Posts

Showing posts from March, 2015

Ocean life can take millennia to recover from climate change

Image
A  new study  reports that ocean life can take thousands of years  to recover fro m climate change. The team, led by Dr Sarah Moffitt,  examined more than 5,400 fossils, from sea urchins to clams, found in a 30 metre sediment core from the ocean floor off Santa Barbara, California. The tube-like sediment core is a slice of ocean life as it existed between 3,400 and 16,100 years ago. An example of an ocean sediment core. It provides a snapshot of what happened during the last major deglaciation —a time of abrupt climate warming, melting polar ice caps, and expansion of low oxygen zones in the ocean. The sediment core revealed a history of a well-oxygenated sea-floor full of life, followed by a period of oxygen loss and warming, that seems to have triggered a rapid collapse of life. A typical view of the ocean floor The study shows that the fossils nearly vanish in layers formed when oxygen levels in the sea dropped. In periods of less than 100 years, ocean oxygen lev

The Atmosphere

Image
Space is not very far away. Aircraft on long-haul flights travel at a height of about 10 km. The lowest layer of the atmosphere, the  Troposphere,  ends at about 15 km. The air in the layers above the troposphere is very thin indeed. Think of a place around 15 km (9 miles) from where you are. That's pretty much how near you are to space. All the waste gases people dump into the air are trapped in the thin layer of air around the Earth.

Did ‘they’ predict an Ice Age in the 1970s? - not really, it's an Urban Myth

Image
It seems to be a common saying..... but it's very misleading. " Why are scientists talking about global warming?  In the 1970s they were warning us an Ice Age was coming.   They can't expect to be taken seriously if they keep changing their minds ."   It's not as simple as that  ... and science has learned a lot since the 1970s. Muir Glacier, Alaska. Left: August 13, 1941. Right: August 31, 2004. Credit: 1941 photo taken by Ulysses William O. Field; 2004 photo taken by Bruce F. Molnia. Courtesy of the Glacier Photograph Collection, National Snow and Ice Data Center/World Data Center for Glaciology. So why does this story keep appearing in so many places? The magazine  "New Scientist"  has looked at this myth…. 1970s "ice age myth" From the article - A survey of the scientific literature has found that between 1965 and 1979,  44 scientific papers predicted warming,  20 were neutral and just 7 predicted cooling. So while

Martian Volcanoes

Image
Mars  is smaller than Earth, but some things are familiar. In this photograph, the great canyon called ' Mariner Valley ' is clear. There are a number of round features, which are  volcanoes . One of the Martian volcanoes,  Olympus Mons , is the biggest volcano in the solar system. Olympus Mons is a  shield volcano .   It is 624 km (374 miles) in diameter.  That's about the same size as France, or the state of Arizona Olympus Mons is 25 km (16 miles) high Its base is encircled by a 6 km (4 miles) high cliff.  A crater 80 km (50 miles) wide is located at the summit of Olympus Mons.  In comparison, the largest volcano on Earth is  Mauna Loa on Hawaii. Mauna Loa is also a shield volcano, 10 km (6.3 miles) high and 120 km (75 miles) across.  The volume of Olympus Mons is about 100 times larger than that of Mauna Loa. 

Climate Change and The Great Plains

Image
Since the 1940s, farming on the southern Great Plains of the USA—Colorado, Kansas, Oklahoma and Texas—has relied on irrigation.  On the high plains of Texas, tens of thousands of wells pumping from the 10-million-year-old Ogallala Aquifer  have reduced the water content by 50 percent.  Most of the  remaining underground water source will probably be useless within about 30 years. Katharine Hayhoe , professor and director of the Climate Science Center at Texas Tech University in Lubbock, says big changes are on the way for agriculture on the Great Plains. "We're seeing major shifts in places and times we can plant, the types of crops we can grow and the pests and diseases we're dealing with.  "If you talk to seed companies, the U.S. Department of Agriculture (USDA) and even farmers, they tell you we can modify our way out of this, that we can overcome all these problems with technology.  "There's no question we can adapt to some of the change, b

The Earth From Space - There's only one Earth

Image
The Chinese spaceprobe  Chang'e 5  took this photograph from space in October 2014. The spaceprobe was beyond the Moon, looking back at Earth. This photograph was taken by the  Cassini  spaceprobe, which is in orbit around Saturn. The dot marked with an arrow is Earth . To see the Earth turning in space is an amazing thing - click here for a video. Finally, an image taken by the  Galileo spaceprobe  - the Earth and Moon.

Antarctic ice shelves thinning quickly

Image
Professor Helen Fricker  and colleagues at    Scripps Institution of Oceanography  have used two decades of data from European radar satellites to compile an assessment of  Antarctica's floating ice shelves.   In the first decade, the total losses from the   ice shelves  averaged 25 cubic km per year. But during the second decade, this had jumped to 310 cubic km per year. "For before 2003, ice-shelf volume for all Antarctica did not change much," said Fernando Paolo, one of the team. "Since then, volume loss has been significant. The western ice shelves have been persistently thinning for two decades, and earlier gains in the eastern ice shelves ceased in the most recent decade," he told BBC News. In the Amundsen and Bellingshausen regions, some ice shelves have lost up to 18% of their thickness in less than two decades. “The ice shelves buttress the flow from grounded ice into the ocean, and that flow impacts sea-level rise, so that’s a key c

New research on habitable exoplanets

Image
The Earth is a planet orbiting the Sun.                        Exoplanets  are  planets of stars other than the Sun. There are likely to be hundreds of billions of Earth-like planets in our galaxy which might support life. Tim Bovaird and Charley Lineweaver from The Australian National University    found that many stars could have two planets in the Goldilocks zone. The  Goldilocks Zone  is a band of space where liquid water can exist. Too near the star, or too far, is bad for life. In the case of the Sun, Venus lies inside the inner edge of the Goldilocks Zone. Mars lies at the outer edge. Finding  exoplanets  is exciting science.

