Amid the COP‑30 climate summit, a troubling geopolitical fault line has emerged: the US is visibly retreating from global climate leadership, leaving the rest of the world, especially the European Union (EU) and the Global South, to decide whether they should act against US inaction through diplomatic pressure or sanction-style mechanisms, and if so, how. What is the available leverage, the legal and practical constraints on sanctions, and what concrete steps can be taken to convert collective frustration into actionable resolution?The US, historically the second-largest emitter of greenhouse gases, has taken a notably adversarial posture by withdrawing from the Paris Agreement and deciding not to attend COP-30. The consequences are already manifest: the UN projects that even with current NDCs (Nationally Determined Contributions) the global emissions reduction by 2035 will amount to only about 10% relative to 2019 levels – far short of the 60% reduction scientists say is required to limit warming to 1.5°C.Global emissions continue to rise: it is about 53.2 billion tCO2-eq in 2024, up 4.7% on 2019, with the U.S. alone up +0.4% in 2023-24.The US withdrawal introduces both a leadership vacuum and a systemic risk to the multilateral architecture of climate action. If one major emitter is dragging its feet, others must punish or isolate it, just as the U.S. had done with countries that opposed its political wars. In this case, the war is against the planet!Imposing standalone climate-sanctions would require a binding legal framework, which presently doesn’t exist at the multilateral level for climate non-compliance. Unlike trade disputes under the World Trade Organisation (WTO), there is no global “climate sanction” mechanism for nations that duck commitments. The bigger question is, how many nations will rally against the US without jeopardising their national interests in trade?The EU may have some leverage because of trade and investments, but it also has its own internal emission reduction issues. The Global South has dependency on climate finance and doesn’t have the structural ability to stand against the U.S. in stronger terms even if their leaders may want that.The idea of sanctions is to bring back the dialogue, but how should the world punish a bully nation over climate? Climate experts argue that sanctions and blockages may not work as much as engagement and collaboration.Given the constraints on punitive measures, the EU and Global South can pursue a multi-pronged strategy combining diplomatic pressure, alternative norm-setting, and step-change solidarity. Here are some thoughts for COP-30:Diplomatic pressure and reputational accountability: The EU and a coalition of vulnerable countries can establish a public “non-compliance registry” at COP-30 for major emitters failing to align with Paris goals. While not legally binding, such a registry creates reputational cost. The EU can include climate-policy evaluation in trade and investment dialogues, making access to cooperation conditional on climate-risk mitigation.Create an alternative leadership bloc: With the US absent, the rest of the parties can form a “Climate Leadership Alliance.” This bloc would pledge enhanced NDCs, propose transparent monitoring, and publish annual “progress-to-target” dashboards. Already, around 100 countries representing roughly two-thirds of global emissions have submitted new climate targets ahead of COP-30.Financial mechanisms and climate justice diplomacy: At the heart of the climate contest is money: at COP-29, nations agreed to mobilise US$ 1.3 trillion per year by 2035 for mitigation and adaptation in developing economies. The EU and Global South can jointly demand that conventional finance for development be decoupled from fossil-fuel expansion. They can also move to establish regional financing pools (e.g., African Green Transition Fund) less reliant on US participation.Trade-policy conditionality and carbon border adjustments: The EU is already pioneering a Carbon Border Adjustment Mechanism (CBAM). It could extend this to measure compliance of imports from major emitters that fail climate commitments. While not directed at the US as a whole, it sends a signal.Technology sharing and infra-innovation partnerships: Rather than merely isolating the US, the Global South can seek direct tech-transfer partnerships with other major players to bypass fossil-fuel supply chains reliant on the U.S. This reduces dependence on an uncooperative actor.Legal pathways for loss & damage and liability claims: Countries most affected by climate change (small island states, African nations) can press ahead with international legal frameworks seeking compensation for “loss and damage” arising from historic emissions. The US’s retreat adds moral-leverage. The EU can support this legally and litigatively, driving the principle that massive historical emitters must participate or face legal costs.With global warming accelerating, the 1.5°C target now seems increasingly unlikely: current NDCs point to only 12% reduction by 2035 rather than the required 60%. The stakes are enormous: climate stability, development justice and geopolitical alignment. If the U.S. absents itself from global climate leadership, the cost will fall disproportionately on developing nations that did the least to cause the crisis.Hence the window for action is narrow. COP-30 offers a platform to recalibrate global diplomacy. The EU and Global South must act together to shift the paradigm from US leadership dependence to plural-centre governance. Through targeted sanctions alone the US cannot be forced back to the negotiating table, but through a smart combination of norms, conditionalities, alliances, finance and legal pressure, the rest of the world can reshape the incentives.So here we are… the planet’s burning, and the US has RSVP’d “maybe” to the apocalypse. The rest of the world can either keep waiting for America’s moral Wi-Fi to reconnect or start governing without the self-proclaimed sheriff. As one weary negotiator sighed, “If Washington won’t join the green revolution, we’ll recycle its leadership instead.”Muneer is a Fortune-500 advisor, start-up investor and co-founder of the non-profit Medici Institute for Innovation. X: @MuneerMuh.