Intergovernmental Panel on Climate Change

Based on Wikipedia: Intergovernmental Panel on Climate Change

In 1988, the Reagan administration faced a dilemma. Climate scientists were growing increasingly alarmed about greenhouse gases, and the United States Environmental Protection Agency was pushing for an international treaty to restrict emissions. But the White House worried that if independent scientists controlled the conversation, the resulting policies might be too aggressive for American industry to stomach.

Their solution was elegant: create a new scientific body, but make it accountable to governments.

This is how the Intergovernmental Panel on Climate Change—the IPCC—came into existence. It would become the most influential scientific organization on the planet regarding climate, quoted by presidents and protesters alike, and would eventually share a Nobel Peace Prize with Al Gore. But its very DNA carries the tension of that founding compromise: rigorous science filtered through political consensus.

What the IPCC Actually Does

Here's what surprises most people: the IPCC doesn't do any original research. Not a single experiment. Not one temperature reading.

Instead, it reads. Everything.

Thousands of scientists volunteer their time to comb through every relevant scientific paper published on climate change—the physics, the economics, the social impacts, the potential solutions. They then distill this ocean of research into comprehensive "Assessment Reports" that tell policymakers what the scientific community actually knows, how confident they are about it, and what might happen next.

Experts have called this the largest peer review process in the scientific community. Think about that for a moment. Every major climate claim you've heard cited in the news, every graph showing rising temperatures or melting ice sheets, every projection about future warming—these have typically passed through this massive sieve of scientific scrutiny before reaching public discourse.

The organization operates on six to seven year assessment cycles. A bureau of elected scientists oversees each cycle, selecting experts through a formal nomination process involving both governments and scientific organizations. These experts then spend years reading, synthesizing, and arguing about what the evidence actually shows.

The Awkward Marriage of Science and Politics

The IPCC occupies peculiar institutional territory. It's simultaneously a scientific body and a governmental organization. Scientists participate as both experts and government representatives. Every report must be endorsed by consensus among its 195 member states.

This creates an interesting dynamic. On one hand, the requirement for government buy-in means that when the IPCC speaks, it carries enormous weight. These aren't just scientists making claims that politicians can dismiss as ivory tower speculation. These are findings that every major government in the world has formally endorsed.

On the other hand, consensus requirements can water down conclusions. The most alarming findings, the ones that might demand the most dramatic policy responses, must survive approval by nations whose economies depend heavily on fossil fuels.

Yet despite this built-in conservatism, IPCC reports have grown steadily more urgent over three decades. The Sixth Assessment Report, released between 2021 and 2023, prompted The Guardian to describe it as the "starkest warning yet" of "major inevitable and irreversible climate changes." Newspapers worldwide echoed this theme.

The Organizational Machinery

Understanding how the IPCC works requires understanding its structure, which is more complex than most people realize.

At the top sits the Panel itself—representatives from all 195 member governments who meet roughly twice a year. They control everything: structure, procedures, work programs, budgets. They're the ones who must ultimately approve each report.

Below that sits the Bureau, currently 34 members from different geographic regions, elected by the Panel. The Bureau provides scientific and technical guidance. Its current chair is Jim Skea, a British energy scientist who took the position in July 2023.

The actual scientific work happens in three Working Groups, each led by two co-chairs—deliberately one from a developed country and one from a developing country:

• Working Group I tackles the physical science. What's actually happening to the climate system? How do we know? How certain are we?
• Working Group II examines impacts and adaptation. What will climate change do to human societies and natural ecosystems? How might we adjust?
• Working Group III focuses on mitigation—the technical term for stopping climate change by limiting greenhouse gas emissions. What would it take to actually solve this problem?

There's also a Task Force on National Greenhouse Gas Inventories, which develops the methodologies countries use to calculate their emissions. This might sound like dry accounting, but it's crucial. You can't manage what you can't measure, and international climate agreements depend on everyone measuring emissions the same way.

The Money Question

The IPCC runs on a surprisingly modest budget. In 2021, it operated on approximately six million euros—less than many medium-sized companies spend on marketing. By 2022, this had grown to just under eight million euros.

