Princípios da Agroecologia

Agricultura sustentável tem que considerar aspectos socioeconômicos e culturais dos grupos sociais implicados. Não basta proteger e melhorar o solo ou a produtividade agrícola se não resulta em melhorias nas condições de vida das pessoas envolvidas. Portanto, agricultura sustentável é um conceito que implica aspectos políticos e ideológicos que tem a ver com o conceito de cidadania e libertação dos esquemas de dominação impostos por setores de nossa própria sociedade e por interesses econômicos de grandes grupos, de modo que não se pode abordar o tema reduzindo outra vez as questões técnicas.

Francisco Roberto Caporal


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Florestas no Artico

How Climate Change Is Growing Forests in the Arctic

B.C. Forbes
Shrubs in the Arctic region of western Siberia
If there’s a single lesson for early 21st century life on the planet Earth, it’s this: everything connects. That’s true whether we’re looking at the global economic system, in which sickness is now spreading from the euro zone to China to a wobbly U.S., or the global environment, as we can see in a new study showing the Arctic rapidly responding to climate change by sprouting sudden trees in the tundra.
Researchers in Britain and Finland studied an area of 38,600 sq. mi. (100,000 sq km) in what’s known as the northwestern Eurasian tundra, which stretches from western Siberia to Finland. Surveys of vegetation in the region using both satellite data and local observations from reindeer herders showed that in 8% to 15% of the territory, willow and alder shrubs had grown into trees over 6.5 ft. (2 m) tall over the past 30 to 40 years. That’s a period of time when temperatures in the Arctic have increased significantly, even faster than in other parts of the planet.
As Andrew Revkin of Dot Earth puts it, warming has led to “pop-up forests” in regions of the planet that usually see little more than summer shrubs. That’s a sign of just how fast the Arctic in particular can respond to global environmental change. And as the Arctic greens, it could speed warming even more as the darker foliage absorbs sunlight that would have been reflected back into space by the white tundra. While short shrubs can be covered completely in snowfall — thus reflecting sunlight — tall trees are usually above the white.
The advance of forest into the Arctic could increase Arctic warming by as much as 1° to 2°C by the end of the 21st century. In a statement, Dr. Marc Macias-Fauria of Oxford University — and the lead author on the paper — noted how unusual the advance of Arctic forest was:
It’s a big surprise that these plants are reacting in this way. Previously people had thought that the tundra might be colonized by trees from the boreal forest to the south as the Arctic climate warms, a process that would take centuries. But what we’ve found is that the shrubs that are already there are transforming intro trees in just a few decades.
The planet is changing, and the Arctic is a bellwether of that change. And what happens there will affect us.
Bryan Walsh is a senior editor at TIME. Find him on Twitter at @bryanrwalsh. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.
Related Topics: Arcticclimate changefeedbackforestsglobal warmingtundraClimate Science

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Assine o Abaixo-Assinado virtual que pede o banimento dos agrotóxicos já proibidos em outros países do mundo e que circulam livremente no Brasil.

A Campanha tem o objetivo de alertar a população sobre os perigos dos agrotóxicos, pressionar governos e propor um modelo de agricultura saudável para todas e todos, baseado na agroecologia.

Assine já, pelo banimento dos banidos! Entre no link abaixo.