Coastal Heritage Magazine
Climate Change and Ocean Health
Warmer, more acidic oceans threaten global fisheries.
Altered Fate. Timmy Simmons guides clams through a grading-and-counting machine at Livingston’s Bulls Bay Seafood in McClellanville. Scientists say that increasing ocean acidity will probably disrupt the growth of clams and other marine species that build shells. Photo by Wade Spees.
Coastal Heritage Magazine
Volume 23 – Number 1
John H. Tibbetts
Climate Change and Ocean Health
The sea is feeling the heat. Over the past half-century, the ocean has absorbed about four-fifths of the warmth added to the Earth’s climate. Arctic sea ice is retreating at an unprecedented pace. Ice sheets are melting into the ocean at a faster and faster clip. During the 1990s, global mean sea level—and sea level along the Atlantic coast—rose more quickly than at any other time during the twentieth century, contributing to erosion along vulnerable shorelines.
These trends are troubling. But, perhaps most alarming, fisheries around the globe are threatened by a one-two punch of rising temperatures and increasing acidity of seawater.
Ocean acidity has been called “climate change’s other problem.” Global warming doesn’t cause ocean acidity. Instead, escalating emissions of carbon dioxide, which mostly drive global warming, have also altered the ocean’s chemical balance.
By 2050, increasing ocean acidity is expected to disrupt the growth of marine creatures that build shells, including oysters, clams, lobsters, scallops, whelks, blue crabs, and many others. These animals could become increasingly smaller and malformed. Blue crabs in the Atlantic estuaries, for instance, would probably become runts by mid-century.
“Acidification would directly affect anything in the ocean that has a shell—about half of the total value of U.S. fisheries,” says Scott Doney, a senior scientist with the Woods Hole Oceanographic Institution.
Meanwhile, coral reefs around the world are dying. By 2050, scientists predict, coral reefs could disappear from the world’s oceans.
This graphic illustrates two projected warming scenarios and their impacts over the next two centuries. One is a business-as-usual, pessimistic scenario; the other is an optimistic projection in which national governments drastically limit greenhouse-gas emissions.
Shallow, sunlit waters, sparkling with brilliantly colored fish and coral species—we’ve all seen spectacular images of coral reefs. Over the past two decades, though, ocean warming has overheated many reefs, seriously threatening one of the ocean’s richest repositories of biological wealth. Corals reefs, moreover, would erode in more acidic waters, diminishing catches of grouper, snapper, and other reef fish.
“We are undertaking a massive experiment on coral reefs and on the ocean in general,” says Nancy Knowlton, a coral-reef biologist with the Smithsonian National Museum of Natural History.
Climate change’s most immediate threat in the ocean is to coral reefs, which provide habitat for one-fourth of all marine fish species, protect coasts from waves and storms, contain potential pharmaceuticals, and support tourism and fishing industries worth billions of dollars. About 2.6 billion people worldwide rely to some degree on seafood for animal protein, according to the United Nations Food and Agriculture Organization. Without coral ecosystems, many coastal economies, particularly those in poor countries, would suffer.
In early 2008, food riots followed rapidly escalating grain prices in nations from Mexico to Pakistan. Seafood prices would similarly skyrocket if fish catches decline and if aquaculture couldn’t maintain its aggressive pace of expansion. Over-harvesting, pollution, coastal development, and invasive species are increasingly damaging fishing grounds—and wild catches have been stagnant for years.
Climate change is adding a further burden to marine ecosystems. “We are now observing what may become, in the absence of policy changes, a collapsing (ocean) ecosystem with climate the final coup d’grace,” asserts Achim Steiner, executive director of the United Nations Environment Programme, in a February 2008 report.
In tropical reefs, ocean warming is breaking down the crucial symbiotic relationship between coral animals and algae called zooxanthellae, which live in healthy coral tissue. Zooxanthellae provide nutrients to coral animals through photosynthesis and help make the spectacular colors for which corals are known. But they are surprisingly sensitive to small increases in average temperatures.
