Tuesday, 31 March 2015

Ocean life can take millennia to recover from climate change

new study reports that ocean life can take thousands of years to recover from climate change.

D8H_6787.jpeg

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 levels decreased significantly.

Quite small changes in oxygen in seawater can cause big changes for seafloor life.

The study results suggest that future periods of global climate change may result in similar effects, with life taking thousands of years to recover.

"It’s not just about temperature," says Sarah Moffitt. 

               Dr Moffitt examining a fossil marine gastropod (sea-snail)
"It’s about disrupting fundamental earth processes that we as humans have understood to be very stable. They’re not stable." 

"These systems have the capacity to be very unstable when you poke the climate system with a sharp stick."

The Atmosphere



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.



Monday, 30 March 2015

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

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….
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 predictions of cooling got more media attention, the majority of scientists were predicting warming even then.
So 'global cooling' was a minority idea, and was never the mainstream idea in science.



Peter Gwynne says 
"The vast majority of climatologists now assure us that Earth's atmosphere is not cooling.  Rather, it's warming up.   And the main responsibility for the phenomenon lies with human activity."



Martian Volcanoes

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. 

Sunday, 29 March 2015

Climate Change and The Great Plains

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, but whether we can adapt to all of it is a very open question."

The Earth From Space - There's only one Earth

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.

Saturday, 28 March 2015

Antarctic ice shelves thinning quickly



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. Ice shelf
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 concern from our new study,” said Professor Fricker.

New research on habitable exoplanets

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.



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.


Friday, 27 March 2015

What's going on with the Gulf Stream?

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.Land and Ocean Temperatures

This cold pool may be an indicator of a dramatic slowdown in the Gulf Stream.

The 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," according to the National Oceanic and Atmospheric Administration.

A rapid slowdown in the current would increase sea level rise rates along the Mid-Atlantic and Northeast coasts of the U.S. 

It could also bring much cooler conditions to parts of northern Europe.

The Tomb of Richard III - Crinoidal Limestone from Yorkshire

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.




Thursday, 26 March 2015

Early steps in Climate Change science


1800-1870 

Level of carbon dioxide gas (CO2) 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 Fourier 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.





1930s 
Milutin Milankovitch proposed orbital changes as the cause of ice ages. 

1938 
Guy Callendar showed that global warming was underway, 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 beetle fossils in 'Ice Age' layers.

1958 
Telescope studies showed a greenhouse effect raises temperature of the atmosphere of Venus far above the boiling point of water. 



1960 

Charles David Keeling accurately measured CO2 in the Earth's atmosphere.

He was not expecting to detect an annual rise.

The CO2 level was 315 parts per million (ppm)and global temperature (five-year average) was 13.9°C.

Keeling's measurements have been continued.

At the end of 2014 the level was around 400 ppm.

Global temperature in 2014 was 14.57°C.

Current chart and data for atmospheric CO2

Nautilus

The nautilus is the only cephalopod that has a fully developed shell.

Chambered nautilus

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.

Wednesday, 25 March 2015

Volcanoes are not the main reason for melting Antarctic ice

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" 

The Thwaites Glacier is behaving more like a warm-based glacier.



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 under the ice,” Richard Alley, a geologist at Penn State, told VICE News. 

“This paper doesn’t tell you anything about why the ice is now thinning.”


Eric Rignot, an earth science professor at University of California Irvine and a principal scientist at NASA, said geothermal heating causes a few millimetres of glacial melting each year.
Rising sea temperatures can melt up to 100 metres of a glacier each year, he said.
A photo of Thwaites glacier in West Antarctica taken by NASA Operation IceBridge. A new study finds a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea. Credit: NASA     
A NASA photo of the Thwaites Glacier at the point it meets the ocean.
The Thwaites Glacier is one of a number of glaciers in that part of Antarctica.

The heat flow out of the crust is highest at the spreading ocean ridges.


1816 - The Year Without a Summer

The weather in 1816 was unprecedented. 

Spring arrived but then everything seemed to turn backward, as cold temperatures returned. 

The sky seemed permanently overcast. 


The 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 to write dark tales inspired by the gloomy and chilly weather.

During the miserable weather Mary Shelley wrote her classic novel Frankenstein.

Tuesday, 24 March 2015

2014 - Warmest Year in Modern Record

The year 2014 ranks as Earth’s warmest since records began in 1880.


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.

Chart showing global mean temperature anomaly in comparison to the El Nino phase

Ammonites

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.