巴西总统大选可能成为亚马逊雨林的转折点，亚马逊是世界上最大的热带雨林。总统路易斯·伊纳西奥·卢拉·达席尔瓦面对极右翼参议员弗拉维奥·博尔索纳罗。
Brazil's presidential election could be a turning point for the Amazon, the world's largest rainforest. President Luiz Inácio Lula da Silva faces far-right Sen.
加布里埃拉·萨·佩索阿 圣保罗讯——虽然巴西总统候选人尚未将亚马逊政策作为竞选的主要议题，但气候科学家和环保人士表示，周日选举的胜负可能决定世界上最大的热带雨林是否以及何时会达到“临界点”。这一关键阈值在科学家中争议颇多，简单来说，就是茂密、潮湿、能产生水分的森林转变为更干燥的生态系统。
GABRIELA SÁ PESSOA SAO PAULO — While Brazil’s presidential candidates have not made policy of the Amazon a major campaign topic, climate scientists and environmentalists say the winner of Sunday’s race could determine whether, and how soon, the world’s largest rainforest could reach a “tipping point.”The key threshold, heavily debated among scientists, in simple terms would be when the dense, humid, moisture-generating forest shifts to a drier ecosystem.
这将对生物多样性和气候造成不可逆转的后果，因为森林吸收了大量二氧化碳，而二氧化碳是推动全球气温上升的温室气体。巴西拥有约60%的亚马逊雨林，该雨林横跨南美洲多个国家。
That would come with irreversible consequences for biodiversity and the climate, as the forest absorbs massive amounts of carbon dioxide, a greenhouse gas that drives global temperature to rise. Brazil contains about 60% of the Amazon, which is spread across several countries in South America.
以下是两位总统候选人及其对亚马逊不同愿景如何与潜在临界点交汇的情况：两位候选人预计将以不同方式处理亚马逊政策。总统路易斯·伊纳西奥·卢拉·达席尔瓦正在争取第四个非连续任期，他致力于遏制森林砍伐，并通过国际捐款以及公共和私人资金支持可持续经济。如果他获胜，预计将延续此类政策。
Here is a look at the two presidential candidates and how their different visions of the Amazon may intersect with a potential tipping point: Both candidates expected to handle Amazon policy differently President Luiz Inácio Lula da Silva, trying to win a fourth nonconsecutive term, has sought to curb deforestation and finance a sustainable economy through international donations and public and private funding. If he wins, he is expected to continue such policies.
参议员弗拉维奥·博尔索纳罗是前总统雅伊尔·博尔索纳罗的儿子，他表示不相信气候变化是真实存在的，同时将自己塑造为环境捍卫者。他对森林保护和融资计划的细节阐述甚少。他呼吁对环境法进行“现代化”，并赋予亚马逊地区土地所有者更多决策权，环保人士认为这将削弱保障措施，并导致森林砍伐加速。
Sen. Flávio Bolsonaro, son of former President Jair Bolsonaro, has said he doesn’t believe climate change is real while casting himself as an environmental defender. He has offered few details on his plans for forest protection or financing. He has called for a “modernization” of environmental laws and giving landowners in the Amazon more decision-making power, which environmentalists say would weaken safeguards and allow deforestation to accelerate.
临界点是指超过该关键阈值后，微小变化就可能引发生态系统或气候系统发生重大转变。科学家在亚马逊、南极冰盖和大西洋环流等区域或系统中研究此类风险。
A tipping point is a critical threshold beyond which a small change can trigger a major shift in an ecosystem or climate system. Scientists study such risks in regions or systems like the Amazon, Antarctic ice sheets and circulation patterns of the Atlantic Ocean.
对于亚马逊，一些研究表明，森林损失超过20%，加上自19世纪初以来全球升温约2摄氏度（3.6华氏度），可能引发广泛变化。目前亚马逊已有约17%的森林被砍伐，气温上升约为1.4摄氏度（2.5华氏度）。
For the Amazon, some research suggests that losing more than 20% of the forest, combined with global warming of around 2 degrees Celsius (3.6 degrees Fahrenheit) since the early 1800s, could trigger widespread changes. About 17% of the Amazon has already been cleared and temperature rise is currently at about 1.4 C (2.5 F).
跨越该阈值可能引发自我强化循环，雨林部分地区将失去从干旱、火灾及其他干扰中恢复的能力，转而让位于更干燥的生态系统。
Crossing that threshold could set off a self-reinforcing cycle in which parts of the rainforest lose their ability to recover from drought, fire and other disturbances, giving way to a drier ecosystem.
“随着气候变化对亚马逊造成日益严重的压力，森林会撑到撑不住为止，然后崩溃，要么局部崩溃，要么整体崩溃，一旦跨越临界点，这一过程可能持续数十年甚至数百年，”伯纳多·弗洛雷斯说。他是地球系统韧性专家，也是亚马逊科学小组成员，该小组是一个致力于保护流域并指导可持续发展的独立科学倡议。
“As the climate changes and puts increasing stress on the Amazon, the forest holds until it can’t anymore and collapses, either in parts or all at once, a process that could take decades or centuries once the tipping point is crossed,” said Bernardo Flores, an Earth system resilience expert and member of the Science Panel for the Amazon, an independent scientific initiative dedicated to protecting the basin and guiding sustainable development.
