Crustose Coralline Algae growing on the rock under a juvenile kelp (Ecklonia radiata). CCA can cover up to 80% of the rock surface in the temperate waters of Australia and is essential for the settlement of many species.
Photo: Dr Andrew Irving.
A student emailed me yesterday to request a letter that I wrote to the editors of Science a couple of years ago (“Honing the geoengineering strategy“). At the time, I was incensed by talk that we could stop global warming by dumping tonnes of sulphur into the atmosphere (which has a cooling effect) or a range of other “engineering” solutions. There is a series of excellent reports published by the UK Royal Society on the topic for anyone who is interested.
It wasn’t the ridiculous nature of these suggestions that got my attention though. I was more concerned by two things:
1. Anything that we do other than cutting carbon emissions is only buying time and I believe will only give us a false sense of security; and
2. The disregard that many geoengineering solutions have for the other effects of pumping millions of tonnes of CO2 into the atmosphere (but note, not all geoengineering fits into this category – something I will post on later).
Yes, there is warming, but from an ocean’s perspective there is also Ocean Acidification. Whether you believe in “Climate Change” or not, ocean acidification is happening and will continue to happen – its basic chemistry. As carbon dioxide dissolves into seawater it forms carbonic acid, which in turn reduces the pH of the water. Now, the ocean won’t become acidic like the acid you find in car batteries, but this increased acidity does reduce the amount of carbonate in the water. This carbonate is essential for all of the organisms that form hard structures from calcium carbonate, including everything from corals to snails to crustose coralline algae.
I’m sure that everyone reading this will have heard about the corals, but who really cares about coralline algae (or CCAs as we term them)? In fact, do you know what they are? (the pink algae covering the rock in the picture above). Though they may be humble, thousands of species rely on them. In tropical systems they form a hard reef crest to protect corals from waves. In temperate kelp forests they are essential for the settlement of species like abalone, which are not only important to the ecosystem but support multi-million dollar fishing industries.
So, not only does the talk of geoengineering provide us with a false sense of security about our ability to treat the symptoms of climate change, but the discussion often disregards the multifaceted problems that are caused by excess carbon in our atmosphere. Ultimately, the only way to fix the problem is to treat the cause – reduce our reliance on carbon based sources of fuel.
Other excellent blogs on Ocean Acidification:
Australian and New Zealand Ocean Acidification Project
http://oceanacidification.wordpress.com/
Active Oceans 