Paris Agreement

When the COVID-19 pandemic swept across the world, it exposed how vulnerable human civilization is to global-scale crises. But even as the pandemic dominated headlines, scientists warned of a far greater long-term threat: climate change. Unlike a pandemic, which can be addressed with vaccines and public health measures, climate change is a slow-burning catastrophe that accumulates over decades and centuries. Rising sea levels, devastating wildfires, extreme weather events, and food insecurity are no longer distant predictions—they are present-day realities.

The international community has been grappling with the climate crisis for over four and a half decades. Countless scientific reports, diplomatic summits, and political debates have shaped the global response. Yet for most of that time, no single agreement managed to unite the world behind a binding, universal commitment to reduce greenhouse gas emissions. That changed on December 12, 2015, when delegates at the 21st Conference of the Parties (COP-21) in Paris, France, reached a historic consensus.

The Paris Agreement was adopted by nearly 196 countries, making it the most broadly endorsed international climate treaty in history. It entered into force on November 4, 2016, after the threshold of 55 countries representing at least 55% of global greenhouse gas emissions had ratified it. The speed of ratification was unprecedented for an international environmental agreement, reflecting both the urgency of the crisis and the depth of global commitment.

But what exactly does the Paris Agreement seek to achieve? How did it come about? And why has its implementation been anything but smooth? To answer these questions, we need to trace the long arc of international climate diplomacy, understand the agreement's mechanisms, and examine the political forces that have both advanced and undermined it.

The Paris Agreement did not emerge in a vacuum. It was the product of decades of scientific research, political negotiation, and hard-won diplomatic compromise. Understanding its significance requires a look at the major milestones that paved the way.

The UNFCCC and the Rio Earth Summit (1992)

The modern era of international climate policy began with the United Nations Framework Convention on Climate Change (UNFCCC), which was established at the 1992 Earth Summit in Rio de Janeiro, Brazil. The UNFCCC acknowledged that climate change was a serious concern and set the stage for future negotiations. It established the principle of "common but differentiated responsibilities," recognizing that while all nations share the obligation to address climate change, developed countries bear a greater historical responsibility for greenhouse gas emissions. The convention entered into force in 1994 and has since served as the institutional backbone for all subsequent climate agreements.

The Kyoto Protocol (1997)

The first major step toward legally binding emission reductions came with the Kyoto Protocol, adopted in 1997 in Kyoto, Japan. This was a landmark achievement: it established, for the first time, binding emission reduction targets for developed nations. Under the protocol, 37 industrialized countries and the European Community committed to reducing their emissions by an average of 5% below 1990 levels during the first commitment period (2008–2012). However, the Kyoto Protocol had significant limitations. The United States, then the world's largest emitter, never ratified it. And developing nations, including rapidly industrializing countries like China and India, were exempt from binding targets. These gaps meant the protocol, while historically important, could not deliver the scale of emission reductions the planet needed.

COP-15 Copenhagen (2009)

The 2009 United Nations Climate Change Conference in Copenhagen, Denmark (COP-15), was widely anticipated as the moment the world would agree on a successor to the Kyoto Protocol. Expectations were enormous. But the summit ultimately failed to produce a legally binding agreement. Deep divisions between developed and developing countries, disagreements over financing, and political friction between major emitters prevented a consensus. The Copenhagen Accord, drafted by a small group of nations including the United States and China, was merely "taken note of" rather than formally adopted. The failure at Copenhagen was a sobering reminder of how difficult multilateral climate negotiations could be.

COP-16 Cancun (2010)

After the disappointment of Copenhagen, the international community regrouped at COP-16 in Cancun, Mexico, in 2010. While Cancun did not produce a binding treaty, it achieved several important outcomes. Most notably, it established the Green Climate Fund (GCF), a financial mechanism designed to help developing countries reduce emissions and adapt to the effects of climate change. The Cancun Agreements also formally anchored the goal of limiting global temperature rise to 2°C above pre-industrial levels and established frameworks for technology transfer and capacity building in developing nations.