Green Technology. Tom Gion, a laboratory technician at Southeast BioDiesel in North Charleston, draws a sample for a quality-control test. Processed from poultry fat, this fuel in a diesel engine can reduce a vehicle’s carbon emissions up to 78 percent, the company says. Photo by Wade Spees.
When summer ocean temperatures increase one to two degrees Celsius (1.8 to 3.6 degrees Fahrenheit) above normal, zooxanthellae die or flee the coral. The corals bleach (lose their color), starve, get sick, and often die. During the summer of 1998, about 80 percent of coral reefs bleached in the Indian Ocean, and about 20 percent subsequently died.
“What I’ve seen in the past few decades is beyond strange,” says Knowlton. “This is an environmental catastrophe. The question has been whether coral reefs are the canary in the coalmine for the oceans. The answer to that is clearly yes. But the canary has already passed out on the floor of the cage. The question now is whether we can revive the canary.”
One piece of good news is that U.S. policymakers have started to acknowledge the seriousness of global warming because of a “drumbeat of new climate science and experience,” says John P. Holdren, a professor of environmental policy at Harvard University.
Climate science, he says, shows that global warming is occurring at a pace and scale that is “faster, bigger, and more dangerous than anyone thought possible before.”
Americans are experiencing symptoms of climate change in their own communities and reading news reports of warming trends around the world. Major corporations, religious groups, labor organizations, national-security enterprises, and other interested parties have recently urged policymakers to take action on climate change. The Intergovernmental Panel on Climate Change (IPCC), which shared the Nobel Peace Prize with Al Gore in 2007, raised global awareness of the problem.
State and local governments, meanwhile, have begun addressing climate change. South Carolina is one of 25 states that have completed or are working on climate-action plans.
South Carolina’s transportation sector (mostly cars and trucks) produces a larger percentage of the state’s greenhouse-gas emissions than the national average.
In June 2005, Charleston Mayor Joseph Riley, Jr., signed the U.S. Mayors Climate Protection Agreement, setting goals for the city to reduce its carbon dioxide emissions to seven percent below 1990 levels by the year 2012. The mayors of Rock Hill, Columbia, Greenville, and Sumter also signed
the agreement. Charleston created a citizen Green Committee, which is forming a comprehensive plan to meet specific emissions targets.
Even so, state and local actions, while important, won’t stem acceleration of U.S. greenhouse-gas emissions and provide global leadership on the problem, Holdren says. That’s why federal action is urgently needed. “We are near a political tipping point” regarding a U.S. policy to manage climate change, which “needs to be national, mandatory, stiff, and soon.”
A Threshold is Approaching
There’s a number that climate scientists watch with special concern: the atmospheric concentration of carbon dioxide (CO2).
Since the 1750s, industrializing societies have drilled or mined for fossil fuels (coal, oil, natural gas) and burned them to run vehicles, power plants, and factories. The resulting waste—carbon dioxide—rises into the atmosphere where it captures a portion of the sun’s radiant energy and, in turn, raises the temperature of the Earth. Numerous studies have confirmed links between rising atmospheric CO2 concentrations and warmer global temperatures over geological timeframes.
Since the beginning of the Industrial Revolution, the atmospheric concentration of carbon dioxide has gone up from 280 parts per million (ppm) to 385 today, the highest it’s been in more than a half-million years. (The most important greenhouse gas is carbon dioxide; others include water vapor, methane, and nitrous oxide.)
From 1750 to 2007, the atmospheric CO2 concentration rose at an average annual rate of 0.40 ppm. During the last few decades of that period, however, this rise accelerated. From 1970 to 2000, the concentration increased about 1.5 ppm each year, as human activities sent more of the gas into the atmosphere. That’s almost four times faster than the historical rate since the beginning of the Industrial Revolution.
From 2001 to 2007, the concentration accelerated even further, by an average of 2.1 ppm annually, according to the National Oceanic and Atmospheric Administration (NOAA). That’s more than five-fold above the average since 1750. From 2006 to 2007, it rose 2.6 ppm, more than a six-fold increase.
