Climatide

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If you thought my State of the Oceans report was scary, get this: An international panel of ocean experts known as the International Programme on the State of the Ocean has released a new report that says human activities are driving marine life extinct at an unprecedented and accelerating pace. No sugar coating there.

The group points to problems like pollution and overfishing, but says that rising levels of carbon dioxide from fossil fuel combustion pose the greatest risks. The State of the Ocean experts aren’t alone in their thinking; many scientists think the ocean is in the early stages of the sixth mass extinction – the first in the history of the Earth to be caused by humans.

Here’s the basic argument:

• Ocean acidification. As carbon dioxide accumulates in the ocean (approximately a third of human carbon dioxide emissions are absorbed by the ocean), it causes a fundamental shift in ocean chemistry. The ocean becomes more acidic and it gets harder for marine plants and animals to extract the minerals and nutrients they need to grow.
• Rising temperatures. Rising water temperatures cause physiological stress and change the locations where plants and animals can survive.
• Falling oxygen levels. Warmer water holds less oxygen. Pumping up carbon dioxide levels could make the problem even worse by feeding algal blooms that, in turn, feed oxygen-consuming bacteria; it’s worth noting that it’s still unclear whether rising carbon dioxide levels will actually increase algal growth or whether the other impacts of carbon dioxide in the oceans will cause decreases. Still, scientists say permanent low-oxygen ‘dead zones’ could cover a quarter of the oceans by 2100.
• Climate change makes everything else worse. Low-oxygen conditions caused by climate change compound the already expanding problem of dead zones that result from algal blooms fertilized by agricultural run-off and wastewater discharges. Changes in water temperature and chemistry make it harder for overfished populations to rebound. And warmer waters may make it easier for organisms introduced into new areas by human activities to take hold and out-compete native species. In other words, climate change compounds all the other major threats facing marine life. For this reason, it has been called The Great Exacerbator.

One of the main points of the State of the Ocean report is that the current pace of changes is unprecedented, and appears to be accelerating.

The State of the Ocean report argues that the speed of change makes it imperative we take immediate action to address the problem. Their first recommendation, of course, is to quickly and dramatically reduce carbon dioxide emissions. They also recommend “urgent actions” to stop overfishing, reduce pollution, control ocean mining, and establish marine protected areas.

In a commentary about the report, Kelly Rigg, Executive Director of Global Campaign for Climate Action, says those actions could actually have the effect of decreasing the problematic carbon dioxide levels:

The best way to get existing CO2 out of the atmosphere is to increase the CO2-absorption capacity of natural ecosystems — both on land and at sea. This means halting deforestation and overfishing, stopping the production and discharge of dangerous pollutants, and preventing habitat degradation, to name just a few examples.

Rigg, however, is adamantly opposed to the use of geo-engineering – large-scale technical manipulations of the global climate system. Coincidentally, the Intergovernmental Panel on Climate Change is meeting this week to discuss that very topic.