I’ve got a piece in the latest issue of Prospect (not yet online) about the recent report on the state of the oceans from the IPSO project. Here’s what the full draft looked like.
“Unprecedented… shocking… what we face is a globally significant extinction event.” These judgements on the state of the global oceans, pronounced by the scientists who attended a recent workshop of the International Programme on the State of the Ocean (IPSO), sound truly scary. The future of the ocean’s ecosystem look “far worse than we had realised”, says IPSO’s director, Oxford zoologist Alex Rogers. “If the ocean goes down, it’s game over.”
When the IPSO report was released in June, it made apocalyptic headlines. But such is the prevailing public mood on climate and environmental change that strong words may do little to alter opinions. Sceptics will dismiss them as scaremongering in a bid for research funding, while they will fuel righteous indignation among those already convinced of impending catastrophe. And if you haven’t already made up your mind, this seems an invitation to paralysing despair.
So how seriously should we take the IPSO report? According to Hugh Ducklow, director of the Ecosystems Center at Woods Hole, Massachusetts, one of the US’s most prestigious marine biology laboratories, it isn’t exaggerating. “If anything”, says Ducklow (who is not a part of IPSO), “the true state of the ocean is likely worse than the report indicates.”
The IPSO workshop, held in Oxford in April, brought together leading marine scientists, legal experts and NGO representatives. They considered threats to ocean ecosystems ranging from over-exploitation of fish stocks to acidification of the waters, caused by increased amounts of dissolved carbon dioxide (CO2) as atmospheric levels of this greenhouse gas rise. Many fish populations have been literally decimated – even since the report was released, a paper in Science says that the state of some species of high commercial value, such as bluefin tuna, is worse than thought. Almost half of the world’s coral reefs, the most diverse ecosystems on the planet, have disappeared in the past 50 years, and the rest are now under severe threat because of overfishing, global warming and ocean acidification. But perhaps the greatest concern rests with the unglamorous plankton on which the entire the food chain depends. The microscopic plants (phytoplankton) that bloom seasonally in the upper ocean dictate the cycling of carbon, particularly CO2, between the ocean and atmosphere. But some phytoplankton are toxic, and when their growth is artificially stimulated by nutrients in fertilizers and sewage (a process called eutrophication), they can poison their environment. Worse, bacteria feeding on the decaying phytoplankton may use up all the available oxygen in the water, turning it into a dead zone for other life. In the longer term oxygen depletion (hypoxia or, if total, anoxia) is also caused in deep water by warming of the upper ocean, which suppresses the circulation of oxygen-rich surface water to the depths.
It’s not just marine biology that stands at risk. The melting of Arctic sea ice has been far faster than expected – summer at the North Pole could be essentially ice-free within 30-40 years. This doesn’t affect sea level, but is disastrous for Arctic life and the influx of fresh water could change patterns of ocean circulation. The melting of grounded ice from Antarctica and Greenland, however, is also proceeding apace – at least as quickly as the worst-case predictions of climate models. Coupled to expansion of water caused by warming, this means that sea-level rise is also tracking worst-case models: it could reach four feet or so by 2100, which will redraw the map of many coastlines.
Perhaps most troubling of all, the IPSO group concluded that these individual processes seem to exacerbate one another. For example, coral reefs damaged by ocean warming are further weakened by pollution and the overfishing of reef populations, making them even more fragile. The worry is that the combination of stresses could push ecosystems to a tipping point at which they collapse catastrophically.
Such things have happened naturally several times in the distant past. The geological record clearly shows at least five global mass extinctions, in which most species all around the planet vanished, as well as many more minor extinction events. The reasons for them are still not fully understood, but the prevailing ocean conditions in which they occurred are similar in some ways – warming, anoxia and acidification – to those we are seeing now. “We now face losing marine species and entire marine ecosystems, such as coral reefs, in a single generation”, the IPSO report avers. “Unless action is taken now, the consequences of our activities are at high risk of causing the next globally significant extinction event in the ocean.”
Sounds bad? Ducklow thinks that feedbacks and synergies could make things even worse. “Working in Antarctica, we’re seeing profound changes rippling through the food chain and affecting biogeochemical processes such as CO2 uptake.” Ducklow admits that any conclusions he and his colleagues have drawn so far, like those of the IPSO team, are based on inadequate observations – over too small a spatial scale, and for too short a time. But his informed hunch is that this merely means we’re not seeing the worst of it. “I expect that as we pass through another decade, with increased concern and surveillance, we will discover things are worse, not better, than we think.”
Ducklow isn’t alone in confirming that the IPSO report’s warnings are not exaggerated. “I agree that the oceans have been greatly impacted by human activity”, says Andrew Watson at the University of East Anglia, one of the foremost UK experts on the interactions of oceans and climate. “They have changed enormously and alarmingly fast over the past 100 years or so.” In Watson’s view, analogies with past mass extinctions are appropriate. “We suspect that at past crises, the real killer was widespread ocean anoxia. This is something that eventually the changes brought about by humans, particularly increased eutrophication and global warming, could bring on.”
But has IPSO pitched its warning wisely? The team seems to have sided with the view of some climatologists, such as NASA scientist James Hansen, that concerns will be heeded only if voiced forcefully, even stridently. Watson isn’t convinced. “In human terms such a change to the life-support systems of the Earth is still a long way in the future. Such disasters unfold over very long time scales compared to a human life: thousands or tens of thousands of years.” So while Watson feels that “the report authors state their case that way with the best of intentions” and agrees on the urgent need for action, he feels uncomfortable with some of the alarming statements. “We create a false impression if we say that we have to act tomorrow to save the Earth or ‘it will be game over’. I don’t find that kind of environmental catastrophism very helpful because it simply fuels a bad-tempered ideological and political argument instead of a well-informed scientific one.”
It’s an irresolvable dilemma forced on the scientists by manufactured controversy and political inaction: risk either being ignored or damned as alarmists. However, the tone of the report is a side issue; all agree on the necessary response. “What’s really needed is a long-term plan to reduce our impact on the oceans,” says Watson. Ducklow insists that this must include not just serious and immediate regulation of fishing, pollution and carbon emissions, but “a comprehensive, global ocean observation system, including ecological and biogeochemical measurements, to determine the current and evolving state of the ocean’s health.” Any suggestion that this is merely a gambit for more research funds now deserves nothing but scorn.