Nearly 200 countries are arriving in Belém, on the edge of the Amazon rainforest, to negotiate the next round of global climate action at COP30, the UN climate conference running from 10 to 21 November. It is a symbolic setting: the Amazon is both a vital carbon sink and a region already scarred by deforestation and extreme heat, and Brazil has branded this as a “COP for implementation,” focused on forests and nature-based solutions, renewable energy and climate justice, according to official COP30 information and Brazil’s host site. Yet one of the biggest stories before the talks even begin is who is not coming. The Trump White House has chosen not to send any cabinet-level figures, leaving the U.S. almost invisible in the negotiations even as it remains one of the world’s top historic and current emitters, as detailed in a Los Angeles Times report on the summit.

California is trying to fill the void. Governor Gavin Newsom has flown in with a large delegation including top officials from the state’s natural resources, agriculture, air quality, utilities and tribal affairs agencies, positioning California as a “proxy” for the United States. In interviews and statements ahead of the trip, Newsom has argued that climate policy is not just about avoiding catastrophe but about capturing “the defining economic opportunity of the 21st century,” a theme echoed in a recent press release from his office. He is also a likely 2028 presidential contender, and his high-profile speeches in Belém and at the Milken Institute’s Global Investors’ Symposium in São Paulo double as a contrast with Trump’s fossil-fuel agenda. Where the federal government is rolling back climate rules and championing oil and gas, Newsom is selling California as proof that strict climate targets, clean-energy tech and jobs can go hand in hand.

This COP is taking place exactly ten years after the Paris agreement was struck at COP21 in 2015, committing nations to hold global warming “well below” 2°C and to pursue efforts to stay under 1.5°C. A decade later, that safer 1.5°C threshold is slipping out of reach. In late October, UN Secretary-General António Guterres told delegates at the World Meteorological Organization that “we will not be able to contain the global warming below 1.5 degrees in the next few years” and that “overshooting is now inevitable,” warning of a period of higher temperatures and escalating climate shocks before the world can hope to cool back down, in remarks published by the UN’s Geneva office and the WMO and summarized by UNOG’s news service. The last decade has been the hottest on record, driven overwhelmingly by the burning of coal, oil and gas; each new fraction of a degree means more deadly heatwaves, crop failures, floods and wildfire seasons.

The latest science backing up those warnings is stark. UNEP’s new Emissions Gap Report 2025 finds that if all current national climate pledges (NDCs) are fully implemented, the world is still headed for about 2.3–2.5°C of warming by 2100; if countries simply stick to policies already in force, temperatures could climb to around 2.8°C. The report notes that methodological tweaks account for about a tenth of a degree of apparent “progress” since last year, and that the upcoming U.S. withdrawal from the Paris agreement will wipe out another 0.1°C of that gain, leaving real-world ambition barely changed. The Los Angeles Times, drawing on UNEP’s analysis, reports that Trump’s decision to leave Paris is expected to add roughly 0.18°C to projected warming compared with a world where the U.S. stayed in the accord. For vulnerable communities already facing loss and damage, that small-sounding number translates into higher seas, more violent storms and spiralling adaptation costs.

Trump, for his part, has doubled down on his long-standing rejection of multilateral climate deals. On his first day back in office he signed an order again pulling the U.S. out of the Paris agreement, arguing that international climate compacts place an “unfair burden” on American taxpayers and benefit other countries at U.S. expense, as described in the executive order cited by the Los Angeles Times. His administration has also moved to weaken or revoke California’s authority to set tougher vehicle emissions standards and has cancelled federal support for major clean-energy projects, including a planned hydrogen hub and a large offshore wind investment. At a separate event in Athens, the U.S. Energy Secretary attacked COP30 as “dishonest,” and promoted expanded gas exports instead, according to coverage by the Associated Press. For many leaders and activists in Belém, that combination of absence and hostility is a bitter symbol of backsliding at precisely the wrong time.

California’s message, by contrast, is that climate action works – and pays. The state has cut its greenhouse gas emissions by about 21% since 2000 while its economy has grown 81%, and it now relies on roughly two-thirds clean electricity, according to figures compiled by the Newsom administration. Green jobs outnumber fossil fuel jobs seven to one, and a multi-billion-dollar climate investment plan is funding everything from grid-scale batteries to building retrofits. Californians are also seeing direct financial benefits: millions of households received credits on their power bills this year funded by the state’s carbon market. Decades of aggressive rules – such as early zero-emission vehicle standards that helped push automakers toward hybrids and EVs – have turned the state into a testbed for technologies that later spread worldwide, something highlighted in both the Los Angeles Times coverage and in California’s own climate briefings.

Beyond its borders, California has stitched together a dense network of climate alliances that it is keen to showcase in Belém. The state links its cap-and-trade system with Quebec’s, collaborates with Denmark on groundwater monitoring technology, and has signed memorandums of understanding with regions in Mexico and China on clean ports, zero-emission freight, pollution control and offshore wind – examples highlighted both in the Los Angeles Times article and in documents from the California Energy Commission. It also pioneered a Tropical Forest Standard in 2019, setting criteria for high-quality forest carbon credits and forging ties with Amazonian regions trying to halt deforestation. Through its 30x30 program to conserve 30% of land and coastal waters by 2030, described in state conservation plans, California is trying to align its domestic conservation push with the global effort to protect forests and biodiversity that is central to this year’s COP30 agenda.

Many observers argue that this kind of “subnational” action – from states, cities and businesses – is no longer just a sideshow at UN climate talks. Analysts like Rachel Cleetus of the Union of Concerned Scientists note that these actors can keep momentum alive when national governments falter, and can turn vague pledges into real policies on the ground, as quoted in the Los Angeles Times climate piece. Networks such as the U.S. Climate Alliance and coalitions like “America Is All In,” which Newsom co-chairs, are using COP30 to argue that “the other face of the United States” still takes climate science seriously and is willing to act. They see California’s presence in Belém not as a substitute for federal leadership – which they insist must eventually be restored – but as a stopgap to reassure partners that the U.S. cannot be reduced to the decisions of a single administration.

Still, no amount of state-level ambition can fully compensate for a missing superpower when the clock is this close to midnight. UNEP’s Emissions Gap report warns that, to keep 1.5°C within reach, global emissions in 2035 must be cut by about 55% below 2019 levels; even to stay under 2°C requires reductions of roughly 35%, a scale of transformation far beyond current plans, as laid out in the UNEP analysis. Guterres is pressing leaders in Belém to agree a credible plan to mobilize around $1.3 trillion a year in climate finance for developing countries by 2035, and to rapidly expand renewable energy, which he calls “the cheapest, fastest and smartest” path out of the crisis, according to his WMO speech summary. The Trump administration’s choice to sit out the summit sends the opposite signal: that a major emitter is prepared to bet the planet on more fossil fuel extraction and delayed action.

For people watching from flood-hit river deltas, wildfire towns or overheated cities, that political drama is not an abstract diplomatic spat – it is a matter of survival. California’s leaders insist that they will keep pushing, signing deals and exporting technology even if Washington refuses to lead. They point to their own experience as proof that cutting emissions can clean the air, lower bills and create jobs, not kill them. But the brutal arithmetic of the carbon budget means that time is almost up: every extra tonne of CO₂ emitted now locks in decades of added heat. COP30 is therefore not just a stage for Newsom vs. Trump. It is a test of whether the rest of the world – with or without the U.S. federal government – can move fast enough to avoid turning a dangerous overshoot into an irreversible free fall.