Ocean acidification is often referred to as the evil twin of Climate change. But what is it, why should we worry, and what can we do about it?
Nature has a natural buffer for the excess hydrogen ions in terms of Carbonate buffering.
Carbonate ions enter sea water through the natural weathering of rocks such as limestone, and from the shells of dead marine animals. So the processes that put carbonate into seawater is a very slow processes.
The carbonate combines with some of the excess hydrogen ions acting as a natural buffer.
CO32-+ H+–> HCO3–
The sting in the tail is that it leaves less of these Carbonate ions in the ocean.
We’ll cover Climate change in a separate post. But as the planet is warming most of the extra heat being trapped by the thickening blanket of ‘greenhouse’ gases in the atmosphere is going into the oceans, warming them up from the top down.
The oceans have a high capacity to retain heat, and have so far absorbed over 90% of Earth’s excess heat in recent decades. Most of this heat is being absorbed by the top 700m. This is also leading to the thermal expansion of water and contributing to sea-level rise.
For coral reef environments, heat stress may lead to bleaching (whereby corals loose their colour as their photosynthetic symbiont is expelled, effectively leading to starvation). We saw this ourselves in our 2016 trip to Madagascar when talking to local fishermen in the North-West of Island near Nose Be.
Madagascar wasn’t the only region affected.
The 2016-17 El Niño event caused over 90% of corals in the Northern section of the Great Barrier Reef to bleach, as well as reefs in the Maldives, south-east Asia, the Caribbean and the Pacific, as surface temperatures rose in the shallow waters where corals exist.
While a single bleaching event doesn’t usually destroy a reef, the IPCC suggest that 2˚C of global warming will result in the loss of 99% of warm water corals by 2100 (we’re currently on track for over 2˚C of warming). (2)
How to Check your own environmental footprint
The World Wildlife Fund have a carbon footprint calculator where you can check your own carbon footprint with tips on how to reduce it…
If you want to really experiment with policies for 2050 the UK government have an interactive tool where you can play with the energy mix and see how we can reduce emissions
In a subsequent post we’ll look in more detail at Climate change, why it’s happening and how we can help.
(1) Thank you to Ceri Lewis, Marine Biologist at the University of Exeter for the ongoing research used as the basis of this article.
(2) The Science of Climate Change and Climate Change Solutions – University of Exeter.