Nuclear triad
Israel is known to have nuclear-capable aircraft and land-base missiles, with the addition of nuclear-armed submarines this would mean that they now have a full triad of land-, air-, and sea-based nuclear delivery systems some of which would be invulnerable to a first strike by an enemy for the first time in their country's history. No other nation in the Middle East in known to be in possession of nuclear weapons, even though Iran, Iraq, Syria and Libya have started development programs that were never completed.
Nuclear holocaust
As of 2016, humanity has about 15,000 nuclear weapons, thousands of which are on hair-trigger alert. While stockpiles have been on the decline following the end of the Cold War, every nuclear country is currently undergoing modernization of its nuclear arsenal. Some experts believe this modernization may increase the risk of nuclear proliferation, nuclear terrorism, and accidental nuclear war.