by Al Gore
Coal has the highest carbon content of any fuel and emits the most CO2 for each unit of energy it produces. It causes local and regional air pollution, including emissions of nitrous oxide (the leading cause of smog), sulfur dioxide (the continuing cause of acid rain), and toxic pollutants like arsenic and lead. The burning of coal also leaves huge quantities of toxic sludge—the second largest industrial waste stream in the United States—that is typically pumped to huge lagoons like the one that burst a holding wall and flooded portions of Harriman, Tennessee, in my home state four years ago.
Of particular importance, coal burning is the principal source of human-caused mercury in the environment, an extremely toxic pollutant that causes neurological damage, negatively impacting cognitive skills, the ability to focus, memory, and fine motor skills, among other effects. In the United States nearly all fish and shellfish include at least some amount of methyl-mercury that originated in coal-burning power plants. It is primarily for this reason that many fish and shellfish are considered dangerous in the diets of pregnant women, women who may become pregnant, nursing mothers, and young children. (Since the eating of fish is beneficial for brain development, pregnant women are advised to seek out fish that are low in mercury content and not avoid fish altogether.)
But the worst harm from coal burning is its dominant role in causing global warming. Although public opposition in the U.S. has contributed to cancellation of 166 new coal plants that had been planned, coal use is still growing rapidly in the world as a whole. An estimated 1,200 new coal plants are now planned in 59 countries. Under current plans, the global use of coal is expected to increase by another 65 percent in the next two decades, replacing oil as the single largest source of energy worldwide.
Coal is considered cheap, primarily because the absurdly distorted accounting system we use for measuring its cost arbitrarily excludes any consideration of all of the harm caused by burning it. Some engineers are working on improvements to a long-known process for converting underground coal reserves into gas that could be brought to the surface as fuel. But even if this technology were to be perfected, the CO2 emissions would continue destroying the Earth’s ecosystem.
Oil, the second largest source of global warming pollution, contains 70 to 75 percent of the carbon in coal for each unit of energy produced. Moreover, most of the projected new supplies of oil—in the form of shale oil, deep ocean drilling, and tar sands (not only in Canada, but also in Venezuela, Russia, and elsewhere)—are considerably more expensive to produce and carry even harsher impacts for the environment.
Conventional oil is burdened with other problems that coal does not have. Most of the easily recoverable oil in the world is found in regions such as the Persian Gulf that are politically and socially unstable. Several wars have already been initiated in the Middle East for reasons that include competition for access to oil supplies. And with Iran’s determined effort to develop nuclear weapons, and ongoing political unrest in multiple countries in the region, the strategic threat of losing access to these oil supplies makes the price of oil highly volatile.
Although most of the discussions about reductions of CO2 emissions have focused on industrial, utility, and vehicle emissions, it is also important to reduce CO2 emissions and enhance CO2 sequestration in the agriculture and forestry sectors, which together make up the second largest source of emissions. As the Keeling Curve demonstrates, the amount of CO2 contained in vegetation, particularly trees, is enormous. It is roughly equal to three quarters of the amount in the atmosphere.
The largest tropical forest, the Amazon, has been under assault from developers, loggers, cattle ranchers, and subsistence farmers for decades, and even though the government of former president Luiz Inácio Lula da Silva took effective measures to slow down the destruction of the Amazon, his successor has made policy changes that are reversing some of the progress, though the rate of deforestation fell in 2012. In the last decade, the Amazon region was hit hard in 2005 and again in 2010 by “once-in-a-century” droughts (or rather, by what used to be once-in-a-century droughts before human modification of the climate). This led some forest researchers to renew their concern about a controversial computer model projection that has predicted the possibility of a dramatic “dieback” of the Amazon by mid-century if temperatures continue rising.
An increasing amount of the world’s CO2 emissions are coming from the cutting, drying, and intentional burning of peat forests and peat lands—especially in Indonesia and Malaysia—in order to establish palm oil plantations. According to the United Nations Environment Programme, peatlands contain more than one third of all the global soil carbon. Although both governments have given lip service to efforts to rein in this destructive practice, endemic corruption has undermined their stated goals. Extremely poor governance practices are among the chief causes of deforestation almost everywhere it is occurring—partly because 80 percent of global forest cover is in publicly owned forests.
Tropical forests are also under assault in central and south-central Africa—particularly in Sudan and Zambia, and the Southeast Asian archipelago—including areas in Papua New Guinea, Indonesia, Borneo, and the Philippines. In many tropical countries, the increased demand for meat in the world’s diet has contributed greatly to the clearing of forests for ranching—especially cattle ranching. As noted in Chapter 4, the growing meat intensity of diets around the world has an especially large impact on land use because each pound of animal protein requires the consumption of more than seven pounds of plant protein.
The enormous northern boreal forests in Russia, Canada, Alaska, Norway, Sweden, and Finland (and parts of China, Korea, and Japan) are also at great risk. Recent reestimates of the amount of carbon stored in these forests—not only in the trees, but also in the deep soils, which include many carbon-rich peatlands—calculate that as much as 22 percent of all carbon stored on and in the Earth’s surface is in these boreal forests.
