Much of the mercury emitted, although toxic, falls outside the umbrella of international conventions, or even national laws. Perhaps because of past successes in controlling mercury releases from industry, it is coal burning and waste incineration, not chemical use by manufacturers, that releases the bulk of mercury today (although precious metal mining is a big contributor in some places). Mercury gives us another excellent reason, alongside greenhouse gas reduction, to move away from coal as a source of power. Given the rising mercury contamination of marine predators and the role of methyl mercury as an insidious poison, I don’t think this problem has yet got the attention it deserves. Following close on mercury’s heels, pharmaceuticals are emerging as another class of pollutants that needs to be taken more seriously. Again, the only way to clean up pharmaceuticals is to prevent them getting to the sea in the first place. Sophisticated scrubbing technologies are being trialled on sewage treatment plants in the European Union, but they are expensive and energy intensive. The search is on for cheaper and more environmentally friendly alternatives.3
Despite my concerns, I am encouraged by recent efforts to deal with pollution. Clean air and water laws are continuously introduced and upgraded, and these directly benefit marine life and water quality. The tide even seems to be turning against plastics. By one estimate nearly six million plastic bits and pieces are discharged into the sea every day; if we include microplastic particles like the ones we find in facial scrubs that number rises to billions. In a fine example of the way in which an individual can make a difference, a UK wildlife camerawoman named Rebecca Hoskins became concerned about the impacts of plastic bags on marine turtles who mistake them for jellyfish. She persuaded her home village of Modbury in England to do away with plastic bags, beginning a fight back against the tyranny of plastic waste that has since led to a countrywide reduction in plastic bag use by UK supermarkets. In the United States, first California, then other states and cities, all the way to Washington, D.C., started charging customers five cents per plastic bag—the impact has been quick and impressive. The backlash against plastic is also reaching the developing world. In 2005, the Indian state of Maharashtra reached its breaking point when plastic refuse choked their streets, creeks, and storm drains, and the authorities banned plastic bags. South Africa similarly banned the thinnest plastic bags in 2003; they had become so common blowing around the countryside that they had been dubbed the country’s “national flower.”
For several decades now, environmental groups the world over have mounted beach cleanups, often to great effect. The trash piles heaped up at the end of the day are horrific testaments to how messy we are. Recently, efforts have moved offshore to tackle garbage at sea and on the seabed. In Europe a project called “fishing for litter” aims to get the fishing industry to bag up the junk they catch in their nets and bring it ashore for disposal, reversing their previous practice of shoveling it back over the side with the bycatch. Were this approach to be applied more widely, it could make a big difference to the amount of trash lying at fishable depths. The European Commission announced in 2011 that it would trial a scheme to pay fishers to catch plastic in the Mediterranean, Europe’s filthiest sea.4 The Mediterranean has earned this epithet because it is surrounded by populous countries visited by millions of beachgoers and is almost completely enclosed, so junk has accumulated. The state of Hawaii also has a program to collect lost and discarded fishing gear that is then burned to produce power for the islands.
What has shocked the world into taking plastic more seriously are the great ocean garbage patches circling endlessly on voyages without destinations. Unfortunately, these are not of much interest to fishermen. They are short on critical nutrients and have low levels of plankton productivity, so there aren’t many fish. Unless we do something, these places will continue to suck in trash like oceanic black holes. The Great Pacific Garbage Patch is said to be twice the size of Texas: enormous at nearly 440,000 square miles, but not beyond the bounds of control. In a way, the ocean gyres do us a favor by concentrating floating garbage into places where we could gather it up without bankrupting ourselves. Twenty boats equipped with hundred-yard-wide skimmers could sweep the gyre in the North Pacific in five years if they worked round the clock. Such boats don’t yet exist but more conventional cleanups have been attempted at smaller scales.
This would only work for stuff that floats, and only for fragments above a certain minimum size. To save the albatrosses we would have to fish up everything larger than a bottle cap, which would be a technical challenge. Is it worth going to so much trouble for a bunch of silly birds? The answer is yes. Even if you can’t care less about the albatross, self-interest might compel you to do something. Plastics crumble into ever smaller fragments over time, picking up toxins and passing them up the food chain, potentially ending up on our plate as we enjoy a tuna sandwich or sushi lunch. They take hundreds, in some cases thousands, of years to degrade, so unless we clean up the ocean garbage patches, they will continue to accumulate and break down until we stop making our plastic so durable. Fishing for litter will make little difference in the long run, however, unless it is married with efforts to stop littering in the first place.