Because of our past and current actions, the concentration of atmospheric CO2 will continue to accelerate—unless leading industrial nations find ways to reduce greenhouse-gas emissions drastically.
The core of the problem is that the global economy depends on burning fossil fuels for its energy needs. Today, about 80 percent of worldwide energy use—and 88 percent of U.S. energy use—is derived from burning fossil fuels.
What does all this mean for marine ecosystems, particularly coral reefs? Scientists say there is a tipping point of CO2 beyond which coral reefs worldwide would bleach and disappear. That tipping point is probably about 500 ppm of atmospheric CO2, though it could be as low as 450 ppm, says Ove Hoegh-Guldberg, a coral biologist with the University of Queensland in Australia. (Remember, it’s now 385 ppm.)
If the atmosphere reached 500 ppm, the Earth would eventually warm about three degrees Celsius (4.8 degrees Fahrenheit) above pre-industrial levels —which might not sound like much. Even so, scientists say, it would burn up coral reefs around the world and cause more extreme droughts, storms, and floods with catastrophic effects on agriculture and water supplies.
Can we prevent the planet from passing the 500 ppm threshold? It’s possible, but difficult. National governments would have to collaborate very soon on a new global system of producing and consuming energy that releases scant or no carbon dioxide into the atmosphere.
What if the tipping point is 450 ppm? No one has come up with a politically and economically feasible plan to avoid crossing 450 ppm, a number that’s “right around the corner,” says Hoegh-Guldberg. The planet will breach 450 ppm within about three decades, he says. “We’re very, very close.”
The Acidifying Oceans
The ocean absorbs about a third of the carbon dioxide that industrial society puts into the atmosphere. The sea, in fact, takes in almost a million tons of CO2 per hour. That’s a good thing and a bad thing.
If the ocean at some point failed to dissolve atmospheric CO2, the planet would overheat very rapidly. But that won’t happen for some time, according to the IPCC. The ocean will continue dissolving CO2 for hundreds or thousands of years to come.
What keeps many marine scientists up at night, however, is that when the ocean absorbs increasing amounts of carbon dioxide, it turns acidic. The ocean is naturally slightly alkaline, but the ocean has become 30 percent more acidic since 1750.
Coral reefs will be among the earliest casualties of acidification. Corals use calcium compounds in seawater to form protective skeletons, or shells. A coral starts out as a very simple free-floating larva. When it attaches to a hard surface such as older coral, a rock, or a sunken ship, it becomes a polyp. Then the animal, scarcely more than a mouth and a gut, begins extracting calcium carbonate from seawater to build a chalky skeleton shaped like a cup.
Today, acidity is reducing the saturation levels of calcium carbonate in surface layers of the ocean. Corals, as a result, can’t build healthy structures as efficiently. In acidic water, a coral’s skeleton is weakened in a process similar to osteoporosis. Field experiments have shown that acidification has lowered growth rates —that is, calcification—of some corals on Australia’s Great Barrier Reef by 20 percent.
Perhaps the most troubling aspect of acidification is that “it’s essentially irreversible” once it’s started, says Scott Doney of the Woods Hole Oceanographic Institution. The only way to slow the acidification process is to prevent further CO2 emissions.
Pteropods, like this one, are a crucial link in the food chain, but they could be harmed by ocean acidification. Photo by Larry Madin, Woods Hole Oceanographic Institution.
“We will have to do something very drastic in terms of reducing CO2 emissions or we will bring about the end of coral reefs as we know them,” says Knowlton of the Smithsonian.
To escape hotter temperatures, some tropical coral reefs might be able to migrate toward higher latitudes—from Florida and the Caribbean up into the Carolinas, for instance. But many reefs won’t relocate quickly enough and will succumb to heat stress. In any case, coral reefs that migrate pole-ward would almost certainly get hit by acidification and fade away by mid-century.
Says Knowlton, “Coral animals don’t necessarily die in highly acidic waters. Instead, they turn into little sea anemone-like creatures, attached to a hard substrate, but they stop building skeletons. Over time, storms and currents pound what’s left of the three-dimensional complexity of reefs that can be seen from space. The reef structures would eventually disappear.”
