how many times could the u s blow up the world with it's nukes without any other country involved except Trump?

begin quote from Google AI and Internet:

 

The concept of the US "blowing up the world" with its nuclear arsenal is misleading and not supported by scientific understanding of nuclear weapons effects

. While the US possesses a large number of nuclear weapons, the effect of detonating them would not be to literally "blow up" the Earth in a physical sense. 

Here's a breakdown of the effects of nuclear war:

• Massive destruction and death: A nuclear war would cause widespread devastation and death due to the immediate blast, intense heat, and ensuing firestorms. Even a small nuclear exchange could lead to significant global casualties.
• Climate disruption: Nuclear detonations would release massive amounts of soot and smoke into the atmosphere, potentially blocking sunlight and causing a "nuclear winter," leading to drastic cooling, agricultural collapse, and famine.
• Long-term health effects: Nuclear weapons produce ionizing radiation which contaminates the environment and has long-term health consequences, including increased cancer rates and genetic damage.
• Nuclear arsenal size: The US has a significant nuclear arsenal, with an estimated 3,748 nuclear warheads as of September 2023, according to USAFacts. The total number of warheads in the US inventory, including retired ones awaiting dismantlement, is higher. The US has reduced its stockpile significantly since the Cold War peak of over 31,000 warheads. 

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It's important to understand that the focus is on the catastrophic impact on human civilization and the environment, not the physical destruction of the Earth itself.