Can we solve global warming? Lessons from how we protected the ozone layer | Sean Davis

192,639 views ・ 2019-02-12

TED


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00:13
So, I'm a climate scientist,
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and if this room is representative of the country we live in,
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that means about 60 percent of you, so maybe from about there over,
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don't strongly trust me for information on the causes of climate change.
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Now, I promise to tell the truth tonight,
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but just to humor that demographic,
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I've started this talk with a falsehood.
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[The Paris Climate Accord is a product of the recognition
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that climate change is a global problem ...]
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This statement was not made by President Obama.
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It was made by President Reagan,
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and it wasn't about climate change and the Paris Climate Accord.
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It was actually about the Montreal Protocol
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and stratospheric ozone depletion.
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Now, I'm sure that many of you aren't familiar with this environmental problem,
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but you should be,
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because it's a rare environmental success story.
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And it's worth revisiting,
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because sometimes, we need to examine the world we've avoided
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in order to find guidance for the choices we make today.
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So let's go back to the 1970s,
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when some questionable choices were made:
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first of all -- hoo -- hairstyles. (Laughs)
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Second of all, objectively terrible quantities of hairspray,
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and third, CFCs, chlorofluorocarbons,
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man-made chemicals that were used as propellant in aerosol spray cans.
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And see, it turns out these CFCs were a problem
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because they were destroying the ozone layer.
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Now I'm sure most of you have heard of the ozone layer,
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but why does it matter?
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Well, quite simply, the ozone layer is earth's sunscreen,
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and it's really fragile.
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If you could take all of the ozone,
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which is mostly about 10 to 20 miles up above our heads,
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and compress it down to the surface of the earth,
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it would form a thin shell only about two pennies thick,
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about an eighth of an inch.
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And that thin shell does an amazing amount of work, though.
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It filters out more than 90 percent of the harmful UV radiation
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coming from the sun.
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And while I'm sure many of you enjoy that suntan that you get
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from the remaining 10 percent, it causes a lot of problems:
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cataracts,
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damage to crops,
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damage to immune systems
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and also skin cancer.
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It's not an exaggeration
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to say that a threat to the ozone layer is a threat to human safety.
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And actually, ironically, it was human safety
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that motivated the invention of CFCs in the first place.
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You see, in the early days of refrigeration,
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refrigerators used toxic and flammable chemicals
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like propane and ammonia.
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For good reason, the refrigeration industry
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wanted a safe alternative,
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and they found that in 1928,
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when a scientist named Thomas Midgley
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synthesized the first commercially viable CFCs.
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And in fact, Midgley famously inhaled CFCs and blew out a candle
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to demonstrate, at a scientific conference,
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that they were safe and nonflammable.
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And in fact, as a scientist, I can tell you there is no way
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you could get away with that kind of antic today.
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I mean, wow.
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But really, at the time,
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CFCs were a really remarkable invention.
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They allowed what we now know as modern-day refrigeration
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and air-conditioning and other things.
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So it wasn't actually until over 40 years later, in the 1970s,
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when scientists realized that CFCs would break down high in the atmosphere
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and damage the ozone layer.
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And this finding really set off a lot of public concern.
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It led, ultimately, to the banning of CFC usage in aerosol spray cans
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in the US and a few other countries in 1978.
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Now, the story doesn't end there,
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because CFCs were used in much more than just spray cans.
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In 1985, scientists discovered the Antarctic ozone hole,
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and this was a truly alarming discovery.
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Scientists did not expect this at all.
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Before the Antarctic ozone hole,
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scientists expected maybe a five or 10 percent reduction
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in ozone over a century.
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But what they found over the course of less than a decade
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was that more than a third of the ozone had simply vanished,
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over an area larger than the size of the US.
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And although we now know that CFCs are the root cause of this ozone hole,
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at the time, the science was far from settled.
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Yet despite this uncertainty,
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the crisis helped spur nations to act.
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So that quote that I started this talk with,
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about the Montreal Protocol, from President Reagan --
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that was his signing statement when he signed the Montreal Protocol
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after its unanimous ratification by the US Senate.
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And this is something that's truly worth celebrating.
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In fact, yesterday was the 30th anniversary of the Montreal Protocol.
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(Applause)
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Because of the protocol,
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ozone-depleting substances are now declining in our atmosphere,
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and we're starting to see the first signs of healing in the ozone layer.
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And furthermore, because many of those ozone-depleting substances
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are also very potent greenhouse gases,
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the Montreal Protocol has actually delayed global warming
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by more than a decade.
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That's just wonderful.
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But I think it's worth asking the question,
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as we face our current environmental crisis, global warming,
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what lessons can we learn from Montreal?
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Are there any? I think there are.
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First, we don't need absolute certainty to act.
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When Montreal was signed,
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we were less certain then of the risks from CFCs
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than we are now of the risks from greenhouse gas emissions.
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A common tactic that people who oppose climate action use
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is to completely ignore risk and focus only on uncertainty.
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But so what about uncertainty?
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We make decisions in the face of uncertainty all the time,
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literally all the time.
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You know, I'll bet those of you who drove here tonight,
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you probably wore your seat belt.
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And so ask yourself,
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did you wear your seat belt because someone told you
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with a hundred percent [certainty]
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that you would get in a car crash on the way here?
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Probably not.
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So that's the first lesson.
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Risk management and decision making always have uncertainty.
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Ignoring risk and focusing only on uncertainty is a distraction.
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In other words, inaction is an action.
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Second, it takes a village to raise a healthy environment.
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The Montreal Protocol wasn't just put together by industry and governments
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or environmental advocacy groups and scientists.
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It was put together by all of them.
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They all had a seat at the table,
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and they all played an important role in the solution.
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And I think in this regard,
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we're actually seeing some encouraging signs today.
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We see not just environmental groups concerned about climate change
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but also civic and religious groups,
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the military and businesses.
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So wherever you find yourself on that spectrum,
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we need you at the table,
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because if we're going to solve global warming,
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it's going to take actions at all levels,
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from the individual to the international
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and everything in between.
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Third lesson:
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don't let the perfect be the enemy of the good.
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While Montreal has become the brake pedal for stopping ozone depletion,
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at its beginning, it was more just like a tap on the brakes.
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It was actually the later amendments to the protocol
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that really marked the decision to hit the brakes on ozone depletion.
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So to those who despair
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that the Paris Climate Accord didn't go far enough
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or that your limited actions on their own won't solve global warming,
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I say don't let the perfect be the enemy of the good.
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And finally, I think it helps us to contemplate the world we've avoided.
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Indeed, the world we have avoided by enacting the Montreal Protocol
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is one of catastrophic changes
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to our environment and to human well-being.
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By the 2030s, we'll be avoiding millions of new skin cancer cases per year
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with a number that would only grow.
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If I'm lucky, I'll live long enough to see the end of this animation
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and to see the ozone hole restored to its natural state.
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So as we write the story for earth's climate future
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for this century and beyond,
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we need to ask ourselves, what will our actions be
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so that someone can stand on this stage
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in 30 or 50 or a hundred years
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to celebrate the world that they've avoided.
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Thank you.
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(Applause)
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