Whatever happened to acid rain? - Joseph Goffman

2,612,556 views ใƒป 2021-04-13

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: Ido Dekkers ืขืจื™ื›ื”: Naama Lieberman
00:07
In 1963, scientists studying Hubbard Brook Experimental Forest in New Hampshire
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ื‘-1963, ืžื“ืขื ื™ื ืฉื—ืงืจื• ืืช ื™ืขืจ ื”ื‘ืืจื“ ื‘ืจื•ืง ื”ื ื™ืกื™ื•ื ื™ ื‘ื ื™ื• ื”ืžืคืฉื™ื™ืจ
00:13
made a shocking discovery.
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ื’ื™ืœื• ืชื’ืœื™ืช ืžื—ืจื™ื“ื”.
00:15
Their most recent rainfall samples were nearly 100 times more acidic than usual.
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ื“ื•ื’ืžื™ื•ืช ื”ื’ืฉื ื”ืื—ืจื•ื ื•ืช ืฉืœื”ื ื”ื™ื• ื—ื•ืžืฆื™ื•ืช ื›ืžืขื˜ ืคื™ 100 ืžื”ืจื’ื™ืœ.
00:21
At these levels, additional downpours of acid rain
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ื‘ืจืžื•ืช ื”ืืœื•, ื’ืฉืžื™ื ื ื•ืกืคื™ื ืฉืœ ื’ืฉื ื—ื•ืžืฆื™
00:25
would destroy the regionโ€™s marine and arboreal ecosystems
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ื™ื”ืจืกื• ืืช ืžืขืจื›ื•ืช ื”ืžื—ื™ื” ื‘ื’ื•ืคื™ ื”ืžื™ื ื•ื‘ื™ืขืจ ืฉืœ ื”ืื–ื•ืจ
00:29
in a matter of decades.
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ืชื•ืš ืขืฉื•ืจื™ื ื‘ื•ื“ื“ื™ื.
00:30
Urgently sharing their findings with fellow researchers,
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ื”ื ื—ืœืงื• ืืช ื”ืžืžืฆืื™ื ื‘ื“ื—ื™ืคื•ืช ืขื ื—ื•ืงืจื™ื ื ื•ืกืคื™ื,
00:34
they were determined to answer two questions:
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ื”ื ื”ื™ื• ื ื—ื•ืฉื™ื ืœืขื ื•ืช ืขืœ ืฉืชื™ ืฉืืœื•ืช:
00:37
what was causing this deadly rainfall? And what could be done to stop it?
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ืžื” ื’ืจื ืœื’ืฉื ื”ืงื˜ืœื ื™ ื”ื–ื”? ื•ืžื” ืืคืฉืจ ืœืขืฉื•ืช ื›ื“ื™ ืœืขืฆื•ืจ ืื•ืชื•?
00:43
Rain is never just composed of water.
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ื’ืฉื ืœืขื•ืœื ืœื ืžื•ืจื›ื‘ ืจืง ืžืžื™ื.
00:46
Chemicals and particulates in the atmosphere can be found in every drop,
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ื›ื™ืžื™ืงืœื™ื ื•ื—ืœืงื™ืงื™ื ื‘ืื˜ืžื•ืกืคื™ืจื” ื™ื›ื•ืœื™ื ืœื”ื™ืžืฆื ื‘ื›ืœ ื˜ื™ืคื”,
00:51
and some compoundsโ€” like carbon dioxideโ€”
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ื•ื›ืžื” ืจื›ื™ื‘ื™ื -- ื›ืžื• ืคื—ืžืŸ ื“ื• ื—ืžืฆื ื™ --
00:54
make even regular rainfall slightly acidic.
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ื”ื•ืคื›ื™ื ืืคื™ืœื• ื’ืฉื ืจื’ื™ืœ ืœืžืขื˜ ื—ื•ืžืฆื™.
