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 CO2 in 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.

Popular posts from this blog

Climate Change - The link with mass extinctions

Image
What is the worst-case scenario for climate change? The geological record shows that when the atmosphere suddenly changes, there are big effects on living things. 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. This photo shows geologists investigating tilted sedimentary rocks at Shangsi in South China. Triassic rocks (at the top right) lie over 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 CEs' and some are 'positive CEs'. Negative CEs  indicate that lots of gaseous carbon compounds escaped into the air, causing warming. These are sometime
Read more

Climate Change - The Greenhouse Effect

Image
What do scientists mean by the " Greenhouse Effect "? 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. The gases then re-emit the energy into the air. If there are more of those gases, less heat escapes into space. An extreme case has happened on Venus. 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.
Read more

Climate Change - Coal and carbon dioxide

Image
Coal, oil and natural gas are  fossil fuels . When they are burned, they  change the Earth's atmosphere. How is that possible?       C oal  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 CO 2  in the air seen in   the ice core record (800,000 years)  is  20 ppm in 1000 years. The CO 2  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 i
Read more