UK-California Climate Alliance Set to Deepen Despite Trump Opposition: What Comes Next

5 predicted events · 14 source articles analyzed · Model: claude-sonnet-4-5-20250929

The Collision of Climate Diplomacy and Presidential Politics

A new fault line has emerged in transatlantic relations following the UK's agreement with California on climate cooperation. UK Energy Secretary Ed Miliband and California Governor Gavin Newsom signed a memorandum of understanding (MOU) at the Foreign Office on February 16, 2026, triggering an immediate and forceful rebuke from President Donald Trump. This incident reveals a strategic tension that will likely define climate diplomacy throughout Trump's presidency: the emergence of sub-national climate alliances that circumvent federal opposition.

The Current Situation

According to Articles 1-14, the UK and California have formalized their 12th such state-level agreement with a US jurisdiction, joining existing MOUs with Washington, Florida, and others. The partnership aims to boost transatlantic clean energy investment, facilitate California market access for UK businesses, strengthen research collaborations, and share expertise on climate resilience. Trump's response was characteristically blunt and personal, using derogatory nicknames and declaring the partnership "inappropriate" for both parties. His criticism centers on two key arguments: that state governors shouldn't conduct international agreements, and that California's environmental policies represent failure rather than success. Notably, Trump stated that this deal exists "separately from British efforts to find common ground on energy with Mr Trump's administration," acknowledging parallel diplomatic tracks.

Key Trends and Signals

**Paradiplomacy on Climate**: The UK's strategy of engaging US states directly represents a calculated bet on "paradiplomacy"—diplomatic relations conducted by sub-national governments. With 12 state-level MOUs now signed, this isn't opportunistic but systematic. The British government appears to be building a resilient climate partnership infrastructure that can survive federal-level opposition. **Constitutional Ambiguity**: Trump's claim that state-level international agreements are "inappropriate" tests constitutional boundaries. While the US Constitution restricts states from making treaties, MOUs occupy a legal grey zone—they're typically non-binding frameworks for cooperation rather than formal treaties. This ambiguity will likely become a point of contention. **The Newsom Factor**: Trump's personal animosity toward Newsom—a potential Democratic presidential candidate—adds a political dimension beyond climate policy. This personal rivalry suggests Trump may view UK-California cooperation as implicit support for his domestic political opponents.

Predictions: What Happens Next

### 1. The UK Will Double Down on State-Level Climate Partnerships Rather than backing away from the California agreement, the UK government will likely accelerate state-level climate diplomacy. With Labour's Ed Miliband committed to aggressive climate action and the UK seeking post-Brexit international partnerships, abandoning this strategy would signal weakness and undermine years of relationship-building. Expect announcements of additional MOUs with states like New York, Massachusetts, and potentially even traditionally Republican states with strong renewable energy sectors like Texas. ### 2. Trump Administration Will Apply Indirect Pressure Direct interference in state-level MOUs faces constitutional obstacles, but the Trump administration has tools for indirect pressure. Look for potential linkage to UK-US trade negotiations, with climate cooperation becoming a bargaining chip. Trump may also direct federal agencies to scrutinize any California-UK projects receiving federal funding or operating on federal lands. The threat of consequences, even if not immediately implemented, could create a chilling effect. ### 3. Other US States Will Accelerate International Climate Partnerships Trump's criticism may paradoxically encourage other progressive-leaning states to formalize their own international climate agreements. Governors in Washington, New York, Illinois, and Michigan will likely view UK willingness to weather presidential opposition as validation of state-led climate action. This could spark a broader movement of "climate federalism," with states forming a parallel diplomatic architecture on environmental issues. ### 4. California-UK Business Activity Will Increase in the Near Term The publicity surrounding Trump's criticism will likely boost awareness of the partnership among businesses in both jurisdictions. Clean energy companies seeking to demonstrate climate credentials will view UK-California projects as politically symbolic as well as economically viable. Expect announcement of specific joint ventures, particularly in offshore wind technology (where the UK leads) and battery storage (where California has extensive experience) within the next quarter. ### 5. This Becomes a Template for Other Countries European nations, particularly those with strong climate commitments like Germany, France, and the Netherlands, will observe the UK's strategy closely. If the UK successfully maintains state-level partnerships despite federal opposition, expect other countries to formalize similar arrangements with US states. This could fundamentally alter how international climate cooperation functions during periods of climate-skeptic federal leadership.

The Broader Implications

This incident represents more than a diplomatic spat—it's a stress test of whether international climate action can persist through hostile federal administrations via sub-national partnerships. The outcome will influence climate diplomacy for years to come, potentially establishing precedents that outlast any single presidency. The UK's calculation appears clear: California's economy alone would rank as the world's fifth-largest nation, and its environmental regulations often set de facto national standards. A partnership with California, Washington, New York, and other large states might deliver more practical climate progress than negotiations with a reluctant federal government. Trump's criticism, while politically predictable, may prove strategically counterproductive. By elevating the UK-California partnership into a major news story, he's inadvertently highlighted the viability of sub-national climate cooperation, potentially encouraging rather than deterring similar arrangements. The coming months will reveal whether this represents a sustainable model for climate diplomacy in an era of nationalist federal governments, or whether presidential pressure can effectively undermine state-level international cooperation. Early indicators suggest the former—but the pressure has only just begun.