Take a look outside a window. What is the season where you are? How do you know?
看看窗外，看看现在是哪个季节？你是怎么知道的？
Most likely, you looked at a tree or plant
很可能，你是通过观察树或植物，
and noticed details about its leaves and assessed the qualities of sunlight streaming outside.
注意到它叶子上的细节，以及根据外面阳光的强弱来进行判断的。
Observing the timing of biological events in relation to changes in season and climate is called "phenology".
观察一些生物现象的发生时间和季节、气候变化之间的联系，叫做“生物气候学”。
When you notice the daffodil buds are poking through the snow and think spring is on its way, you're using phenology.
当你注意到黄水仙的新芽正要破雪而出，进而想到春天即将来临，你就正在运用生物气候学。
When you see leaves turn from green to red, and watch migrating birds fly past,
当你看到叶子由绿转红，并看到成群候鸟飞过，
and realize that summer is over, autumn is here, you're using phenology.
进而想到夏天将尽、秋天已到，这也是生物气候学。
Literally meaning, "the science of appearance",
phenology字面上的意思是“景象的科学”，
phenology comes from the Greek words "pheno," to show or appear, and "logos," to study.
它源自希腊词汇“pheno”，意思是“表现”或“出现”，而“logos”是“研究”的意思。
Humans have relied on phenology since the time of hunters and gatherers.
早在打猎和采集的时代，人类就已经开始依赖生物气候学的知识了。
We've watched changes in seasons to know when to plant and harvest food and when to track migrating animals.
我们通过观察季节的变化，来了解何时种植及收割作物，以及何时可以追踪候鸟。
Scientists observe and document seasonal changes in nature and look for patterns in the timing of seasonal events.
科学家观察并记载自然界的季节变化，试图寻找各季节事件发生的规律。
Timing of these natural signs has remained consistent until recently.
这些自然现象的发生时间长久以来一直保持不变。
Increasing global temperature is causing rhythms of nature to shift.
然而最近的全球变暖正在造成大自然规律的改变。
Bud burst, the day when a tree or plant's leaf or flower buds open, is occurring earlier in the year for some species.
萌芽，也就是树和植物的叶子、或是新芽长出的那天，对于某些物种来说提前了。
For every one degree Celsius rise in temperature, bud burst happens five days earlier than usual.
温度每上升1摄氏度，植物就比以往更早五天萌芽。
Differences in timing affect not only plants,
这些时间上的差异并不只影响植物，
but the insects and birds that depend on the plants for food.
同时也影响那些以植物为食物的昆虫和鸟类。
For example, oak trees in the Arnhem Forest of the Netherlands
比如说，荷兰阿纳姆森林的橡树，
now experience bud burst ten days earlier, as compared to twenty years ago.
相较于二十年前，提前了十天萌芽。
New oak leaves are a favorite food of winter moth caterpillars.
橡树的嫩叶是冬尺蛾幼虫最爱的食物。
To survive, the caterpillars adapted to the change in the tree's timing,
为了生存，幼虫适应了树生长的时间变化，
and now hatch 15 days earlier than before.
进而比以往提早十五天孵化。

Migrating pied flycatcher birds, however, aren't doing as well.
然而，随季节迁徒的班姬鹟并没有这么做。
The birds prefer to feed their chicks winter moth caterpillars.
这些鸟喜欢用冬尺蛾幼虫来喂食他们的雏鸟。
The caterpillars are now hatching earlier, but the birds' chicks are not.
现在幼虫提早孵化，但雏鸟并没有。
This delay is costing the birds a food source.
这个差异让鸟类失去了食物来源。
The pied flycatcher population has decreased by up to 90% in some areas as a result.
因此，班姬鹟的数量在某些地方减少了接近九成。
Changes to a seemingly simple event, leaves opening, has ripple effects throughout a food web.
再看看另一个看似简单的事件，叶子成熟，在食物网中存在着涟漪效应。
Earlier bloom times can also have an economic impact.
提早的花开时间也会产生生态上的冲击。
The famed cherry blossoms in Washington D.C. are blooming five days earlier than before.
华盛顿特区里著名的樱花比以往早了五天开花。
Since the cherry trees are blooming earlier, the blossoms also fade earlier,
由于樱花提早开花，也会提早凋谢，
frustrating thousands of tourists who visit for the Cherry Blossom Festival.
这使得数千名前来参加樱花节的游客大失所望。
High school marching bands plan all year to attend the parade and perform, surrounded by a majestic white canopy.
高中的游行乐队计划了一整年来参加游行以及表演，希望被环绕在壮观的白色树冠之中。
How disappointing for them to find, well, trees rather than the famous cherry blossoms!
但当他们发现只有樱花树，却见不到声名远扬的樱花时，将会多么沮丧！
Plants and animals react to changes in natural light and temperature.
动植物们会应对大自然的光线和温度的变化。
Increasing temperatures cause plants to bloom earlier than before,
温度上升使得植物提早开花，
and become out of sync with the insects and birds in a food web.
因而和食物网中的昆虫鸟类不同步。
So, the next time you look out your window and notice what season it is,
所以，当下一次你再看着窗外去感受当下的季节时，
you may be fooled by those blooming trees.
你也许是被那些开花的树迷惑了。
Think of phenology, then think of how you can play a part to slow climate change.
想想生物气候学，然后再想想对于减缓气候变迁你能做些什么。