Florian Hofhansl

Tropical Ecosystem Research

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Amazonas-Regenwald: Welche Blüten der Klimawandel treibt

Download von http://www.picturedesk.com am 30.05.2017 (15:32).
View from the ATTO tower at the ATTO research center in the rain forest in Manaus, Brazil, 7 November 2016. PHOTO: GEORG ISMAR/dpa – 20161107_PD13343

Der Klimawandel macht auch vor dem Amazonas-Regenwald nicht halt. Ein internationales Forscherteam ergründet nun, wie seine Bäume darauf reagieren Manaus/Wien – (derstandard.at›WissenschaftForschung Spezial, Text von Bernadette Strohmaier, 12.6.2017)


Amazon Rainforest Losing Its Ability to Store Carbon

absorb carbon

For years climate skeptics have argued that increased levels of CO2 won’t be as severe as anticipated, as trees will grow bigger and faster in the presence of elevated CO2 thus increasing their capacity to sequester it. However, a study of the biomass dynamics of the Amazon rainforest published this week in Nature has put this argument to bed once and for all.

The 30 year study found that while trees are being seen to grow faster as CO2 levels increase, the rainforest has lost almost half its capacity to sequester and store CO2. This is on account of the fact that faster living is accompanied by earlier dying, and with trees dying younger than ever before their ability to act as a carbon sink is being diminished.

These findings, of over 100 researchers led by a team in the University of Leeds, revealed that rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. The study focused on 321 forest plots comprising 200,000 trees, and recorded rates of tree deaths and growth and the appearance of new trees. The analysis indicates that the surge in the rate of trees dying across the Amazon is a consequence of growth stimulation from unprecedented elevations of atmospheric CO2.

According to lead author Dr Roel Brienen, ‘climate change models that include vegetation responses assume that as long as carbon dioxide levels keep increasing, then the Amazon will continue to accumulate carbon. Our study shows that this may not be the case and that tree mortality processes are critical in this system’.

This latest research contradicts the projections of many climate models in regard to vegetation, and undermines the assumption that our global forests will continue to act as a COsink in the face of continued elevations.

With global pressure to reduce greenhouse gas emissions at an all-time high, this research adds to the barrage of evidence reinforcing the urgent need to take immediate action against human-induced climate change.

Project analyses the impact of increased levels of CO2 to the Amazon Rainforest

increased levels of CO2 amazon

In order to analyse the effects that the rising global CO2 levels have on the Amazon region, caused mainly by the burning of fossil fuels, the Brazilian government created a project named “Amazon Face” in partnership with the Inter-American Development Bank (IDB) and the Foundation for Research Support of the State of Amazonas (Fapeam).

“The problems are not only restricted to the Amazon region, but there are also regional and global consequences” – Carlos Alberto Quesada

The project will increase the concentration of CO2 by 50%, meaning it will reach 600 parts per million (ppm), in plots of forests 30 metres in diameter. The goal is to see to what extent fertilisation with an extra supply of CO2, which is used in the photosynthesis process of plants, increases the resilience of the forest; that is, its ability to compensate for adverse factors such as warming temperatures and changes in rainfall. “The problems are not only restricted to the Amazon region, but there are also regional and global consequences” – Carlos Alberto Quesada 

The experiment will be implemented in a forest area located about 60 kilometres to the north of Manaus, the capital of the Brazilian Amazonas State, and run by the National Institute for Amazonian Research (INPA). The first phase of the project, budgeted at $11 million, is due to start in 2017. The second phase, which will last for ten years, is budgeted at $78 million.

