The carbon cycle - Nathaniel Manning

643,772 views ・ 2012-10-02

TED-Ed


Please double-click on the English subtitles below to play the video.

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Transcriber: tom carter Reviewer: Bedirhan Cinar
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Carbon dioxide, or CO2, is the main greenhouse gas in climate change.
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So how does CO2 get into our atmosphere?
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Well, carbon is part of a cycle. It starts with the sun,
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which heats the Earth's surface with more energy
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in one hour than the whole world uses in a year.
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Plants, which are kind of like biological chefs,
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take that sunlight, and then suck in some CO2 from the air,
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mix them together, and BAM!
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They create a stored form of energy, in the form of carbohydrates
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such as glucose and sucrose.
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The process is called photosynthesis.
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When animals like us eat those plants
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our stomachs convert that food back into energy for our own growth.
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Greenhouse gases are a byproduct of this process,
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and are released through waste.
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If those plants die, they decompose, and tiny microorganisms break down those carbohydrates
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and again, release greenhouse gases as a byproduct.
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As you see, energy originates from the sun. It is then transferred as it moves through the food chain.
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But sometimes, carbon based organisms like plants or animals get stuck in the earth.
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When this happens, they're compressed under tons of pressure,
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and turned into carbon-based fossil fuels
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like oil, coal or natural gas.
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Since the Industrial Revolution, humans have been pulling those fossil fuels out of the ground
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and burning them, activating the stored energy
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to make electricity and power engines.
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But the thing is it also releases millions of years worth of stored CO2 back into the air.
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In addition, humans breathe in oxygen and breathe out CO2.
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But plants do the opposite.
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Trees suck up huge amounts of CO2, which balances the cycle.
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Thus, deforestation reduces the plants that store CO2.
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We're attacking the cycle from both sides.
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Think of it like a computer. A computer can operate a few programs at a time, right?
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Normally, when you've finished with a document, you save, and you close it,
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so as not to overwork the computer.
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Then, imagine you stopped closing your documents.
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So they were all open at once.
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Your computer wouldn't be able to process it all.
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It would start to slow down, and then to freeze, and eventually it would crash.
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Which might be where our environment is heading if we keep overloading the carbon cycle.
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So is there any way to rebalance the ecosystem?
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What about technology? Technology is defined as a technique to solve a problem.
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And so, sustainable technologies are those whose output is equal to their input.
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They do not create negative externalities,
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such as CO2, in the present or the future.
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They sort of cancel themselves out to solve the problem.
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To achieve this, we need to invent sustainable technologies.
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If we put all the ideas and technologies ever created into one circle,
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then invention is the pushing of the boundaries of that circle.
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And the area outside of the circle is infinite,
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meaning the potential for invention is limitless.
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Think about some of the incredible clean technologies we have today. [Wind; Electric & Solar Cars; Biogas]
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[Biofuels; Photosynthetic Algae; Compost] All those ideas have one thing in common.
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They all came from people. People innovate.
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People create. It's the limitless potential of creative people
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to build unimagined technologies that is going to stop climate change
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and rebalance the ecosystem. And that is something to be hopeful about.
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