Nuclear winter - still possible but preventable: Alan Robock at TEDxHoboken

[Music] thanks for the warm welcome but I'm here to tell you about something terrible but you have to know about this problem because then we can solve it together here's our beautiful planet but after a nuclear war it might look like this with smoke covering the planet blocking out the Sun and making it cold and dark at the Earth's surface and this would produce a nuclear winter that is the temperatures would get below freezing even in the summertime which would kill all the crops and produce a global famine we discovered this working in the 1980s this is the most important work I've ever done as a as a climate scientist and what the the good news about that that this could be produced is that this helped to change the world here's a graph showing the number of nuclear weapons on the planet and there used to be zero then there were two than the u.s. started the first nuclear war than they were zero and then the number started going up and the u.s. number went up and the Russians cut up and in the 1980s there were 70,000 nuclear weapons on the planet the arms race was going crazy and this research came out it was done jointly by Russian and American scientists getting the same results and so it couldn't be considered propaganda from one side or the other and I published a paper the next year and well and then the Soviet Union ended five years later so people say why did the arms race end it wasn't because the Soviet Union ended maybe part of it was because of demonstrations or the Soviet Union was running out of money but there was really a lot of controversy about this nuclear winter research and people started realizing how horrible the direct effects of nuclear war would be and an arms race ended and why do I tell you that it was because of nuclear winter because you can ask the person that made the decision Mikhail Gorbachev was interviewed and in the year 2000 and he said you know models made a Russian and American scientist showed that a nuclear war would result in a nuclear winter it would be extremely destructive to all life on Earth the knowledge of that was a great stimulus to us to people of honor morality to act in that situation so you might think okay the problem-solve the number of weapons are going down but actually the number of countries with weapons is going up it used to be one country every five years would would have nuclear weapons the Soviet Union ended there were some countries that had them and didn't want them and gave them back but then Pakistan and North Korea got them there are nine countries now with nuclear weapons and even though it's going down there's still a lot of them on the planet the US and Russia each have about 10,000 and the other countries with them have chosen to stop at 100 or 200 how many nuclear weapons you have to drop on the capital of your enemy in order for to deter them from attacking you one that's correct maybe you need to in case the first one doesn't doesn't work so why do you need thousands of them these other countries figure a couple hundred is more than enough but it also brings up the question what would happen if they fought a nuclear war now there's 32 more countries that could build them if they wanted to they have the uranium or plutonium that they need that it's not a secret how to do it but they've chosen not to so what happens when there's a nuclear weapon when it goes off it's like bringing a piece of the Sun to the surface of the earth for a fraction of a second it's so bright everything nearby catches on fire burst into flames and it's the smoke from the fires that would go up in the atmosphere and block out the Sun and stay fur for almost for more than a decade that would cause the effects of nuclear war more people in countries that didn't have bombs dropped on them would die than people and where the bombs had the direct effects now here's a photo drawing done by one of the survivors of Hiroshima and what they remember is the fires and this is what Hiroshima looked like afterwards there were no no more buildings they all went up in flames and here's a cartoon of what some of these plumes of smoke might look like after a nuclear war started so seven years ago at a conference Bryant inand rich Turco the people that invented the term nuclear winter told me that somebody asked them what would happen if India and Pakistan fought a nuclear war they've each got about a hundred nuclear weapon and we calculated how much smoke you would get from the fires and it turns out it would be quite a bit it'll be five million tons of smoke imagine along the Kashmir border there's some Indian soldier there and and a Pakistani soldier and they get in some sort of disagreement and it just goes out of control and because of fear or panic or miscommunication it develops into a nuclear war so I said to them I said that's interesting who's gonna calculate the climate response to that as five million tons of smoke they say well we thought maybe you would and I had a student Luhan who was ready to do that he was studying volcanic eruptions and climates that's what we did we sassed what would happen if a hundred nuclear bombs were dropped in India and Pakistan on targets that would produce smoke this is much less than 1% of the current nuclear arsenal we use these very small Hiroshima sized bombs because that's what we know are the easiest to make it would be a horrible 20 million people would die from the direct effects of the blast the reactivity and the fires but it would produce this five million tons of smoke so we put it into a climate model the same ones we used to calculate global warming effects of volcanic eruptions and here's a movie showing what would happen the smoke is coming out and