Ocean warming and acidification together would probably harm reefs faster than each impact could alone. “Oceans are going to change in a very complex fashion as they warm and become acidic at the same time,” says Gretchen Hofmann, a biologist at the University of California, Santa Barbara. “We’re facing double jeopardy, with potential synergistic influences between increasing acidity and higher seawater temperature.”
In response, the U.S. House of Representatives is considering the Federal Ocean Acidification Research and Monitoring Act (H.R. 4174). The act would authorize appropriations totaling $55 million from 2009 through 2012 to develop an interagency monitoring and research plan, which would be chaired by NOAA, and establish an ocean-acidification program at NOAA.
A similar Senate bill (S. 1581) would authorize appropriations totaling $100 million during 2009 to 2013 to establish a NOAA program to conduct research and public outreach on ocean acidification.
Generation after generation of corals have built intricate, complex structures not only in the tropics but also in cold, deepwater regions, including ones 60 to 70 miles off the South Carolina coast.
South Carolina’s corals are much less understood than their tropical cousins because they’re hard to reach and study. In frigid, dark, dense water along the continental shelf, these corals are nourished by tiny particles drifting down like snow from the surface of the Gulf Stream.
The Gulf Stream in fact supports a necklace of deepwater corals—also called cold-water corals—from Florida to North Carolina, which scientists have explored by submersible and sonar technologies. At least 67 fish species—grouper, snapper, jacks, and many others—use these corals for shelter, feeding grounds, or nurseries.
At depths of 200 feet to two miles, most of the world’s deepwater corals were undiscovered until a decade or two ago. Corals have been found in deep water in every ocean as far north as the Arctic Circle and as far south as the Southern Ocean surrounding Antarctica. Most of world’s coral species, scientists have learned, actually live in the cold and the dark.
Fragile Ecosystem. Deep-water corals off the U.S. southeastern coast are vulnerable to increasing ocean acidity. A rich variety of species depend on these ecosystems for food and shelter, including (above) a brisingid sea star (Novodinia antillensis), which is called a “star fish,” and (below) a Conger eel (Conger oceanicus). Photos by Ross et al., NOAA, Harbor Branch Oceanographic Institution.
Acidification has not reached deeper waters yet. But, by 2050, it is expected to spread there as well. Like their tropical counterparts, deepwater corals build reef structures by extracting calcium carbonate from seawater. In an acidifying ocean, these structures would start to disappear.
“It doesn’t take much more CO2 in the atmosphere to have a world without carbonate coral ecosystems, says Hoegh-Guldberg. “We’re near the threshold where you can’t have these systems anymore.”
The fisheries that are dependent on reef systems would also collapse. But so would many other fisheries.
All of the marine creatures that extract calcium compounds from seawater to build shells would become stunted or malformed in their development. Many plankton and snails that form the base of the marine food chain would also be affected. “We’re expecting a significant hit on U.S. fish catch” from acidification by mid-century, says Doney of Woods Hole.
Today, U.S. regional fishery management plans don’t include potential future impacts from acidification on marine resources. “Environmental conditions are changing,” says Doney. “If management plans don’t address acidification, you might force a (commercial) species into functional extinction.”
Satellite Observations are Crucial
Global warming is starting to erase plant life along the edges of the ocean’s natural biological “deserts.”
Three ingredients are needed to grow floating single-celled plants—phytoplankton—living in the surface layers of the ocean. Phytoplankton blooms require sunlight, iron, and surges of nutrients brought up by currents from the deep. Recently, though, a hotter ocean is disrupting this recipe. The ocean surface has been warming rapidly, by about one percent a year from 1998 to 2007.
“When you warm the surface water, you increase its buoyancy,” says Michael Behrenfeld, an Oregon State University botanist and expert on remote sensing of the ocean. The more buoyant surface layers of the ocean, which are nutrient-poor, are increasingly separate from the denser, colder, nutrient-rich deep. This stratification has changed the sea’s circulatory system, causing a reduced mixing of deep water and the sunlit surface waters.
