Almost everybody outside the United States thinks this would be a bad outcome, but for a wide variety of different reasons.
China thinks Trump would abandon Taiwan, for example (good for China), but fears his threat to impose tariffs of between 60% and 100% on Chinese imports (very bad for everybody concerned).
On one topic, however, everybody agrees: Trump would be dreadful on climate.
As mega-hurricanes Helene and Milton devastated much of the southeastern US a month ago, Trump talked of the climate emergency as "one of the greatest scams of all time." Many expect him to pull out of the 2015 Paris Agreement again as he did in his first term.
That mattered quite a lot when he first took office in 2017, because America had much more of a leadership role then. Governments that saw action on climate issues as optional, but wanted to avoid a major public backlash from people who wanted action now, viewed Trump as a useful idiot.
No other government on the planet actively denied climate change, but many used the Trump administration’s stance as an excuse for similar inaction themselves. Indeed, the ratification of the famous "never exceed +1.5°C" policy at a special international meeting in 2018 was an attempt to give those defectors a push in the right direction.
The thinking was that the existing "never more than +2.0°C" target was too far away to motivate politicians who think that "a week is a long time in politics" (as former British prime minister Harold Wilson once put it).
At the current rate of emissions that level of warming would not be reached until the early 2040s, and who cares about the 2040s?
The +1.5°C limit, on the other hand, would be crossed by the early to middle 2030s. That was close enough that it might get the attention of even the most near-sighted politicians. (The scientists were not making this up; they were just quoting their existing predictions for an earlier date.)
Did it really help? Probably not much, but some countries that faced particularly early and highly disruptive climate changes — notably China, which faces a 38% fall in food production at +2.0°C — began to work hard on decarbonising their economies. And in 2020 Trump lost the US election. (Yes, really, he did.)
The Biden administration promptly rejoined the Paris Agreement, but its great achievement was the Inflation Reduction Act (IRA) of 2022, an enormous piece of climate legislation that authorises $US783 billion in federal spending on energy and climate-related issues.
Unless the Republicans win the presidency and majorities in both Houses of Congress, this legislation cannot be repealed. The IRA spending will continue into the early 2030s, and in conjunction with private investment will reduce American greenhouse gas emissions to half the 2005 level.
The United States would still lag behind most other developed countries in its response to global warming. The United Kingdom, the first country to burn coal for energy, just shut down its last coal-fired plant, while the United States still has 204 of them.
But this is not just Trump’s doing: the fossil fuel lobby is still very strong in the US.
As for the international impact of a second Trump presidency, the world has learned to work with the bizarre delays and roadblocks in America’s arcane 18th-century political system. Everybody accepts, for example, that the US often signs treaties but leaves them unratified for decades.
Could a second Trump presidency actually derail international efforts to cope with the climate emergency? No, the US is not that powerful any more, and the countries where a majority of people understand the gravity of the situation — practically all of them — will simply work around the obstacles a Trump administration tries to put in the way.
A victorious Trump could do a great deal of damage to the political stability of his own country if he takes vengeance against his opponents in the ways that he has threatened (and he will certainly attack the constitutional order again if he is defeated.)
But that is mostly a problem for Americans.
Most people elsewhere have finally understood that the absolute priority is preserving a climate hospitable to human beings.
We have left it very late, but that consensus provides a basis for global cooperation that can, if necessary, do without the United States for a while.
Besides, Trump could still lose.
— Gwynne Dyer is an independent London journalist.
