Throughout Earth's history, 90,000 out of every 100,000 years have been ice ages - and it's been 12,000 years since the last one. You can thank global warming, it seems.
Future ice ages may be delayed by up to 500,000 years by greenhouse gas emissions from fossil fuels, according to recent work by Dr Toby Tyrrell of the University of Southampton.
If their numerical model is accurate, this sets a new standard for detailing the disruption of long-term planetary processes by human activity.
Volcanoes sometimes get a bad rap for belching CO2 but today it turns out they're also responsible for the air we breathe.
National Science Foundation-funded research published this week in the journal Nature indicates that billions of years ago, when the Earth was home largely to undersea volcanoes, a previously unknown agent was removing the gas.
The researchers suggest that mixture of gases and lavas produced by submarine volcanoes scrubbed oxygen from the atmosphere and bound it into oxygen-containing minerals.
An artist's cross-section of an underwater volcano and the processes that drive them. Submarine volcanoes can sometimes form islands. Credit: Zina Deretsky, National Science Foundation
The earth sciences rely on highly accurate timing to unravel past causes and effects, and understand the forces driving many events from ice ages to mass extinctions. Other scientific disciplines, such as evolutionary biology and climate science, in turn depend on accurate timing of geological processes to provide a baseline for their investigations.
While significant progress has been made over recent decades, great uncertainties remain that are inhibiting investigations of major past events and formative processes in the earth sciences. In the case of the dinosaur extinction, knowledge of how long the process took would help resolve whether this was caused by a sudden asteroid strike or more gradually following a period of intense volcanic activity for example.
Pressures and temperatures at the Earth’s core are stupendous – more than 3.5 Mbar and 7000K – and currently it is impossible to recreate these conditions in the laboratory. Our information about the core comes from observing the way that seismic waves travel through the core, extrapolating from experimental studies and studying iron rich meteorites.
As a result we know that the core is mostly iron, but that it also must contain some light impurities such as oxygen, silicon, sulphur, hydrogen and magnesium (because the density of the core is too low to be pure iron). The most significant impurity is thought to be nickel, which makes up between 5 and 15% of the composition.
Most studies on the Earth’s core have approximated the composition to be pure iron.
Permafrost, the perpetually frozen foundation of the north, serves like a platform underneath vast expanses of northern forests and wetlands that are rooted in many northern ecosystems. But rising atmospheric temperatures are accelerating rates of permafrost thaw in northern regions, says MSU researcher Merritt Turetsky.
“The loss of permafrost usually means the loss of terra firma in an otherwise often boggy landscape,” Turetsky said. “Roads, buildings and whole communities will have to cope with this aspect of climate change.
The DNA of ancient microorganisms, long frozen in glaciers, may return to life as the glaciers melt, according to a paper published online this week in the Proceedings of the National Academy of Sciences by scientists at Rutgers and Boston University.
The finding is significant, said Kay Bidle, assistant professor of marine and coastal sciences at Rutgers, because scientists didn’t know until now whether such ancient, frozen organisms and their DNA could be revived at all or for how long cells are viable after they’ve been frozen.
A new substance analyzer has been developed by the All-Russian Scientific Research Institute of Technical Physics and Automation in Moscow.
Its functionality is to automatically determine the content of up to 20 chemical elements in the periodic table between calcium and bismuth but in a package small enough to fit in a rucksack.
Basically it runs an X-ray generator over the surface of the core, stimulating all atoms of the specimen within a radius of slightly less than 2 centimeters. It will then independently measure “secondary” fluorescent radiation: the atoms stimulated by X-ray, when coming back to the quiescent state, exude excess energy in the form of radiation and the device records that radiation.
If you've never heard of Lake Agassiz, it's no surprise. It disappeared over 8,000 years ago. Yet it may have been the global warming trigger that ended the last Ice Age.
Using remains from lakes, bogs and channels, a multi-disciplinary group of scientists recently tackled the secrets of glacial Lake Agassiz and Big Stone Moraine.
Knowing the chronology of glacier retreat, and when glacial lakes formed, is important in linking physical events on the landscape with paleoclimate records. At the close of the last ice age, glacial ice in the upper Midwest of the United States retreated very quickly, likely in response to the warming climate.
Volcanologist Sarah Fagents from the University of Hawaii at Manoa had an amazing opportunity to study volcanic hazards first hand, when a volcanic mudflow broke through the banks of a volcanic lake at Mount Ruapehu in New Zealand.
Fagents and colleagues were there on a National Science Foundation (NSF)-funded project to study the long-forecast Crater Lake break-out lahar at Mount Ruapehu.
Indonesia’s Mount Gamkonora volcano is spewing hot ash and smoke into the air, as seen in this image taken by the MERIS instrument aboard ESA’s satellite Envisat, causing more than 8000 people to be evacuated amid fears of an imminent eruption, according to officials.
Officials raised the alert to the highest level on Tuesday after the volcano, located in the eastern province of North Maluku, started spitting out flaming material, indicating magma was approaching the crater’s surface making an eruption more likely, Saut Simatupang of Indonesia's Vulcanological Survey told Reuters news agency.
The 1635m volcano, located about 2400 km northeast of Jakarta, began releasing smoke and ash on Saturday and spewed it as high as 4000m on Monday.