In Russia’s boreal forest—by far the largest continuous expanse of trees on the planet—the larch trees that used to predominate are disappearing and are being replaced by spruce and fir. When the needles of the larch fall in the winter, unlike those of the spruce and fir, the sunlight passing through the barren limbs is reflected by the snow cover back into space, keeping the ground frozen. By contrast, when the conifer needles stay on the trees and absorb the heat energy from the sunlight, temperatures at ground level increase, thus accelerating the melting of the snow and the thawing of the tundra. The intricate symbiosis between the larch and the tundra is thereby disrupted, causing both to disappear. Millions of similar symbiotic relationships in nature are also being disrupted.
Although some Canadian provinces have impressive policies requiring sustainable forestry and limiting the damage from logging operations, Russia does not. And in both Russia and North America, the forests are being ravaged by the impact of global warming on droughts, fires, and insects. Beetles have expanded their range as average temperatures have increased, and have multiplied quickly as the number of cold snaps that used to hold them back has diminished. In many areas they are now reproducing three generations per summer rather than one. In the last decade, more than 27 million acres (110,000 square kilometers) of forests in the Western U.S. and Canada have been devastated by what the United Nations biodiversity experts described as “an unprecedented outbreak of the mountain pine beetle.”
In mountainous areas, the earlier melting of snowpacks is depriving trees of needed water supplies during the hot summer months, which further increases their vulnerability to drought. One expert studying these issues, Robert L. Crabtree, told The New York Times recently, “A lot of ecologists like me are starting to think all these agents, like insects and fires, are just the proximate cause, and the real culprit is water stress caused by climate change.”
The drought conditions weaken the trees and make them more vulnerable to beetles. And the increasing numbers of forest fires, scientists have long since established, are going
up in direct proportion to the rising temperatures. There is no doubt that changes in forest management practices over the last several decades have contributed to the risk, frequency, and size of many forest fires. But the myriad impacts of global warming on fires far exceeds the impact of management practices.
The scale of the losses in the areas being deforested is completely unprecedented, according to experts, and as a result, enormous quantities of CO2 are being released to the atmosphere. Like the Arctic tundra, the great forests of the world contain large amounts of CO2, in the trees and plants themselves, in the soil beneath them, and in the forest litter that covers it. The great northern boreal forest of Canada and Alaska may have already become a net contributor to CO2 levels in the atmosphere, rather than a net “sink,” withdrawing CO2 as the trees grow.
If adequate nutrients are available, the extra CO2 in the atmosphere has the potential to stimulate some additional tree growth, though most experts point out that other limiting factors such as water availability and increased threats from insects and fire are overwhelming this potential. However, in spite of these devastating losses in forestland, the net loss of forests has slowed in recent years, primarily due to the planting of new forests and due to the natural regrowth of trees on abandoned agricultural land. According to the United Nations, most of the regrowth has been in temperate zones, including in forested areas of eastern North America, Europe, the Caucasus, and Central Asia. According to one study, successfully cutting the rate of deforestation in half by 2030 would save the world $3.7 trillion in environmental costs.
China has led the world in new tree planting; in fact, over the last several years, China has planted 40 percent as many trees as the rest of the world put together. Since 1981, all citizens of China older than age eleven (and younger than sixty) have been formally required to plant at least three trees per year. To date, China has planted approximately 100 million acres of new trees. Following China, the countries with the largest net gains in trees include the U.S., India, Vietnam, and Spain. Unfortunately, many of these new forests include only a single tree species, which results in a sharp decline in the biodiversity of animals and plants supported by the monoculture forest, compared to the rich variety supported by a healthy, multispecies primary forest.
For all of the needed attention paid to the sequestration of carbon in trees and vegetation, the amount of carbon sequestered in the first few feet of soil (mainly on the 10.57 percent of the Earth’s land surface covered by arable land) is almost twice as much as all the carbon in the vegetation and the atmosphere combined. Indeed, well before the Industrial Revolution and the adoption of coal and oil as the world’s principal energy sources, the release of CO2 from plowing and land degradation contributed significantly to the excess of CO2 in the air. By some estimates, approximately 60 percent of the carbon that used to be stored in soils, trees, and other vegetation has been released to the atmosphere by land clearing for agriculture and urbanization since 1800.
Modern industrial agricultural techniques—which rely on plowing, monoculture planting, and heavy use of synthetic nitrogen fertilizers—continue to release CO2 into the atmosphere by depleting the organic carbon contained in healthy soils. The plowing facilitates wind and water erosion of topsoils; the reliance on monocultures, instead of mixed planting and crop rotation, prevents the natural restoration of soil health; and the use of synthetic nitrogen fertilizers has an effect not dissimilar from steroids: they boost the growth of the plants at the expense of the health of the soil and interfere with the normal sequestration of organic carbon in soils.
