字幕列表 影片播放 列印英文字幕 The world is burning. In California alone, some 3 million acres have burned since 2017. Since the beginning of 2019, there have been more than 121,000 fires in Brazil, and more than half of those have been in the Amazon rainforest. These fires cost the planet trees, which help fight climate change. The 2018 wildfire season in California is estimated to have released about 68 million tons of carbon dioxide into the atmosphere. That's roughly fifteen percent of all emissions in California. In short, one of the world's best defenses against climate change is being destroyed at an alarming rate. A recent study from the Swiss Federal Institute for Technology, ETH Zurich, says reforestation of forested lands at a global scale could help capture atmospheric carbon and mitigate climate change. According to the study, 0.9 billion hectares of land worldwide are available to be reforested and one hectare is the equivalent of 2.47 acres. In short, 0.9 billion hectares is an area the size of the United States. It's enough space to plant more than one trillion trees, and the resulting carbon capture, according to the study, would be more than 200 gigatons. That's about 32 percent of human carbon emissions since the beginning of the industrial revolution. In fact, after the study was first published, articles appeared with headlines like 'Tree planting has mindblowing potential to tackle climate change'. Simply put, trees capture carbon dioxide. "My first reaction was, wow, wouldn't that be wonderful? And actually, in a way, goes back to some earlier studies that show that, you know, there are probably less than half the trees growing in the world right now than we're growing, say, after the Ice Age retreated." Bill Moomaw is professor emeritus of international environmental policy at Tufts University. He spent 20 years of his career looking at technological solutions to climate change. A forest of 50-year-old oak trees, for example, would absorb or sequester about 30000 pounds of CO2 per acre. You've probably heard of the greenhouse effect. It's what happens when heat radiating from earth gets trapped in the atmosphere. "This isn't something that we're going to be seeing in the distant future. Climate change is happening. Humans are responsible for climate change and CO2 emissions that are causing climate change to happen, along with emissions of methane from agriculture and oil and gas activities. To some extent, emissions of nitrous oxide gases that come from agricultural practices primarily. Certain gases exacerbate the problem, such as methane, nitrous oxide, chlorofluorocarbons and of course, carbon dioxide. Moomaw maintains that while planting trees is one part of the solution, that alone won't stop climate change. "We should simultaneously reduce our emissions as much as possible, as rapidly as possible. That means that the energy sector and the industrial sector into agriculture and everything you can imagine." NASA has several initiatives to track climate change or carbon sequestration, the process of absorbing and storing carbon over a long period of time. For example, the Global Ecosystem Dynamics Investigation mission is a laser based on the International Space Station, one that measures canopy height and forest structure around the world. And there's also ICEsat, which measures the elevation of ice surfaces. And there's Landsat, which monitors where deforestation or regrowth is happening. While the evidence for climate change seems clear, there's no consensus for how to deal with it. Some have argued for carbon taxes, which would tax fossil fuels as a means of reducing emissions. Others have suggested a complete overhaul in agricultural and livestock practices. But planting trees is something almost everyone can agree is beneficial to the planet. But would it really help fight climate change? That part is far more controversial. While the ETH Zurich study says there are 0.9 billion hectares of land available for planting, there is little chance all of it will ever be used for that purpose. Much of the available land is on private property, so private landowners would have to be convinced to do the planting and a great deal of that land is used for farming and grazing or beef cattle and dairy cows. Reforestation also requires careful planning. For example, too many trees in northern forests and warming could be exacerbated. That's because too many trees block winter snows in winter snows reflect sunlight. At the same time, trees absorb the heat without redirecting it. And that can create a local warming effect. "Let's make sure we plant them in the right way. Let's make some decisions about which species we're going to plant. Let's not plant. Let's let's focus on on native species rather than bringing in other species." The Amazon rainforest is enormous. It covers more than 2 million square miles, including a large chunk of northwestern Brazil and extends to Peru, Colombia, Venezuela, Ecuador, Bolivia, Guyana, French Guiana and Suriname. Since January, more than 121,000 fires have ravaged Brazil, with more than half of those burning in the country's Amazon rainforest. Many of them were set as a result of slash and burn agriculture. Farmers burned the land to create space for crops and grazing. And it could get worse, especially under current President Jair Bolsonaro's aggressive land use policies. The country