spreading around the world and this is the vertical distribution so this is the tropopause beneath here there's rain to wash it out but it gets heated by the Sun it's black and locked it up into the upper atmosphere into the stratosphere where it would stay we discovered for more than a decade we were surprised how long it would stay so then we looked at what would be the effects of this on the climate so we did a calculi mint response this is a graph of the global average temperature the global warming that we're quite concerned about rightly so if this smoke went in the atmosphere would rapidly plummet the temperatures to below little ice age changes now first of all this is not a solution to global warming that that's called geoengineering and people have proposed putting a layer of particles like volcanoes do and that wouldn't kill anybody it's still not a good idea but this would produce climate change unprecedented in recorded human history and it would get temperatures below what it was in a Little Ice Age so we said what would happen then to the crops so we took temperature and precipitation and sunlight changes and put it into a model that calculates crop productivity here's an example in China the crop productivity in China for rice would get twenty five percent below the normal which is the black line for five years and even 20 percent for another five years this would be this means China would only grow the amount of rice that they had when they had 300 million fewer people than they have now and the same thing what happened in other places we did calculations the United States and here's a table of some of our results corn production in the US soybean production 10 or 15 percent 20 percent below normal for a decade this would be a global food crisis people people trade food around the world remember a couple years ago there were these fires and drought in Russia get very hot in Moscow they stopped exporting wheat because that affected their wheat crop so people would stop trading rich countries might be able to do ok but countries that depend on imported food would have huge problems and if they knew that this effect was gonna happen it would really be a global panic now there's about a billion people now that have chronic malnutrition and so they might really be severely affected and maybe a 2 billion people might be dead from starvation from a nuclear war fought around the other side of the world between India and Pakistan with a tiny fraction of our current arsenal because the smoke would cover the world and stay there for a long time IRA health and a colleague of mine wrote an article about this he called it nuclear famine and he was able to show this report to Mikhail Gorbachev last year and Gorbachev said I'm convinced that nuclear weapons must be abolished their use in military conflict is unthinkable using them to achieve political objectives is morale over 25 years ago President Reagan and I ended our summit meeting in Geneva with a joint statement the nuclear war cannot be won and must never be fought and this new study underscores in stunning and disturbing detail why this is the case but it's a lot worse than that this is a u.s. Trident submarine it has about a hundred nuclear weapons much bigger than the ones we use in this simulation maybe a thousand Hiroshima is on each submarine and the US has 14 of them and that's less than half of our arsenal and the Russians have us have an arsenal about the same size so we went back and said what would be the effects on climate if the US and Russia had a war today with the current Arsenal's this would produce a much larger cloud of smoke causing much larger climate change and it could still produce nuclear winter today you can still bring temperatures below freezing in the summertime and there would be no agriculture around the world and we calculated what would happen to the globe and the now had to rescale the figure the red line is what I showed you before the green and brown are what would happen for not five million tons but 50 million tons or 150 million tons of smoke which is still possible today it would indeed be a little ice age it would be tragedy for the entire planet what I've been telling you about so far is theory it's calculations done with a climate model we don't actually want to test this in the real world so how can we tell if it's right we look at analogs we look at things that have happened it can inform us about it such as nighttime you know when it gets nighttime it gets cold and and and and or the seasonal cycles which gave the name to it a nuclear winter or we can look at forest fires that actually can pump smoke up into the stratosphere or we look at volcanic eruptions here's one of my favorite paintings by Edouard Monk it's the red and yellow is the volcanic sunset that he saw over the oslo harbour in 1883 after the Krakatoa eruption and ten years later he painted this this famous painting and how I feel about this and so so we can learn about this from volcanic eruptions the Tambora eruption took place in 1815 and the next year was called the year without a summer the climate was about a couple degrees Fahrenheit colder around the world because of the effects of this volcanic eruption that summer in 1816 Mary Shelley Percy Shelley and and Lord Byron were taking their vacation in this house on the shores of Lake Geneva and they wanted to go hiking and boating but it was cold and dark and gloomy and they couldn't go outside so they said well we're writers let's try and have a contest to see who can write the scariest ghost story and Mary Shelley wrote Frankenstein inspired by the climatic effects of a volcanic eruption now byron didn't write a book but he wrote a poem called darkness which i learned about from russian scientists in