The vast majority of stuff picked up by beach cleanups is local. At a remote beach in Brazil, collectors found bleach and detergent bottles, hypodermic syringes, and a host of other things washed downstream from towns and villages by a nearby river. In Majorca, beach trash is dominated by cigarette butts, plastic water and soda bottles, and tampon applicators. Litter peaks in summer, when the island is busiest. A former student who went to work in Asia wrote to me of her horror at the huge quantities of plastics and other garbage that choked the banks of rivers in Nepal. She asked a villager if it was ever taken away. He said, “Yes, yes… when the monsoon rains come, it is all taken away.” She met this detritus again when she sailed across the Bay of Bengal, where junk carried from the Himalayas piles up in the ocean. Local efforts to tackle garbage would make a big difference, and in some places skimmers have been strung across rivers to catch things before they head to sea. But skimmers are really a last resort, and create problems of their own like blocking the passage of boats.
It would be far more effective to tackle pollution at its source. In the case of plastics, the three r’s apply: reduce, reuse, recycle. To them we can add recover and redesign.5 By recover we mean energy recovery using waste plastic to generate power, as in Hawaii. But burning produces other kinds of pollution, so it is better to recycle where possible. Anyone who has wrestled three layers of plastic from their box lunch knows manufacturers could do much more to reduce their use of plastic and design recyclability into their products. In a promising development, some new plastics are made from biodegradable materials like corn starch. More problematically, others are designed to crumble rather than biodegrade. They break down when exposed to ultraviolet light from the sun. That isn’t much good in a landfill or out at sea, where floating plastic bags are quickly covered in algae that block much of the light and prevent breakdown.6 Setting this difficulty aside, making a bag that shreds into small pieces will only thicken the broth of microplastic particles circulating in the sea.
Preventive measures will ultimately do more to reduce the problem of plastics than laws that are impossible to enforce on the open sea. Despite the fact that it is illegal to dump plastics from ships, the amount of rubbish picked up from British beaches in cleanups sponsored by the Marine Conservation Society increased 88 percent between 1994 and 2010, much of it jetsam from boats, and nearly two-thirds of it plastic.7 In South Australia, a ban on dumping from fishing vessels failed to reduce wildlife entanglement.8 The number of sea lions from Kangaroo Island wrapped in bait box packing straps increased sixfold and more than twice as many fur seals were trapped. The results of a similar scheme in South Georgia in the southern Atlantic were more encouraging, as incidence of seal entanglement halved.
Just before the Beijing Olympics, a flotilla of small boats se
t forth every day into a green sea near Qingdao. For weeks their crews forked great heaps of seaweed into the boats, piling it up like marine haystacks. Qingdao had become so polluted by nutrients from sewage, agriculture, and industrial runoff that thick masses of seaweed obstructed the passage of boats. The Olympic sailors would have recorded some pretty feeble times without their efforts.
It is relatively easy to regulate sewage or factory effluents that can be traced back to their sources and much harder to regulate nutrients washed to sea from farms and city streets, or blown offshore from plowed fields. Nonetheless success is possible, as an unintended experiment with the Black Sea proved.9 By the early 1980s, fertilizers bled from the plains of the southern Soviet Union had turned the Black Sea into a green soup with few fish and an alarming number of jellyfish. The collapse of communism triggered a slump in fertilizer use, as state-controlled farms ran out of money to buy agrochemicals. Water quality has significantly improved since the early 1990s, with fewer and less intense plankton blooms and less oxygen depletion in coastal waters. Better water quality seems to have made life harder for the invasive comb jellyfish Mnemiopsis. Its population has collapsed and fisheries for small open-water fish have recovered. The Black Sea experience offers hope for other enclosed coastal seas that now suffer from pollution-induced dead zones, jellyfish explosions, and harmful algal blooms.