This money comes from voluntary contributions by member states. There's no required amount. The biggest donors include the United States, Japan, France, Germany, and Norway. Many developing countries contribute "in kind" by hosting IPCC meetings rather than writing checks.

The World Meteorological Organization covers the operating costs of the IPCC secretariat in Geneva, Switzerland, and sets the financial rules. Given the organization's global influence, the whole operation runs remarkably lean.

Before the IPCC: A Brief Prehistory

The IPCC didn't emerge from nothing. Its predecessor was something called the Advisory Group on Greenhouse Gases, or AGGG, established in 1986 by three organizations: the International Council of Scientific Unions, the United Nations Environment Programme, and the World Meteorological Organization.

The AGGG reviewed scientific research on greenhouse gases and studied how their concentrations were increasing. But climate science was growing more complicated by the year, spanning more disciplines, generating more data. This small group of scientists simply lacked the resources to keep up.

When the United States government pushed for something more structured—but also more politically controlled—the World Meteorological Organization and the United Nations Environment Programme obliged by creating the IPCC.

The United Nations General Assembly formally endorsed the new body in 1988, noting in its resolution that human activity could change the climate in ways that might cause "severe economic and social consequences." The effects on humanity, the resolution warned, "would be disastrous if timely steps were not taken."

That was thirty-seven years ago.

The Assessment Reports: A Timeline of Mounting Alarm

Since 1990, the IPCC has published six comprehensive assessment reports, each building on its predecessor, each reflecting the accumulating evidence.

The First Assessment Report arrived in 1990, with an update in 1992. It established the basic framework: yes, greenhouse gases trap heat; yes, human activities are increasing those gases; yes, this will likely warm the planet.

Each subsequent report, arriving roughly every six years, has added detail, refined projections, and—crucially—increased confidence levels. The progression tells a story. Early reports spoke in tentative terms about what "might" or "could" happen. Recent reports speak with near-certainty about what "will" happen and what is already happening.

The Fifth Assessment Report, completed in 2014, proved particularly influential. It provided much of the scientific foundation for the Paris Agreement in 2015, the landmark international accord where nations committed to limiting global warming.

The Sixth Assessment cycle, running from approximately 2015 to 2023, was the most ambitious in IPCC history. Beyond the main assessment reports from each working group and the synthesis report, it produced three special reports on focused topics.

The 1.5 Degree Report That Changed Everything

Of those special reports, one stands out: the 2018 Special Report on Global Warming of 1.5 Degrees Celsius.

The Paris Agreement had set two temperature targets—limiting warming to "well below" 2 degrees Celsius above pre-industrial levels, with efforts to limit it to 1.5 degrees. But what was the actual difference between those two targets? Was half a degree really that significant?

The IPCC's answer: yes, profoundly so.

The report detailed how that extra half degree would mean substantially more heat waves, more species extinctions, more crop failures, more coral reef death, more Arctic ice loss. It wasn't a matter of "slightly worse." The difference between 1.5 and 2 degrees represented qualitatively different futures for hundreds of millions of people.

The report also delivered a stark timeline: to have a reasonable chance of limiting warming to 1.5 degrees, global carbon dioxide emissions would need to fall by about 45 percent from 2010 levels by 2030, reaching net zero around 2050.

This report landed differently than previous IPCC publications. It sparked something. The youth climate movement, led by figures like Greta Thunberg, exploded into global prominence in the months following its release. "Listen to the scientists" became a protest chant, and "the scientists" increasingly meant the IPCC.

How Reports Get Made

The process of creating an IPCC report is byzantine but deliberate.

It begins with governments and observer organizations nominating experts. The Bureau selects from these nominations, trying to balance geographic representation, gender, and expertise. Selected authors spend years reviewing published scientific literature, debating interpretations, and drafting text.

Those drafts then face multiple rounds of review. Other experts submit comments—hundreds or thousands of them per chapter. Authors must respond to each comment, either incorporating the feedback or explaining why they haven't. These review comments are archived and publicly available on the IPCC website.

