Curiously, those plans are the one thing countries willnotbe discussing in Baku. In UN-speak, they are “nationally determined contributions,” or NDCs, and the clue is in the name.Countries are legally bound to publish an NDC, but the Paris Agreement leaves the contents entirely up to them. Even though the aggregate total of emissions resulting from all NDCs is extremely unlikely to achieve the agreement’s own 2C or 1.5C goals, the principle of national sovereignty prevents them being discussed by anyone else. The fate of the world’s climate rests not on negotiations between states, but on how the largest emitting countries make economic, energy and environmental policy at home. This is where Trump’s climate impact will really be felt.How will the path of American greenhouse gas emissions differ under a Trump presidency from a Kamala Harris one? And what impact will that have on other countries’ willingness to cut theirs?Trump’s views are clear. In September he described climate change as a “scam” even as Hurricane Helene was leaving a trail of destruction along the eastern US seaboard. In his first term he severely constrained the work of the Environmental Protection Agency, whose anti-pollution regulations will gradually cause most coal-fired power stations to close. This time round he says he will permit oil and gas drilling in Alaska, end the requirement that more than half of all cars sold in 2032 are electric, and repeal Joe Biden’s Inflation Reduction Act, which has moved hundreds of billions of dollars into low-carbon manufacturing sectors.By 2030, according to oneanalysis, US emissions could be four billion tonnes higher than otherwise under a full Trump program, equivalent to more than a quarter of the emissions of the European Union and Japan combined. Where Harris would have sought to meet the Biden administration’s goal of cutting US emissions 50–52 per cent on 2005 levels by 2030 (en route to net zero by 2050), a Trump presidency could see them fall only 28 per cent.In practice, though, the new president’s impact may not be as large as this. US emissions are not primarily determined by federal policy. Energy is mainly the responsibility of states, most of whom have strong green energy mandates. Energy markets have hugely favoured renewables over the last decade.In 2023renewable energy and energy storage accounted for more than three-quarters of new capacity, taking renewables to around 25 per cent of US power generation. Wind and solar installation dominate not just in California but in oil-rich Texas. As former EPA head Gina McCarthysaidthis week, “the shift to clean energy is unstoppable.”Electric vehicle regulations do come from Washington, andTrump sayshe wishes to “save” the American auto industry from them. But President Biden’s tax incentives are benefiting both consumers and producers, and US manufacturers need to compete in international markets where demand for electric vehicles continues to accelerate. In this area as in others, it is not self-evident that Trump will do what he promises. (And it has not gone unnoticed that one of his chief backers is the world’s most famous electric car manufacturer.)As for Trump’s commitment to expanding the oil and gas industry — “drill baby, drill,” he delights in urging — more sanguine observers note that global conditions will determine whether new licences lead to an increase in production. A glut of new oil coming onto a global market in which demand isexpected to peakby 2030 would not benefit US producers, whose costs are higher than in other countries.Perhaps the greatest uncertainty relates to President Biden’s radical Inflation Reduction Act, which channels huge investment incentives and tax breaks — anestimated$493 billions’ worth in its first two years — to low-carbon manufacturing and its products. Although Trump has lambasted the IRA and said he will repeal it, many commentators doubt he will go ahead. The IRA is already estimated to havecreatedaround 150,000 jobs, of which two-thirds are in Republican congressional districts. Plenty of Trump’s own supporters in Congress are likely to lobby to keep it in place.Trump’s anti-climate rhetoric is plain, but there is reason to think it may not be matched by his policies over the next four years.Internationally, Trump will almost certainly withdraw the US from the Paris Climate Agreement, as he did four years ago. There is even talk that he might pull the US out of the original 1992 UN Framework Convention on Climate Change, though that would be a much more complicated task and would face legal challenge. But how far would these actions reduce the international effort to tackle climate change?American withdrawal would unquestionably be destabilising for the UN process. The US would presumably not submit an NDC next year, and for the next four years it is likely to provide little in climate finance to developing countries. Hopes had been high that a Harris presidency would inject new funds into the World Bank, significantly increasing the finance available to poorer countries; it’s hard to now see that happening.But a US withdrawal is unlikely to slow other countries’ pursuit of their own climate commitments. Four years ago, when Trump was first elected, this was the fear. Climate change is a “collective action problem”: if one country isn’t willing to bear its share of the global burden, why should others? But this line of reasoning no longer applies. Countries are cutting their coal use because they want to get rid of urban air pollution. They are installing renewable energy because it is cheaper. They are investing in public transport and cycling because this makes their cities function better. They are slowing deforestation because its environmental and social impacts are disastrous.These “co-benefits” of climate action have given most major economies domestic economic and political reasons to pursue climate policies. Indeed, it is because few have been willing to go further than domestic benefits that climate policies have been inadequate to achieve a 1.5C or 2C global trajectory. But that also means few countries are likely to change their climate policy commitments just because the US — for the next four years at least — is no longer in the game.China is the key factor here. Gone are the days when Beijing would have calibrated its own domestic emissions reduction plans according to what Washington was doing. The Chinese government is planning for national emissions topeakby 2030 because it is in its interests to do so, and a US retreat from climate policy will make little or no difference.More than that, China will almost certainly see an opportunity to parade its global leadership. Already the world’s largest supplier of wind and solar equipment and electric vehicles, along with the critical minerals needed by them, it will be able to say it now leads the world in tackling climate change. As the US pulls back, China is likely to increase its already considerable investment in Africa, Latin America and Asia with the claim that it is now among the world’s major providers of climate finance.More widely, US withdrawal will strengthen the position of the BRICS grouping in climate diplomacy and beyond. Driven by China, Russia Brazil, India and Saudi Arabia, the alliance has expanded to ten countries, with another two dozen in the queue to join. Itsmeetinglast month in Kazan, Russia, made clear its ambition to create a comprehensive alternative power bloc to the Western alliance. That claim will look stronger with the US led by Donald Trump. As host of the all-important COP30 next year, Brazil will be pushing the BRICS into more progressive positions on climate change and will see China as its key ally.Paradoxically, it’s possible that Trump’s election may even help COP29. The big issue in Baku over the next two weeks is the negotiation of a new goal for climate finance, the sums richer countries will pay poorer ones over the next decade to help them reduce their emissions and cope with climate impacts. After three years of negotiations, developed and developing countries still differ starkly over the the amounts required, and who should pay them. In the run-up to the conference there have indeed been genuine fears that it may not be possible to reach agreement at all.But a looming Trump administration may concentrate minds. Both developed and developing countries may feel it is imperative to do a deal with the Biden administration, while it’s still around, for fear of a worse outcome if the issue is left to next year. The sum of money agreed to may be smaller than it would otherwise have been — the EU will certainly not want to be on the hook for the missing American amount — but the likelihood of agreement may just have gone up.The first few days of COP29 will see speeches from assembled heads of government. Rather than pulling back, expect them to proclaim their redoubled commitment to multilateralism and to stronger international cooperation on climate change. They won’t mention Trump. But they won’t have to. •