the 1980s who had read it in a russian translation and it sounds just like nuclear winter I had a dream which was not all a dream the bright Sun was extinguished and the stars did wander darkling in the eternal space rayless and pathless and the icy earth swung blind and blackening in the moonless air and more inque man went and came and brought in no day and men forgot their passions in the dread of this their desolation and all hearts were chilled into a selfish prayer for life and they did live by watch fires and the thrones the palaces of Crown Kings the huts the habitants of all things which dwell were burnt for beacons cities were consumed so what does this mean Brian tonight last year wrote an article called self assured destruction we used to think it was mutually assured destruction that if one country attacked the other the other would attack you back and everybody would die and that would deter you from attacking but now it turns out the use of nuclear weapons would be suicidal if you attacked another country and they did nothing the smoke from those fires would come back and get you so you can't use them you can't use nuclear weapons why do we keep so many now President Obama and President Medvedev signed the new start agreement in Prague in 2010 and this country to go down to about 2000 nuclear weapons by 2017 but our calculations showed that would still be enough to produce nuclear winter and so we really need to get rid of them much faster than mister than that only nuclear disarmament will prevent will prevent this possibility of this catastrophe and Obama you might remember last week offered to bring the u.s. Arsenal down by about a third and that's great that's set an example for the rest of the world but how can we expect Iran not to have nuclear weapons if we we keep ours it's like sitting on a bar still telling people not to drink why should now the the problem with our weapons is not no rational person would use them but there have been cases of panic cases of irrational people and the closest we came to a nuclear war was in the 50 years ago during the Cuban Missile Crisis this is one of the Russian missiles that was given to Cuba with atomic weapons on and we're really lucky that we ended up without a nuclear war then I took that picture a couple months ago in Havana and as John said one person found out about my work and invited me down to Havana and I gave a talk with Fidel Castro sitting at the front for an hour and this is a signed picture go to my website you can see more of those and nine days later he wrote an essay he said while the United States and Russia each committed to reducing their operative nuclear arsenals down to some 2,000 weapons in Prague the only way to prevent a global climate catastrophe from taking place would be by eliminating nuclear weapons that's a good sign he got it now I just need the people that have the nuclear weapons still to get it to and there's a good sign there was a meeting in Oslo in Norway in March where it's called the humanitarian impact of nuclear weapons and 132 nations attended and they agreed about this you know though there are other weapons of mass destruction that are prohibited by international treaty you can't use chemical weapons you can't use cluster munitions you can't use biological weapons but nuclear weapons the worst weapon of mass destruction is not prohibited there is no tree abolishing them that's what we have to work toward and all these countries agree to it and then there's me another meeting in in Mexico to try and put pressure on the countries with them so we're going in the right direction now you might say but you know they're useful nuclear weapons are the course of world war two that's not true we'd already burned 66 cities in Japan two more didn't make a difference and the Japanese gave up because the Russians came into the war you might say killing all these people will will win a war it won't killing killing soldiers will you might say there's nuclear deterrence well which nuclear look look at what happened in the past the Russians invaded Eastern Europe when the US was the only nuclear power that didn't deter them the Argentinians attacked England in the Falkland Islands England was the one with nuclear weapons who won the first Afghanistan war who won the second one the country with nuclear weapons who won the war in Vietnam so nuclear weapons don't deter anybody from attacking you and you can't prove that they've kept the peace even though we've been lucky enough not to have a nuclear war and you you can't get rid of the of their knowledge of them but you can get rid of them so how have I made you feel so I'm really sorry you've been a bummer Oh told you about this horrible thing but the question is what do you do about this information as Mark Twain said denial ain't just a river in Egypt the natural thing is to try and forget about it and go home and forget about it but actually what you can do is put it to work you have to work join the international movement to try and get rid of nuclear weapons and there's a couple organizations once called global zero global zero org the other is I can the international campaign to abolish nuclear weapons I can W org and is it's starting up in the United States and you can go to these places and join it and try and rid the world of nuclear weapons so we had the luxury of worrying about all the other problems you've heard about today thanks very much [Applause] [Music]

Channel: TEDx Talks

Views: 30,019

Rating: 4.7936964 out of 5

Keywords: elizabeth barry, TEDxHoboken, hoboken, tedx talk, alan robock, ted x, United, TEDx, \global issues\, english, technology, ted talks, tedx talks, tedx, ted talk, ted

Id: qsrEk1oZ-54

Length: 17min 57sec (1077 seconds)

Published: Sat Aug 31 2013