When the summer rains in China are weak, they are strong in Australia, and vice versa – scientists have discovered a previously unknown see-saw relationship between these two monsoon regions. This effect does not occur from one year to another, but on decadal and centennial time scales. To detect the pattern, the team developed a novel mathematical method to analyze traces of climatic events of the past 9000 years archived in ancient dripstones from caves.
The regional monsoon has huge effects on agriculture and hence on the livelihoods of half of the world’s population, including India and Indonesia. Understanding how seasonal periods of rainfall in the Northern and Southern Hemispheres of our planet are linked is important for assessing possible long-distance effects of climate change.
“We’ve been surprised by how clearly the ups and downs of precipitation in East Asia on the one hand and Australia on the other hand are opposed, it’s really a giant see-saw,” says Deniz Eroglu from the Potsdam Institute for Climate Impact Research (PIK) and University of São Paulo, lead author of the study to be published in Nature Communications. “We needed to cut through the data clutter to detect this pattern. While our method of sophisticated statistical time series data analysis might seem quite complicated, our findings have substantial real-world consequences.”
Data from caves in China and Australia – these countries are most affected
Australia, just like China, heavily depends on the monsoon summer rains. “Both countries have experienced drier and wetter periods in the past. For instance the Northwest of Australia’s tourism and agriculture industries are vulnerable to flooding and bush fires, so any change from the current precipitation pattern will have huge impacts for the people living here,” says co-author Thomas Stemler from the University of Western Australia.
“However, this is an issue way beyond the region – in fact, the East-Asian-Indonesian-Australian summer monsoon provides a heat source that drives global circulation of airstreams during what is the winter season in the US, Russia and Europe. It will be exciting to investigate how the see-saw we found may be affecting these far-away parts of the world.”
Since there are no direct records of monsoon dynamics over past millennia, the scientists need to work with indirect data evidence. “Dripstones in ancient caves are amazing witnesses of the Earth’s past. Since they’re growing just fractions of a millimeter per year, we can see changes in the chemical composition over time from one layer to another,” says co-author Norbert Marwan from PIK who himself explored various caves, for instance in India. For the new study, the team used data from Dongge Cave in Southern China and cave KNI-51 in Northwestern Australia.
“Though it might seem challenging to climb into the caves to access the dripstones,” says Marwan, “the real challenge is to decrypt the information they carry – analyzing thousands of isotope samples and attributing them to specific climatic conditions. For this, we need sophisticated statistics.” A key partner in this process has been the Institute for Geology, Mineralogy & Geophysics at Ruhr-Universität Bochum.
Mechanics of the heavens are a driver, but human-made warming can change the dynamics
“The monsoon see-saw is likely driven by factors humans cannot influence, including the tilt of our Earth’s axis and solar activity, so that’s celestial mechanics,” says co-author Jürgen Kurths, co-chair of PIK’s research domain Transdisciplinary Concepts and Methods.
“However, disturbing circulation and precipitation patterns is something we unfortunately can do and already are doing by emitting greenhouse gases and thereby warming our planet. Understanding the natural East-Asian-Australian monsoon variability will help us to better understand certain human-caused climate risks in the future.”
Article: Deniz Eroglu, Fiona H. McRobie, Ibrahim Ozken, Thomas Stemler, Karl-Heinz Wyrwoll, Sebastian F. M. Breitenbach, Norbert Marwan, Jürgen Kurths (2016): See-saw relationship of the Holocene East Asian-Australian summer monsoon. Nature Communications [10.1038/NCOMMS12929]
Weblink to the article once it is published: http://dx.doi.org/10.1038/NCOMMS12929
For further information please contact:
PIK press office
Phone: +49 331 288 25 07
Mareike Schodder | Potsdam-Institut für Klimafolgenforschung
Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck
Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
24.05.2017 | Physics and Astronomy
24.05.2017 | Physics and Astronomy
24.05.2017 | Event News