Europes Little Ice Age coincided with low solar activity.
Pieter Brueghels painting The Census at Bethlehem.
A solar slump may have chilled the Northern Hemisphere.
The flickering sun may cause rapid climate change, according to a new comparison of climate records. A 200-year cold snap 10, 300 years ago seems to have coincided with a passing slump in the sun’s activity1.
Svante Bjorck of Lund University in Sweden and colleagues looked at sediments in Lake Starvatn on the Faroe Islands and in the Norwegian Sea, the width of growth rings in ancient German pine trees, and ancient ice drilled from deep within the Greenland ice sheet.
Bjorck and colleagues propose that a weakening of solar activity may have caused this mini chill. It coincided, they find, with a large increase in the amount of beryllium-10 trapped in Greenland ice - evidence of a solar flicker.
This radioactive form of beryllium is produced when cosmic rays from space collide with nitrogen and oxygen atoms in the atmosphere. The magnetic field around the Earth protects the planet from cosmic rays. This field is stronger when the sun is more active - emitting more ultraviolet radiation and displaying more sunspots - so fewer cosmic rays can penetrate.
The proposed relationship between solar activity and climate change is controversial, partly because some have tried to pin modern-day global warming on it rather than on a human-induced greenhouse effect.
There is evidence, however, linking changes in solar activity to climate fluctuations in the more recent past. Abnormally high activity around AD 1100-1250, for example, has been mooted as the cause of a period of warming in medieval Europe. And the ’Little Ice Age’ between the sixteenth and eighteenth centuries coincided with a period of low solar activity.
The most pronounced climate swings, such as ice ages, happen slowly and last a long time - 100,000 years or so. Gradual, periodic changes in the shape of the Earth’s orbit around the sun are thought to trigger these larger-scale changes.
Evidence of shorter-term climate change has been observed before in ice-core records from Greenland and Antarctica. Apparently the global average temperature can switch between today’s mild climate and ice-age frigidity in just a few decades.
Sudden shifts are thought to be mostly due to ocean circulation. When ice sheets melt at the end of an ice age, the oceans get an injection of fresh water. By making seawater less salty and therefore less dense, this can suppress the conveyor-belt circulation that normally carries warm water from the tropics to the poles. Deprived of this source of heat, the high latitudes grow cold.
PHILIP BALL | © Nature News Service
Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter
16.08.2018 | National Science Foundation
Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide
15.08.2018 | University of Washington
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences