Indiscriminate logging, mass cultivation and exploitation of natural resources have already made disappear 17% of the Amazon rainforest. An estimated 90% of this activity is illegal. Every hour 1800 hectares of forest disappear in Amazonas. The Amazon, which gives you 20 percent of the fresh water on the planet and much of the oxygen, is almost lost in 40 years. According to Amazon Network for Environmental and Social Information (RAIS), pressures and threats to the continental ecosystem, spread across nine countries (including Colombia), are carrying the landscapes of forest, social and environmental diversity and freshwater are replaced by areas degraded. Between 2000 and 2010, 240,000 square kilometers of forests, equivalent to the entire territory of the United Kingdom were cut extension. Already an arc of deforestation that stretches from Brazil to Bolivia and an area of water pressure and oil exploration in the Andean Amazon. All this casts a conclusion: “if the economic interests they go there (area also shelters the Amazon River) are realized, this will become a savanna with only islands of forest; and in 20 years we would have only 45 percent of what exists today. ”
Some parts of the Amazon rainforest are receiving less rain, leading to trees absorb less carbon, according to a study published in the journal “Proceedings” of the National Academy of Sciences.
The research used a new satellite technology that measures rainfall more precisely than previous approaches because it does cut through the cumulus clouds. It is estimated that since 2000 the rainfall decreased by 69 percent of the territory of the Amazon jungle, an area representing 5.4 million square kilometers. The drop in rainfall is even more important in tropical savannas in the region, where 80 percent of these areas have a history in decreasing rainfall.
This drop in the volume of precipitation is responsible for the decrease in the “greenness” of more than half of the region, as measured by the normalized difference vegetation index (NDVI). This in turn results in a decrease of photosynthetic activity, which means that carbon sequestration by trees is slowing Amazon.
The study results, which are aligned with others who used different methodologies, suggest that the Amazon rainforest may be increasingly resistant to the effects of climate change. That is a worrying prospect given the importance of the Amazon as a carbon source, and the role of ecosystems in the generation of regional rainfall.
That is, up to 70 percent of GDP in South America occurs in areas fed by rainfall in the Amazon. For this reason the authors warn that continuing the warming trend could trigger a positive feedback loop that would shift the intertropical convergence zone (ITCZ) – a band that surrounds the planet and manages the current rainfall patterns – poleward This would increase drought in the region. That in turn would aggravate the damage to life, stimulating increased emissions and further accelerating climate change.
“Our results provide evidence that the persistent dryness may degrade the canopy of the Amazon rainforest, which would have a cascading effect on the global carbon dynamics and climate,” the authors write.
Severe drought in southern Brazil may be linked to deforestation and degradation of the largest rainforest on Earth, says a new report by a Brazilian scientist.
In reviewing data from about 200 studies, Antonio Donato Nobre, the Brazilian National Institute for Space Research (INPE) warns that reducing deforestation will not be enough to restore the ecological function of the Amazon rainforest, which acts as giant water pump that generates precipitation in most of South America.
Southeast Brazilian cities, are currently suffering a severe drought that is drying agricultural areas, cut hydropower generation, and reservoirs drained.
In its report, Nobre explains the role of the great forests, how the Amazon plays in driving regional weather patterns.
“The forest keeps moving moist air, which brings rain to the interior regions of the continent, thousands of kilometers away from the ocean,” said Nobre, who is an advocate of the theory of “biotic pump” that compares large tropical forests to “flying rivers”.
“This is due to the innate ability to transfer large volumes of water from the soil to the atmosphere through transpiration of trees,” writes Nobre, noting that the compounds emitted by trees stimulate the condensation of water vapor, driving cloud formation and precipitation. This phenomenon reduces air pressure above the forests, leading to wet the deep ocean air inland areas, driving a positive feedback loop that usually ensures regular rainfall in the Amazon and beyond.
But deforestation, degradation and fire can break the link, which alters the big pump that provides moisture to the forest and leads to other areas as Nobre.
“Deforestation can jeopardize all these attributes of the jungle. Recognized climate models anticipate various harmful effects of deforestation on the climate, predictions were confirmed by observations. These include the drastic reduction of perspiration, changes in the dynamics of clouds and rainfall and long dry season in deforested areas, “he says and adds,” Other unintended effects, such as soot and smoke damage to the dynamics of rainfall, even in virgin forest areas are also being observed. ”
Nobre says there is a continuing danger that deforestation and degradation can tilt the Amazon biome from rainforests to savannahs. A catastrophe of this kind could undermine the biotic pump, leaving much of South America, including deposits in southern Brazil and Argentina much drier. That, in turn, could put at risk much of the economic activity on the continent.
To avoid that scenario, Nobre urges “massive mobilization of people, resources and strategies” to reverse deforestation and degradation.
“In addition to maintaining the Amazon forest at all costs, must deal with the liability of the accumulated deforestation and begin a comprehensive process of recovering what was destroyed, which in Brazil amounts to an area of 184 million football fields “Nobre said, comparing the effort required to fight a war.
“To address the seriousness of the situation, we need to mobilize [par] with the war effort, but not directed to conflict,” he writes. “Only a minority of society has been and is directly involved in the destruction of forests. And this minority is pushing the nation towards a climate abyss. “