Saturday, 24 June 2017

Climate Change - Comparing the Polar Regions

Earth's poles are warming faster than the rest of the planet.

One reason is that energy is carried to the poles by large weather systems.


The Arctic includes an ocean covered by sea ice.

Arctic sea ice melts in Summer and then refreezes in Winter.

The area of Arctic sea ice is largest in March each year, and at its lowest each September.
It is reducing over time - the graph comes from the US National Snow and Ice Data Center.

Research suggests the remarkable decline of  Arctic sea ice over the last century is far beyond anything seen for a long time. 


The Antarctic is a continent covered by ice, unlike the ocean in the Arctic.

The sea ice surrounding Antarctica melts almost to the coast each summer.



Ice shelves around Antarctica are also affected by global warming.

For a useful comparison of Antarctic and Arctic sea ice follow this link……

Arctic vs Antarctic




You can explore the Earth's melting ice using NASA's Global Ice Viewer.

Friday, 23 June 2017

Climate Change - "Weather on Steroids" in 2010

There were some very unusual weather events in 2010, which may be a warning of future effects of climate change.

Each time there are extreme weather events, people debate "Is there a link to climate change?"

It might be hard to prove in many cases.

Some recent events, however, are extraordinary.

The phrase 'weather on steroids' has been used to describe these events.


In 2010, China and Brazil had serious droughts, and in the first part of the year the Northern Hemisphere warmed fast, melting the winter snow cover very quickly.



The picture shows the dried-up River Negro in Brazil, with a bridge in the distance.  

But the biggest events were the heatwave in Russia and the flooding in Pakistan.

In PakistanGovernment officials said that from July 28 to Aug. 3, parts of Khyber Pakhtunkhwa province recorded almost 12 feet (3.6 metres) of rainfall in one week

The province normally averages slightly above 3 feet (around 1 metre) for an entire year.

        
       Pakistan Floods                                  Russian forest fire
In Russia, the heatwave went on for weeks, causing forest fires and destroying crops.

The Russian harvest was reduced in 2010, so the government stopped exports of grains.



Thanks to the Russian drought of 2010, global food prices in early 2011 were the highest since the food crisis of 1972 - 1974. 

This event has been linked to the "Arab Spring" of 2011.

The link between the floods and the heatwave was a blocked jet stream.

Thursday, 22 June 2017

Climate Change - Glaciation in Antarctica

Around 34 million years ago, at the Eocene-Oligocene Transition (EOT), the Earth was undergoing a period of global cooling. 

Antarctica changed from a green forested continent to the land of ice we know today. 

The cooling was partly caused by declining atmospheric carbon dioxide levels, but it also coincides with changes in the geography of the Southern Ocean.

This is an image of how this ancient world might have looked, created recently by Alan Kennedy of the University of Bristol -



Around 55 million years ago, CO2 levels rose during the Paleocene-Eocene Thermal Maximum (PETM).
Weathering of the newly-building Himalayas caused CO2 levels to begin to fall.
CO2 in rain makes a weak acid, which causes chemical weathering (especially of carbonate rocks like limestone, but of other rocks as well).
Rivers carry the carbon compounds down to the oceans, where various processes (such as the formation of calcareous shells by organisms) eventually deposit the material on the ocean floor.


Antarctic glaciation began when CO2 level fell to around around 750 ppmand spread more widely as the CO2 level continued to fall.

So...... what could be the future for Antarctica as global warming continues?

CO2 concentration in the atmosphere now is just over 400 ppm, but no one expects Antarctic ice sheets to melt entirely at any point soon.

If CO2 stopped rising now, ice would continue to melt from ice sheets and glaciers for a very long time.

There would still be a great deal of ice in Antarctica... the process would stabilise at a certain level of ice coverage.

Making Europe wild again
Even melting a fraction of Antarctica's ice would raise sea levels by a significant amount.
However, if CO2 levels get to over 750 ppm, eventually Antarctica could indeed be ice-free.

It would take time, as it takes a lot of energy to turn ice at zero degrees C into water at zero degrees C.... and the ice needs to warm up to zero degrees C before that.

Researchers have discovered this might take thousands of years, but would eventually happen if all the fossil fuels were to be burned.

Their analysis suggests that this would cause sea level to rise by 3 metres each century during the first thousand years.
Antarctica from space
If all of the Antarctic ice melted, sea levels around the world would rise about 58 metres.

Wednesday, 21 June 2017

Summer Solstice and the Nebra Sky Disc

Summer solstice sunrise.
View of the Heel Stone at summer solstice sunrise, as seen from inside the Stonehenge monument. Image via mysticrealms.org

solstice happens when the Sun in the sky is at its furthest point from the celestial equator. 

In 2017 the Summer Solstice in the northern hemisphere happens on the 21st June.  

On the June solstice the Sun reaches its northernmost point, as the Earth’s North Pole tilts towards the Sun, at about 23.5 degrees. 

