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Africa's Sahara desert is wide open and sparsely populated, a great source of sun and wind,
非洲的撒哈拉沙漠幅员辽阔且人烟稀少，是阳光和风能的重要来源，
and a prime location, some say, to build arrays of solar panels and wind turbines.
有人说，这里是建造太阳能电板和风力涡轮机阵列的最佳地点。
And while replacing fossil fuels is great for fighting climate change,
虽然替代化石燃料是对抗气候变化的好方法，
these power plants could bring more to the region than just tons of green energy.
这些发电厂可以为该地区带来的不仅仅是成吨的绿色能源。
According to computer modeling, they could indirectly alter the region's climate for the better.
根据电脑模型，它们可以间接改善该地区的气候。
Researchers say the Sahara is a great choice for energy production because not many people or animals live there,
研究人员表示撒哈拉沙漠是能源生产的绝佳选择，因为这里居住的人或动物都不多，
and it's adjacent to lots of much more populated areas that need energy, and will need more as time goes by.
并且撒哈拉沙漠邻近许多需要能源的人口稠密地区，随着时间的推移，这些地区将需要更多的能源。
But building renewable energy extraction methods isn't as simple as plopping them down wherever it's super sunny or windy.
但建造可再生能源的开采方法并不像在阳光充足或风大的地方把它们一扫而光那么简单。
Scientists are aware that building these structures can potentially have large-scale effects on the surrounding environment.
科学家意识到建造这些构筑物可能会对周围环境有大规模影响。
So they run climate models using supercomputers to see what those effects might be.
所以他们利用超级计算机建造了一个气候模型，看看可能产生什么影响。
In a 2018 study, one team of researchers used such computer models to determine
在2018年的研究中，一个科学家团队利用这一电脑模型来确定
what could happen if humans scattered the Sahara with wind turbines, solar panels, or both.
如果人类在撒哈拉部署风力涡轮机、太阳能电板或两者都安装，会发生什么。
One thing was certain:if they were real, those solar panels and wind turbines would produce tons of power.
有一件事是确定的：如果真的安装，那么那些太阳能板和风力涡轮机将制造出数吨电能。
Like, over four times what the entire human race uses in an average year.
大概是人类平均年用电量的四倍。
And that's a conservative estimate, using stats for mid-range commercial solar panels
这是使用中档商用太阳能板数据得出的保守估计，
that only convert 15% of the Sun's energy they absorb into electricity. But that wasn't all these power plants would do.
该种太阳能板只能将吸收的15%的太阳能转化为电能。但发电厂都能做到的不仅如此。
The team used climate data from the entire twentieth century to make sure the model had a good grasp of the real world,
该团队利用整个20世纪的气候数据以确保该模型对现实世界有很好的把握，
and then let it simulate the next one hundred years. And they found some surprising changes to the Sahara's climate.
然后再让它模拟下一个一百年的气候。他们发现撒哈拉沙漠气候的一些惊喜的变化。
For one, it got hotter. That's largely because solar panels can decrease the albedo,
其一，沙漠变得越来越热了。这大部分是因为太阳能板可以减少表面的反射率，
or reflectivity, of the surface, because they absorb more sunlight.
因为它们可以吸收更多阳光。
And tall structures like wind turbines affect the overall air flow over the land, which can indirectly raise temperatures, too.
像风力涡轮机这样的高层结构会影响陆地上的整体空气流动，也会间接地提高气温。
So installing either type of power plant can actually make the region around them hotter.
所以不管安装哪种类型的电厂其实都会让电厂周围区域越来越热。
When the team modeled installing either solar or wind farms, or both types together,
当该团队建模安装太阳能或风能电场，或两者同时安装时，
the local average temperatures increased by roughly one to three degrees Celsius.
当地的平均气温上升了大约1到3摄氏度。
But the simulations had a different fate for the region to the Sahara's south.
但是撒哈拉以南的地区却有着不同的模拟结果。
It's known as the Sahel, and serves as a semi-arid transition between desert and savanna.
它被称为萨赫勒，是沙漠和草原之间的半干旱过渡地带。
Down there, temperatures slightly decreased. The culprit?
那里，温度略有下降。罪魁祸首？
An increase in plant coverage. But where did the plants come from? They came from an increase in rain.
植物覆盖率的增加。但这些植物来自哪里呢？它们来自雨水的增加。
Rainfall actually increased in both the Sahara and the Sahel, compared to a control simulation with no power plants.
其实和没有发电厂的模拟对照组相比，撒哈拉和萨赫勒的降雨量都增加了。
But the Sahel saw more. The power plants caused an initial increase in surface friction and decrease in albedo.
但是萨赫勒的降雨量更多。发电厂引起了表面摩擦的增加和反射率的降低。
That allowed more water to collect in the air above the region, and that means more precipitation.
这让该区域上空空气中收集的水分更多，这意味着更多的降水。
With more rain comes more plants. But the plants themselves reduce the areas's albedo and increase surface friction,
更多的植物，就有更多的雨水。但是植物本身减少了该区域的反射率并增加表面摩擦，
so they cause even more precipitation. It's a positive feedback loop.
所以它们会导致更多降水。这是一个正反馈循环。
In fact, these models showed that 80% of the increase in rainfall was driven by the new plant life.
事实上，这些模型表明80%的雨水增加是由新的植物生命驱动的。
That shows how shiny new tech can have ripple effects we don't always expect,
这表明耀眼的新技术可以产生我们并不总是期望的涟漪效应，
and sometimes those things can be positive, sometimes they can be negative, but they need to be explored!
有时这些效应可以是积极的，有时是消极的，但是它们需要被探索！
It is important to note that there were a lot of variables for the researchers to account for in their simulation.
重要的是要注意到，在他们的模拟中有很多变量需要研究人员考虑。
Like how they physically spaced out their wind farms and what percent of land was covered by solar panels.
比如风电场的物理布局以及太阳能电池板覆盖的土地面积。
Or how efficient the panels are at converting sunlight into electricity instead of heat, and how reflective they are.
或者这些太阳能板将阳光转化为电能而非热能的效率，以及它们的反射能力。
Tinker with any of that and the results could change.
改变其中任何一个变量，结果都可能改变。
But altogether, the solar and wind farms could increase rainfall in the Sahel region by twenty to fifty centimeters per year.
但总的来说，太阳能和风电场可以使萨赫勒地区的降雨量每年增加20到50厘米。
Talk about blessing the rains down in Africa...
说说祝福非洲的雨吧……
That much rainfall would drastically affect the ecology of the region and the lives of people living there.
如此多的降雨将极大地影响该地区的生态和当地居民的生活。
Like changes in agricultural yields and access to fresh water.
比如农业产量的变化和淡水的获取。
We're not qualified to say whether such deliberate climate manipulation is a good idea, since the effects are so complicated.
我们没有资格说，这种蓄意的气候操纵是否是一个好主意，因为其影响非常复杂。
And it's not clear who'd actually get to use the energy produced.
目前还不清楚谁会真正使用产生的能量。
Those calls are best left to the people who actually living there.
那些调用最好是留给真正生活在那里的人。
But computer simulations like these can show us just how much our tech can affect the planet and at a potentially remarkable scale.
但像这样的电脑模拟可以表明，我们的科技能够对地球产生多大的影响，且影响的范围可能非常大。
Thanks for watching this episode of SciShow.
感谢收看本期节目。
If you want to help us make smart, informative videos that are definitely not just one long buildup to a Toto joke,
如果大家想帮助我们制作内容丰富的视频
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请考虑登录patreon.com/scishow前往Patreon支持我们。
