If climate change doesn’t grab you, meet its evil twin

Charles Clover
Whoever leaked that clutch of Climategate emails last month must be laughing his socks off. For he has unleashed upon the rest of us the phenomenon of the born-again climate sceptic, the kind of man (always a man, almost invariably wearing a tweed jacket) who now materialises beside me at parties and confides that he has been having second thoughts about climate change.
My first instinct is always to humour him. I say I would be absolutely overjoyed if in a few years’ time we were to find out that Richard Lindzen, the most distinguished sceptic among the academic meteorologists, has turned out to be right and that the early 21st century got itself into a hysterical panic on the basis of trends based on highly uncertain computer predictions. But, I add, there are reasonable odds that he is wrong. My follow-up question is this: “Do you know that climate change is not the only reason to be uneasy about carbon emissions?”
On each occasion I am met by a look of puzzlement, followed by a perplexed nod, and I realise the person in question hasn’t a clue what I am talking about. He hasn’t heard of the acidification of the sea, a phenomenon quite separate from global warming but just as alarming. The reason, I suspect, is that it does not rate a line in the bestselling sceptical books on global warming by Christopher Booker or Nigel Lawson — which seem to be all that my tweedy friends have read on the subject.
Ocean acidification has been quite scandalously left out of the reckoning in the past few weeks. I am not for a moment belittling the science behind man-made global warming. This still seems to me solid, despite the shenanigans at the University of East Anglia. That levels of carbon dioxide in the atmosphere are rising is not disputed. We have known since the 19th century that carbon dioxide was a crucial greenhouse gas. Venus has a lot of it and is hot as hell. Mars has almost none and is cold as ice.
However, even if you happen to believe that everything we know about greenhouse gases is illusory — unlikely though that is — we would still need to agree at Copenhagen this week to cut our emissions of carbon dioxide because of what is happening to the sea, the source of roughly half our food and provider of other useful services that we tend to take for granted.
We know the ocean absorbs about 25% of the carbon dioxide we emit each year. This CO2 dissolves through wind and wave action to form carbonic acid. This is altering the chemistry of the seas in ways that are not disputed and are far simpler to understand than the effect the same pollutants are having on the atmosphere. I recommend the startling practical demonstration on YouTube of what acidity will do to the oceans given by Jane Lubchenco, administrator of the US National Oceanic and Atmospheric Administration, to a congressional select committee this month.
Since the beginning of the industrial revolution in about 1750, sea water acidity has increased by 30%. The speed and degree of this change are faster than anything that had happened for 55m years. The changes being observed are beginning to disrupt the ability of any organism to make shells out of calcium carbonate. Organisms that do this include corals, crabs, lobsters, small creatures vital to the diet of fish and plankton of the kind that die and form chalk deposits such as the white cliffs of Dover.
Projections show that by 2060, given the current rate of fossil-fuel emissions, sea water acidity could have increased by 120%. Lubchenco showed Congress a scary picture of what a shell would look like if it had spent a month in water as acidic as this. The shell had begun to dissolve.
Such an effect could trigger a chain of reactions through entire ecosystems, from whales to fish and shellfish, with huge implications for economies and wildlife. It could even stop the sea absorbing as much carbon dioxide as it does now, accelerating global warming. It is pretty scary stuff.
Predictably, the science of ocean acidification, which is accepted by governments on both sides of the Atlantic, does not go uncontested by the global warming sceptics. They say you can’t acidify the ocean because it washes over alkaline rocks. This process of weathering rocks is indeed how the alkalinity of the ocean will recover, but leading scientists say it will take hundreds of thousands of years. At the unprecedented speed that acidification is happening, the marine organisms will be knocked out before the rocks can dilute the acid.
There is plenty we still need to know about the acidification of the ocean. However, it looks as if unpleasant things start to happen if we go beyond 450 parts per million of carbon dioxide in the atmosphere (bear in mind we reached 390ppm earlier this year). That is, coincidentally, the threshold for holding the Earth’s average temperature rise down to a relatively “safe” 2C.
So ocean acidification, which people are beginning to call climate change’s “evil twin”, may be an even more pressing reason to move to a low-carbon economy than climate change itself. And that makes it doubly irresponsible for those people who scorn the need to cut carbon emissions to ignore what is going on in the oceans.