Apart from the well-known links between the solstice and ancient stone structures, another extraordinary ancient object has connections to this celestial phenomenon.

The Nebra Sky Disc is a 3,600-year-old bronze disc which, according to UNESCO, features the oldest known depiction of cosmic phenomena in the world.

The disc is such an extraordinary piece that it was initially believed to be a forgery.


The Nebra Sky Disc was discovered in 1999 by two amateur treasure hunters illegally using a metal detector in Ziegelroda Forest, Saxony-Anhalt, Germany.  

It had been ritually buried in a prehistoric enclosure atop a hill (the Mittelberg), along with two swords, two axes, two spiral arm-rings and one bronze chisel.

Tuesday, 20 June 2017

Climate Change - Animals are moving

Animals are reacting to climate change very quickly.

Some move to higher places, others move north or south.

Dragonflies love warmer temperatures.

UK dragonflies have mainly stayed in the south of the country, until recently.



Ruddy Darter (Sympetrum sanguineum)
That is over 2km per year..... nearly 6 metres per day.

For example, the ruddy darter (Sympetrum sanguineum) and the hairy dragonfly, (Brachytron pratense), have moved into north-west England. 

This is evidence that the UK’s climate is growing warmer.

"So much has happened to dragonflies in Britain since the 1990s that there is a most compelling case for the Government to adopt them as indicators of climate change", said Steve Brooks.
Mr Stephen Brooks

Scientists from the University of York  found that, on average, living things have "moved uphill" at 12.2 metres per decade.
  They are moving away from the equator at 17.6 kilometres per decade.
“These changes are equivalent to animals and plants shifting away from the Equator at around 20 cm per hour, for every hour of the day, for every day of the year. 
This has been going on for the last 40 years and is set to continue for at least the rest of this century.”
Dr I-Ching Chen said: 


“We have for the first time shown that the amount by which the distributions of species have changed is correlated with the amount the climate has changed in that region.”

I-Ching Chen and her colleagues discovered that moths had on average moved 67 metres uphill on Mount Kinabalu in Borneo.

Comma butterfly. Photo: Butterfly Conservation & Jim Asher
The Comma butterfly has moved 220 kilometres northwards from central     England to Edinburgh, in only two decades.

Monday, 19 June 2017

Climate Change - Where does the heat go?



As global warming continues, heat goes into all parts of the Earth's systems.

The Earth is gaining more heat than it loses, and most of that heat is going into the oceans.

More heat is going into the upper parts of the oceans.

The water in the oceans is expanding, which is one reason sea level is rising.



The deepest oceans are still cold.

Some of the heat is involved in melting ice, including Arctic sea ice.



The recent reduction in Arctic sea ice is very dramatic.

The ice sheets of Greenland and Antarctica are also melting.

Sunday, 18 June 2017

Climate Change - "The climate has always changed .......what is all the fuss about?"

The climate has changed before.


When people say "It's changed before without people, so people can't be involved this time" ....think of forest fires.



Fires happened throughout time, does that mean people can't start fires?

Ice ages, warm times ... the geological record in the rocks shows many events.

Even so, the current changes are very unusual.





Graph based on a paper published in 2013

Fig A2


The recent rise in temperature is very fast.


What other kinds of changes are happening?


Geologists have compared the past with the present.


This report -
Climate Change Evidence: The Geological Society of London


explains what they have discovered.

This is based on part of that report:

"Before the current warming trend began, temperatures were declining.

This cooling took Earth’s climate into the ‘Little Ice Age’ (1450 – 1850). 

Calculations indicate that this period of cool conditions should continue for about another 1,000 years. 

Nevertheless, after 1900 the overall decline in temperature sharply reversed." 

So the Earth should be cooling.

There's lots of evidence for human involvement in these changes.  
Atmospheric CO2 is now around 400 parts per million (ppm).
It last reached similar levels during the Pliocene, 5.3-2.6 million years ago.
Outcrop view

In the middle Pliocene, the concentration of carbon dioxide in the air ranged from about 380 to 450 parts per million. 

During this period, the area around the North Pole was much warmer and wetter than it is now.

Summer temperatures in the Arctic were around 15 degrees C, which is about 8 degrees C warmer than they are now.
Global average temperatures were 2-3°C warmer than today.

Sea level rose by up to 20 metres in places.

What are the risks?
This source gives examples relating mainly to the USA ..........

but applicable more widely too.

For more interesting information, see -

Fact Sheets produced by 

Saturday, 17 June 2017

Climate Change - Greenland

The invention of the name Greenland may mark the start of the advertising industry.

The Saga of the Greenlanders tells how Erik the Red, the Icelandic Viking who wanted to get people to join his planned settlement, called it Greenland because a pleasant name would attract more settlers:

He called the land which he had found Greenland, because, quoth he, "people will be attracted thither, if the land has a good name." 

