Although it is no doubt next to impossible to be able to change such entrenched mindsets as those of this particular baby boomer, there is still extremely limited public understanding of the insidious changes currently taking place in our oceans. In addition to the rise in both sea temperature and sea level (approaching a centimetre every two-to-three years) a rapid increase in ocean acidity is now on course to profoundly disrupt marine life.
With the USA pulling out of the Paris Agreement, will the rest of world manage to pull together in order to prevent another tipping point? After all, increasing ocean acidification isn't something us non-marine scientists can directly observe. One key point that is immediately obvious is that it isn't a localised issue: as a third of atmospheric carbon dioxide is absorbed into the oceans, all the planet's seas will be affected. The decrease of 0.1pH unit in the past few centuries equates to an astonishing 26-29% increase in acidity. What's more, this change is predicted to have doubled by the end of this century. Clearly, the effect on marine life is set to be substantial.
So what is being done to assess the probable issues? Various projects around the world are using mesocosms - transparent cylinders up to ten metres long - to understand the effects of current and predicted near-future acidity levels on marine life. Coral bleaching is possibly the one condition people will have heard of (although there appear to be an astonishing number of people who think that coral is a plant rather than invertebrate animal) but sea temperature changes are as much a cause as increased acidity. Apart from causing stress to some marine organisms, leading to such conditions as lowered immune systems and so the spread of disease, acidification reduces the material available for shell and carapace formation, especially for juveniles and nauplii.
The problem isn't so much the change itself as the rate of change, which is far faster than normal geophysical processes. Indeed, one report states that over the past 20 million years, changes in oceanic acidification have been barely one percent of the current rate. Obviously, there is minimal chance of the non-directed mechanism of natural selection keeping pace with adaptations to the new conditions.
While many organisms will suffer, some such as jellyfish and toxic algae may benefit, with the latter leading to the poisoning of key fishing industry species. This in turn could lead to toxins entering the human food chain, on top of the economic issues from the decline in fish and shellfish stocks. Indeed, the US Pacific coast aquaculture industry is already experiencing a reduction in the shellfish populations. This will be in addition to the pollution of fresh waterways already explored in a post last year.
Of the various experiments aiming to understand the impact of the rapid increase, the largest project is the pan-European Biological Impacts of Ocean Acidification (BIOACID) scheme. Giant mesocosms sunk in a Swedish fjord have been sealed with local ocean water (and associated organisms) and half of them modified with the projected pH level.
Similar but small projects are underway in New Zealand and the Canary Islands, with preservation of edible stocks a key priority. Another problem with a decline in shellfish species destined for human consumption would be the loss of the raw material for chitosan, which may prove to be an ecologically-friendly replacement for plastic packaging.
Clearly, there could be numerous - and some as yet unknown - knock-on effects from the ocean acidification. Unlike the rise in atmospheric temperature, it is much more difficult to see the results of this fundamental change and for the public to understand the consequences. Yet again, the life forms affected are far from the cute poster species usually paraded to jump-start the public's environmental consciousness. Unfortunately, these may prove to be far more critical to the future of humanity and the wider world than say, giant pandas or Amur leopards. It's time for some serious sci-comm to spread the warning message!