00:57
But this pales in comparison to the powerful acids produced
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ืื‘ืœ ื–ื” ืžืชื’ืžื“ ื‘ื”ืฉื•ื•ืื” ืœื—ื•ืžืฆื•ืช ื—ื–ืงื•ืช ืฉื ื•ืฆืจื•ืช
01:01
when water interacts with oxides of nitrogen or sulfur dioxide.
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ื›ืฉืžื™ื ืžื’ื™ื‘ื™ื ืขื ืชื—ืžื•ืฆื•ืช ืฉืœ ื—ื ืงืŸ ืื• ื’ื•ืคืจื™ืช ื“ื• ื—ืžืฆื ื™ืช.
01:07
On the pH scale which measures acidity,
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ื‘ืกืงืืœื” ืฉืœ pH ืฉืžื•ื“ื“ ื—ื•ืžืฆื™ื•ืช,
01:10
each whole number is 10 times more acidic than the one above it.
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ื›ืœ ืžืกืคืจ ืฉืœื ื”ื•ื ืคื™ ืขืฉืจ ื™ื•ืชืจ ื—ื•ืžืฆื™ ืžื–ื” ืฉืžืขืœื™ื•.
01:15
And where normal rain has a pH of roughly 5.4,
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ื•ื›ืฉืœื’ืฉื ืจื’ื™ืœ ื™ืฉ pH ืฉืœ ื‘ืขืจืš 5.4,
01:19
rain thatโ€™s interacted with these gases can rank as low as 3.7.
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ื’ืฉื ืฉื”ื’ื™ื‘ ืขื ื”ื’ื–ื™ื ื”ืืœื” ื™ื›ื•ืœ ืœืจื“ืช ืขื“ 3.7.
01:24
Oxides of nitrogen and sulfur dioxide can appear naturally
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ืชื—ืžื•ืฆื•ืช ืฉืœ ื—ื ืงืŸ ื•ื’ื•ืคืจื™ืช ื“ื• ื—ืžืฆื ื™ืช ื™ื›ื•ืœื™ื ืœื”ื•ืคื™ืข ื‘ืื•ืคืŸ ื˜ื‘ืขื™
01:29
as a short-lived byproduct of volcanic eruptions or lightning strikes.
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ื›ืชื•ืฆืจื™ ืœื•ื•ืื™ ืงืฆืจื™ ื—ื™ื™ื ืฉืœ ื”ืชืคืจืฆื•ื™ื•ืช ื’ืขืฉื™ื•ืช ืื• ืคื’ื™ืขื•ืช ื‘ืจืงื™ื.
01:34
But power plants, refineries, and vehicles that use fossil fuels
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ืื‘ืœ ืชื—ื ื•ืช ื›ื•ื—, ื‘ืชื™ ื–ื™ืงื•ืง ื•ืจื›ื‘ื™ื ืฉืžืฉืชืžืฉื™ื ื‘ื“ืœืงื™ ืžืื•ื‘ื ื™ื
01:38
consistently pump large quantities into the air.
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ื›ืœ ื”ื–ืžืŸ ืžื–ืจื™ืžื™ื ื›ืžื•ื™ื•ืช ื’ื“ื•ืœื•ืช ืœืื•ื•ื™ืจ.
01:43
These dangerous gases travel with the wind
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ื”ื’ื–ื™ื ื”ืžืกื•ื›ื ื™ื ื”ืืœื” ื ืขื™ื ืขื ื”ืจื•ื—
01:46
spreading hundreds of kilometers from the pollutionโ€™s source.
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ื•ืžืชืคืฉื˜ื™ื ืœืžืื•ืช ืงื™ืœื•ืžื˜ืจื™ื ืžืžืงื•ืจ ื”ื–ื™ื”ื•ื.
01:49
Acting like roaming clouds of destruction,
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ื”ื ืคื•ืขืœื™ื ื›ืžื• ืขื ื ื™ื ืžืฉื•ื˜ื˜ื™ื ืฉืœ ื”ืจืก,
01:52
their presence dramatically increases the acidity of local precipitation,
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ื”ื ื•ื›ื—ื•ืช ืฉืœื”ื ืžื’ื‘ื™ืจื” ื“ืจืžื˜ื™ืช ืืช ื”ื—ื•ืžืฆื™ื•ืช ืฉืœ ืžืฉืงืขื™ื ืžืงื•ืžื™ื™ื,
01:57
creating acid rain, acid snow, and acid fog.
