Nature · 人与自然 / 气候 / 城市 / 科普
若无城市树木，城市"热岛"热度将翻倍
Combining data from 8,919 large cities globally, a study highlights the extent to which trees cool cities — and the urgent need to green vulnerable neighbourhoods
📌 本文为外刊原文：The Nature Conservancy（大自然保护协会）新闻稿原文，未做改写，仅作生词标注与拆解。原文载于 Nature.org Newsroom，基于 Nature Communications 论文（McDonald et al., 2026）。
中文导读
如果没有城市树木，全球城市的"热岛"热度将翻倍。由大自然保护协会（TNC）牵头、发表于《自然·通讯》的这项史无前例的研究，汇集了全球近 9000 个大城市、约 36 亿人口的数据，发现树冠目前可抵消近一半（约 48.6%）的城市热岛效应，全球逾 2 亿城市居民因此享受到比无树情景低 0.5°C 以上的气温。但研究也揭示了一个鲜明的不公平：树木的降温作用目前集中在高收入国家、湿润气候和郊区——恰恰是需求最不紧迫的地方；到 2050 年，现有及未来的树冠最多也只能抵消 9%–10% 的气候升温。科学家呼吁，扩大树冠覆盖固然关键，但仅靠树木远远不够，人类还需多种策略适应更热的世界，并尽快减少温室气体排放。
一、原文精读
以下为 The Nature Conservancy 新闻稿英文原文（全文）。鼠标悬停在带 蓝色虚线下划线 的生词上，即可查看词性和释义。
🔊 英音朗读 · British English
由英音语音合成（en-GB）朗读全文原文，共 9 段。播放时原文会随进度逐句高亮，建议先盲听抓大意，再对照下方原文跟读，留意重音、连读与停顿。
【1】The world's 'urban heat islands' (UHIs) would be twice as hot without the cooling effect trees have on superheated cityscapes, according to an unprecedented study that also highlights stark inequalities in access to this powerful form of nature-based air conditioning.
【2】Led by The Nature Conservancy (TNC) and published in Nature Communications, the paper pools data from nearly 9,000 large cities worldwide – collectively home to ~3.6 billion people – to find that tree cover currently mitigates nearly half (~48.6%) of the UHI effect that occurs when man-made surfaces like roads, buildings and car parks absorb and release heat from the sun, causing urban areas to heat up more than surrounding rural regions.
【3】Over 200 million city-dwellers globally, the study finds, have trees to thank for ambient air temperatures more than 0.5°C lower than would otherwise be the case in their neighbourhoods – a highly significant contrast when extrapolated across the thousands of cities, billions of citizens and increasingly life-threatening temperatures concerned.
【4】Commenting on the study's significance, Rob McDonald, TNC's lead global scientist for both nature-based solutions and for its European regional team, said, "By combining datasets showing air temperatures at 1km scale with high-resolution land cover maps, we've succeeded for the first time in producing tangible estimates for a natural cooling effect that's long been accepted but never comprehensively measured until now."
【5】Co-authored by scientists from Pacific Northwest National Laboratory (PNNL), SUNY ESF and Western Sydney University, the study also finds that the cooling effect of trees is currently concentrated in places where the need is less acute: high-income countries, humid climates and suburban neighbourhoods.
【6】Compounding this inequality is the study's projection that current and future tree cover will only be able to mitigate 9-10% of the increase in temperatures caused by climate change that is anticipated by 2050. The maximum possible tree planting scenario increases this to around 20%, making it doubly urgent that governments commit to increasing tree canopy cover across their most densely settled and low-income urban areas while there's still time to allow full canopy growth.
【7】Adding further urgency, Rob McDonald said, "While expanding tree cover – particularly in urban areas that don't have enough right now – is an essential part of adapting to rising temperatures, our study suggests that trees by themselves won't be enough. Humanity will need to use multiple strategies to adapt to a hotter world, and we desperately need to reduce greenhouse gas pollution to avoid committing ourselves to catastrophically high temperatures."
【8】TC Chakraborty, Earth Scientist at PNNL, who led the remote sensing analysis for the study, said: "Most global studies rely on satellite land surface temperature, which significantly overstates the cooling benefits of trees. But air temperature alone doesn't tell the whole story. By modeling Wet Bulb Globe Temperature – a metric that also factors in humidity, wind, and solar radiation – at the local scale for a small subset of cities, we found that trees reduce actual human heat stress by an average of three times more than air temperature suggests. This gives us a much more accurate, physiologically relevant estimate of how trees can protect urban residents during hot, sunny, summer days."
【9】"It's increasingly common to see stark temperature differences between neighbourhoods in the same city, driven by unequal amounts of tree canopy," added Johnny Quispe, director of cities programs at TNC. "The impacts of extreme heat often affect the most vulnerable communities. Investing in urban forestry yields cooler streets, cleaner air and more resilient communities for everyone."
原文出处：The Nature Conservancy（TNC）新闻稿 "Urban 'heat islands' would be twice as hot without city trees, major study finds"（2026-05-05），转载标注仅供学习。论文：McDonald R.I. et al., Nature Communications, doi:10.1038/s41467-026-71825-x。
三、长难句分析（三步拆解法）
The world's 'urban heat islands' (UHIs) would be twice as hot without the cooling effect trees have on superheated cityscapes, according to an unprecedented study that also highlights stark inequalities in access to this powerful form of nature-based air conditioning.