What's going on with the Gulf Stream?

Image
The Northern Hemisphere winter of 2014-15 was the warmest on record globally, according to the National Oceanic and Atmospheric Administration.  But one area of the North Atlantic   was the coldest on record... shown in blue on this map. This cold pool may be an indicator of a dramatic slowdown in the Gulf Stream. T he Gulf Stream  transports vast amounts of heat north from the equator to the pole, passing off the East Coast of the U.S. and into the North Atlantic. A slowdown like this in the current has not happened for a very long time, perhaps as long as 1,000 years.  It is most likely related to the melting of the Greenland ice sheet.  The influx of freshwater from the ice sheet  is lighter and colder than heavier, salty water that typically occupies that area.  It tends to sit on top of the water,  interfering with the sinking of dense, cold and salt-rich water. The Gulf Stream transports more water than "all the world's rivers combined," accord

The Tomb of Richard III - Crinoidal Limestone from Yorkshire

Image
The new tomb of King Richard III in Leicester Cathedral is made of limestone from Swaledale in Yorkshire. The limestone was formed at the bottom of a shallow sea that covered much of what was to become the United Kingdom, back in the early Carboniferous geological period.   It is coarse grained, and contains fossil remains of   crinoids . Crinoids  are related to starfish and sea urchins. They are spectacular fossils if they are complete, but that is quite unusual. It is more common to find fragments of them in  limestone.

Early steps in Climate Change science

Image
Some key events in the discovery of climate change 1800-1870  Level of carbon dioxide gas (CO 2 ) in the atmosphere, as later measured in  ancient ice , was about 290 ppm (parts per million). Global temperature for 1850-1870 was about 13.6°C. 1824 Jean-Baptiste Joseph F ourier  calculated that the Earth would be far colder if it lacked an atmosphere.  1859 John Tyndall  discovered that some gases block infrared radiation.  He suggested that  changes in the concentration of the gases  could bring  climate change . 1896  Arrhenius  published first calculation of global warming from human emissions of CO 2 . 1930s  Milutin Milankovitch  proposed orbital changes as the cause of ice ages.  1938  Guy Callendar  showed that  global warming was underwa y,  reviving interest in the question.  1950s  By accident,  Russell Coope  discovered that some past climate change events happened in  just a few decades . This came from  his research into

Nautilus

Image
The nautilus is the only cephalopod that has a fully developed shell. Unlike a squid, cuttlefish or an octopus, the nautilus has poor vision. Its primitive eyes have no lenses. They work like pinhole cameras. The nautilus has more than 90 suckerless tentacles.  Grooves and ridges on the tentacles are used to grip prey. They deliver food to a crushing, parrot-like beak. The spiraled shell of the nautilus is divided into chambers with the animal occupying the outermost chamber.  A newly hatched nautilus begins life with about four chambers. It develops an average of 30 chambers by adulthood.  The inner chambers are filled with gas. They help the nautilus to maintain buoyancy.  The nautilus adds liquid to the chambers in order to dive.

Volcanoes are not the main reason for melting Antarctic ice

Image
There have been very inaccurate stories on various websites claiming ...... "Volcanoes are the main reason for ice melting in Antarctica." This is not the case. The 'volcanoes' story is mainly a misreading of research on the Thwaites glacier . This is the actual paper on this research...... "Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet"                   http://www.pnas.org/content/111/25/9070.full The Thwaites Glacier is behaving more like a warm-based glacier . Warm-based glaciers are usually found in temperate regions like the Alps. Most polar glaciers are cold-based glaciers . The geothermal heat from under the Thwaites glacier is small compared to the overall warming happening around Antarctica. “It is true that there are active volcanoes in West Antarctica, and so there may have been some local changes, but in most cases, at most times, volcanoes are not erupting

1816 - The Year Without a Summer

Image
The weather in 1816 was unprecedented.  Spring arrived but then everything seemed to turn backward, as cold temperatures returned.  The sky seemed permanently overcast.  T he lack of sunlight became so  severe that farmers lost their crops. Food shortages were reported in Ireland, France, England, and the United States. It was over 100 years before anyone understood the reason for this weather disaster. The eruption of an enormous volcano on a remote island in the Indian Ocean a year earlier had thrown enormous amounts of volcanic ash into the upper atmosphere. The dust from  Mount Tambora , which had erupted in early April 1815, had shrouded the globe.  With sunlight blocked, 1816 did not have a normal summer. In Switzerland, the dismal summer of 1816 led to the writing of a famous story.  A group of writers, including Lord Byron, Percy Bysshe Shelley, and his future wife Mary, challenged each other

2014 - Warmest Year in Modern Record

Image
The year  2014  ranks as Earth’s warmest since records began in 1880. This is reported by scientists from NASA and the National Oceanic and Atmospheric Administration. 9 of the 10 warmest years in the  instrumental record have now occurred since the year 2000. The exception was 1998, which was affected by a very strong  El Nino  event. That means nobody born since 1976 has experienced a colder-than-average year. 2014 was not even affected by an  El Nino,  which has been the case for previous record years.

Ammonites

Image
Ammonites are an extinct group of sea creatures. They were cephalopod molluscs, related to squid and octopus. They are found as fossils, formed when the shells of the animals became buried in sediment which later solidified into rock. The oldest ammonite fossils are found in Jurassic rocks, from around 200 million years ago.  They became extinct at the end of the Cretaceous around 65 million years ago. Ammonites had shells made of chambers. The air in the chambers helped them to swim. There are hundreds of types of ammonites, with  different shapes. Here are just a few examples.