The Future (59 page)

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 CO
₂
are being released to the atmosphere. Like the Arctic tundra, the great forests of the world contain large amounts of CO
₂
,
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 CO
₂
levels in the atmosphere, rather than a net
“sink,” withdrawing CO
₂
as the trees grow.

If adequate nutrients are available, the extra CO
₂
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 CO
₂
from plowing and land degradation contributed significantly to the excess of CO
₂
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 CO
₂
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 CO
₂
, 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 CO
₂
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 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 troves 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.

T
HE 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.

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 CO
₂
emissions and drive the speedier adoption of alternative technologies. Most experts consider a large and steadily rising CO
₂
tax to be the most effective way to use market forces to drive a large-scale shift toward a low-carbon economy.

Economists have long understood that taxes do more than raise revenue for the governments that impose them; to some extent, at least, they also discourage and reduce the economic activities that are taxed. By using taxes to adjust the overall level of cost attributed to the production of CO
₂
and other greenhouse gases, governments can send a powerful signal to the market that, in the best case, unleashes the creativity of entrepreneurs and CEOs in searching for the most cost-effective ways of reducing global warming pollution. That is the reason I have advocated the use of CO
₂
taxes for thirty-five years as the policy most likely to be successful. And implementing the tax in a way that escalates over time would provide the long-term signal to industry and the public that is needed to plan effective changes over coming decades.

Taxes, of course, are always and everywhere unpopular with those who pay them. Therefore, the enactment of this policy requires strong and determined leadership and, to the extent possible, bipartisanship. In recognition of those simple but significant political facts of life, I have always recommended that CO
₂
taxes be coupled with reductions in other taxes by an equal amount.

Unfortunately, most people are far more willing to believe that government will indeed impose a new tax, but far less willing to believe that
it will give that revenue back in another form. The forty-year campaign in the U.S. by the conservative counterreform alliance led by corporate interests and business elites has been effective in demonizing government at all levels and pursuing a “starve the beast” strategy that focuses on shrill opposition to any tax of any kind—unless the tax in question falls on low-income wage earners.

Other versions of this proposal have coupled the CO
₂
tax with a rebate plan, to send a check to each taxpayer. Under this approach, sometimes labeled the “fee and dividend” approach or “feebate,” those who were more successful in reducing their CO
₂
emissions would actually
make
money, or use it to pay for more efficient or renewable energy technologies. Yet another version, which was introduced in the U.S. Congress in 2012 but never voted upon, would return two thirds of the revenue raised by a
carbon tax to the taxpayers but would have applied one third to a reduction in the budget deficit. Unfortunately, the ingrained opposition to any new taxes—even if they are revenue neutral—has thus far made it difficult to build support for the single most effective strategy for solving the climate crisis, a CO
₂
tax.