Slowing of Global Warming May Be Cold Comfort for the Oceans

via Wikimedia Commons

via Wikimedia Commons

Pity the planet’s oceans. They have been doing more than their fair share in coping with humanity’s profligate dumping of carbon into the atmosphere and the consequent rise in global temperatures. The oceans have been serving as a buffer, masking the full impact of our species’ voracious need for energy. But their watery intervention seems to come at a tremendous cost.

The Intergovernmental Panel on Climate Change released its latest report on Friday. The big headline news is that the report (the summary of which required unanimous agreement from member nations) provides “unequivocal” evidence that  the atmosphere and oceans have warmed since 1950, and that scientists are now “95 per cent certain” that humans are the “dominant cause”.

Prior to the report’s release, much had been made of the “pause” in global warming over the last fifteen years during which the earth’s temperature has not increased as much as predicted.   Climate change skeptics have been making hay with the discrepancy between climatologists’ predictions of ever increasing temperatures and the apparent leveling off the earth’s surface temperature over the last decade or so. An organized campaign by well-funded climate skeptics have seized on the apparent slowdown to try to discredit a theory supported by the overwhelming majority of climate scientists.

John Church, the IPCC scientist coordinating research on sea change dismissed any notion that the apparent hiatus in rising temperature indicated a slowdown in global warming itself.  Rather, the cause is likely attributable – at least in part – to the oceans absorbing the ever increasing heat. “Oceans can trap huge amounts of heat,” said Church. “But how much and for how long is unclear.” As Church describes the process, heat is being absorbed at deeper levels of the ocean, effectively masking the overall heat load we are asking the planet to take.

The IPCC report is hardly the first time the pause in global warming has been attributed to the oceans acting as giant heat sumps. A recent study in the journal Nature posited that the oceans are absorbing atmospheric heat, pausing the increase in global temperatures even as arctic ice continues to melt at a record pace. That conclusion was echoed in a detailed report by Zeke Hausfather for the Yale Forum on Climate Change and the Media which attributes the  slowdown in global surface temperatures at least in part on more heat going into the deep oceans.

But the heat load is not the only effect carbon is having on the oceans. The very chemistry of the seas is changing.

The Seattle Times, one of the last independent, family-owned major metropolitan newspapers, is running a remarkable series of investigative reports on ocean acidification. The profoundly unsettling articles describe ocean acidification as the lesser-known twin of climate change. Humanity is dumping 100 tons of carbon – the equivalent of a hopper car of coal – every second of the day, according to the Times report. The oceans are already 30% more acidic than they were just 30 years ago. All that carbon dioxide is scrambling marine life on a scale almost too big to fathom. The increasing acidity of the ocean waters can play havoc with crabs, squid, coral, oysters, and especially krill. Krill are the tiny crustaceans which form the base of the food chain in the world’s oceans. If krill populations collapse, the consequences for the entire ecosystem would be dire.

The Times details the growing alarm in Alaska over the threat to the state’s lucrative crab harvest. Experts warn that the entire fishery there could collapse in the coming decades barring a dramatic reduction in greenhouse gas emissions.

As Hausfather points out in his study, there is still much we don’t understand about the many different factors impacting Earth’s climate system. Nobody knows how much heat and carbon the oceans can safely absorb. But the effects of pouring carbon into them are already apparent. And warming water and increasing acidity are only the beginning. Perhaps the spookiest side effect I’ve seen discussed is the alarming growth in jellyfish populations around the globe. Yes, global climate change and ocean acidification are apparently causing massive increases in jellyfish populations, with decidedly unpleasant consequences for divers, beach combers, and other sea life. While acidification is killing off mollusks and krill, jellyfish, which have no hard shell, thrive in more acidic and warmer waters. They’re taking over the oceans.

Jellyfish appear on the menu in some parts of the world. The Chinese, in particular, have long considered them a delectable treat.

We may all end up eating jellyfish, by necessity if not choice. Get used to it.

The Times has performed an invaluable service by publishing its series on acidification, and you owe yourself the the time to read it. The first installment is here

One response to this post.

  1. […] September, the Intergovernmental Panel on Climate Change released its latest, and grimmest, report on climate change. The report underscored the urgent necessity of swift and coordinated action. […]

    Reply

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