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ื•ื™ื•ืฆืจืช ื’ืฉื ื—ื•ืžืฆื™, ืฉืœื’ ื—ื•ืžืฆื™, ื•ืขืจืคืœ ื—ื•ืžืฆื™.
02:02
These all acidify lakes and streams, kill crops and forests,
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ื›ืœ ืืœื” ืžื—ืžื™ืฆื™ื ืื’ืžื™ื ื•ื ื—ืœื™ื, ื”ื•ืจื’ื™ื ื™ื‘ื•ืœื™ื ื•ื™ืขืจื•ืช,
02:07
and damage soil to inhibit future growth.
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ื•ืคื•ื’ืขื™ื ื‘ืื“ืžื” ื›ืš ืฉื”ื ืžืขื›ื‘ื™ื ืฆืžื™ื—ื”.
02:10
Over time, acid rain can even corrode human structures made of stone or metal.
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ื‘ืžืฉืš ื”ื–ืžืŸ, ื’ืฉื ื—ื•ืžืฆื™ ื™ื›ื•ืœ ืืคื™ืœื• ืœืฉื—ื•ืง ืžื‘ื ื™ื ืื ื•ืฉื™ื™ื ืฉืขืฉื•ื™ื™ื ืื‘ืŸ ื•ืžืชื›ืช.
02:17
By the 1970s, scientists in North America and Europe classified acid rain
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ืขื•ื“ ื‘ืฉื ื•ืช ื”-70 ืฉืœ ื”ืžืื” ื”-20, ืžื“ืขื ื™ื ื‘ืฆืคื•ืŸ ืืžืจื™ืงื” ื•ื‘ืื™ืจื•ืคื” ืงื˜ืœื’ื• ื’ืฉื ื—ื•ืžืฆื™
02:23
as a major environmental threat.
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ื›ืื™ื•ื ืกื‘ื™ื‘ืชื™ ืขื™ืงืจื™.
02:25
But despite clear evidence tying the problem to air pollution,
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ืื‘ืœ ืœืžืจื•ืช ืขื“ื•ื™ื•ืช ื‘ืจื•ืจื•ืช ืฉืงื•ืฉืจื•ืช ืืช ื”ื‘ืขื™ื” ืœื–ื™ื”ื•ื ืื•ื•ื™ืจ,
02:29
companies denied responsibility and cast doubt on the research.
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ื—ื‘ืจื•ืช ื”ืชื›ื—ืฉื• ืœืื—ืจื™ื•ืช ื•ื”ื˜ื™ืœื• ืกืคืง ื‘ืžื—ืงืจ.
02:33
In the United States, corporations lobbied against regulating pollution,
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ื‘ืืจืฆื•ืช ื”ื‘ืจื™ืช, ื—ื‘ืจื•ืช ื”ืคืขื™ืœื• ืœื•ื‘ื™ ื ื’ื“ ืจื’ื•ืœืฆื™ื” ืขืœ ื–ื™ื”ื•ื,
02:38
and convinced politicians that such policies
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ื•ืฉื›ื ืขื• ืคื•ืœื™ื˜ื™ืงืื™ื ืฉืžื“ื™ื ื™ื•ืช ื›ื–ื•
02:41
would raise energy costs and threaten jobs.
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ืชืขืœื” ืืช ืžื—ื™ืจื™ ื”ืื ืจื’ื™ื” ื•ืชืกื›ืŸ ืžืงื•ืžื•ืช ืขื‘ื•ื“ื”.
02:44
These obstacles led the government to delay changes,
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ื”ืžื›ืฉื•ืœื™ื ื”ืืœื” ื”ื•ื‘ื™ืœื• ืืช ื”ืžืžืฉืœื” ืœื“ื—ื•ืช ืืช ื”ืฉื™ื ื•ื™ื™ื,
02:47
and mandate further research into the issue.
