Wednesday, 31 December 2014

Greenhouse Effect and the Earth's Energy Budget

When the Sun's energy arrives at the Earth, it travels through the air.

Some is reflected back to space, but some hits the Earth and warms it.

The warm Earth gives off infrared radiation with various wavelengths.  

Some of those waves can pass back out of the air to space, but some are absorbed by certain gases in the air.

If there are more of those gases, less heat escapes into space.

Concentrated 'greenhouse gases' on Venus have caused the surface temperature to rise to 735 Kelvin (462 degrees C; around 900 degrees F)

Carbon dioxide levels in the atmosphere have risen quickly since people began burning large quantities of fossil fuels.

There was carbon dioxide in the air before that, at around 270 parts per million.

Without any carbon dioxide, the Earth would be very cold.

The temperature would be around -18 degrees C.

There have been times when most of the carbon dioxide was trapped in rocks.

The Earth cooled into a state called 'Snowball Earth'

Tuesday, 30 December 2014

The Keeling Curve

Carbon dioxide levels in the atmosphere are rising.

This graph showing the data is called the Keeling Curve.

Atmospheric CO2 data and trend

It is named after the scientist who first produced accurate measurements of carbon dioxide in the air - Charles David Keeling.  

Keeling's data began in 1958.

What about carbon dioxide levels before 1958?

That information has been found by drilling into the ice in places like Antarctica and Greenland.

As layers of ice build up, they trap bubbles of air, which hold the evidence of the atmosphere from the year the layer was formed.

Law Dome is a location in Antarctica.

The evidence shows that since around the late 18th century, as the Industrial Revolution began, carbon dioxide levels have risen.

They had changed from around 280 parts per million to over 300 ppm when Keeling began his records in 1958.

Now it has reached around 400 ppm in just around 50 years.

This is a very fast rise, compared to the past.


Meteorites are objects from space that have reached the surface of the Earth.

Before they hit the ground they are seen as meteors.

Most meteors burn up completely, but some survive - some amazing videos were taken of a meteor event in February 2013 in Russia.

 Meteorites are generally of three main types

From left to right, cut example of an Iron, a Stony-Iron and a Stony meteorite © The Natural History Museum

Iron               Stony-Iron             Stony

One of the best places to find meteorites is Antarctica, because the dark meteorites stand out against ice.

Professor Sara Russell from the Natural History Museum in London has been to Antarctica to collect meteorites.  


Monday, 29 December 2014

Ocean acidification - what does it mean?

The phrase 'ocean acidification' is used to mean that the pH of seawater is reducing.

The pH scale is used by scientists to describe strength of acids and alkalis. 

Sea water normally had a pH around 8.3 but it has now reduced to 8.1 and will continue to reduce as more CO2 is added to the air by human activities.

Some of the extra COin the air dissolves in the sea, and this affects sealife.

Here is what one expert scientist has said about this -

Surface ocean pH has fallen by about 0.1 pH unit from preindustrial times to today — a 0.1-unit pH drop is equivalent to about a 26% increase in the ocean hydrogen ion concentration.
pH is likely to drop by 0.3-0.4 units by the end of the 21st century, and increase ocean hydrogen ion concentration (or acidity) by 100-150% above what it was in preindustrial times.

Humanity's greenhouse gas emissions may be acidifying the oceans at a faster rate than at any time in the last 300 million years. 
Picture A shows healthy coral.
Picture B shows dead and dying coral.
A healthy coral reef with living Acropora palmata and good water quality and a degraded coral reef with dead A. palmata and poor water quality.  

One small step for a "Homo snackiens"....many steps for a couple of dinosaurs.

Astronauts' bootprints on the Moon will stay fresh for a long time.

No rain, no wind will disturb these imprints.

Amazingly, footprints of other kinds of creatures have survived on the Earth.

This can be because they were quickly covered by volcanic ash, or other layers of fine material, preserving the details.

These footprints were most likely made by Australopithecus afarensis, an early human whose fossils were found in the same sediment layer.

They were found at Laetoli in Tanzania.

Looking at much older rocks, footprints of dinosaurs can be used to find out all sorts of things about their lives.

Working out the meaning of dinosaur footprints can be a great example of using scientific thinking.

The MEETING OF THE DINOSAURS is a wonderful activity for anyone who likes dinosaurs.  

Sunday, 28 December 2014

Carbon dioxide and fossil fuels

It’s actually a little easier to look at the impact of fossil fuels using coal as an example, but the principle applies to all fossil fuels.

A typical three-metre (10-foot) coal seam is estimated to have taken between 12,000 and 60,000 years to form.

Ancient trees and plants lived, died and were fossilised, having used carbon dioxide from the atmosphere over those millennia.

Some larger coal seams are, for example, 10 metres thick.

They took around 40,000 years to form but have been mined and burned in a little over 100 years.
We are time-warping vast amounts of ancient carbon (which we are combining with current oxygen) into our modern atmosphere.

The figure of 33.4 billion metric tonnes is for for 2010.  The figure for 2014 is expected to be 40 billion metric tonnes. 
The fastest rise of CO2 in the air seen in the ice core record (800,000 years) is 20 ppm in 1000 years.

