”the Sun has no effect. Three winters will come in succession, and no summer between.” Fimbulvintern as it is portrayed in the prose Edda is, with all certainty, not just a horrific vision of world destruction, but a description of real events. Probably occurred in the two major volcanic eruptions anywhere on earth in the year 536, and 540, and the smoke from them was devastating for the climate in large parts of the world, something that several historical sources testify.

A nuclear war would be able to get the same global implications.

Link to the graphics

– If the nuclear weapons hit cities and industrial areas they will begin to burn and the smoke rises up in the upper atmosphere and is left for several years and obscuring the sun. It gets dark and cold, and drier on the ground. In addition, would the ozone layer be destroyed so that more ultraviolet radiation reaches the earth. All it would adversely affect agriculture, ” says Alan Robock, a professor in the department of environmental sciences at Rutgers University in New Jersey in the united states.

He has conducted research on the climate effects of both volcanic eruptions and nuclear war for several decades, and in a week he went to Sweden, invited by the university of Stockholm and the peace movement Swedish Pugwash, and held a lecture at the institute of Foreign affairs.

– The number of dead civilians and the spread of the radioactive material is terrible in and of itself. But the effects of the smoke from the burning cities is much, much worse than the direct effects, ” says Alan Robock.

heated by the sun and rises up to the stratosphere, therefore the part of the atmosphere where the ozone layer is.

– In the stratosphere there are no clouds and no rain that can wash away the smoke, so where can it be blown around all over the world and remain for years. The lifetime of a sotpartikel in the lower atmosphere is about a week. In the upper is the lifetime of around five years.

Link to the graphics

Link to the graphics

how big the effect will be for the climate.

– A nuclear war between the US and Russia can affect the climate so much that it gets below freezing even in the middle of the summer. It is what we call the atomic winter, ” says Alan Robock.

He and his colleagues have calculated a scenario in which Russia uses 2 000 nuclear warheads against the united states and Western europe, and the united states puts in just as many against Russia and China.

– There are a sufficient number of deployed nuclear weapons and a sufficient number of targets to produce 150 million tons of smoke.

in a conflict between India and Pakistan is based on the idea from a misunderstanding at the border that escalates to a nuclear war with 100 warheads against cities and industrial areas.

– We do not use the concept of realistic scenarios, we hope that none of them is realistic. We call them stories. But let’s calculate what would happen to talk about it to the world in the hope that it will never be done, ” says Alan Robock.

7 million tons of smoke from fires in India and Pakistan would give the cold, darkness, and the harvests in the whole world, and in addition serious economic consequences when countries need to hoard food.

– The most serious effects on the climate we see in the first five years. Then, they start to subside. But starve we to death during the first year, it plays less of a role, ” says Alan Robock.

Link to the graphics

the who warned of the climate effects of nuclear war, The Atmosphere after a Nuclear War: Twilight at Noon of the scientists Paul Crutzen and John Birks, published in the journal Ambio in 1982. In the Soviet union introduced the Russian scientists similar results at the same time. It aroused strong reactions among politicians and the general public.

– Now the general public is not worried about this anymore, because they have other, more immediate, problems. In the 1980s, was commitment, and it was one of the reasons that Gorbachev and Reagan slowed the arms race, where researchers on both sides sounded the alarm.

Alan Robock wish that it was possible to arouse public opinion again. After the us elections in 2016, he wrote an open letter to Donald Trump in the Huffington Post, where he advises the future president to change the defence policy so that nuclear weapons should never be used for attack and to begin to dismantle the country’s land-based missiles.

– I wrote that it would save a lot of money for us, and that he would get the Nobel peace prize. It is, of course, a shiny medal made of gold, so I thought he would like it. Of course, I’m not sure he at all read.

president Barack Obama’s kärnvapenrådgivare.

” I mean, why would Iran listen to what we have to say about nuclear weapons, if we do not nedrustar themselves? It is like sitting in a bar and telling people that they should stop drinking.

a few years ago, Alan Robock Cuba to lecture on his research.

– Fidel Castro sat in the first row, and asked if they could send my lecture on prime-time tv the day after.

Alan Robock said yes, and the next day he went to the bar at the hotel to see yourself on tv.

” But they showed a film with Julia Roberts. So I had to ask them to change the channel, and where I was and gave my talk.

” It taught me that you do not arouse public opinion with a professor who holds lectures. It needed something that people can relate to and identify with and that evokes emotion, as a feature film. I think of the one where a beautiful scientist in Saint Petersburg cooperates with a handsome scientists in the united states. And at the same time, something happens at the border in Kashmir. So there will be both sex and save the world, ” says Alan Robock.

It is also important to not scare people so much that they give up.

” Then it closes the only by, and do not want to hear, because it becomes impossible to manage. We need to find ways to touch people to get them to act.