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ื•ื—ื™ื™ื‘ื• ืžื—ืงืจ ื ื•ืกืฃ ื‘ื ื•ืฉื.
02:50
But after a decade of mounting concern, Congress finally took action.
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ืื‘ืœ ืื—ืจื™ ืขืฉื•ืจ ืฉืœ ื“ืื’ื•ืช ื’ื•ื‘ืจื•ืช, ื”ืงื•ื ื’ืจืก ืคืขืœ ืœื‘ืกื•ืฃ.
02:56
Since the bulk of sulfur dioxide emissions came from power plants,
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ืžืื—ืจ ืฉืจื•ื‘ ืคืœื™ื˜ื•ืช ื”ื’ื•ืคืจื™ืช ื”ื“ื• ื—ืžืฆื ื™ืช ื”ื’ื™ืขื• ืžืชื—ื ื•ืช ื›ื•ื—,
03:00
the government set a limit on the total amount of it
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ื”ืžืžืฉืœื” ื”ืฆื™ื‘ื” ื’ื‘ื•ืœ ืœืกืš ื”ืคืœื™ื˜ื•ืช
03:03
the electric power sector could emit each year.
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ืฉืกืงื˜ื•ืจ ื”ื—ืฉืžืœ ื™ื›ื•ืœ ืœืคืœื•ื˜ ื‘ื›ืœ ืฉื ื”.
03:06
Then, they divided the permitted emissions into a fixed number of โ€œallowancesโ€
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ืื–, ื”ื ื—ืœืงื• ืืช ื›ืžื•ืช ื”ืคืœื™ื˜ื•ืช ื”ืžืื•ืฉืจืช ืœืžืกืคืจ โ€œืžื›ืกื•ืชโ€ ืงื‘ื•ืขื•ืช
03:12
distributed to each power plant.
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ื”ืžื—ื•ืœืงื•ืช ืœื›ืœ ืชื—ื ืช ื›ื•ื—.
03:14
A plant could then choose to emit as much sulfur dioxide as they were allowed,
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ืชื—ื ื” ืชื•ื›ืœ ืœื‘ื—ื•ืจ ืื ืœืคืœื•ื˜ ืืช ื”ื›ืžื•ืช ื”ืžื•ืชืจืช ืฉืœ ื’ื•ืคืจื™ืช ื“ื• ื—ืžืฆื ื™ืช,
03:19
or reduce their emissions and sell their unused allowances to other power plants.
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ืื• ืœื”ืคื—ื™ืช ืืช ื”ืคืœื™ื˜ื•ืช ืฉืœื”ืŸ ื•ืœืžื›ื•ืจ ืืช ื”ืžื›ืกื” ื”ืœื ืžื ื•ืฆืœืช ืœืชื—ื ื•ืช ืื—ืจื•ืช.
03:25
This system, known as โ€œcap and trade,โ€
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ื”ืฉื™ื˜ื” ื”ื–ื•, ืฉื™ื“ื•ืขื” ื›โ€œืžื›ืกื” ื•ืกื—ืจ,โ€
03:29
offered power plants the economic flexibility to keep costs low
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ื”ืฆื™ืขื” ืœืชื—ื ื•ืช ื›ื•ื— ืืช ื”ื’ืžื™ืฉื•ืช ื”ื›ืœื›ืœื™ืช ืœื”ืฉืื™ืจ ืืช ื”ืขืœื•ื™ื•ืช ื ืžื•ื›ื•ืช
03:33
while strictly limiting pollution.
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ื‘ื–ืžืŸ ืฉื”ื’ื‘ื™ืœื• ื‘ืงืฉื™ื—ื•ืช ืืช ื”ื–ื™ื”ื•ื.
03:35
Many critics called these allowances licenses to pollute,
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ื”ืจื‘ื” ืžื‘ืงืจื™ื ืงืจืื• ืœืžื›ืกื•ืช ื”ืืœื• ืจื™ืฉื™ื•ืŸ ืœื–ื”ื,
03:39
or said the government was selling clean air.
