2 Recent Papers Confirm Natural Cycles Are Indisputable, Powerful Climate Drivers
Written by Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
First paper: Insidious pre-industrial warm phase: 4000 years ago glaciers in Norway had almost completely melted away. The University of Bergen in Norway reported 14 February 2017 on the climate in Norway 4000 years ago, when in the summertime it was on average two to three degrees warmer than today. Most glaciers in the country at the time had almost completely melted away and gone. Instead of examining these what for many are unexpected warm phases, the team of authors in the press release chose to focus the public’s attention on concern and fear for the future.
And this time – for sure – the glaciers are never coming back again, even though they did so after the last warm phase.
Instead the scientists worry about the hydropower business. No glacier, no hydro-power. What follows is the press release:
Norwegian ice cap ‘exceptionally sensitive’ to climate change
How will future climate change affect our glaciers? By looking into the past 4000 years, a new study lead by Henning Åkesson at the Bjerknes Centre finds an ice cap in southern Norway to be ‘exceptionally sensitive’ to climate change.
Hardangerjøkulen is over 300 m thick, but has a flat topography an is vulnerable for rising temperatures. Photo: Atle Nesje, 2015
The team of researchers from the Bjerknes Centre for Climate Research, the Netherlands and the US took a glance into the past to understand how the ice cap Hardangerjøkulen in southern Norway responds to climate change. The authors simulated the history of the ice cap over the last 4000 years, from a period called the mid-Holocene, when summer temperature at high northern latitudes were two to three degrees warmer than today. Most if not all glaciers in Norway melted away during this period, Hardangerjøkulen included.
Henning Åkesson, a PhD candidate at the Bjerknes Centre and University of Bergen, used a glacier computer model developed at NASA-Jet Propulsion Laboratory and University of California, Irvine to simulate Hardangerjøkulen’s history. To inform model simulations, he used information on past climates and glacier variations from lake sediments receiving meltwater from the ice cap.
Contest between snow and snowmelt
“Present day Hardangerjøkulen is in a very vulnerable state, and our study of its history over the last several thousand years shows that the ice cap may change drastically in response to relatively minor changes in climate conditions”, says Åkesson. Every year, snow covers a glacier in winter, and melts away to a varying extent the following summer. At a certain altitude on the glacier, the competition between snow accumulation and snowmelt is balanced; glaciologists call this the Equilibrium Line Altitude (ELA). “What is special with Hardangerjøkulen and other similar ice caps”, Åkesson explains, “is their flat topography. Anyone skiing up Hardangerjøkulen to celebrate Norway’s national day on May 17th can testify; first it’s steep, but once you’re higher up things get a lot easier.”
A large part of Hardangerjøkulen’s area is close to the present ELA. This means that a small change in the competition between winter snow and summer melt will affect a very large part of the ice cap. Åkesson says “the topography and present climate is such that we soon expect yearly net melt over the entire ice cap. This has already happened a few times in recent years. In the near future we expect this to occur much more often, and with this, the demise of Hardangerjøkulen will accelerate.” “Today the ice is more than 300 m thick at places, which may sound like a lot. But the implication of our study is that if climate warming continues, this ice cap may disappear before the end of this century. I don’t think most people realize how fast glaciers can change, maybe not even us as scientists,” says Åkesson.
“The economic and cultural implications of disappearing glaciers in Norway are considerable for tourism, natural heritage and the hydropower industry”, Kerim Hestnes Nisancioglu at the Bjerknes Centre, co-author of the study, adds. Practically all of Norway’s electricity is generated from hydropower, of which 15 % depend on glacier meltwater. “The hydropower industry needs to plan for these changes, and we need to work together to find out how fast this transition will happen”, Nisancioglu says. What is more, “if Hardangerjøkulen melts away completely, it would not be able to grow back again given today’s climate”, Åkesson concludes. The study was published in the open-access journal The Cryosphere on January 27th. Read the full study here.
Reference: Åkesson, H., Nisancioglu, K. H., Giesen, R. H., and Morlighem, M.: Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change, The Cryosphere, 11, 281-302, doi:10.5194/tc-11-281-2017, 2017
By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt (German text translated/edited by P Gosselin)
At the end of January 2017 a team of scientists led by Fusa Miyake described in PNAS an unexpected solar event on the sun that ended up being registered in 7000 year old tree rings. What follows is the press release from Nagoya University:
What Happened to the Sun over 7,000 Years Ago? Analysis of tree rings reveals highly abnormal solar activity in the mid-Holocene
An international team led by researchers at Nagoya University, along with US and Swiss colleagues, has identified a new type of solar event and dated it to the year 5480 BC; they did this by measuring carbon-14 levels in tree rings, which reflect the effects of cosmic radiation on the atmosphere at the time. They have also proposed causes of this event, thereby extending knowledge of how the sun behaves.
When the activity of the sun changes, it has direct effects on the earth. For example, when the sun is relatively inactive, the amount of a type of carbon called carbon-14 increases in the earth’s atmosphere. Because carbon in the air is absorbed by trees, carbon-14 levels in tree rings actually reflect solar activity and unusual solar events in the past. The team took advantage of such a phenomenon by analyzing a specimen from a bristlecone pine tree, a species that can live for thousands of years, to look back deep into the history of the sun.
“We measured the 14C levels in the pine sample at three different laboratories in Japan, the US, and Switzerland, to ensure the reliability of our results,” A. J. Timothy Jull of the University of Arizona says. “We found a change in 14C that was more abrupt than any found previously, except for cosmic ray events in AD 775 and AD 994, and our use of annual data rather than data for each decade allowed us to pinpoint exactly when this occurred.”
The team attempted to develop an explanation for the anomalous solar activity data by comparing the features of the 14C change with those of other solar events known to have occurred over the last couple of millennia. “Although this newly discovered event is more dramatic than others found to date, comparisons of the 14C data among them can help us to work out what happened to the sun at this time,” Fusa Miyake of Nagoya University says. She adds, “We think that a change in the magnetic activity of the sun along with a series of strong solar bursts, or a very weak sun, may have caused the unusual tree ring data.” Although the poor understanding of the mechanisms behind unusual solar activity has hampered efforts to definitively explain the team’s findings, they hope that additional studies, such as telescopic findings of flares given off by other sun-like stars, could lead to an accurate explanation.
The article “Large 14C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene” was published in PNAS at: www.pnas.org/cgi/doi/10.1073/pnas.1613144114.”
Could this solar event also have left climatic traces?
– See more at: http://notrickszone.com