deforestation and drought - absorption of water
Like California, much of Brazil has suffered one of the worst droughts in history.
In Sao Paulo, a big city with a population of 20 million, huge reservoirs have dried up and water has been rationed; in Rio;
In many other places.
Drought is often considered a natural disaster beyond human control.
But as researchers look deeper into the changing biological climate of the planet
An extremely complex global interaction between biological and climate forces
They better understand the key role of deforestation.
Deforestation releases stored carbon dioxide, which captures heat and causes the atmosphere to warm up.
But forests also affect the climate in other ways, for example, by absorbing more solar energy than the grassland, or releasing a large amount of water vapor.
Many experts believe that the scale of deforestation, especially in South America, has greatly changed the climate of the world.
Although its dynamics are not very clear.
Abigail L said: "Many people are scrambling to observe on Amazon. it is expected that the big El Nino will come . "S. Swann, an eco-
Meteorologists at the University of Washington.
"Amazon is expected to trigger a severe drought that will change the amount of water available to trees.
"Humans have long settled in places where there is sufficient and predictable precipitation, while large forests play a vital role in generating reliable rainfall.
The trees absorb moisture from the soil and evaporate it, lifting it into the atmosphere.
A fully grown tree releases 1,000 liters of water vapor into the atmosphere every day: the entire Amazon rainforest sends 20 billion tons a day.
Water vapor produces clouds that are sown by volatile gases (such as terpen ENE and ethylene) naturally emitted by trees to form rain. These water-
Rich Bank travel in the cloud Long, wind-
Driving distance, scientists call the conveyor belt for transporting precipitation in flying rivers. The sky-
The Amazon River carries more water than the Amazon itself.
It begins with the accumulated moisture in the Atlantic Ocean, and then flows west through the emerald crown of Amazon, where it absorbs more water.
The full clouds eventually hit the Andes and moved south and east, meaning it would rain in Bolivia and Brazil.
A way for the forest to move water is called "biological pumping ".
The theory holds that when water enters the atmosphere above the forest, it produces a low
Its pressure system absorbs the air around it, eventually continuously delivering moisture from the ocean to the interior.
Deforestation can degrade these low forests.
Basically shut down the pressure system of the pump. Large-
As a result, massive deforestation is considered to be the main cause of extreme drought in Brazil.
Scientists have long known that vegetation has a profound impact on the weather.
In 1907, officials built a 2,000-mile-
Long fences across Australia to prevent invading rabbits from crossing from the wild to the farm.
On one side of the local vegetation, rain clouds are formed in the sky, but the farm-
Clear skies in the wild. The “bunny-
The fence experiment shows that the rainfall on the cultivated land side has dropped by 20%.
Researchers are still trying to explain why, but the leading theory is that darker native plants absorb more heat and release it into the atmosphere with energy and water vapor to form clouds
Today's researchers rely mainly on computer modeling to understand the impact of deforestation, which is a difficult task because the way trees control their climate is very complex: precipitation, carbon storage, complex chemical emissions and large clouds that absorb solar energy.
"The area is a frontier," said David Schimel, an environmental activist.
Climatologist at NASA's Jet Propulsion Lab, author of climate and ecosystem, but this is a cutting edge area because it's hard, not because it's ignored.
In the past year alone, Amazon has reached 2,000 square miles.
About the size of Delaware.
It is mainly used for planting soybeans and raising cattle, but it has not been cleaned up.
More and more scientists warn that,
About 20% of Amazon's forests have disappeared, and almost so many have degraded --
Precipitation may have been guided away from places that have long been used.
A Princeton study suggests that cutting Amazon could lead to drought in places such as California, and other studies suggest that the recent drought in Texas and New Mexico may be linked to production cuts in the Amazon region.
Despite the uncertainty contained in these and other studies, "there is a lot of evidence that changing Amazon's water cycle can have global consequences," Dr. Schimel said.
"This is a fairly robust concept.
Its impact may accelerate.
In a recent report, Antonio Donato Noble, a senior climatologist at the National Space Institute in Brazil, warned that if only 40% of the forest in the Amazon region is cut down, it may
The scale shifts to the grassland, which could significantly change the global weather pattern and lead to the collapse of the current climate system.
If deforestation continues, Sao Paulo is likely to "dry up", he said ".
In the broadest sense, scientists say, forests are an ecological infrastructure that helps maintain comfortable living conditions on Earth, whether it is absorbing and storing carbon dioxide and cleaning water through roots, prevent flooding by stabilizing the soil
Or, in this case, by regulating the climate. Dr.
Nobre and other climate experts urge an immediate end to deforestation
Growing new forests on a large scale serves as a way to basically restore Amazon to health and stabilize its key role in the climate.
Gordon Bonan, a scientist at atmospheric research at the University of Boulder, Colorado.
The authors of eco-climatology say that for many reasons, including the health of the climate system, reducing deforestation and replanting forests should be a priority not only for Brazil, but also for North America and beyond
"The pace of change is far more than we understand what change is doing," he said. "It may be too late when we really understand it.
"Despite the massive planting of trees, the reroutes groundwater performs large-scale and absorbs more energy than the unforested landscape and can have complex and potentially negative effects," he added in general: "If done well, this is a positive strategy to tackle climate change. ".
Instead of waiting for further research, some hope to change the local climate through new forests.
Bishop Frederick shoo, elected bishop of the Gospel Lutheran Church in Tanzania, has been planting trees in Mount Kilimanjaro with his 100,000 parishioners for 12 years, hope is melting the dry wind of the glacier.
He estimated that they had planted three of them during that time. 7 million trees
"I hope we can restore the forest of Mount Kilimanjaro and save the water source of Mount Kilimanjaro," said Bishop Xiao, known as Bishop of the tree.
"We have a moral obligation to take care of creation and to ensure that future generations have a good place of residence.