Sunday, 15 September 2019

Climate Change - Ocean acidification - what does it mean?

The phrase 'ocean acidification' means that the pH of seawater is falling.

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

Sea water normally had a pH around 8.2 

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 -

"A drop of 0.1-unit pH 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. 
"This will increase ocean hydrogen ion concentration (or acidity) by 100-150% above what it was in pre-industrial 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. 

With ocean acidification, corals cannot absorb the calcium carbonate they need to maintain their skeletons.

The stony skeletons that support corals and reefs will dissolve.


The left-hand picture shows healthy coral.    The right-hand picture shows dead and dying coral.

UNESCO: Great Barrier Reef Loses "In Danger" Status ...


The U.S. Geological Survey (USGS) is conducting research on ocean acidification in the Arctic, Gulf of Mexico and Florida estuaries, and the Caribbean and Pacific.

Saturday, 14 September 2019

Climate Change - What's going on with the Gulf Stream?

The Gulf Stream transports vast amounts of heat northwards, from the equator to the pole, passing off the East Coast of the U.S. and into the North Atlantic.



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.

A slowdown like this in the current has not happened for a very long time, perhaps as long as 1,000 years. 

It is possibly related to the melting of the Greenland ice sheet. 

The freshwater from the ice sheet is lighter than heavier, salty water that usually occupies that area. 

It tends to sit on top of the water, interfering with the sinking of dense, cold and salt-rich water.

650x366_10091611_oceancurrent


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 the rate of sea level rise along the Mid-Atlantic and North-east coasts of the U.S. 

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

This is still a matter needing more research.

Friday, 13 September 2019

Climate Change - Coal and carbon dioxide

Coal, oil and natural gas are fossil fuels.

When they are burned, they change the Earth's atmosphere.

How is that possible?      Coal is a good example.


Coal was formed hundreds of millions of years ago.

Geologists say that a three-metre (10-foot) coal seam took between 12,000 and 60,000 years to form.

Ancient trees and other plants lived, died and were fossilised.
All those plants took carbon dioxide out of the atmosphere. 
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.
The fastest rise of CO2 in the air seen in the ice core record (800,000 years) is 20 ppm in 1000 years.
The CO2 level in the atmosphere is now rising at around 20 ppm per decade.

The carbon joins up with oxygen when it burns.


Each carbon atom joins with two oxygen atoms to make a carbon dioxide molecule

As a result, oxygen concentration in the air is slowly reducing.


No need to panic, however, as the reduction is around 2ppm per year.

The atmosphere contains 210,000 parts per million of oxygen, so the reduction in oxygen has little direct impact.

It does, however, confirm that the extra CO2 is being made by burning of materials containing carbon, which combines with atmospheric oxygen.

Several scientific organisations measure the gases in the air.

One major set of measurements are from a laboratory in Hawaii.

Carbon dioxide levels hit record peak in May
We are time-warping vast amounts of ancient carbon (which we are combining with current oxygen) into the modern atmosphere.

Thursday, 12 September 2019

Climate Change - Carbon Sinks

Carbon sinks are natural systems that suck up and store carbon dioxide from the atmosphere.

The main natural carbon sinks are plants, the ocean and soil. 


Plants grab carbon dioxide from the atmosphere to use in photosynthesis; some of this carbon is transferred to soil as plants die and decompose. 

The oceans are a major carbon storage system for carbon dioxide. 

Marine life also takes up the gas for photosynthesis, while some carbon dioxide simply dissolves in the seawater.

35 billion tonnes of CO2 are produced each year by human activities.

The remaining carbon dioxide is building up in the atmosphere.

Wednesday, 11 September 2019

Climate Change - Corals and Coral Bleaching

Healthy coral can be very colourful.



Some coral reefs 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.

Reef-building corals only live in a limited temperature range.

Like porridge, they should 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.

Algae in corals need light

Corals grow in warm, clear, 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.

Tuesday, 10 September 2019

Russell Coope & the Discovery of Abrupt Climate Change

Many people think climate change always happens slowly, but that is not the case......rather than hundreds, or thousands, of years, sometimes it can happen in decades.

"Abrupt climate change" was discovered by accident by Russell Coope (1930-2011), over 50 years ago.

More recently he said:

"We are messing with the trigger that causes climate change....the outcome is likely to be ferocious."


In the 1950s, Russell Coope was a young geologist.

He was studying layers of sediment formed during the "Ice Ages", a time geologists call the Quaternary.

He 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."


A well-developed sequence of ice age deposits at Bridgwalton Quarry near Bridgnorth, Shropshire. (Photo: Dave Evans).

This was the first discovery of evidence that the climate can change really quickly.

His discovery was later confirmed by evidence from ice cores from the Greenland ice sheet.

So how does Russell Coope's method work?

Different beetles prefer different temperatures.

By identifying the beetles in 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 the fossil beetles from fragments.

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

A recent research project links some of the abrupt climate change events in the last glacial stage to changes in ocean circulation.
“We know from ice cores in Greenland that large climate oscillations occurred during this time,” lead study author Gene Henry told Gizmodo. “We wanted to see if those climate oscillations had an imprint in circulation patterns.” 

Monday, 9 September 2019

Climate Change - Is the Sun causing Global Warming? Or about to cause Global Cooling?

It is often claimed that the Sun is causing global climate change.

The Sun is the source of the heat on the Earth, but it has not suddenly become more active recently.

The Sun may be going into a phase of lower activity - but that will not reverse global warming.

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, so the Earth warms.

In the graph below, from the Stanford Solar Center, carbon dioxide data comes from the Law Dome ice core in Antarctica, and from the observatory on Mauna Loa in Hawaii.


There is no doubt why the Earth is warming.

A new study says that even if the Sun's activity did drop off for a while, it wouldn't have much impact on rising global temperatures. 

It could mean a higher chance of some chilly winters in Europe and the US, but the researchers say:

The idea that global temperature over the last few centuries is connected to solar activity has been disproved by astronomers.

There is now too much carbon dioxide in the air for there to be a repeat of the 'Little Ice Age'.


In fact, it is very likely that human activity has finally broken the cycle of glacial and interglacial stages.