The ice sheet on Greenland covers most of this huge island.




Greenland is losing ice, and the mass of ice lost is measured by satellites called GRACE.

Embedded image permalink

A survey of Greenland's glaciers has shown they are speeding up.

The speed has increased by about 30% in 10 years.

A new NASA project called Oceans Melting Greenland (OMG) will observe changing water temperatures on the continental shelf surrounding Greenland, and how marine glaciers react to the presence of warm, salty Atlantic water.

Updates about Greenland's ice sheet are regularly posted by the National Snow and Ice Data Center.

Friday, 16 June 2017

Climate Change - The End-Permian Mass Extinction

Five major mass extinction events are recorded in the rock record of the last 600 million years.
The biggest extinction was at the end of the Permian, around 252 million years ago.

It is called the End-Permian mass extinction.


Only about 8% of species survived to live on in the Triassic Period.



The event played out over 60,000 years.
Acidification of the oceans lasted for about 10,000 years.
Two separate pulses of CO2 into the atmosphere - a "one-two punch" - may have been involved in the die-off, according to new research.
CO2 was released by massive volcanism from the Siberian Traps, now represented as a large region of volcanic rock. 

A large amount of coal had been burned over a period of tens of thousands of years.
The coal was burned by the Siberian Traps volcanic activity.
The burning actually happened underground, with the carbon dioxide and ash mixing with magma.

This produced vast amounts of CO2 which warmed the Earth and changed the chemistry of the oceans.
The research team, led by Dr Matthew Clarkson from the University of Edinburgh, examined rocks in the United Arab Emirates. 
Siberian Traps
The rocks, which were on the ocean floor at the time, preserve a detailed record of changing oceanic conditions. 

The carbon was released at a similar rate to modern emissions. 
Matthew Clarkson image
Dr Clarkson says "Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now.
"This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions."

Thursday, 15 June 2017

Climate Change - The last 22,000 years of global temperature change



This graph shows how temperatures have changed over the last 11,000 years, since the end of the last glacial stage.

The graph uses data from modern temperature records, plus information about the past from a research paper that combined data from over 70 different scientific studies.

The next graph adds data from even further back in time:


The green part covers the time as the last glacial stage was coming to an end, and the great ice sheets were melting.

The last glacial stage ended about 10,000 years ago. 

Then, for nearly 5,000 years, global temperature was surprisingly stable

In the next 5,000 years, up to about 1800, global temperature declined by about 0.7 deg.C.

There were some variations in that slow decline:


From 1800 until 2000, temperature rose by about 0.8 deg.C, according to the World Meteorological Organisation.



This chart shows annual average global temperatures from 1950-2015 using data from NASA's Goddard Institute for Space Studies (GISS)

Wednesday, 14 June 2017

Climate Change - El Nino

El Niño is an oscillation of the ocean-atmosphere system in the tropical Pacific, and has important consequences for weather around the world.

El Niño happens every three to seven years.

“El Niño” is Spanish for “The Little Boy”.

Peruvian fishermen named the event many years ago.

They noticed that every few years around Christmas, virtually no fish could be found in the unusually warm waters. 
El Niño is marked by unusually warm ocean temperatures in the Equatorial Pacific.

The opposite conditions are called La Nina (The Little Girl), characterized by unusually cold ocean temperatures in the Equatorial Pacific. 

El Nino clearly affects global temperatures.

One piece of evidence that world temperatures are rising is that every La Nina ‘year’ since 1998 was warmer than every El Nino ‘year’ before 1995:  



As the Earth warms, each El Nino 'rides' on a higher base-line global temperature:

The record-breaking temperatures of 2015 were partly boosted by an El Nino event ... but 2015 would have been the warmest year in the modern record even if there had been no El Nino.

Information about El Nino is provided in bulletins produced by the US National Weather Service and the Australian Bureau of Meteorology.

Tuesday, 13 June 2017

Planet Earth - Doggerland

For many years, fishermen in the North Sea, between Britain and Denmark, have found fossil bones in their nets.



This fossil catch has yielded over 200 tons of fossil bones, and over 15,000 mammoth teeth.   

The bones include remains of mammoths, three different species of woolly rhinos, hippos, lionsbears, wild horsesbison, elk, reindeer, hyenas, wolves, and Sabre tooth cats of at least two species.   

They tell us about a whole community of animals.

Beneath the North Sea lies a lost landscape.

This land was as big as modern Britain - hills and valleys, rivers and forests, marsh and moor. 

Sometimes warm and marshy, and at other times a frozen tundra.

This has been named "Doggerland".



"Doggerland" is a name given to a vast lowland plain, with the northern coastline stretching from Shetland to Jutland. 

The Thames flowed into the Rhine, which turned south, and made the English Channel its estuary. 

The highest point was a hilly region where the Dogger sand-banks are today.