Behrenfeld and his colleagues have tracked changes in phytoplankton on a global basis from a SeaWiFS sensor on a satellite launched in 1997. The scientists have found that warming ocean temperatures are linked to decreasing photosynthesis in the tropical and subtropical oceans.
About 75 percent of the world’s surface ocean, in fact, has become warmer and more stratified from the deeper ocean. And, throughout the tropics and subtropics, the surface ocean is losing phytoplankton, which photosynthesize and provide oxygen to the marine system and the atmosphere.
In the cold Southern Ocean surrounding Antarctica, microscopic coccolithophores—single-celled algae—could be damaged by more acidic oceans. Photo by Woods Hole Oceanographic Institution.
Natural biological deserts in the Atlantic and Pacific, where already scant plant life grows, are getting larger. The loss of phytoplankton will almost certainly harm the marine food chain and fisheries. Past changes in phytoplankton growth have been shown to influence fishery yields and marine bird populations. In other words, increasing ocean desertification would add another pressure on some fisheries.
The ocean warming since 1998 could be part of a short-term variation. But studies of marine temperatures and photosynthesis are consistent with computer-model predictions of what is likely to happen in the ocean during climate change.
“As the planet warms, we will get even more stratification in the ocean,” says David Karl, an oceanographer at the University of Hawaii.
Observations from instruments, sensors, and other technologies on shore, in the water, and in the atmosphere have been invaluable in helping scientists learn how the ocean is changing. The nation’s ocean-observing system, however, is fragmented and lacks a consistent stream of funding support. For instance, the satellite carrying the SeaWiFS sensor is being discontinued and will no longer send data after next year. Scientists lament that they will lose a crucial source of information about ocean health at a time when it’s most needed.
A Two-Fold Approach
There’s no single answer to slowing down global warming. But the best way to slash greenhouse-gas emissions is to put a price on them, according to many experts. Nations could fix a price on greenhouse pollution with a direct tax or with emissions trading. The latter choice probably is more politically feasible in the United States and many other countries.
In June 2008, a bill died in the U.S. Senate that would have set up a mandatory ceiling or “cap” on carbon-dioxide emissions and a national system for trading emission permits. This is called a cap-and-trade system.The bill would have cut total U.S. global-warming emissions by 66 percent by 2050. But opponents said it would cost jobs and raise fuel prices in an already lagging American economy.
Some members of Congress still support a cap-and-trade system for greenhouse gases. This kind of regulatory structure has already proven successful in reducing emissions of a different pollutant, sulfur dioxide, which causes acid rain.
In 1990, Congress passed the Clean Air Act, enabling regulators to set a cap on sulfur-dioxide emissions, which was lowered annually. A device that measures sulfur-dioxide emissions was attached to each large smokestack. The law also enabled the creation of a marketplace—a trading floor—for buying and selling emissions credits. The market, over time, defined a price tag on polluting but also a price tag on reducing that pollution. Companies could choose how to pay.
Companies set their accountants and engineers to work, and many discovered that it was less expensive to invest in technologies that capture and sequester sulfur dioxide from smokestacks than it was to buy pollution credits. As a result, total emissions have fallen.
Many scientists have expressed cautious optimism that capping-and-trading could similarly reduce U.S. CO2 pollution over time. But even if tough greenhouse-emissions standards were established in developed and developing countries, it would be very difficult to hold atmospheric CO2 concentrations below 500 parts per million.
That’s why some scientists are calling for a two-fold approach. “We need to develop mitigation schemes to reduce the amount of CO2 that we put into the atmosphere,” says Doney. “But we also may need to remove some of the CO2 already there.”
Scientists have proposed several ways of scrubbing carbon dioxide from the atmosphere or “geoengineering” the world’s climate. One idea that’s received serious attention: stimulating plant life in the open ocean.