Nutrient pollution has choked the Baltic Sea, surrounded as it is by fourteen industrialized countries with farms that rely on agrochemicals, heavy industries that produce copious discharges, and a combined population of eighty-five million whose fertile sewage effluent ends up downstream. As I explained in chapter 8, this modest inlet of the North Atlantic is shallow, with an awkward circulation that leaves puddles of dense, salty water to stagnate near the bottom. Over the years there have been many plans to restore the Baltic to health, but none has yet worked. Indeed, as living standards improve in Eastern European countries, their downstream impact on the Baltic grows worse. In desperation, perhaps, engineers have begun to ask whether it is possible to fix the Baltic by brute force, or technological brilliance as they might prefer to call it.10
In recent years, dead zones have swallowed up to twenty-three thousand square miles of the Baltic Sea. Because of its difficult circulation, thick layers of undigested organic matter accumulate in its basins in water that has been drained of all oxygen. If we could just stir some oxygen from the surface back into these lifeless waters, life could return and take care of the heavy burden of waste. That might happen if we could bulldoze Denmark out of the way to improve circulation, but the Danish wouldn’t approve. So instead, how can we mix oxygen from surface waters to the seabed? Engineers have calculated that it would take 2.2 million to 6.6 million tons of oxygen a year to resuscitate the dead zones. It is hard to imagine a figure like this, but easier if you think of it in more concrete terms: 6.6 million tons of oxygen would fill fifty-five thousand railroad cars!
One scheme foresees a sea of wind turbines that would drive pumps to flush surface water to the bottom. Another idea is to install vast arrays of vertical pipes. Waves washing over them would push aerated water down with the help of gravity to exit near the seabed. Another idea is to throw in some alum or powdered limestone to lock up the phosphorus so that plankton blooms will run out of fuel, but the volume is daunting and the addition would contravene the London Dumping Convention. There is now so much phosphorus in Baltic sediments from fertilizer and sewage runoff that there have even been suggestions it should be mined. Some have proposed we should intensively fish sprats, which eat zooplankton, to spare the zooplankton that graze on phytoplankton blooms. I am sure this would be popular with the fishing industry, but it hardly seems a persuasive solution, as it would create as many problems as it would solve. In fact, close scrutiny shows none of these ideas to be realistic or viable right now, so it is back to Plan A: reduce nutrient pollution flowing into the Baltic. Countries around the Baltic have committed to a reduction of 50 percent, but it will take strenuous effort to meet this target.
Bottom trawling multiplies the problems. Organic matter and nutrients can get buried on the bottom so they are no longer available to power blooms of plankton or poisonous algae. Trawlers churn sediments to release those nutrients back into the water so that plankton blooms on and on. A small trawler fitted with two twenty-five-foot-wide nets and a chain that cuts an inch into the seabed can raise approximately two thousand tons of sediment per hour of trawling, of which over two hundred tons will remain in suspension for days.11
Why do we do it? Why do we foul and defile our own living space? To take one recent example, in the 1990s China embarked upon a program of economic expansion based on coal-fired power stations in full knowledge that they would soon choke on their own prosperity. Perhaps they didn’t anticipate just how fast that would happen or with what suffocating vehemence the pollution clouds would envelop them. Throughout the world, rivers and beaches are clogged with the jetsam of civilization, air and water filled with the noxious hallmarks of progress. I think our minds are still stranded in the past. For most of history, the number of people on the planet has been small and the unoccupied space seemed almost limitless. We used natural materials that when discarded soon crumbled back into water or soil to feed new life. Today we are proliferating faster than the adaptive capacity of our biological natures. Before the twentieth century, nobody lived long enough to witness a doubling of the world’s population. It is a mark of just how much the rate of growth of human societies has accelerated that some people alive today have witnessed not just one doubling, but two.12 Adapt we must, because the tide of progress is not about to recede any time soon.
Although cleansing the oceans is a task bigger than any other cleanup attempted in history, pollution control is perhaps among the easiest of the oceans’ problems for which to gain political will. People place health concerns high on their political to-do lists, especially in democracies. Action will only follow public awareness and demand, but the latter is on the increase. However far we get, and there is a long way to go, pollution control and prevention will always remain a work in progress. New pollutants are constantly introduced as by-products of our inventiveness and industry. We must be ever watchful.
