Farsi translation here...
According to National Geographic,
New Design World and many other echoes via Google News.
NASA GISS' computer modelers (Luke Oman et al.) were trying to solve the "global warming crisis" and they found a solution: a regional nuclear war, for example between India and Pakistan, would reduce floods and cool the Earth by 1.25 °C - some places by 3-4 °C. After a decade, the temperature would still be 0.9 °C lower than before the war.
The predictions are a humble version of the nuclear winter scenario.
You see, nuking Iran and a few other thug states away will also revert decades or a century of "global warming" at the same moment. It has not yet been reported whether John Holdren has already asked Barack Obama to press buttons.
More seriously, it's kind of amazing what kind of research is being funded. If there were a nuclear war between similar countries, a cooling by a degree Celsius would clearly be one of the least significant consequences. We had minus 14 Celsius degrees in the morning, fine, so we would have minus 15 Celsius degrees. And irradiated, dying relatives across the world, too.
Concerning the impacts, well, it's very likely that there would be some cooling that would depend on the magnitude of the explosions and that would last for years. It isn't terribly useful to calculate the exact impact because the total size of the hypothetical nuclear war would remain uncertain until its peak - or until its end. Nuclear wars may differ by many orders of magnitude.
Hiroshima and Nagasaki haven't experienced much of a climate impact so one has to speak about much larger conflicts - about 100+ times larger. They would probably have to kill tens of millions of people. Do those people really think that a degree of temporary cooling or warming would be more important than those lives and other political impacts of the war?
I am surely among the top 10% of the Hawks who would use nuclear weapons e.g. against Iran under certain circumstances. (To be sure, I know that this article is mostly read by Persians - so I don't really mean you or your friends haha, as a person who respects the Persian heritage and contributions as as an ex-colleague of two Persian-origin top physicists, Cumrun Vafa and Nima Arkani-Hamed.) But I don't mean carpet bombing without any good reason; what I mean are surgical operations meant to cripple their offensive military. A temperature change by a degree can't be the reason to start the bombing.
By the way, the cooling effects of a nuclear detonation have been vastly exaggerated in the past - see Michael Crichton's comments about "nuclear winter" in his famous speech, Aliens Cause Global Warming.
When we talk about regional nuclear wars, my Persian readers across the world will surely forgive your humble correspondent that he has recorded the song "The [Iranian] Bomb" by Latma TV:
I think that many Iranian folks should try to appreciate things like this Jewish humor. You know, folks, I am as un-Jewish as you are, but it's just fun, and Latma TV is often right on the money when it comes to Iran and other topics.
I wonder whether the Iranians who are abroad can understand that the people like those in this pro-Israeli Internet TV are essentially friendly towards Iran etc. and whether someone has some compassion with the fate of the Jews who are still not treated as fairly as others.
You know, in my hometown of Pilsen, Czech Republic, we used to have thousands of Jews before the war and all of them died. My visit to the local holocaust museum - which I have only saw because my American friend visited me and wanted to see itt - has been a heartbreaking experience and many contemporary attitudes seem way too similar to the developments in Germany of the 1930s (and Czechia in the late 1930s)...