熱帯雨林についてすべて - 世界雨林基金

All About Rainforests - World Rainforest Fund All About Rainforests Understanding the importance, threats, and preservation of Earth's most biodiverse ecosystems Why Should We Preserve Rainforests? Rainforests are Earth's most biodiverse ecosystems, containing half of all species on the planet, and their preservation is critical for multiple interconnected reasons that affect every person on Earth. Rainforests Alleviate Human-Induced Climate Change Trees carry out photosynthesis, which produces oxygen and removes carbon dioxide, the main greenhouse gas, from the atmosphere. But when they are cut or burned, trees can no longer perform photosynthesis, so cannot remove carbon dioxide from the air. Instead, burning or dead and decaying trees release the carbon dioxide stored in their trunks into the atmosphere, exacerbating the greenhouse effect. Rainforests are often destroyed by flooding from huge megadams. In this case, the trees decay under water in the absence of oxygen, which means they release methane instead of carbon dioxide. This is much worse for Earth's climate, because methane is 25 times as powerful a greenhouse gas as carbon dioxide . Thus, destroying rainforests makes human-induced climate much worse, heating the Earth. Destruction of tropical rainforests accounts for about 17% of global carbon emissions! The climate crisis cannot be solved without stopping the destruction of rainforests. Without a solution to the crisis of human-induced climatic disruption, there will be a tremendous catastrophe greater than humankind has ever experienced, with crop failures and mass starvation, unprecedented shortages of drinkable water, global pandemics, coastlines going under water, record high temperatures, huge droughts and floods, and many other catastrophes. The Vicious Cycle of Climate Change and Rainforest Destruction Human-induced climate change is rapidly destroying rainforests worldwide. The increased heat from greenhouse gasses causes droughts in rainforests. Hotter air can hold more moisture without dropping it as rain than colder air can. So the warmer air over the forest does not lose its water as rain, but moves away from the equator, and drops rain in temperate regions. Thus, rainforests are experiencing droughts all over the Earth. When rainforests are dry from droughts, fires are more easily started and can burn much larger areas. Since the droughts from global warming have appeared, there have been massive fires in rainforests in Mexico, Brazil, Africa, Indonesia, and other rainforests, destroying tremendous areas. The droughts also cause the edges of rainforests to die. After the trees on the edges die and fall over, there is a new edge whose trees then dry out and die, in an endless cycle that can continue until the entire rainforest is gone. In 2005 and 2010 , the Amazon experienced the worst droughts ever recorded. Rivers dried up, isolating communities, and millions of acres burned. The smoke caused widespread health problems, interfered with transportation, and blocked the formation of rain clouds. In palm tree plantations that produce palm oil, corporations drain out much of the water to dry out the area to make a monoculture. These plantations easily catch fire. They often have a great deal of peat in the soil, so hot fires that are very hard to put out burn. Many of these are underground, so hard to access to put out. Many have burned for years. Some are still burning now. This happens in many parts of the world, but mainly in Southeast Asia. The smoke pollutes large areas, affecting the breathing and health of many people. Rainforests Regulate the Global and Local Water Cycles Rainforests are important in the regulation of the global water cycle. Thus, the destruction of rainforests affects Earth's water cycle and causes floods and droughts far from rainforests. São Paulo, Brazil's largest city, is suffering from serious droughts due to the destruction of the Amazon rainforest. This megacity of over 12 million people is literally running out of water [3]. Deforestation in the Amazon and Central America severely reduces rainfall in the lower U.S. Midwest during the spring and summer seasons and in the upper U.S. Midwest during the winter and spring, respectively, and deforestation of Southeast Asia affects rainfall in China and the Balkan Peninsula significantly [4]. High-resolution simulations of destruction of the Amazon rainforest showed 10-20% less rainfall for the coastal northwest US and the Sierra Nevada, and declines of snowpack in the Sierra Nevada of up to 50% [5]. Rainforests also play an important role in the local water cycle. Rainforest trees add water vapor to the atmosphere by transporting water in the ground through their roots, up their trunks, and through their leaves into the atmosphere in a process called evapotranspiration. This causes rain. Half of the rain in the Amazon rainforest is caused by the trees there, while the other half comes from water