The diversion of cropland to biofuel plantations also results in a net increase in CO2, while encouraging the destruction of yet more forestland, either directly, as in the case of the peat forests—or indirectly, by pushing subsistence farmers to clear more forests to replace the land they used to plant. As I have previously acknowledged publicly, I made a mistake supporting first generation ethanol programs while serving in the U.S. government, because I believed at the time that the net CO2 reductions would be significant as biofuels replaced petroleum products. The calculations done since then have proven that assumption to be wrong. I and others also failed to anticipate the rapid growth of biofuels and the enormous scale they have now reached worldwide.
THE EXTINCTIONS OF SPECIES
The destruction of forests—particularly tropical forests that are rich in biodiversity—is also one of the principal factors, alongside global warming, that is driving what most biologists consider the worst consequence of the global environmental crisis: a spasm of extinction that has the potential to cause the loss of 20 to 50 percent of all living species on Earth within this century.
So much heat is already being trapped by global warming pollution that average world temperatures are increasing much more rapidly than the pace to which many animals and plants can adapt. Amphibians appear to be at greatest risk during this early stage, with multiple species of frogs, toads, salamanders, and others going extinct at a rapid rate all over the world. Approximately one third of all amphibian species are at high risk of extinction and 50 percent are declining. Experts have found that in addition to climate change and habitat loss, many amphibians have been hit by a spreading fungal disease, which may also be linked to global warming. Coral species, as noted earlier, are also facing a rapidly increasing risk of extinction.
According to experts, the other factors driving this global extinction event include, in addition to global warming and deforestation, the destruction of other key habitats like wetlands and coral reefs, human-caused toxic pollution, invasive species, and the overexploitation of some species by humans. Many wildlife species in Africa are particularly threatened by poaching and the encroachment of human activities into their territories, particularly the conversion of wild areas into agriculture.
There have been five previous extinction events in the last 450 million years. Although some of them are still not well understood, the most recent, 65 million years ago (when the age of the dinosaurs ended) was caused by a large asteroid crashing into the Earth near Yucatan. Unlike the previous five extinction events, all of which had natural causes, the one today is, in the words of the distinguished biologist E. O. Wilson, “precipitated entirely by man.”
Many species of plants and animals are being forced to migrate to higher latitudes—north in the northern hemisphere and south in the southern hemisphere (one large study found that plants and animals are moving on average 3.8 miles per decade toward the poles)—and to higher altitudes (at least where there are higher areas to migrate to). One study of a century of animal surveys at Yosemite National Park found that half of the mountain species had moved, on average, more than 500 meters higher.
Some, when they reach the poles and the mountaintops and can go no farther, are being pushed off the planet and into extinction. Others, because they cannot move to new habitats as quickly as the climate is changing, are also being driven toward extinction. A recent Duke University study for the National Science Foundation found that more than half of the tree species in the eastern United States are at risk because they cannot adapt to climate change quickly enough.
Almost 25 percent of all plant species, according to scientists, are facing a rising risk of extinction. Agricultural scientists are especially concerned about the extinction of wild varieties of food crop plants. There are twelve so-called Vavilovian Centers of Diversity, named after Nikolai Vavilov, the great Russian scientist whose colleagues died of starvation during the siege of Leningrad protecting the seeds he had gathered from all over the world. One of them left a letter along with the enormous untouched collection of seeds, saying, “When all the world is in the flames of war, we will keep this collection for the future of the people.” Vavilov himself died in prison after his criticism of Trofim Lysenko led to his persecution, arrest, conviction, and death sentence.
The ancient homes of food crops are sources of abundant genetic diversity that serve as treasure trov
es for geneticists looking for traits that can assist in the survival and adaptation of food crops to new pests and changing environmental conditions. But many of these have already gone extinct and others are threatened by a variety of factors, including development, monoculture, row cropping, war, and other threats.
The United Nations Convention on Biological Diversity notes, among other examples, that the number of local rice varieties being cultivated in China has declined from 46,000 in the 1950s to only 1,000 a few years ago. Seed banks like the one Vavilov first established are now cataloguing and storing many seed varieties. Norway has taken the lead with a secure storage vault hollowed out of solid rock in Svalbard, north of the Arctic Circle, as a precautionary measure for the future of mankind.
THE LOSS OF living species with whom we share the Earth and the widespread destruction of landscapes and habitats that hundreds of generations have called “home” should, along with the manifold other consequences of the climate crisis, lead all of us to awaken to the moral obligation we have to our own children and grandchildren. Many of those who have recognized the gravity of this crisis have not only made changes in their own lives but have begun to urge their governments to make the big policy changes that are essential to securing the human future.
THE PATH FORWARD
Generally speaking, there are four groups of policy options that can be used to drive solutions to the climate crisis. First and most important, we should use tax policy to discourage CO2 emissions and drive the speedier adoption of alternative technologies. Most experts consider a large and steadily rising CO2 tax to be the most effective way to use market forces to drive a large-scale shift toward a low-carbon economy.