World Science
New clues for finding alien life
Climate change sparked rise of the lizards
Technology delivers net through TV aerial
Indigenous burn control a myth: study
Galapagos whales hold pollutant mystery
Bicycle scheme reveals rider behaviour
Frog bladder holds a surprise
Relocating species to ensure survival
Plant growth could slow warming: NASA
Astronomers find planet with a diamond heart
Free radicals not such a bad thing
Ants lay trail to complex problem-solving
Imagine more, eat less: study
'Stealth fungus' seeks, destroys crops
Saturn rings born from Titanic collision
New thinking on asteroid belt
Hungry Maoris burned forests to grow food
Ocean may contain nuclear powered microbes
Voyager reaches edge of solar system
Medical science examines urban myths
Clusterwinks bask in the afterglow
Cyclone batters Saturn for five years
Arctic icecap 'safe' from runaway melting
Fearless woman helps unlock anxiety puzzle
Climate matched Europe's ups and downs
Ancient tree rings show links between climate change and major events in human history, like migrations, plagues and the rise and fall of empires, according to a new study.

The study, which appears in the journal Science, shows moist, balmy temperatures were seen during prosperous Medieval and Roman times, while droughts and cold snaps coincided with mass migrations.

To match the environmental record with the historical one, researchers looked at more than 7200 tree fossils from the past 2500 years, says lead author Ulf Buntgen of the Swiss Federal Research Institute for Forest, Snow and Landscape .

Oak rings are sensitive to changes in precipitation, and can show changes according to what was happening in the environment.

"The rise and fall of past civilisations have been associated with environmental change, mainly due to effects on water supply and agricultural productivity, human health and civil conflict," says the study.

"Wet and warm summers occurred during periods of Roman and Medieval prosperity," says the study which looked at tree samples from Europe and other parts of the world.

"Increased climate variability from (around) AD 250-600 coincided with the demise of the Western Roman Empire and the turmoil of the Migration Period."

They could also glean signs about what was happening from changes in how many trees were being cut.

"Reduced tree harvesting (around) AD 250-400 coincides with the biggest CE (central Europe) historical crisis, the Migration Period, a time marked by lasting political turmoil, cultural change and socio-economic instability," it says.

"Increasing timber harvest for construction is represented by abundant felling parallel to socio-economic consolidation from the 6th to the 9th centuries."

The study says "unfavourable climate may have contributed to the spread of the second plague pandemic, the Black Death, which reduced the CE population after AD 1347 by 40 to 60 per cent."

Researchers also noted that a sharp decline in North American temperatures around the same time saw an "abrupt desertion of former Greenland settlements."

Technological advances have made the modern human population less vulnerable to environmental changes to a certain extent, the study says.

But we are "certainly not immune to the predicted temperature and precipitation changes, especially considering that migration to more favourable habitats as an adaptive response will not be an option in an increasingly crowded world."

Reefs reeling from Queensland floods
Public asked to define a galaxy
Polygamy produces more virile offspring
Sleep best time to reinforce memory
Some Himalayan glaciers advancing: study
Massive coal fires caused Great Dying
Kid's self-control predicts health, wealth
Fish in groups decide quicker, better
One-clawed dino found in China
Conservationist and marine photographer recognised
Awards for medical research pioneers
Tough conditions favour giants
Bat uses carnivorous plant as a toilet
Telescope spots 'oldest galaxy' yet seen
Scientists unravel probiotics gut defence
Humans came out of Africa via Arabia: study
Bovine bellies yield biofuel clues
Saturnian moon's ocean full of gas
Sun rises on next solar generation
New test targets 'mad cow' disease
Dogs sniff out cancer in stool
Great drying reveals clues to big wet
Ant genome may reveal survival secrets
Dud mates stress out female finches
Kepler dramatically boosts exoplanet count
Scientists grow blood vessels
CO2 gets Martian sand dunes moving
Team makes nanosheet breakthrough
Music thrills trigger reward chemical
Lunar water may have come from comets
Birds falling from the sky 'not unusual'
NASA spots hot, Earth-like planet
Lifespan of early humans, Neanderthals same
Echidnas' unusual mating habits revealed
Funky frogs sniff out danger
La Nina lives up to predictions
Cuckoos ramp up effort in 'arms war'
Lensing putting universe out of focus
Penguins to shrug off flipper band
Device may silence ringing in the ears
Scientists find tiny 'dawn runner' dinosaur
'Goldilocks' planet lost in translation
Smoking causes gene damage in minutes
Climate matched Europe's ups and downs
Accuracy gave bows the early upper hand
Chemistry comes from the genes
Researchers aim to resurrect mammoth
Smaller corals take the heat
Blood drug could save crash victims
Gaps in flood knowledge: experts
Malaria parasite caught in the act
White blood cell protein aids melanoma
Visit Statistics