CHAPTER 18
Can We Cool Our Warming World?
Wouldn’t it be wonderful if the world had a thermostat that could be reset a couple of degrees? How many of our problems would disappear! In one sense, it does, for greenhouse gases such as carbon dioxide and methane act as a control. Add more to the atmosphere, and you dial up the heat. Remove them, and we could regain our cool. Technologists and governments, while searching for ways to reduce emissions, are also on the hunt for engineered fixes to our climate problem.
The planet has ways of dealing with high levels of atmospheric carbon dioxide. The greenhouse worlds of the past did eventually cool through reactions that removed carbon dioxide and methane from the atmosphere. The carbonic acid formed when carbon dioxide dissolves in the oceans is neutralized in a reaction that converts carbonate to bicarbonate. This reduces the amount of dissolved carbonate and so expands the layer of deep water that is undersaturated with carbonate toward the surface. This exposes billions of tons of carbonate sediments on the seabed to corrosive water, which can dissolve them. As the carbonate dissolves, it buffers the effects of acidification, so the oceans keep taking carbon dioxide from the atmosphere. The weathering of silicate rocks above water also takes up carbon dioxide. The awkward problem for us is that these feedbacks take tens or hundreds of thousands of years. In this respect, the effects of fossil fuel burning could outlast pollution from nuclear energy. (After ten thousand years, mixed nuclear waste becomes about three thousand times less radioactive, whereas the effects of a massive release of carbon on world temperatures will have declined far less, to between a half and a quarter of the peak.1) Conditions in the sea took one hundred thousand years to return to normal after the Paleocene-Eocene spike in world temper
atures and ocean acidity 55 million years ago, and probably a million years after the Permian-Triassic greenhouse episode 251 million years ago. We can’t wait that long. This means we must prevent the release of further carbon dioxide and find ways to take some back.
There is an emerging global consensus that we should restrict the rise in temperatures from greenhouse gases to four degrees Fahrenheit at most, which means we cannot go above about 450 parts per million of carbon dioxide in the atmosphere. Beyond that the risk of dangerous climatic upheaval is deemed too high. But even that target leaves us exposed to a small chance that we will pass an unknown tipping point and suddenly find ourselves on a headlong course toward catastrophe. To date the world has concentrated on ways to reduce emissions. These include greater efficiency in energy use and tapping more green energy from renewable sources. The oceans already play their role in the fight against climate change, as the biggest and most reliable sink for carbon dioxide, but maybe could do more. They cover more than two thirds of the planet and are, for the most part, uninhabited by people, so they offer considerable opportunities for engineered solutions.
Hydropower and wind have long provided us with energy, but there are severe constraints to their expansion on land. Most major rivers have been dammed, at least in the developed world, and new megadam projects are highly controversial because of the harm they cause to people and the environment. Wind farms are sprouting around us but are often bitterly opposed by those who feel they disfigure the landscape. The restless sea, out there and once offshore not in anyone’s back yard, offers a less obtrusive world of opportunity. Because the sea is pretty much flat and covers 71 percent of the planet, nearly 90 percent of the world’s wind energy is offshore.2
Already wind farms dot the horizon around many countries, and huge blocks of shallow sea are being licensed for development. In one extraordinary case of fractured thinking, the UK Crown Estate, which owns the seabed, licensed Britain’s entire share of the Dogger Bank, a shallow hill in the middle of the North Sea, for wind farm development. The Dogger Bank also happens to be one of the richest fishing grounds, but it seems nobody thought to ask for the fishermen’s views on the plan, nor the conservationists, who have now declared the place a Special Area of Conservation. Wind farms have yet to be built there, and it looks like there will be tense discussions when that stage is reached. Completed and proposed wind farms will soon grow to cover more than 20 percent of the UK’s territorial waters, which extend up to twelve nautical miles offshore. They are expected to supply about twenty-five gigawatts of electricity by 2020 (a gigawatt is one billion watts), roughly 7 percent of projected demand. If all of the world’s accessible offshore wind energy were tapped, it could supply around five thousand terawatts (a terawatt is one thousand billion watts), which is equivalent to about one third of the world’s current energy use.
The Ocean of Life Page 29
