After declining for three consecutive years, forest clearing in the Brazilian Amazon rose sharply during the last five months of 2007, nearly doubling over the same period a year earlier. The increase, largely attributed to the global commodity boom, dashed hopes that recent conservation initiatives and law enforcement efforts had finally wrested control of the rain forest from development interests in the region.
It also hinted at the growing role that globalization and economic growth will play in the fate of the world’s largest rain forest. The soaring economies of China, India, Southeast Asia, Russia, and of Brazil itself are fueling an international demand for agricultural commodities that is contributing to the steady degradation of the Brazilian Amazon. If left unchecked, this commodity-fueled development — combined with previous logging, agricultural settlement, and large-scale changes such as fire and drought — is projected to lead to more than half the Amazon being logged, burned, or degraded within the next 20 years, according to recent studies. Factoring in the impact of climate change — which is expected to dry and warm parts of the Amazon — losses in the region could be even worse.
Historically, the Amazon has proven resilient to climate change, human disturbance by pre-Colombian populations, and even periods of fire and extreme drought during millennial El-Niño-like events. Yet the present onslaught of forces affecting the Amazon is unprecedented. Never before has the region experienced the simultaneous impact of large-scale forest loss and degradation, fragmentation, fires, and global warming. Many scientists and conservationists are deeply worried, not only because of the loss of biodiversity that accompanies destruction of the forest, but also because the cutting and torching of this vast repository of carbon will further heat up a planet already warming at an alarming pace.
“Amazon deforestation releases vast quantities of greenhouse gases,” said Philip M. Fearnside, research professor at the National Institute for Research in the Amazon in Manaus, Brazil. “Unlike other tropical areas in the world that are also undergoing rapid deforestation, Amazonia could release much larger amounts of gases in the future because there is still so much forest left to clear. This is part of a vicious cycle set in motion by global warming, especially because of its role in triggering more-damaging El Niño events. These cause Amazon forest trees to die from drought and fire, releasing gases that lead to more warming and still more dead trees. Emissions from dying trees and warming soils could contribute to a runaway greenhouse effect.”
Drivers of Deforestation in the Brazilian Amazon
Unlike the 1970s, when deforestation was often tied to government-sponsored development schemes that promoted colonization by subsistence farmers, land-use change in the Brazilian Amazon is dominated today by large-scale conversion of forest for industrial agriculture and sprawling cattle pastures. The notion of the Amazon as a “green desert” — scarcely worth clearing and developing — is a thing of the past. Today, Brazilians see the Amazon as South America’s next agricultural frontier, a rival to the heartland of the United States, which will put fuel in gas tanks and food on tables around the world. This transition — with its profound implications for the future of the Amazon — has been made possible by infrastructure expansion, the near eradication of foot-and-mouth disease in cattle, and agricultural innovation that has converted the region’s poor acidic soils into land suitable for extensive soy farms.
As it becomes a major agricultural zone, the Amazon finds its fate increasingly tied to global markets for food and biofuels, with rising prices providing an incentive for forest clearing. Many factors feed the spike in burning and land clearing. Among them are the recent run-up in commodity prices driven by rising international demand for agricultural staples; climbing meat consumption in developing and emerging markets, which buoy demand for grain as feed; and surging interest in biofuels, fed by record high oil prices and U.S. subsidies for corn ethanol. Another catalyst of Brazil’s agricultural expansion is a $43 billion program known as Avanca Brasil (Forward Brazil) that is funding construction of roads, ports, pipelines, hydroelectric dams, and other infrastructure improvements in and around the Amazon.
Brazilian satellite data from late 2007 show a marked increase in the number of fires and deforestation in the key soy and cattle-producing states of ParÃ¡ and Mato Grosso. Both experienced increases in forest loss of 50 percent or more over the same period in 2006, coupled with a large jump in burning — in the case of Mato Grosso, a spike of more than 100 percent. The 123,000 fires detected across the Brazilian Amazon by the Terra and AQUA satellites are the most since such measurements began in 2003. Deforestation in the last five months of 2007 was expected to exceed 7,000 square kilometers, an area more than twice the size of Rhode Island.
Politics and economics, both in Brazil and abroad, are playing a key part in agricultural expansion in the Amazon. U.S. energy policy, which grants generous subsidies for corn ethanol, has effectively discouraged American farmers from growing soybeans, promoting the crop’s expansion in Brazil.
“We’re seeing a corn [ethanol] connection to Amazon deforestation,” said Dr. William F. Laurance, a researcher at the Smithsonian Tropical Research Institute and author of a December 2007 letter published in Science on the subject.
“We see soy prices going up partly because less soy is being grown in the U.S. as corn expands to meet the surging demand for the emerging ethanol industry,” added Dr. Daniel Nepstad, director of the Woods Hole Research Center’s Amazon program in BelÃ©m, Brazil. “Similarly, as sugar cane expands in southern Brazil, soy production is heading northward, encroaching on the Amazon.”
Although major soy growers in the Amazon are currently observing a two-year moratorium on new clearing for soy, no moratorium exists in the neighboring Cerrado region, a savanna ecosystem that is being converted at a rate three times faster than in the Amazon rain forest. As soy and sugar cane — the source of Brazil’s ethanol — expand their acreage into the Cerrado, they compete with cattle ranching, the dominant form of agricultural land use in the region. Low-intensity ranching, which yields significantly less revenue per hectare than industrial agriculture, is then displaced to frontier areas, increasing deforestation. Ranchers who sell their land to soy and cane growers can buy 10 times as much land on the frontier.