lost 53.8 million hectares of tree cover from 2001 to 2018. That's a 10 percent decrease since 2000. And deforestation is harmful in another way. When a tree is cut down, it releases captured CO2 back into the atmosphere. NASA estimates between 15 and 20 percent of carbon emissions each year come from deforestation. Much of the deforested lands in Brazil was planted over with soybeans or used for cattle grazing. About 80 percent of Amazon's deforestation is due to cattle ranching. In fact, Brazil is now among the world's biggest soy and beef exporters. Meanwhile, President Bolsonaro, who was a climate change skeptic, is not inclined to stop deforestation anytime soon. Since he took office, his administration has cut Brazil's Environmental Protection Agency budget by 24 percent. He's fired the director of the National Institute for Space Research, the agency that tracks rainforest activity, and he's eliminated a number of fines for environmental damage. Still, earlier this year, Bolton R-OH told the U.N. the Brazilian rainforest remains pristine and virtually untouched. But really, Brazil lost more than five thousand two hundred square miles of rainforest in 2018. That's an area roughly the size of Connecticut. Aside from saving the planet, there are sound fiscal reasons for planting trees around the world. In 2015, Citigroup estimated the cost of not taking action to fight climate change would be 44 trillion dollars by 2016. Citigroup went on to say that incremental costs of action are limited, offer reasonable returns on investment and should not have too detrimental an effect on global growth. Adding renewable energy and improving efficiency. The study found, may actually boost the global economy. There's also another issue to consider and that single use paper products, paper napkins, tissues, diapers, toilet paper. I mean, we're flushing we're flushing forests down the toilet. Literally reinforce sustainability has even brought a number of new business opportunities as well and range from one that manages sustainable timber plantation to a company that works with smaller farmers to one that sells beverages made from rainforest products. BioCarbon engineering was started by a former NASA employee, Lauren Fletcher. The company uses drone technology to reforest on a large scale by firing seeds into the ground to people. Planting trees can plants up to three thousand a day. But a team operating 10 drones can plant up to 400,000. The company estimated revenues for 2020 of nearly 100 million dollars. Another called Guayaquil Sustainable Rainforest Products, has created a market in the US around drink, made from here yerba mate a species from the Holly family. The drink is popular in Paraguay, Chile, Uruguay and southern Brazil and has been adapted to American tastes. More than 600 social media stars recently raised over 16 million dollars to plant trees all over the world. The effort was spearheaded by YouTube star Jimmy Donaldson, who's also known as Mr. Beast. Donaldson post videos of stunts performed by himself and his friends. Donaldson was challenged by a fan to plant 20 million trees. It was part of the hashtag Team Trees Project. The program raised over five million dollars in two days and all donations went directly to the Arbor Day Foundation, a non-profit organization that plants trees. Even Elon Musk committed to donating a million trees to the project. The planting is slated to begin in January and should be finished in three years. In July, Ethiopia planted more than 350 3 million trees in just 12 hours. The idea was to meet with the country calls its hashtag Green Legacy goal, a program instituted by prime minister be met. Ethiopia's efforts surpassed India's 2017 initiative, which planted 66 million trees in a single day. There's also the bond challenge, which intends to plant 864 million acres of trees by 2030. And the Nature Conservancy has its own plant, a billion trees effort under way. The program was launched in 2008 and it was originally intended to bring back Brazil's Atlantic Forest. It's since expanded to the U.S., Mexico and China. And so what's needed is a comprehensive monitoring program where we can look at the changes in land cover. We can estimate the associated changes in carbon that's being removed from the atmosphere and then scale this globally or over long periods of time. Let's make sure that that carbon removal is permanent. Reforestation efforts are also a major part of the Paris climate agreement, which President Trump just formally moved to end U.S. participation. The withdrawal will be complete at the end of 2020 in the Paris Climate Agreement. A handful of key countries, including Brazil, Indonesia, Peru and the United States committed to intensifying efforts to protect forests because while it doesn't take long to destroy forests, replacing them can take decades. The most important thing is to slow down or stop deforestation and conserve our existing forests. The second is then to identify the areas that have been recently deforested and go about restoring those ecosystems. And then the third is to very carefully consider the forestation options that are in the context of how those might affect land tenure, biodiversity and food security.
B2 中高級 美國腔 種植數十億棵樹能阻止氣候變化嗎? (Can Planting Billions Of Trees Halt Climate Change?) 79 3 ayami 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字