evaporated by the sun in the Atlantic Ocean. The rain that rainforests produce is needed by local farmers to grow food, people and animals for drinking, trees and plants to grow, and the rivers and lakes of the forest. These rivers lakes support fish, freshwater dolphins, turtles, and invertebrates, such as insect larvae and shrimp. Rainforest water is purified by tree roots and fungi underground, where toxins are removed. Roots of rainforest trees store large amounts of water. Without the rainforest to soak up rain and release it slowly, floods and droughts become more common. In the Amazon rainforest, more than half the water in the ecosystem is stored within the plants. Medicine and Resources Rainforests are the source of many essential foods, medicines (including 70% of plants identified as having anti-cancer properties), and everyday products we use. More than one fourth of the medicines we use today have their origins in rainforests, yet only 1% of rainforest plants have been studied for their medicinal properties. These forests harbor millions of undiscovered species that could provide future medical and agricultural breakthroughs. Soil Protection Rainforest trees and plants protect soil from erosion. When forests are cleared, heavy tropical rains wash away the thin, nutrient-poor soil within just a few years, leaving land unsuitable for agriculture and unable to support forest regrowth. This creates permanent ecological damage and contributes to desertification. Trees shade rivers and keep them cool enough for fish and other animals and plants in them to thrive. They stabilize river banks and prevent their erosion. Without this, sediment from soil would pollute rivers and lakes in the forest, and many fish, river dolphins, and aquatic invertebrates would die. Rainforest trees shade and protect the soil, blocking the hot, intense tropical sun from hitting it during the day. They hold heat in at night. Destroying the forest leads to more extreme temperature swings that are harmful to plants and animals. The trees also protect the soil from intense tropical rains. When the trees are removed, the rain washes the soil away, and the sun bakes the soil into a hard, brick-like state. In a short time, this can result in a desert on which no trees or food crops can grow. Rainforests Regulate Earth's Reflectivity Rainforests affect the reflectivity of sunlight by the Earth. This is called the Earth's albedo. When they are cut, the albedo changes, and sunlight is reflected differently. This changes wind patterns and therefore rain patterns of our planet. This causes floods and droughts, reducing our agricultural yields and ability to obtain clean drinking water. The floods cause soil erosion, making it harder for wild plants and trees to grow and for humans to grow food. Economic Value The economic value of rainforest biodiversity alone is estimated at 2-5 trillion dollars annually through ecosystem services, yet current destruction rates threaten to eliminate over three-quarters of unknown species before they can even be discovered. Sustainable use of rainforests provides long-term economic benefits that far exceed short-term extraction profits. How Rapid is Rainforest Loss? Alarming Statistics: 5 acres every second - or 300 acres per minute 80,000 acres destroyed daily - with another 80,000 significantly degraded Half of California every year - area of rainforest permanently lost annually 135 species extinct daily - almost 50,000 species per year Globally, rainforests are being destroyed at the rate of about 5 acres every second, or 300 acres per minute. We are losing over 80,000 acres, and significantly degrading another 80,000 acres, of tropical rainforest every single day. This is not a distant problem - it is happening right now, every minute of every day. Every year, the area of rainforests destroyed is equal to one half the size of the state of California. To put this in perspective, imagine losing an area the size of a football field every single second of every day throughout the year. This is the actual rate at which we are losing these irreplaceable ecosystems. The destruction of rainforests alone is causing the extinction of 135 plant and animal species every day, which is almost 50,000 species a year. This represents an extinction rate that is 1,000 to 10,000 times higher than the natural background extinction rate. We are in the midst of the sixth mass extinction event in Earth's history, and rainforest destruction is a primary driver. According to the United Nations' Food and Agriculture Organization, overall tropical deforestation rates this decade are 8.5 percent higher than during the 1990s, meaning the problem is getting worse, not better. Worse, the loss of primary tropical rainforest—the wildest and most diverse areas—has increased by as much as 25 percent since the 1990s. Thus, sadly, deforestation rates are rising rapidly. It is estimated that if the destruction is not stopped, rainforests will ce