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
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research