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ืื• ืืžืจื• ืฉื”ืžืžืฉืœื” ืžื•ื›ืจืช ืื•ื•ื™ืจ ื ืงื™.
03:42
But since the cap was set to lower five years into the program,
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ืื‘ืœ ืžืื—ืจ ืฉื”ืžื›ืกื” ืคื—ืชื” ื—ืžืฉ ืฉื ื™ื ืœืชื•ืš ื”ืชื•ื›ื ื™ืช,
03:46
it forced every utility company to reduce emissions in the long term.
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ื”ื™ื ื”ื›ืจื™ื—ื” ื›ืœ ื—ื‘ืจืช ื—ืฉืžืœ ืœื”ืคื—ื™ืช ืืช ื”ืคืœื™ื˜ื•ืช ื‘ื˜ื•ื•ื— ื”ืืจื•ืš.
03:51
Some plants added desulfurizing scrubbers to their smokestacks,
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ื›ืžื” ืชื—ื ื•ืช ื”ื•ืกื™ืคื• ืกื•ืœืงื ื™ ื’ื•ืคืจื™ืช ืœืืจื•ื‘ื•ืช ืฉืœื”ืŸ,
03:55
or switched to low-sulfur coal and natural gas.
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ืื• ืขื‘ืจื• ืœืคื—ื ื“ืœ ื’ื•ืคืจื™ืช ื•ืœื’ื– ื˜ื‘ืขื™.
03:59
Oxides of nitrogen emissions were also reduced
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ืคืœื™ื˜ื•ืช ืชื—ืžื•ืฆื•ืช ื—ื ืงืŸ ื’ื ื”ื•ืคื—ืชื•
04:02
with relatively low-cost technologies.
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ื‘ื˜ื›ื ื•ืœื•ื’ื™ื•ืช ื‘ืขืœื•ืช ื™ื—ืกื™ืช ื ืžื•ื›ื”.
04:05
These advances allowed the power sector to grow
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ื”ืคื™ืชื•ื—ื™ื ื”ืืœื” ืืคืฉืจื• ืœืžื’ื–ืจ ื”ื—ืฉืžืœ ืœื’ื“ื•ืœ
04:08
while the cap kept pollution under control.
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ื‘ื–ืžืŸ ืฉื”ืžื›ืกื•ืช ื”ืฉืื™ืจื• ืืช ื”ื–ื™ื”ื•ื ืชื—ืช ืฉืœื™ื˜ื”.
04:11
By 1985, Canada and the European Union adopted their own solutions,
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ืขื“ 1985, ืงื ื“ื” ื•ื”ืื™ื—ื•ื“ ื”ืื™ืจื•ืคืื™ ืื™ืžืฆื• ืคืชืจื•ื ื•ืช ืžืฉืœื”ื,
04:16
and international treaties began circulating
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ื•ืืžื ื•ืช ื‘ื™ืŸ ืœืื•ืžื™ื•ืช ื”ืชื—ื™ืœื• ืœื”ืกืชื•ื‘ื‘
04:19
to reduce air pollution worldwide.
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ื›ื“ื™ ืœื”ืคื—ื™ืช ืืช ื–ื™ื”ื•ื ื”ืื•ื•ื™ืจ ื‘ืขื•ืœื.
04:23
Today, this science-driven economic policy has largely eliminated acid rain
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ื”ื™ื•ื, ื”ืžื“ื™ื ื™ื•ืช ื”ื›ืœื›ืœื™ืช ืžื•ื ืขืช ื”ืžื“ืข ื”ื–ื• ื—ื™ืกืœื” ืืช ืจื•ื‘ ื”ื’ืฉื ื”ื—ื•ืžืฆื™
04:28
across the United States and Canada.
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ืœืจื•ื—ื‘ ืืจืฆื•ืช ื”ื‘ืจื™ืช ื•ืงื ื“ื”.