COP-21 Paris (2015)

By the time delegates gathered in Paris in late 2015, the political landscape had shifted considerably. Years of scientific reports—most notably from the Intergovernmental Panel on Climate Change (IPCC)—had made the case for urgent action increasingly undeniable. Public awareness and activism had grown. And critically, the United States and China, the world's two largest emitters, had signaled their willingness to participate in a new agreement, although both were initially hesitant about certain provisions.

On December 12, 2015, the Paris Agreement was adopted by consensus. The agreement was formally signed on April 22, 2016—Earth Day—at a ceremony at United Nations headquarters in New York, where 175 countries signed it on the first day alone, setting a record for an international agreement. The Paris Agreement was fundamentally different from its predecessors. Rather than imposing top-down targets on select countries, it invited every nation to define its own commitments through Nationally Determined Contributions (NDCs), creating a bottom-up framework with universal participation.

The Paris Agreement is built around several interconnected goals and objectives. Together, they represent a comprehensive vision for how the world can confront the climate crisis.

Temperature Targets

The agreement's most well-known goal is to limit the increase in global average temperature to well below 2°C above pre-industrial levels, while pursuing efforts to cap warming at 1.5°C. The 1.5°C target was included largely at the insistence of small island developing states and other vulnerable nations, for whom even 2°C of warming would be catastrophic. According to the IPCC's Special Report on Global Warming of 1.5°C (2018), limiting warming to 1.5°C rather than 2°C could reduce the number of people exposed to climate-related risks and poverty by several hundred million by 2050.

Nationally Determined Contributions (NDCs)

Rather than imposing uniform targets, the Paris Agreement relies on Nationally Determined Contributions. Each country submits its own plan for reducing emissions and adapting to climate change, reflecting its unique circumstances, capabilities, and development priorities. NDCs are not legally binding in terms of their specific targets, but the process of submitting and updating them is a legal obligation under the agreement. This flexible approach was key to achieving universal participation, as it allowed both developed and developing nations to engage on their own terms.

Climate Finance

The agreement recognizes that developing countries need financial support to transition to clean energy and adapt to the impacts of climate change. Developed nations committed to mobilizing $100 billion per year in climate finance by 2020, a target that was carried forward from earlier commitments. This funding flows through various channels, including the Green Climate Fund, multilateral development banks, and bilateral arrangements. While the $100 billion goal has been a source of contention—many argue it is insufficient and that delivery has fallen short—it remains a cornerstone of the agreement's framework for equity and shared responsibility.

Net-Zero Emissions

The Paris Agreement calls for achieving a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of the 21st century. In practical terms, this means reaching global net-zero emissions—a state where any remaining greenhouse gas emissions are fully offset by carbon removal through forests, oceans, technology, and other sinks. This long-term goal sends a powerful signal to governments, businesses, and investors that the global economy must ultimately decarbonize.

The Paris Agreement introduced several innovative mechanisms to drive global climate action. These mechanisms work together to create a system of continuous improvement and accountability.

NDC Submission and Updates

Each party to the agreement is required to prepare, communicate, and maintain successive NDCs. Countries must submit updated NDCs every five years, with each new submission expected to represent a progression beyond the previous one. This cycle ensures that ambition increases over time as technology, financing, and political will evolve. As of now, most countries have submitted their second or third round of NDCs.

The Global Stocktake

Every five years, a comprehensive Global Stocktake assesses collective progress toward the agreement's goals. The first Global Stocktake was completed at COP-28 in Dubai in 2023. This process evaluates not only emission reductions but also progress on adaptation, climate finance, and technology transfer. The results of the stocktake inform the next round of NDCs, creating a feedback loop designed to ratchet up ambition over time. The stocktake does not single out individual countries but provides an aggregate picture of where the world stands.

Climate Finance for Developing Nations

The financial architecture of the Paris Agreement is designed to channel resources from developed to developing countries. This includes mitigation finance (supporting the transition to renewable energy and low-carbon technologies), adaptation finance (helping communities prepare for and respond to climate impacts), and loss and damage finance (addressing the irreversible impacts of climate change). The Green Climate Fund, established at COP-16, serves as a primary vehicle for this financial support. Negotiations around a New Collective Quantified Goal (NCQG) for climate finance beyond 2025 are ongoing, with developing countries pushing for significantly higher commitments.

