IPCC Climate Change Reports – Findings, Purpose, Report History

The IPCC has been sounding the alarm on climate change for decades, putting out regular, comprehensive assessments that summarize the most current research on our warming planet. Periodically, it also issues special reports on topics like land use, the ocean and cryosphere (frozen portions of the earth), and the consequences of 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming.

The IPCC’s warnings began in 1990 with its First Assessment Report, which successfully predicted the pace of global warming, even without the highly complex computer models of today. The Second Assessment, published in 1995, expressed greater certainty that climate change was largely caused by human activities. In 2001, the Third Assessment warned that the temperature increases would become worse than previously feared if we didn’t reduce our carbon emissions. Meanwhile, the world ramped up fossil fuel production and consumption.

By the time of its Fourth Assessment, in 2007, the IPCC was using words like unequivocal to describe the consensus that humans were the main cause of warming. In 2014, the Fifth Assessment dealt the world a hard truth: Greenhouse gas emissions were higher than ever, causing an unprecedented acceleration of climate change’s impacts.

And in the Sixth Assessment—which was released in three main parts, beginning in 2021, and concluded with a final synthesis report in 2023—the panel warned that the world is reducing climate pollution far too slowly, risking severe damages, costs, and upheaval. Even if we sharply reduced emissions today, it concluded that decades’ more warming should be expected. Adaptation is essential, particularly for the world’s most vulnerable populations.

These report releases often coincide with and help shape critical moments of international climate collaboration. The First Assessment Report supported the creation of the UNFCCC, which has become a foundation for coordinated political action. The Second Assessment provided key input to the 1997 Kyoto Protocol, a historic agreement that put binding emissions targets on developed countries for the first time. The Fifth Assessment informed 2015’s Paris Agreement, the landmark global accord that has since been adopted by every nation to address climate change. And the urgent message—“the survival guide for humanity”—in the Sixth Assessment synthesis report should inform the decisions made by the world leaders and climate experts who will gather at the next Conference of the Parties to the UNFCCC, COP28, scheduled for December 2023 in Dubai. 

Yet despite three decades of warnings by the IPCC—and sporadic displays of global coordination—leaders have done far too little, far too slowly to stop further warming. The concentration of carbon dioxide in the atmosphere is now the highest ever recorded when looking back two million years. As the IPCC’s latest report shows, the need for deep and immediate action is clearer than ever. Every ton of emissions reduction matters. Every investment in building resilience matters.