04:30
And while many ecosystems still need time to recover,
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ื•ื‘ื–ืžืŸ ืฉื”ืจื‘ื” ืžืขืจื›ื•ืช ืžื—ื™ื” ืขื“ื™ื™ืŸ ืฆืจื™ื›ื•ืช ื–ืžืŸ ืœื”ืฉืชืงื,
04:33
scientists have sped up the restoration of other areas
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ืžื“ืขื ื™ื ื”ืื™ืฆื• ืืช ื”ืฉื™ืงื•ื ืฉืœ ืื–ื•ืจื™ื ืื—ืจื™ื
04:37
by reintroducing essential organisms killed off by acid rain.
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ืขืœ ื™ื“ื™ ื”ืฉื‘ื” ืฉืœ ืื•ืจื’ื ื™ื–ืžื™ื ื—ื™ื•ื ื™ื™ื ืฉื—ื•ืกืœื• ืขืœ ื™ื“ื™ ื’ืฉื ื—ื•ืžืฆื™.
04:42
Some countries, like Russia, India, and China
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ื›ืžื” ืžื“ื™ื ื•ืช, ื›ืžื• ืจื•ืกื™ื”, ื”ื•ื“ื• ื•ืกื™ืŸ
04:45
still rely heavily on high-sulfur coal
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ืขื“ื™ื™ืŸ ืžืกืชืžื›ื•ืช ืžืื•ื“ ืขืœ ืคื—ื ืขืฉื™ืจ ื‘ื’ืคืจื™ืช
04:48
and continue to struggle with the environmental consequences.
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ื•ืžืžืฉื™ื›ื•ืช ืœื”ืชืžื•ื“ื“ ืขื ื”ืชื•ืฆืื•ืช ื”ืกื‘ื™ื‘ืชื™ื•ืช.
04:52
However, acid rainโ€™s relatively quick journey from major threat to minor issue
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ืขื ื–ืืช, ื”ืžืกืข ื”ืžื”ื™ืจ ื™ื—ืกื™ืช ืฉืœ ื’ืฉื ื—ื•ืžืฆื™ ืžืื™ื•ื ืขื™ืงืจื™ ืœื ื•ืฉื ืžืฉื ื™
04:57
is rightly celebrated as a victory for policies that protect the environment.
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ื ื—ื’ื’ ื‘ืฆื“ืง ื›ื ื™ืฆื—ื•ืŸ ืœืžื“ื™ื ื™ื•ืช ืฉืžื’ื ื” ืขืœ ื”ืกื‘ื™ื‘ื”.
05:02
Cap and trade canโ€™t solve every environmental problem.
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ืžื›ืกื” ื•ืกื—ืจ ืœื ื™ื›ื•ืœื™ื ืœืคืชื•ืจ ื›ืœ ื‘ืขื™ื” ืกื‘ื™ื‘ืชื™ืช.
05:05
But by using scientific consensus to guide policy,
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ืื‘ืœ ืขืœ ื™ื“ื™ ืฉื™ืžื•ืฉ ื‘ืงื•ื ืฆื ื–ื•ืก ืžื“ืขื™ ื›ื“ื™ ืœื”ื ื—ื•ืช ืžื“ื™ื ื™ื•ืช,
05:09
adopting efficient technology,
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ืื™ืžื•ืฅ ื˜ื›ื ื•ืœื•ื’ื™ื•ืช ื™ืขื™ืœื•ืช,
05:11
and being unafraid to impose reasonable costs for pollution,
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ื•ืœื ืœืคื—ื“ ืœื”ืฉื™ืช ืขืœื•ื™ื•ืช ืกื‘ื™ืจื•ืช ืขืœ ื–ื™ื”ื•ื,
05:15
countries can stop a growing storm of destruction before itโ€™s too late.
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ืžื“ื™ื ื•ืช ื™ื›ื•ืœื•ืช ืœืขืฆื•ืจ ืกืขืจื” ื’ื“ืœื” ืฉืœ ื”ืจืก ืœืคื ื™ ืฉื™ื”ื™ื” ืžืื•ื—ืจ ืžื“ื™.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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