Transparency Framework

A robust transparency framework is essential to the agreement's credibility. Under the Enhanced Transparency Framework (ETF), all parties are required to report regularly on their emissions, progress toward NDCs, and the support they provide or receive. This system of monitoring, reporting, and verification helps build trust among nations and allows the international community to assess whether collective efforts are on track. The framework is designed to be flexible, recognizing the differing capacities of developed and developing countries, while still maintaining a high standard of accountability.

The Ratchet Mechanism

Perhaps the most important design feature of the Paris Agreement is its ratchet mechanism—the requirement that each successive NDC must be more ambitious than the last. This "progression" principle, combined with the five-year update cycle and the Global Stocktake, creates a built-in system for escalating climate action. While the agreement does not include enforcement mechanisms or penalties for falling short, the ratchet mechanism relies on peer pressure, public accountability, and the evolving economics of clean energy to drive increasingly ambitious commitments.

No country's relationship with the Paris Agreement has been more consequential—or more turbulent—than that of the United States. As the world's second-largest greenhouse gas emitter, responsible for approximately 15% of global emissions, America's participation (or absence) carries enormous symbolic and practical weight.

Obama and the Signing of the Agreement

President Barack Obama was a driving force behind the Paris Agreement. His administration worked closely with China—in a landmark bilateral announcement in November 2014—to build the political momentum needed for a successful outcome at COP-21. Obama signed the agreement in 2015, and the United States formally joined it in September 2016. Under the Obama administration, the US committed to reducing its greenhouse gas emissions by 26–28% below 2005 levels by 2025. The agreement was structured as an executive agreement rather than a treaty, meaning it did not require Senate ratification—a deliberate choice given the political difficulty of securing a two-thirds vote in the Senate.

Trump's Withdrawal

President Donald Trump campaigned on a promise to withdraw the United States from the Paris Agreement, calling it "unfair" to American workers and businesses. On June 1, 2017, he announced that the US would begin the formal withdrawal process. Under the agreement's rules, a country cannot withdraw until three years after it has joined, and the withdrawal takes effect one year after notification. As a result, the US withdrawal did not become effective until November 4, 2020—the day after the US presidential election. The withdrawal made the United States the only country in the world to leave the Paris Agreement, drawing widespread international criticism and raising questions about American climate leadership.

Biden's Return to the Agreement

On his first day in office, January 20, 2021, President Joe Biden signed an executive order to rejoin the Paris Agreement, and the US officially re-entered it on February 19, 2021. The Biden administration set a new, more ambitious NDC, pledging to reduce US greenhouse gas emissions by 50–52% below 2005 levels by 2030. This commitment was backed by significant legislative action, including the Inflation Reduction Act of 2022, which represented the largest climate investment in American history. Biden's return signaled to the world that American climate policy, while subject to political swings, could still aspire to global leadership.

The Paris Agreement stands as one of the most significant diplomatic achievements of the 21st century. Born from decades of scientific research, political negotiation, and the growing urgency of the climate crisis, it represents a global consensus that the world must act—decisively and collectively—to avert catastrophic warming. Its framework of Nationally Determined Contributions, the Global Stocktake, the ratchet mechanism, and climate finance provisions are designed to drive continuous, escalating action.

Yet the agreement is far from a finished story. The gap between current NDC pledges and what is needed to meet the 1.5°C target remains significant. Climate finance commitments have not always been met. Political shifts—as demonstrated by America's withdrawal and re-entry—can disrupt momentum. And the effects of climate change continue to intensify, demanding ever more ambitious responses.

Ultimately, the Paris Agreement is not a solution in itself—it is a framework for solutions. Its success depends not only on the commitments made by governments but on the actions taken by businesses, communities, and individuals around the world. The agreement has created the architecture for global climate action. Now, the work of building a sustainable future within that architecture must continue with renewed urgency and determination.