In March 2008, Climos, a San Francisco company, announced that it had raised $3.5 million to pour iron particles into the sea in an effort to stimulate algal growth. The plants would bloom, absorb carbon dioxide from the atmosphere, and when the algae die, they would sink as carbon particles, supposedly into the deep ocean where the carbon could be sequestered for decades or perhaps hundreds of years.
This process would take carbon out of the global carbon system for a long enough period to give us breathing room to develop new technologies that emit less carbon.
Climos hopes to make money by entering today’s growing U.S. “carbon-offset” market, which is a largely unregulated cap-and-exchange system for greenhouse-gas emissions. Companies like Climos would sell carbon credits to other companies that produce greenhouse-gas emissions.
At the Chicago Climate Exchange, 400 corporations have made voluntary but legally binding promises to meet a reduction cap on emissions of carbon dioxide and other greenhouse gases. Companies that don’t meet the cap must buy credits from other companies through the exchange. One goal of the companies is to prepare for the day when the purchase of carbon credits would be part of a mandatory, national system of carbon regulation.
Individuals can also buy carbon offsets. For instance, you could buy an offset from a carbon broker to protect trees in the Amazon that soak up the greenhouse gas from the atmosphere.
But who decides whether a carbon offset is genuine? The market, after all, trades in something that can be difficult to measure: units of a gas that are not produced. It can be difficult to certify that the trees were actually saved from burning or logging. And what happens to the carbon offset if the trees are burned by an apparently “natural” wildfire?
Seeding the ocean with iron has its own complexities.
A number of major scientific projects have studied iron dumping and the phytoplankton blooms that result. But studies have been too brief and geographically small to determine how much and how far carbon from dead plant life sinks into the deep and stays sequestered there, says Ken Buesseler, a senior scientist at the Woods Hole Oceanographic Institution.
Thorough studies would have to track the life and death of marine plants and determine how much carbon sequestration occurs in the deep ocean. “That’s not easy to measure,” Buesseler adds.
In January 2008, leading marine scientists issued a warning that it’s too early to sell carbon offsets from putting iron in seawater, although eventually this technique could prove useful. In the journal Science, the scientists argued that demonstration projects should first prove that the technique removes carbon dioxide, retains carbon in the deep ocean for a long time, and has “acceptable and predictable environmental impacts.”
But entrepreneurs could sell carbon offsets for iron dumping anyway. There’s “no one in charge” of the carbon-offset market in the United States, says Buesseler. “A voluntary market can happen at any time by anyone with a Web site. The markets are moving ahead with or without good science, and small offset markets are big business.”
Climos has pledged to work transparently with academic scientists who could collaborate on studies or review research results. Other companies that want to pour iron into the ocean have not been as forthcoming.
“Some thought you could dump iron off the back of a ship, measure the chlorophyll, and be done with it,” says Buesseler.
In 2008, the Federal Trade Commission, the regulator of advertising claims, is holding a series of hearings on green marketing, which includes carbon offsets. The commission has become increasingly concerned that some green-marketing claims are unsubstantiated.
In any case, some geoengineering techniques could end up worsening global warming. Seeding the ocean with iron is likely to create a moral hazard—that is, it would encourage people to continue polluting because they believe CO2 can be scrubbed out of the atmosphere later on, says Dale Jamieson, a philosophy professor at New York University. “It’s like giving methadone to a heroin addict.”
Still, serious climate-engineering proposals should be considered and studied, says Ove Hoegh-Guldberg.
“We already have an ocean that’s fundamentally different from what’s existed over the past half-million years” because of pollution that acidifies and warms the sea.
“We are at a point,” he adds, “where the context of the climate-change problem is so much larger and it’s moving so much more quickly than we anticipated that we will probably move into geoengineering the climate. That’s probably part of the future. We have to look at all of these ideas, no matter how radical they sound, and give them a really good airing. We may have to do some very difficult, challenging things.”
South Carolina Aims to Stem Greenhouse-Gas Pollution
An advisory committee recommends 52 policy changes to reduce South Carolina’s greenhouse-gas emissions.