主干：The world's 'urban heat islands' (UHIs) would be twice as hot（主语 + would be + 表语）
条件状语（without + 名词短语）：without the cooling effect trees have on superheated cityscapes（内含省略关系词的定语从句 trees have on superheated cityscapes，修饰 effect）
定语从句：that also highlights stark inequalities in access to ...（修饰 study）
考点：虚拟语气 would be（without 作含蓄条件）；省略关系词的定语从句；that 引导定语从句
译文：一项史无前例的研究显示，如果没有树木对过热城市景观的降温作用，世界各地的"城市热岛"（UHI）热度将是现在的两倍；这项研究同时揭示，在享用这种强大的"自然空调"方面存在鲜明的机会不平等。
Led by The Nature Conservancy (TNC) and published in Nature Communications, the paper pools data from nearly 9,000 large cities worldwide – collectively home to ~3.6 billion people – to find that tree cover currently mitigates nearly half (~48.6%) of the UHI effect that occurs when man-made surfaces like roads, buildings and car parks absorb and release heat from the sun, causing urban areas to heat up more than surrounding rural regions.
主干：the paper pools data ... to find that ...（主语 + pools + 宾语 + 不定式状语）
过去分词作状语：Led by The Nature Conservancy (TNC) and published in Nature Communications（"由……牵头并发表于……"）
宾语从句 + 定语从句 + 时间状语从句：that tree cover currently mitigates nearly half ... of the UHI effect that occurs when man-made surfaces ... absorb and release heat
现在分词作结果状语：causing urban areas to heat up more than surrounding rural regions
考点：过去分词作状语；that 宾语从句与定语从句的区分；when 时间状语从句；现在分词作结果状语
译文：这项由大自然保护协会（TNC）牵头、发表于《自然·通讯》的研究，汇集了全球近 9000 个大城市（约 36 亿人口）的数据，发现树冠目前可抵消近一半（约 48.6%）的热岛效应——当道路、建筑和停车场等人造表面吸收并释放太阳热量、使城市比周边乡村升温更高时，这一效应就会显现。
Over 200 million city-dwellers globally, the study finds, have trees to thank for ambient air temperatures more than 0.5°C lower than would otherwise be the case in their neighbourhoods.
主干：Over 200 million city-dwellers ... have trees to thank for ambient air temperatures（主语 + have sth to thank for）
插入语：the study finds（"研究发现"）
比较结构（后置定语）：more than 0.5°C lower than would otherwise be the case in their neighbourhoods（修饰 temperatures）
考点：插入语；比较级 lower than；have sth to thank for 固定搭配
译文：研究发现，全球有超过 2 亿城市居民要感谢树木——他们所在街区的环境气温比没有树木时低了 0.5°C 以上。
Compounding this inequality is the study's projection that current and future tree cover will only be able to mitigate 9-10% of the increase in temperatures caused by climate change that is anticipated by 2050.
主干（倒装句）：the study's projection ... is Compounding this inequality（表语提前的完全倒装：正常语序为 The study's projection ... is compounding this inequality）
同位语从句：that current and future tree cover will only be able to mitigate 9-10% of the increase in temperatures（解释 projection 的具体内容）
过去分词作定语：caused by climate change（修饰 the increase in temperatures）；that is anticipated by 2050（定语从句，修饰 climate change）
考点：现在分词提前的倒装结构；that 同位语从句；过去分词作后置定语
译文：让这种不平等雪上加霜的是研究的预测：到 2050 年，现有及未来的树冠覆盖最多只能抵消由气候变化造成的 9%–10% 的气温上升。
By modeling Wet Bulb Globe Temperature – a metric that also factors in humidity, wind, and solar radiation – at the local scale for a small subset of cities, we found that trees reduce actual human heat stress by an average of three times more than air temperature suggests.
主干：we found that ...（主语 + found + that 宾语从句）
方式状语：By modeling Wet Bulb Globe Temperature ... at the local scale for a small subset of cities（by doing，"通过……"）
同位语 + 定语从句：a metric that also factors in humidity, wind, and solar radiation（破折号引出，解释 Wet Bulb Globe Temperature）
考点：by doing 方式状语；that 定语从句；比较结构 three times more than
译文：通过在局部尺度上、针对一小部分城市模拟"湿球黑球温度"（一个同时纳入湿度、风速和太阳辐射的指标），我们发现树木对人体实际热应激的缓解程度，平均是气温数据所显示的三倍。
四、全文大意
这篇大自然保护协会（TNC）的新闻稿报道了一项发表于《自然·通讯》的重大研究：如果没有城市树木的降温作用，全球城市的"热岛"热度将翻倍。研究汇集了近 9000 个大城市、约 36 亿人口的数据，发现树冠目前可抵消近一半（约 48.6%）的城市热岛效应，全球逾 2 亿城市居民因此享受到比无树情景低 0.5°C 以上的气温。然而研究也揭示了一个鲜明的不平等：树木的降温作用目前集中在高收入国家、湿润气候和郊区——恰恰是降温需求最不紧迫的地方；更糟的是，到 2050 年，现有及未来的树冠最多只能抵消 9%–10% 的气候升温，即使是最激进的植树情景也仅约 20%。科学家因此强调，扩大树冠覆盖固然重要，但仅靠树木远远不够，人类必须采用多种策略适应更热的世界，并尽快减少温室气体排放。研究还改进了测量方法——用"湿球黑球温度"替代卫星地表温度，发现树木对人体的实际降温（热应激缓解）是气温数据的三倍。最终，研究者呼吁投资城市林业，让最脆弱的社区也能享有更凉爽的街道、更清洁的空气和更有韧性的未来。
五、思考与仿写
思考题：结合第 5、6 段，为什么"树木降温集中在高收入国家、湿润气候和郊区"恰恰是一种不公平？这种"降温"与"需求"错配的现象，在你的城市里能观察到吗？
仿写题：仿照第 1 段 "The world's 'urban heat islands' would be twice as hot without the cooling effect trees have on superheated cityscapes"（without + 名词短语表含蓄条件 + would be 虚拟语气）的句式，围绕「绿色校园」或「环境保护」写一个句子。