CO2 level in the atmosphere is now rising at a rate of around 20 ppm per decade.

Atmospheric CO2 data and trend

The Orion Nebula

The Orion Nebula is a fuzzy area among the stars of Orion's sword, which is seen below the three Belt Stars.

To the naked eye, it looks like a star in the sword.

With binoculars or a telescope, it is actually a large glowing cloud of material. 

This nebula is about 1630 light years away. 

Many newborn stars shine on the gas cloud that they collapsed from.

This makes the gas glow.

Saturday, 27 December 2014

Ice age postponed?

The Earth is warming because humans are producing lots of carbon dioxide.

Without that, the Earth would be cooling towards a new 'ice age' - a glacial stage, to use the better term.

We know this because most of the things that cause glacial stages are regular patterns of movement by the Earth as it orbits the Sun.

The ice would start to return in around 1,500 years, but only if there was a lot less carbon dioxide in the air.

So is it a good thing that a lot of carbon dioxide is being made?

No.... the COneeded to hold back the ice was made by simple things like farming long before the Industrial Revolution.

The huge amount made over the last 150 years has taken things to a different situation, where very fast warming is happening.

This is going to change all kinds of things.

Atmospheric CO2 is now just below 400 parts per million (ppm) on average.

That has not happened since the Pliocene (5.3-2.6 million years ago).

At that time, temperatures rose to levels 2-3°C warmer than today.

Sea level rose by up to 20 metres (65 feet) in places.

It was a very different world.

Orion the Hunter

The constellation of Orion dominates the southern sky during winter in the Northern Hemisphere.

The brightest stars of Orion have wonderful names.

The Red Giant star Betelgeuse marks one shoulder, the other shoulder is marked by Bellatrix.

The three Belt Stars (left to right) are Alnitak, Alnilam and Mintaka.

The knees are marked by Saiph and the very bright Rigel.

Like many star names they are of Arabic origin.

The stars of Orion act as signposts to other stars seen at the same time of year.

Stars shown here are good examples of some of the variety of types of stars.


The Sun is really rather small compared to many stars

Friday, 26 December 2014

What does 'climate' actually mean?

Lots of people discuss 'climate change' but what does the word 'climate' mean?

Folks forget how climate is defined.....

Climate is normally defined as 'an average over 3 conventional decades'.

A conventional decade is, for example, 2001-2010, or 1961-1970.

So ..... 3 full, conventional decades......such as 1981 to 2010.

For example .... rainfall in Ireland.

And another example - 'Average temperature 1951-1980'

The definition of 'climate' goes back at least 100 years.

So if we are discussing climate change, that is what 'climate' means.

But in recent times, there has been a lot of variation in global temperatures.

So it can be useful to look at single conventional decades.

Data from the World Meteorological Organisation.

The Atmosphere

Space is not very far away.

Aircraft on long-haul flights travel at a height of about 10 km.

The Troposphere ends at about 15 km, and the air in the upper atmosphere 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 dumped into the air are basically trapped in the thin layer of air around the Earth.

Wednesday, 24 December 2014

Where can we go to read accurate information about climate change?

There are very many websites with opinions on climate change.

Where is there something we can trust?

Let's see what long-established scientific organisations tell us.

The Royal Society has been the home of science in the UK since the 1660s, and Sir Isaac Newton was a President of the Royal Society in its early days.

Coat of Arms of the Royal Society

What do they say now about climate change?

Scientists know that recent climate change is largely caused by human activities from an understanding of basic physics, comparing observations with models, and fingerprinting the detailed patterns of climate change caused by different human and natural influences. 

The speed of the current climate change is faster than most of the past events, making it more difficult for human societies and the natural world to adapt. 

Climate Change: Evidence and Causes

Which was put together by the Royal Society and the National Academy of Sciences, their equivalent in the USA.

Another important organisation offering something important is the Geological Society of London.

The Geological Society of London say -

This rate of increase of CO2 is unprecedented, even in comparison with the massive injection of carbon into the atmosphere 55 million years ago that led to the major PETM warming event, and is likely to lead to a similar rise in both temperature and sea level. 


Climate Change: Evidence from the Geological Record

Planet Earth or Planet Water?

Only about 29% of the Earth is above sea level, so perhaps it should be called 'Water' or 'Ocean'?

For most of human history, almost nothing was known about the deep oceans.

The science of the oceans - Oceanography - is still full of chances to discover new things.

The deeper you go, the darker it gets, and most of the deep ocean never sees any sunlight.

To get a sense of the excitement of oceanography..

These oceanographers give a hint of their work.

Tuesday, 23 December 2014

Corals and Coral Bleaching

Healthy coral can be very colourful.


Some coral reefs recently have started to look rather different.


This is called 'coral bleaching'.

To understand this, we need to start by looking at corals.

Corals are animals that make a framework around them that looks like rock.

Coral animals (polyps) have tiny plants - algae - living in their tissues.

The algae provide food to the corals, which they produce by photosynthesis.

Corals only live in a limited temperature range.

Like porridge, they need to be not too hot and not too cold.