“Is it an expensive project? Yes, but how much is knowing more about the future of the Amazon worth? Whether it will be a scenario of sustainability or catastrophe?”, questioned the forestry engineer and researcher at INPA, Carlos Alberto Quesada, who is one of the scientific coordinators of the experiment. He also mentioned the increase in frequency of fires, damage to agriculture and difficulties in infrastructure projects planned for the region. “The problems are not only restricted to the Amazon region, but there are also regional and global consequences,” he warned.

increased levels of CO2 amazon

The Amazon Rainforest

“Talking about Amazon Face is, in a sense, speaking of the importance of the Amazon to Brazil and to the world,” said Lapola. “It contains perhaps the planet’s greatest biodiversity and plays an important role in the carbon cycle – stocking 90 billion tons of carbon – and in the hydrological cycles, as it has a basin that contributes with a significant amount of fresh water to the oceans.”

The researcher pointed out that climate change puts both of these natural processes and the lives of around 25 million people who inhabit the region at risk. CO2 is considered to be the main driver of this phenomenon and since the beginning of the industrial revolution, the amount of CO2 in the atmosphere has been increasing. According to projections released by the Intergovernmental Panel on Climate Change (IPCC), this trend will not be reversed until the end of the century.

The Environmentalist David Lapola, from the Paulista State Univeristy (UNESP) in Brazil, observed that by only considering the indirect effects of climate change (increase in temperature and disturbance of the rainfall cycle), the current projection models for the Amazon predict an increase in areas of savanna and dry forest. “But this is largely speculative. We have no empirical knowledge about this effect,” he pointed out.

Amazon FACE – “Experiment in the Amazon forest will test the reaction to global warming”

To find an answer to the question if global warming might provide a solution to one of the problems it creates, a team of scientists started investigations for what may be the most ambitious experiment the Amazon forest has seen in some 20 years. Ecologists are hoping the project, called Amazon FACE (Free-Air CO2 Enrichment), can tell them whether the forest will survive the drought that global warming is expected to cause.


Study set-up of the Amazon FACE project

Project Homepage: https://www.inpa.gov.br/amazonface/

Medienportal Universität Wien

Tropische Waldökosysteme bedecken weniger als zwölf Prozent der gesamten Landfläche der Welt und spielen doch eine der Hauptrollen im globalen Kohlenstoff- und Wasserkreislauf. Ein Team der Universität Wien publiziert ein neues Prognosemodell zur Entwicklung unserer Regenwälder im Klimawandel. Tropische Wälder sind nicht nur wichtig, weil sie mehr als die Hälfte der weltweit vorkommenden Pflanzen- und Tierarten beherbergen. Sie beinhalten auch über ein Viertel des global in pflanzlicher Biomasse gespeicherten Kohlenstoffs und gelten daher als sogenannte “Kohlenstoff-Senken”. Dabei spielen die Regenwaldbäume eine besondere Rolle: Sie können Kohlenstoff langfristig in ihrer Biomasse speichern – manche Arten mehr, manche weniger – und damit den Anteil des klimaaktiven Treibhausgases Kohlendioxid in der Atmosphäre verringern. “Der Verlust tropischer Regenwälder hat daher einen immensen Einfluss auf die globale Biodiversität und das Weltklima”, so der Ökosystemforscher Florian Hofhansl, Doktorand in der Forschungsgruppe von Wolfgang Wanek am Department für Mikrobiologie und Ökosystemforschung der Universität Wien.


Link to article: http://medienportal.univie.ac.at/uniview/forschung/detailansicht/artikel/klimawandel-szenarien-fuer-den-regenwald/

EGU 2014 conference meeting, Vienna, Austria

EGU, the European Geosciences Union, is Europe’s premier geosciences union, dedicated to the pursuit of excellence in the geosciences and the planetary and space sciences for the benefit of humanity, worldwide. It was established in September 2002 as a merger of the European Geophysical Society (EGS) and the European Union of Geosciences (EUG), and has headquarters in Munich, Germany. The EGU General Assembly 2014 was held at the Austria Center Vienna (ACV) in Vienna, Austria, from 27 April – 02 May 2014.


Link to article: http://meetingorganizer.copernicus.org/EGU2014/EGU2014-10223.pdf


Link to article: http://meetingorganizer.copernicus.org/EGU2014/EGU2014-10585.pdf