Possibly as early as this autumn, Israel may start a large-scale war in the Middle East and elsewhere by bombing Iran. The consequences are unforeseeable, but there are several ways in which the conflict could escalate into a nuclear war, particularly if the US supports the Israeli attack, and if Pakistan, Russia and China become involved.
Why is the threat especially worrying? Because of the massive buildup of US naval forces in the Persian Gulf. Because of Netanyahu's government's stated intention to attack Iran, despite opposition from the people of Israel. Because of President Obama's declarations of unconditional support for Israel; and because Pakistan, a nuclear power, would probably enter the war on the side of Iran.
Most probably, a military attack on Iran by Israel would provoke an Iranian missile attack on Tel Aviv, and Iran might also close the Strait of Hormuz. The probable response of the US would be to bomb Iranian targets, such as shore installations on the Persian Gulf. That might well provoke Iran to sink one or more US ships by means of rockets, and if that should happen, the US public would demand massive retaliation against Iran.
Meanwhile, in Pakistan, the unpopularity of the US-Israel alliance, as well as the memory of numerous attrocities, might lead to the overthrow of Pakistan's less-than-stable government. Israel's response might be a preemptive nuclear attack on Pakistan's nuclear installations. One reads that Russia has already prepared for the conflict by massing troops and armaments in Armenia, and China may also be drawn into the conflict.
In this tense situation, there would be a danger that a much larger nuclear exchange could occur because of a systems failure or because of an error of judgement by a military or political leader. A thermonuclear war would be the ultimate environmental disaster.
Recent research has shown that thick clouds of smoke from firestorms in burning cities would rise to the stratosphere, where they would spread globally and remain for a decade, blocking the hydrological cycle, and destroying the ozone layer. A decade of greatly lowered temperatures would also follow. Global agriculture would be destroyed. Human, plant and animal populations would perish.
We must also consider the very long-lasting effects of radioactive contamination. One can gain a small idea of what it would be like by thinking of the radioactive contamation that has made large areas near to Chernobyl and Fukushima permanently uninhabitable, or the testing of hydrogen bombs in the Pacific in the 1950's, which continues to cause leukemia and birth defects in the Marshall Islands more than half a century later. In the event of a thermonuclear war, the contamination would be enormously greater.
We have to remember that the total explosive power of the nuclear weapons in the world today is 500,000 times as great as the power of the bombs that destroyed Hiroshima and Nagasaki. What is threatened today is the complete breakdown of human civilization and the destruction of much of the biosphere.
The common human culture that we all share is a treasure to be carefully protected and handed down to our children and grandchildren. The beautiful earth, with its enormous richness of plant and animal life, is also a treasure, almost beyond our power to measure or express. What enormous arrogance and blasphemy it is for our leaders to think of risking these in a thermonuclear war!