Finally, the Summary for Policymakers—the document that actually gets read by world leaders and journalists—must be approved line by line in plenary sessions. Government representatives haggle over wording while the scientists who wrote the underlying report watch and sometimes wince. Every sentence must survive consensus.

This isn't a fast process. A typical assessment cycle runs six to seven years. But the result carries extraordinary authority. When the IPCC says something, it means the global scientific community and the world's governments have agreed to say it together.

The Communication Challenge

For decades, the IPCC struggled with a fundamental problem: its reports were unreadable. Dense, technical, hedged with qualifications, littered with jargon—they were written by scientists for scientists, then handed to policymakers who couldn't parse them.

The organization has worked to address this. For the Fifth Assessment Report, it began making reports available to registered media under embargo before official release, allowing journalists time to actually read and understand the material. It expanded outreach activities.

In February 2016, at the start of the Sixth Assessment cycle, the IPCC held an Expert Meeting on Communication. Old and new Bureau members worked with communications professionals to develop recommendations. Several were adopted: embedding communications expertise in the technical support units, considering how findings would be communicated from the earliest stages of report preparation.

The results showed. Media coverage of the 1.5 degree report in 2018 and the Working Group I contribution to the Sixth Assessment in 2021 dramatically exceeded coverage of earlier reports. The IPCC had finally learned to speak to the public, not just to other scientists.

The Paradox of Authority

The IPCC occupies a strange position in public discourse. It is simultaneously the most authoritative voice on climate science and a frequent target of attack.

Climate skeptics dismiss it as alarmist, pointing to its governmental structure as evidence of political bias toward exaggerating threats. Climate activists sometimes criticize it as too conservative, noting how consensus requirements force the organization to understate risks that more aggressive scientists consider likely.

Both critiques contain kernels of truth, which is perhaps inevitable for an organization designed to bridge science and politics.

What's harder to dispute is the IPCC's influence. Its reports shape the United Nations Framework Convention on Climate Change negotiations that happen every year. They inform national policies. They provide the evidentiary foundation for climate litigation. They set the terms of debate.

When policymakers want to know what climate science says, they ask the IPCC. When journalists need an authoritative source, they cite the IPCC. When corporations calculate climate risks, they reference IPCC scenarios.

The Seventh Cycle Begins

The seventh assessment cycle began in 2023, with Jim Skea at the helm. The new Bureau was elected in July of that year, and work has commenced on what will become the Seventh Assessment Report.

Each cycle builds on what came before. The Seventh Assessment will incorporate new research published since the Sixth Assessment's cutoff dates. It will refine projections, update scenarios, and assess whether mitigation efforts are having any effect.

Meanwhile, the IPCC's model has spawned imitators. The Intergovernmental Platform on Biodiversity and Ecosystem Services, established in 2012, applies similar methods to the biodiversity crisis. In 2025, a new Intergovernmental Science-Policy Panel on Chemicals, Waste and Pollution launched to address those environmental challenges.

The template works: gather the world's experts, make them read everything, force them to agree, make governments sign off. It's slow, it's cumbersome, it frustrates both scientists who want stronger statements and politicians who want fewer constraints. But it produces something rare in a fractured world: a shared foundation of agreed-upon facts.

What the IPCC Cannot Do

For all its influence, the IPCC has important limitations.

It cannot tell governments what to do. Its reports must be "policy relevant but not policy prescriptive." It can say that limiting warming to 1.5 degrees would require certain emissions reductions. It cannot say governments should mandate those reductions.

It cannot conduct original research. If a critical question hasn't been studied, the IPCC can only note the gap and hope someone fills it before the next assessment cycle.

It cannot move quickly. By the time an assessment report is published, its deadline for including new research is already a year or more in the past. The climate system keeps changing while the IPCC deliberates.

And it cannot force anyone to act on its findings. It can only provide information. The decisions remain with governments, with voters, with individuals.

The IPCC's own founding resolution recognized this tension. It warned of disastrous effects "if timely steps were not taken." Whether steps have been timely enough remains, more than three decades later, an open question that the IPCC itself is not empowered to answer.

It can only keep reading, keep synthesizing, keep reporting. What the world does with that information is beyond its mandate.