Did you know that South Carolina’s greenhouse-gas emissions are unusually large for the size of the state’s population? Or that South Carolina’s emissions are increasing twice as fast as national trends?
Those are among the findings of a broad-based advisory committee that has outlined 52 recommendations for state policymakers. If enacted, these recommendations could reduce South Carolina’s greenhouse-gas emissions while enhancing energy and economic efficiency.
By executive order, Governor Mark Sanford in 2007 established the South Carolina Climate, Energy, and Commerce Advisory Committee (CECAC). The committee reported its findings in mid-July 2008.
The committee comprises representatives from industry, environmental groups, government agencies, academic institutions, agriculture, forestry, coastal interests, real estate, tourism, banking, insurance, and other sectors. The non-profit Center for Climate Strategies has provided facilitation and technical support.
“We took a holistic view of energy, economic, and climate-change issues, and looked for win-win opportunities to address greenhouse-gas emissions,” says Ben Hagood, committee chairman and a Mt. Pleasant environmental attorney.
The committee reviewed, updated, and approved a comprehensive inventory and forecast of greenhouse-gas emissions in South Carolina from 1990 through 2020. The committee’s report shows that South Carolina’s greenhouse-gas emissions grew by 39 percent between 1990 and 2005, over twice the national average of 16 percent. The state’s emissions growth was driven largely by population growth and emissions associated with electricity generation.
South Carolina’s greenhouse-gas emissions could be cut dramatically by 2020, according to a state advisory committee.
The principal sources of South Carolina’s emissions are in electricity use and transportation, accounting for 35 percent and 34 percent of South Carolina’s emissions, respectively. Other sources include industrial processes, agriculture and industrial fuel use, and residential and commercial fuel use.
The committee’s 52 policy recommendations address four sectors: residential, commercial, and industrial; energy supply; transportation and land use; and agriculture, forestry, and waste management. Most recommendations are market- and incentive-based.
For instance, South Carolina should establish energy-efficiency programs, funds, or goals for electricity that would reduce the state’s carbon-dioxide emissions, according to the committee report. Other recommendations are to establish building energy codes and other efficiency projects. Improvements in South Carolina’s capacity to generate renewable and nuclear energy could substantially reduce future emissions.
The committee’s goal is to encourage South Carolina to bring down its greenhouse-gas emissions to five percent below 1990 levels by 2020, and stabilize emissions at that level. Many of the committee’s recommendations, if implemented, could save South Carolinians money through increased efficiency, according to the committee report.
The Most Threatened Marine Ecosystems
The fragile four.
The 2007 assessment by the Intergovernmental Panel on Climate Change (IPCC) named the planet’s four most vulnerable marine ecosystems:
- Tropical coral reefs face stress from global warming and acidic oceans caused by increasing CO2 emissions.
- Deepwater corals (such as ones found 60 to 70 miles off the South Carolina coast) are threatened by ocean acidification.
- Sea-ice ecosystems along the disappearing Arctic ice cap are under extreme stress. Sea ice in the Arctic is disappearing at a very rapid rate. Summer ice could be gone in 25 years. Species dependent on productive ecosystems along sea-ice edges could disappear.
- Acidification of the cold Southern Ocean could harm the growth of single-celled algae that provide a large proportion of the planet’s oxygen and form the basis of the food web in that part of the world. These carbonate-encased algae are called coccolithophores. Studies have found that more acidic waters hinder the algae’s ability to build the carbonate disks that form its shell. However, a 2008 British study showed the opposite—that the algae grew larger in acidic water.
Cleaner-Burning Coal a Necessity
Scientists urge governments to speed up research on methods of capturing and storing carbon.
If you had to choose just one word that best defines the challenge of addressing global warming, it might be coal.
Of all fossil fuels, coal produces the most carbon dioxide (CO2) per unit of energy, accounting for about 40 percent of global CO2 emissions. Because it’s so plentiful and cheap, and because the world’s fastest-growing economies depend on it for their energy needs, CO2 emissions from coal burning are likely to increase dramatically over the next two decades.
