New research from the Niels Bohr Institute at the University of Copenhagen shows that it may be due to an accumulation of different chaotic influences and as a result would be difficult to predict. The results have just been published in Geophysical Research Letters.
For millions of years the Earth's climate has alternated between about 100,000 years of ice age and approximately 10-15,000 years of a warm climate like we have today. The climate change is controlled by the Earth's orbit in space, that is to say the Earth's tilt and distance from the sun. But there are also other climatic shifts in the Earth's history and what caused those?
Dramatic climate change of the past
By analysing the ice cores that are drilled through the more than three kilometer thick ice sheet in Greenland, scientists can obtain information about the temperature and climate going back around 140,000 years.
The most pronounced climate shifts besides the end of the ice age is a series of climate changes during the ice age where the temperature suddenly rose 10-15 degrees in less than 10 years. The climate change lasted perhaps 1000 years, then - bang – the temperature fell drastically and the climate changed again. This happened several times during the ice age and these climate shifts are called the Dansgaard-Oeschger events after the researchers who discovered and described them. Such a sudden, dramatic shift in climate from one state to another is called a tipping point. However, the cause of the rapid climate change is not known and researchers have been unable to reproduce them in modern climate models.
The climate in the balance
"We have made a theoretical modelling of two different scenarios that might trigger climate change. We wanted to investigate if it could be determined whether there was an external factor which caused the climate change or whether the shift was due to an accumulation of small, chaotic fluctuations", explains Peter Ditlevsen, a climate researcher at the Niels Bohr Institute.
He explains that in one scenario the climate is like a seesaw that has tipped to one side. If sufficient weight is placed on the other side the seesaw will tip – the climate will change from one state to another. This could be, for example, an increase in the atmospheric content of CO2 triggering a shift in the climate.
In the second scenario the climate is like a ball in a trench, which represents one climate state. The ball will be continuously pushed by chaos-dynamical fluctuations such as storms, heat waves, heavy rainfall and the melting of ice sheets, which affect ocean currents and so on. The turmoil in the climate system may finally push the ball over into the other trench, which represents a different climate state.
Peter Ditlevsen's research shows that you can actually distinguish between the two scenarios and it was the chaos-dynamical fluctuations that were the triggering cause of the dramatic climate changes during the ice age. This means that they are very difficult to predict.
Warm future climate
But what about today – what can happen to the climate of the future? "Today we have a different situation than during the ice age. The Earth has not had such a high CO2 content in the atmosphere since more than 15 million years ago, when the climate was very warm and alligators lived in England. So we have already started tilting the seesaw and at the same time the ball is perhaps getting kicked more and could jump over into the other trench. This could mean that the climate might not just slowly gets warmer over the next 1000 years, but that major climate changes theoretically could happen within a few decades", estimates Peter Ditlevsen, but stresses that his research only deals with investigating the climate of the past and not predictions of the future climate.
Peter Ditlevsen, climate researcher, PhD. Dr. Scient., Associate professor, Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, +45 3532-0603, +45 2875-0603, firstname.lastname@example.org
Link to article in Geophysical Research Letters: http://www.agu.org/journals/gl/papersinpress.shtml#id2010GL044486
Gertie Skaarup | EurekAlert!
UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine
Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences