What If The Paris Agreement Was Never Abandoned?

The Actual History

On December 12, 2015, at the United Nations Climate Change Conference (COP21) held in Paris, 196 parties adopted the Paris Agreement—a legally binding international treaty on climate change. The agreement represented a landmark in global climate efforts, establishing the goal of limiting global warming to "well below 2 degrees Celsius above pre-industrial levels" while pursuing efforts to limit the temperature increase to 1.5 degrees Celsius. Unlike its predecessor, the Kyoto Protocol, the Paris Agreement required all countries—not just developed nations—to submit their plans for climate action through "nationally determined contributions" (NDCs).

The United States, under President Barack Obama's administration, played a pivotal role in negotiating the agreement. On April 22, 2016, Secretary of State John Kerry signed the Paris Agreement on behalf of the United States, and President Obama formally ratified it on September 3, 2016. The agreement officially entered into force on November 4, 2016, just days before the U.S. presidential election.

The political landscape shifted dramatically when Donald Trump won the 2016 U.S. presidential election. During his campaign, Trump had expressed skepticism about climate change and criticized the Paris Agreement as an economic burden on the United States. On June 1, 2017, President Trump announced his intention to withdraw the United States from the Paris Agreement, claiming it disadvantaged American workers and taxpayers. He stated: "I was elected to represent the citizens of Pittsburgh, not Paris."

Due to the agreement's withdrawal provisions, the U.S. could not immediately exit. The formal notification of withdrawal was submitted on November 4, 2019, and the U.S. officially left the agreement on November 4, 2020—one day after the 2020 presidential election. This made the United States the only signatory nation to withdraw from the accord.

The withdrawal was short-lived. After winning the 2020 election, President Joe Biden signed an executive order to rejoin the Paris Agreement on his first day in office, January 20, 2021. The U.S. officially became a party to the agreement again on February 19, 2021.

This three-year absence had significant repercussions. During this period, the U.S. federal government rolled back numerous climate policies, including the Clean Power Plan, vehicle emission standards, and methane leak regulations. Federal agencies were directed to avoid mentioning climate change in their communications, and climate science was marginalized in policy decisions.

Internationally, the U.S. withdrawal created a leadership vacuum in global climate efforts. While countries like China and the European Union stepped up their rhetorical commitment to climate action, the absence of the world's second-largest emitter weakened global momentum. The withdrawal also damaged U.S. diplomatic credibility, as other nations questioned whether American commitments would survive changes in administration.

By the time the U.S. rejoined in 2021, precious time had been lost in the critical decade when emissions reductions were most urgently needed. The Biden administration faced the challenge of rebuilding trust with international partners while implementing ambitious domestic climate policies to make up for lost time.

The Point of Divergence

What if the United States had never abandoned the Paris Agreement? In this alternate timeline, we explore a scenario where the U.S. maintained its commitment to global climate action despite the change in administration in 2017.

Several plausible mechanisms could have led to this divergence:

First, President Trump might have moderated his position on the Paris Agreement after taking office. While Trump campaigned on withdrawing from the agreement, actual governance often differs from campaign rhetoric. Upon receiving briefings from national security, diplomatic, and economic advisors about the potential consequences of withdrawal, Trump might have reconsidered. He could have chosen to remain in the agreement while reinterpreting America's commitments to align with his "America First" agenda—perhaps announcing a revised, less ambitious nationally determined contribution rather than a full withdrawal.

Alternatively, key advisors might have wielded more influence. In our timeline, figures like Rex Tillerson (then Secretary of State and former ExxonMobil CEO) and Ivanka Trump reportedly advocated for remaining in the agreement. In this alternate timeline, they could have been more persuasive, perhaps framing continued participation as a way to ensure American interests were represented at the negotiating table while emphasizing the voluntary nature of the commitments.

A third possibility involves the business community. Major corporations including Apple, Google, Microsoft, and even energy companies like ExxonMobil and ConocoPhillips publicly urged Trump to remain in the agreement. In this alternate timeline, their lobbying efforts might have been more coordinated and effective, convincing the administration that withdrawal would disadvantage American businesses in the growing global clean energy market.

Finally, political calculations might have differed. If polling had more clearly indicated that withdrawal would be unpopular with moderate voters in swing states, political advisors might have cautioned against it. Trump might have seen maintaining the agreement—while reshaping America's approach to implementation—as a way to appear moderate on environmental issues while still pursuing deregulation domestically.

Whatever the specific mechanism, in this alternate timeline, President Trump announces in June 2017 that while his administration will approach the Paris Agreement differently than his predecessor's, the United States will remain a signatory, maintaining a seat at the international climate diplomacy table throughout his presidency.

Immediate Aftermath

Domestic Political Reactions

The decision to remain in the Paris Agreement would have created immediate political ripples throughout the American landscape. The Trump base, which had expected withdrawal based on campaign promises, would have expressed disappointment and confusion. Right-wing media outlets like Fox News would likely have criticized the decision, framing it as capitulation to globalist interests. To counter this narrative, the Trump administration would have emphasized how they were "renegotiating" America's role while remaining at the table.

Congressional Republicans would have been divided. Climate-skeptical hardliners like Senator James Inhofe would have expressed disappointment, while moderates like Senator Susan Collins would have quietly approved. Democrats, caught off-guard by the decision, would have cautiously welcomed the move while remaining skeptical about implementation.

To appease his base, Trump would likely have coupled the announcement with executive orders rolling back domestic climate regulations like the Clean Power Plan—arguing that the U.S. would meet its climate commitments through innovation and private sector leadership rather than regulation. This "having it both ways" approach would characterize the administration's climate positioning.

International Response and Diplomacy

The international community would have expressed surprised relief. European leaders like French President Emmanuel Macron and German Chancellor Angela Merkel would have welcomed the decision while remaining cautious about America's new approach. The decision would have preserved diplomatic channels on climate cooperation that, in our timeline, were severely damaged.

At international climate meetings in 2017 and 2018, U.S. representatives would have taken a markedly different approach than under Obama, emphasizing fossil fuel efficiency, nuclear power, and market mechanisms while downplaying regulatory approaches. This would have created tension but maintained dialogue that was lost in our timeline.

The U.S. position would have evolved into what diplomats might call "constructive obstruction"—technically participating while working to slow ambitious measures and emphasizing national sovereignty over collective action. America would have remained the difficult but essential partner rather than becoming the outsider.

Business and Economic Impacts

The business community's response would have been notably positive. Major corporations had publicly advocated for remaining in the agreement, and the decision would have provided policy certainty that was absent in our timeline. Stock prices for renewable energy companies would have seen less volatility, and international businesses would have faced fewer complications in their climate planning.

The fossil fuel industry would have had mixed reactions. While some traditional oil and gas companies had supported staying in the agreement (recognizing the inevitability of transition and wanting influence over its pace), coal companies would have been disappointed. The administration would have worked to reassure coal country that their interests would be protected through domestic policy even while participating internationally.

Clean energy investment, which stalled in some sectors during our timeline's withdrawal period, would have maintained steadier growth. The investment community would have continued integrating climate considerations into their long-term planning with greater confidence, accelerating the flow of capital toward low-carbon technologies.

State and Local Government Actions

One of the most significant differences from our timeline would involve state and local climate initiatives. In our history, the "We Are Still In" coalition formed in direct response to the federal withdrawal, uniting states, cities, businesses, universities, and other organizations committed to meeting Paris Agreement goals despite federal abdication.

In this alternate timeline, without the catalyst of federal withdrawal, state-level climate action would have taken a different form. Rather than positioning themselves in opposition to federal policy, states like California, New York, and Washington would have worked to complement and extend federal efforts while maintaining their own ambitious programs.

The absence of the stark federal-state divide on climate policy would have reduced some legal battles. California's authority to set vehicle emission standards, for example, might not have been challenged as aggressively by the federal government, leading to more regulatory certainty for automakers and accelerating the electric vehicle transition.

Long-term Impact

Altered Political Dynamics (2018-2020)

By remaining in the Paris Agreement while pursuing domestic deregulation, the Trump administration would have created a more complex political narrative around climate change. Climate would have been less of a binary partisan issue, with positions existing along a spectrum rather than in stark opposition. The 2018 midterm elections might have seen slightly different messaging, with Republican candidates in moderate districts able to claim a more balanced position on climate issues while maintaining opposition to regulatory approaches.

The Democratic primary campaigns for the 2020 presidential election would have developed differently. Without federal withdrawal as a clear point of opposition, Democratic candidates would have needed to differentiate themselves through the ambition of their climate proposals rather than simply promising to rejoin the agreement. This might have pushed candidates toward even more detailed climate plans, with greater emphasis on implementation rather than reversing Trump's actions.

The 2020 general election would have featured more nuanced climate debate. Rather than Biden promising to rejoin the agreement (a clear, simple position), the candidates would have debated how to implement America's commitments—with Trump defending his market-oriented, nationally-determined approach and Biden advocating for more ambitious targets and regulatory measures.

International Climate Diplomacy Evolution

The continued presence of the United States in international climate negotiations would have maintained different power dynamics in global climate diplomacy. Without the vacuum created by U.S. withdrawal, China's attempt to position itself as the global climate leader would have faced greater competition. The EU-China climate alliance that developed during America's absence would have taken a different form, perhaps creating a more balanced trilateral dynamic between the U.S., EU, and China.

The COP25 climate conference in Madrid (2019), widely considered disappointing in our timeline, might have produced more substantive outcomes with continued U.S. engagement. While the Trump administration would have advocated for less ambitious measures, their presence would have maintained pressure on other major emitters like India and Brazil to engage constructively.

Most significantly, the global stocktake of climate progress scheduled for 2023 would have occurred with five continuous years of U.S. participation rather than the disjointed engagement of our timeline. This continuity would have enabled more coherent evaluation of progress and recalibration of targets.

Energy Transition Acceleration

The most profound long-term differences would manifest in the pace and nature of the global energy transition. With the U.S. maintaining its participation in the Paris framework, several key developments would have emerged:

Investment Patterns and Market Signals

Without the policy uncertainty created by U.S. withdrawal, investment in clean energy would have followed a steadier upward trajectory. The "green recovery" from the COVID-19 pandemic would have built upon existing momentum rather than attempting to restart it. By 2023, global investment in clean energy technologies would have reached higher levels than in our timeline, where it finally hit $1.7 trillion according to the International Energy Agency.

Financial markets would have incorporated climate risk more rapidly and thoroughly into their assessments. The development of green bonds, sustainability-linked loans, and climate risk disclosure frameworks would have accelerated, creating stronger market signals for decarbonization across all sectors.

Technological Development and Deployment

The continuous U.S. participation would have particularly accelerated development in areas where American innovation excels. Advanced nuclear designs, carbon capture technologies, and green hydrogen would have received more consistent support and clearer market signals. The bipartisan Infrastructure Investment and Jobs Act of 2021 might have included even stronger climate provisions, building on existing programs rather than reestablishing them.

Electric vehicle adoption would have followed a smoother curve. Without the uncertainty created by the Trump administration's attempts to revoke California's emissions authority, automakers would have made earlier, firmer commitments to electrification. By 2025, the percentage of electric vehicles in new car sales would be noticeably higher than in our timeline.

Fossil Fuel Industry Transformation

Major oil and gas companies would have accelerated their diversification strategies. Rather than the stop-start approach many adopted—retreating from renewables during the withdrawal period before recommitting after U.S. reentry—they would have maintained more consistent investment in low-carbon technologies. By 2025, European majors like BP and Shell would be further along in their transition to becoming integrated energy companies, while American counterparts like ExxonMobil and Chevron would have begun more substantial diversification.

