year: 2016
Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales ( 1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales.
News Article | February 21, 2017
The reason for the scientific interest in the eruption of the volcano Samalas is that it is considered the largest in the last thousand years throwing as much as 10 cubic miles of rock into the atmosphere, which lead to destroying Pamatan, the capital of the ancient Kingdom of Lombok. The ice cores in Greenland evidence this as the study of their chemical composition in the 1980s pointed out that there was one of the largest in history volcanic eruptions in the XIII century. The volcano itself has long remained unknown, and scientists have searched for it all over the world. After studying the writings on the palm leaves in Old Javanese, in 2003 Franck Lavigne found that this volcano could be Samalas located on the island of Lombok in Indonesia. Lake Segara Anak formed in the crater later and made it difficult to detect the volcano. One of the existing scientific theories in climatology over the impact of the eruption Samalas volcano on global climatic conditions in the XIII century says that this event may be the cause of the abnormal cold weather (chronicles describe the following year as the "year without a summer"), widespread crop failure, famine, and social upheavals in Europe after 1257. In January 2017 a paper under the title "Climate response to the Samalas volcanic eruption in 1257 revealed by proxy records" was published in the British scientific journal Nature Geoscience with high impact factor among the nature journals (12.508 for 2 years). The international writing team includes scientists from Switzerland, Russia, France, Britain, the United States, China and Canada. Vladimir Myglan (School of the Humanities of Siberian Federal University) and Olga Churakova (Sidorova) (University of Bern, Institute of Geological Sciences, V.N. Sukachev Institute of Forest, SB RAS) are the Krasnoyarsk scientists who took part in the research. In the scientific world, the leading hypothesis is that the eruption of the volcano Samalas in 1257 was the cause of the Little Ice Age, and more than a hundred years of social crisis in Europe. Based on the analysis of reliable sources the paper refutes this hypothesis. The international team of scientists base their studies on the chronicles of European cities (Speyer, Worms and others) and Siberia, chronicles of harvests and climate data of the annual rings of trees. During the interdisciplinary analysis of data sources, it was found that the impact of the volcanic eruption Samalas on the European climate and the severe cooling after 1257 is greatly exaggerated as the heterogeneity of climate change occurs in the places of distribution of volcanic sediments. Vladimir Myglan: "Western Europe, Siberia and Japan experienced the strongest cooling, which coincided with warmer than normal conditions in Alaska and Northern Canada. It is assumed that in North America volcanic radiation was modeled on the positive vibrations of the warm phase of the El Niño. Historical data confirm a severe famine in England and Japan, but it had started before the eruption. We believe that the eruption of the volcano Samalas only aggravated an existing crisis but it was not the cause".
Huttich C.,Friedrich - Schiller University of Jena |
Schmullius C.C.,Friedrich - Schiller University of Jena |
Thiel C.J.,Friedrich - Schiller University of Jena |
Bartalev S.,Space Research Institute |
And 4 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2012
ZAPÁS investigates and cross validates methodologies using both Russian and European Earth observation data to develop procedures and products for forest resource assessment and monitoring. Products include biomass change maps for the years 2007 to 2009 on a local scale, a biomass and improved land cover map on the regional scale as input to a carbon accounting model. The geographical focus of research and development is Central Siberia, which contains two administrative districts of Russia, namely Krasnoyarsk Kray and Irkutsk Oblast. The results of the terrestrial ecosystem full carbon accounting are addressed to the Federal Forest Agency as federal instance. The high resolution products comprise biomass and change maps for selected local sites. These products are addressed to support the UN FAO Forest Resources Assessment as well as the requirements of the local forest inventories. © 2012 IEEE.