Coral reefs are concentrated in a band around the equator, between 30°N and 30°S latitude.

Corals grow in warm shallow waters that receive plenty of light.

Most corals grow in the warmest water they can stand (about 85° F or 29° C). 

This means that slight increases in ocean temperature can harm corals.

High sea temperature is the main reason for coral bleaching.

Why is a Pterodactyl called a Pterodactyl?

The name means 'wing-finger'.

Bird wings are supported on 'arm bones'.

The outer part of bat wings are supported on finger bones.

The outer part of the wings of pterodactyls and other pterosaurs are supported on long 'little finger' bones.

One well-known larger pterosaur is Pteranodon.

Monday, 22 December 2014

Mass Extinction and the link to atmospheric carbon

Geologists have discovered five major mass extinction events in the rock record of the last 600 million years.
The extinction at the end of the Permian period, around 252 million years ago, was the most extreme.

It is called the End-Permian mass extinction.

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

This photo shows tilted sedimentary rocks at Shangsi in South China, with Triassic rocks at the top right overlying the older Permian rocks.

Each mass extinction in the rocks matches with a change in the chemistry of the rocks called a 'carbon excursion'.

Some of the carbon excursions are 'negative' and some are 'positive'.

Negative CEs involve lots of gaseous carbon compounds adding to the air, causing warming.

Positive CEs involve the reverse.... processes absorb the gases and cooling follows.

Examples of positive CEs include 

The 'Snowball Earth' events.

An example of a negative CE is 

the Palaeocene-Eocene Thermal Maximum.

Ecosystems recovered from the PETM ..... it 'only' took 100,000 years.

In the PETM link above, see Section 9 ..Conclusions... last sentence.....

"the PETM is a natural analogue for increases in atmospheric COdue to fossil fuel burning over the next century, and implies a relatively high climate sensitivity."

The earth systems simply react to the chemistry ..... how the gases get into the air is unimportant.
And currently CO2 is rising at 20 ppm per decade.

Nothing like this has happened in the time of Homo sapiens.

Uncontrolled addition of CO2 is dangerous and will have serious consequences.

Photographs of ice core drilling

Fossil fish from Scotland

Fossils from the Devonian ‘Age of Fishes’ are found across Scotland. 

They lived in a time when life flourished in rivers and lakes. 

In the Devonian period, 417 to 354 million years ago, Scotland lay south of the equator. 

Fish had evolved in the sea, but by Devonian times they also lived in rivers and lakes.

The Devonian rocks in which these fossils are found is often called the "Old Red Sandstone", seen here in south-east Scotland.

Sunday, 21 December 2014

Climate Change and Food - how will Agriculture be affected?

Agriculture needs nice predictable conditions. 

Farmers can put up with some bad weather, but climate change will make unusual events more likely.

20-30% of plant and animal species will be more likely to become extinct if the temperature rises by more than 1.5-2.5C.

There will be big effects on farming from droughts and floods.

The biggest effects will be seen first near the equator.

Just being near the equator makes it more difficult for countries to make economic progress.

Hotter conditions affect how crops grow.

Our agriculture is heavily reliant on grasses from the temperate regions.

Corn, wheat, rice and so on are all types of grass.

The tropics is a hard place to grow an industrial society.

Jupiter and its Atmosphere

Jupiter is the biggest object orbiting the Sun.

Jupiter is mainly composed of gases, mostly hydrogen and helium. 

In this image, Jupiter's moon Io is the 'bead' just above the Great Red Spot.

The Great Red Spot is bigger than Earth. Studies have indicated that the Great Red Spot is travelling around the planet.

The Great Red Spot is a storm bigger than Earth, and has been seen since Jupiter was first examined through telescopes hundreds of years ago.

It appears to be shrinking.

Saturday, 20 December 2014

Russell Coope - the man who counted beetles, and discovered abrupt climate change.

Most people think climate change always happens slowly, but that is wrong.

Rapid climate change was discovered by accident by Russell Coope.

In the 1950s, Russell Coope was a young geologist who spotted something unusual in a quarry in the English Midlands.  This is his own description of what he found ...

"I happened, entirely by accident, to visit a Quaternary gravel pit in which were exposed the spectacular bones of mammoth, woolly rhinoceros and bison. 

Looking at their sediment matrix I was amazed to find enormous numbers of equally spectacular, if somewhat smaller, insect remains. 

I was hooked instantly! 

Particularly exciting to me was the fact that these insect fossils showed that Quaternary climates had changed abruptly. 

Thus, at times, fully glacial climates gave place to temperate interglacial conditions within the span of one human lifetime."

This discovery was the first time it had been realised that the climate can change really quickly.

Russell Coope died in 2011, but gave an interview that year......

The key word is "Ferocious".

So how does this work?

Different beetles like different temperatures.

By counting the fossil beetles and types of beetles in a set of layers of sand or gravel, Coope could tell what climate existed in that place, and how it changed.

Experts still use Russell Coope's method.

This fossilised beetle is well preserved.


Scientists often identify fossil beetles from fragments.

This particular fossil is of a diving beetle found in the La Brea Tar Pits in California.