The coal industry's decline would have continued along similar lines to our timeline, but with less political polarization around its fate. Federal programs for supporting transition in coal communities might have developed earlier and with more bipartisan support, potentially creating better outcomes for regions dependent on coal mining.

Global Geopolitical Implications

By 2025, the geopolitical landscape around climate and energy would look substantially different from our timeline:

Reduced Climate Skepticism

Without the amplification effect of America's withdrawal, climate skepticism would have continued its decline globally. Countries like Brazil and Australia, which moderated their climate ambitions following the U.S. withdrawal, would have maintained more consistent approaches. The international norm of climate action would have strengthened more continuously, making it harder for national leaders to dismiss climate concerns.

Energy Security Realignment

The Russia-Ukraine conflict in 2022 created a global energy crisis that dramatically accelerated Europe's transition away from Russian fossil fuels. In this alternate timeline, with stronger pre-existing momentum behind clean energy, European countries would have been slightly less dependent on Russian gas when the conflict erupted. The response would have emphasized clean energy solutions even more strongly, with greater international coordination through existing climate diplomacy channels.

Developing Nation Transitions

Perhaps most significantly, developing nations' climate trajectories would differ. In our timeline, the U.S. withdrawal complicated climate finance and technology transfer—key components of supporting developing nations' low-carbon development. With continuous U.S. engagement, countries like India, Indonesia, and Nigeria would have received more consistent support for their energy transitions, potentially enabling them to peak their emissions earlier.

The Green Climate Fund, intended to provide $100 billion annually to support climate action in developing countries, would have maintained stronger U.S. backing. While the Trump administration would likely have reduced financial contributions compared to Obama-era pledges, complete abandonment would have been avoided, maintaining institutional momentum that was lost in our timeline.

Expert Opinions

Dr. Jonathan Pershing, former Lead U.S. Negotiator for the Paris Agreement and Senior Fellow at the World Resources Institute, offers this perspective: "The three-year absence of the United States from the Paris Agreement created a trust deficit that continues to complicate international climate diplomacy. In an alternate timeline where the U.S. maintained continuous participation, we would likely see two major differences today: First, other countries would have greater confidence in America's long-term commitment to climate action, enabling more ambitious collective targets. Second, the technical work of designing implementation mechanisms—carbon markets, transparency frameworks, and financial instruments—would be significantly more advanced. While the Trump administration would certainly have advocated for different approaches than the Obama or Biden administrations, their continued presence at the negotiating table would have preserved institutional knowledge and diplomatic relationships that took years to rebuild."

Professor Leah Stokes, political scientist at the University of California, Santa Barbara specializing in energy and climate policy, suggests: "Continuous U.S. participation in the Paris Agreement would have fundamentally altered the domestic politics of climate change. Without the clear break of withdrawal, climate policy might have evolved more as an issue of 'how' rather than 'whether.' This could have reduced political polarization around climate science itself, potentially creating space for bipartisan approaches to clean energy and climate resilience. The Infrastructure Investment and Jobs Act of 2021—which passed with significant Republican support and included substantial climate provisions—offers a glimpse of what might have been possible under a less binary political framing. That said, I'm skeptical that the Trump administration would have implemented policies aligned with Paris goals; more likely, they would have remained in the agreement while pursuing domestic policies that undermined its objectives."

Zhang Wei, Director of Climate Policy at Beijing's Global Environmental Institute, provides an international perspective: "Had the United States remained in the Paris Agreement during the Trump years, China's approach to climate diplomacy would have developed quite differently. Without America's absence creating a leadership vacuum, China might have been less assertive in positioning itself as the responsible global actor on climate issues. The EU-China climate partnership that blossomed during the U.S. withdrawal period would have been more balanced, potentially creating a trilateral dynamic that could have accelerated global progress. Most importantly, continuous U.S. participation would have maintained pressure on China to implement its commitments to peak emissions—pressure that temporarily diminished during the American absence. By 2025, this might have translated to more concrete policies limiting coal expansion in China, as international accountability mechanisms would have remained stronger."