大卫·拉波拉研究亚马逊如何应对二氧化碳浓度上升，他更为谨慎。作为即将发布的联合国气候报告关于临界点章节的主要作者之一，他表示，模型显示存在崩溃风险，但观测和实验尚未证实森林损失20%会引发崩溃。
David Lapola, who studies how the Amazon responds to rising carbon dioxide levels, is more cautious. A lead author of an upcoming U.N. climate report chapter on tipping points, he said models suggest a risk of collapse, but observations and experiments have yet to establish that losing 20% of the forest would trigger it.
“这并不意味着我们应该停止担忧，忘记这个问题。我们需要调查它，需要成立一个科学专项工作组，彻底查明真相，”他说。
“That doesn’t mean we should stop worrying, that we should forget about this problem. We need to investigate it, to have a scientific task force to get to the bottom of it,” he said.
由韧性专家弗洛雷斯牵头、2024年发表在《自然》杂志上的研究估计，到2050年，亚马逊雨林10%至47%的区域可能面临多重威胁，部分森林可能转变为不同的生态系统，并加剧该地区的气候变化。
How far away the Amazon may be from a tipping point A 2024 study led by Flores, the resilience expert, and published in Nature, estimated that 10% to 47% of the Amazon could face multiple threats by 2050, potentially turning parts of the forest into different ecosystems and worsening climate change in the region.
不过，弗洛雷斯表示，我们无法确切知道亚马逊距离临界点有多近，森林退化可能意味着它比模型预测的更接近临界点。“我认为主要的迹象将是亚马逊开始变得非常干燥，并经历大规模燃烧，”他说。
Still, Flores said that we cannot know precisely how closely the Amazon is to a tipping point, and forest degradation could mean its closer than models suggest. “I think the main sign would be the Amazon starting to become very dry and experiencing extensive burning,” he said.
由野火、伐木和干旱驱动的森林退化影响了亚马逊约40%的面积，且近年来已超过皆伐（注：指完全砍伐）的速度。
Forest degradation, driven by wildfires, logging and drought, affects about 40% of the Amazon and has outpaced clear-cutting in recent years.
雨林已经发生的变化 气候科学家卡洛斯·诺布雷是最早警告大规模毁林可能将亚马逊推向临界点的人之一，他说，已经在发生的变化表明森林正在接近这一阈值。
How the rainforest has already changed Climate scientist Carlos Nobre, among the first to warn that extensive deforestation could push the Amazon past a tipping point, said changes already underway show the forest is approaching that threshold.
“如今，我们知道亚马逊南部特别脆弱，”诺布雷说。“旱季现在延长了四到五周。条件大约干燥了20%到30%，气温升高了两到三摄氏度。”联合国报告作者之一拉波拉表示，气温上升和更频繁的干旱正在给树木带来压力并增加死亡率，削弱了即使是完整森林吸收碳多于释放碳的能力。如果这种衰退持续下去，这些森林可能在2030年代中期不再成为净碳汇，尽管这一预测仍存在不确定性。
“Today, we know that the southern Amazon is particularly vulnerable,” Nobre said. “The dry season is now four to five weeks longer. Conditions are approximately 20% to 30% drier, and temperatures are two to three degrees Celsius higher.”Rising temperatures and more frequent droughts are stressing trees and increasing mortality, weakening even intact forests’ ability to absorb more carbon than they release, Lapola, the U.N. report author, said. Those forests could cease to be a net carbon sink by the mid-2030s if the decline continues, though the projection remains uncertain.
根据巴西国家空间研究院卢西亚娜·加蒂的研究，亚马逊部分地区排放的二氧化碳（一种导致全球变暖的温室气体）已超过其吸收量。
Parts of the Amazon already emit more carbon dioxide, a greenhouse gas that drives global warming, than they absorb, according to research by Luciana Gatti of Brazil’s National Institute for Space Research.
她最新的研究于周三发表在《自然》杂志上，发现从2010年到2024年，亚马逊雨林每年平均释放的二氧化碳比吸收的多11.7亿公吨。气候变化加剧的火灾是排放的主要来源。
Her latest study, published Wednesday in Nature, found that the Amazon released an annual average of 1.17 billion metric tons more carbon dioxide than it absorbed from 2010 through 2024. Fires, worsened by climate change, were the main source of emissions.
诺布雷表示，防止进一步破坏需要持续削减温室气体排放，并为清理森林以发展养牛业和耕作——这是毁林的主要驱动因素——提供经济替代方案。“我们必须实现零毁林、零森林退化和零火灾，”他说。
Nobre said preventing further damage requires sustained cuts in greenhouse gas emissions and economic alternatives to clearing forests for cattle ranching and farming, the leading drivers of deforestation. “We must achieve zero deforestation, forest degradation and fires,” he said.
在2023年的联合国气候谈判上，巴西启动了“复苏弧”倡议，旨在通过重新造林和推广农林复合经营实践，恢复巴西南部亚马逊地区2400万公顷土地：到2030年恢复600万公顷，到2050年再恢复1800万公顷。但能否实现这些目标，可能取决于巴西人周日选出谁。
At the U.N. climate talks in 2023, Brazil launched its “Arc of Restoration,” an initiative to replant and foster agroforestry practices to restore 24 million hectares in the southern Brazilian Amazon: 6 million by 2030 and another 18 million by 2050. But meeting such goals could depend on who Brazilians elect on Sunday.
“如果我们成功，就能拯救亚马逊——世界上最大的热带雨林，也是世界上最大的生物多样性宝库之一，”诺布雷说。
“If we succeed, we can save the Amazon, the world’s largest tropical rainforest and one of its greatest reservoirs of biodiversity,” Nobre said.