As demand for biofuels continues to grow, there is a very real possibility that oil palm could become a dominant crop in the Amazon — an ominous development considering that the planting of oil palm plantations has been the driving force behind the recent destruction of huge areas of rain forest in Indonesia and Malaysia. Scientists estimate that Brazil has 2.3 million square kilometers of forest land suitable for oil palm, equal to the forested areas conducive to soy and sugar production combined.
Getting these agricultural products to market, long an impediment to development of the Amazon, is rapidly becoming easier thanks to the numerous road projects being financed by the Avanca Brasil program. The improvement of the Transoceanic Highway, which links the heart of the Amazon to Pacific ports in Peru, promises to stimulate further agricultural expansion. Roads like the Transoceanic give loggers, land speculators, ranchers, farmers, and colonists access to otherwise remote areas. These economic interests, especially the agro-industrial and logging sectors, then build “unofficial” spur roads, opening up even more forest to development.
As global demand grows for agricultural commodities produced in the Amazon, the region is being increasingly buffeted by drought, fragmentation, and forest fires, all of which are exacerbated by climate change. The synergistic impact of these forces raises the biggest questions for the future of Amazonia.
Aware of the powerful influence of climate change, scientists are working to understand its potential impact on the planet’s largest rain forest. Some models suggest parts of the Amazon will experience elevated temperatures and less rainfall, while other regions will get more rain, but the debate is far from settled when it comes to predicting the sensitivity of the region’s ecosystems to global warming.
What little is known about current change in the Amazon is worrisome. Giant clearings suck moisture from surrounding forest fragments and allow winds to blow down trees, thinning the canopy and enabling sunlight to reach the forest floor. This dries leaf litter and kills trees. Dying trees drop leaves and branches, creating tinder for knee-high surface fires that spread to the forest from nearby agricultural clearings. While these fires are small, they cause significant damage in an ecosystem not well adapted to fire.
“Although these fires appear relatively innocuous, they are actually very destructive as most rain forest trees have a low tolerance of heat,” said Jos Barlow, a researcher at Lancaster University in the United Kingdom and at the Museu Paraense Emílio Goeldi in Brazil. “And their slow speed means that flames stay in contact with trees for long periods of time. As a result, even low-intensity fires kill up to 40 percent of trees.”
As vegetation goes up in smoke, the forest’s own rain-generating capacity is reduced — as much as half the moisture in some parts of the Amazon is recycled through evapotranspiration. Fewer trees mean less rainfall, while the heavy smoke from burning has been found to inhibit cloud formation and reduce rainfall. These effects are not limited to Brazil; research led by Roni Avissar of Duke University suggests that changes in the Amazon may have an even wider impact, influencing rainfall patterns from Mexico to Texas.
A 2003 simulation by Peter Cox and his colleagues at the Hadley Centre for Climate Prediction and Research provoked alarm and controversy when it forecast significant “dieback” of the Amazon rain forest by mid-century and a virtual collapse of the ecosystem by 2100. The projection, which evaluated only the impact of increased atmospheric carbon dioxide concentrations on temperature and precipitation in the region, has since been eclipsed by models forecasting an even more accelerated path due to interaction of climate and land-use change.
Writing in Philosophical Transactions of the Royal Society B earlier this year, Daniel Nepstad and colleagues predicted that 55 percent of Amazon forests will be “cleared, logged, damaged by drought, or burned” in the next 20 years if deforestation, forest fires, and climate trends continue apace. The damage will release 15 to 26 billion tons of carbon into the atmosphere, adding to a feedback cycle that will worsen both warming and forest degradation in the region. Nepstad says this scenario is a conservative one — forest loss and emissions could be far worse.
“The Hadley model [points] to the end of the century when there will be a big forest dieback in the Amazon,” he said. “But before global warming is going to kick in, there is going to be all sorts of damage from the droughts we are already seeing, as well as deforestation, logging, and the fires that are part of that regime.”
Nepstad and other scientists point to the 2005 drought as the direction the Amazon may be headed. That drought, which has recently been linked to warming in the tropical Atlantic rather than to El Niño, was the worst in memory. As rivers dried up, remote communities were isolated and commerce slowed to a standstill. Thousands of square kilometers of land burned for months, releasing more than 100 million metric tons of carbon into the atmosphere.
While it may seem inevitable that much of the Amazon will be burned, plowed for cattle pasture and industrial soy farms, or turned into savanna by climate change, emerging trends show that there is reason to believe the Amazon can avoid the worst. In a future beset with uncertainty over the looming impact of global warming and massive shifts in the international economy, it is these same drivers that could hold the key to the Amazon’s salvation.
Should the world’s major industrialized powers finally agree to place a price on the billions of tons of greenhouse gases spewed into the atmosphere every year, it could set the stage for innovative conservation measures that could help bring deforestation in the Amazon under control within a decade. Under one major initiative, known as REDD (Reducing Emissions from Deforestation and Forest Degradation), both private investors and governments would pay Brazil and the people of the Amazon not to log or burn the rain forest. REDD markets would be driven by the need of industries and countries to offset their greenhouse gas emissions by paying others to preserve their carbon-absorbing forests. Support for REDD projects is growing as it becomes clear that traditional conservation measures alone will not be enough to slow the continuing destruction of the Amazon.