More than half of U.S. power generation comes from burning coal. India depends on it too. But it’s China that is rapidly becoming the biggest coal burner. Coal accounts for about 70 percent of China’s total energy consumption.
China constructs the equivalent of more than two 500-megawatt, coal-fired power plants per week. In fact, each week, China completes construction of a coal-fired, power-generating infrastructure that is comparable to the entire power grid used by Great Britain each year, according to a March 2007 Massachusetts Institute of Technology (MIT) study, “The Future of Coal.”
The global economy, according to the MIT report, can’t switch quickly from coal-fired power to nuclear power or alternative energies (wind, solar, geo-thermal, biomass, and other technologies) in time to address the challenges of climate change.
CO2 Culprit. More than half of U.S. power generation comes from burning coal, which produces the most carbon dioxide per unit of energy of any fossil fuel. Photo by Wade Spees.
What to do? An urgent priority for the United States and other coal-burning nations is to develop cost-effective technologies for new, cleaner coal-fired power plants, says John P. Holdren, a professor of environmental policy at Harvard University.
Many climate scientists and policymakers are pressing for public funding and support for technological innovations that could clean up emissions from power plants.
It’s technically feasible to capture CO2 from coal-fired plants—before or after burning the coal—and then liquefy, transport, and inject it underground at the depths of at least one kilometer. Porous rock formations in certain geological formations would absorb the CO2.
This entire process is called carbon capture and sequestration—or CCS—and it is “the critical enabling technology to reduce CO2 emissions significantly while allowing fossil fuels to meet growing energy needs,” states the MIT report.
CCS could also be used for natural gas and biomass electricity generation facilities, and in cement, ammonia, and iron manufacturing.
Still, there are major hurdles. An expensive pipeline infrastructure would have to be constructed to transport the liquefied CO2 between power plants and dumping grounds. It also would be politically difficult to designate enough underground dumping sites to receive the concentrated gas.
A CCS system that captures 90 percent of CO2 from a coal-based plant, using the best current technology, would require an increase in fuel consumption of 14 to 25 percent, according to a 2005 IPCC special report. Additional (non-coal) fuels and chemicals are required to extract carbon dioxide and prepare the gas for transport and storage. This would mean higher utility rates for customers.
A March 2008 U.S. Environmental Protection Agency analysis suggested that all power plants in the United States could have CCS technology by 2040.
But early demonstration plants would have to receive some public funding because they’d be so expensive to build and operate, according to Jeffrey Sachs, director of the Earth Institute at Columbia University. Writing in the April 2008 Scientific American, he criticizes the U.S. government for failing “to get even one demonstration CCS power plant off the ground.”
In January 2008, the U.S. Department of Energy (DOE) nixed a plan for FutureGen, which was to be the nation’s first demonstration coal-fired plant to collect and dispose of its own CO2 emissions underground. Citing escalating costs, the federal government pulled funding for this joint project with 13 utilities and coal companies. The DOE even had a site for the plant in central Illinois. Now, DOE says it plans to help industry add CCS capability to coal plants already in the works.
In March 2008, China and Australia signed an agreement to build and install a pilot CCS plant in Beijing. The plant would rely on post-combustion capture, a process that uses a liquid to capture carbon dioxide from power station flue gases. It can reduce CO2 releases from coal-fired power plants by more than 85 percent.
Sachs writes, “By 2010 at the latest, the world should be breaking ground on demonstration CCS coal-fired plants in China, India, Europe, and the U.S.”
Reading and Websites
Buesseler, Ken O. et al. “Ocean iron fertilization—moving forward in a sea of uncertainty.” Science, January 11, 2008.
Doney, Scott C. “The dangers of ocean acidification.” Scientific American, March 2006.
Flannery, Tim. The Weather Makers. New York: Atlantic Monthly Press, 2005.
Sachs, Jeffrey. “Keys to climate protection.” Scientific American, April 2008.
United Nations Environment Programme. In Dead Water: Merging of Climate Change with Pollution, Over-harvest, and Infestations in the World’s Fishing Grounds, February 2008.