A controversial climate study by the Potsdam Institute for Climate Impact Research (PIK) is one of the biggest scientific scandals of recent years. Media outlets like “Tagesschau” and “Spiegel” made it headlines in 2024. “Scientifically completely invalid,” economist Richard Rosen declared. However, politicians and the financial world made far-reaching decisions based on the PIK study. The alleged annual economic damage of $38 trillion shaped global debates. (welt: 25.08.25)
Alarmism instead of serious climate studies
The PIK press release promised maximum drama: “Even if CO₂ emissions were to be drastically reduced starting today, the global economy … is already doomed to a 19 percent loss of income by 2050.” These words brought the PIK study worldwide attention. But the science behind the model is crumbling. Experts are discovering serious errors.
The OECD, the World Bank, and the US government adopted the scenarios without review. The Network for Greening the Financial System (NGFS), an association of central banks, also adopted the figures. The European Central Bank even used them for stress tests. Critics warn: policies based on a flawed climate study mean setting the wrong course. Jessica Weinkle sees “NGFS-driven maneuvers” as drivers of deindustrialization.
Natural science doubts climate study – politics at risk
The publication of the PIK study by “Nature” lent its brilliance. But internal documents show that all four reviewers reported serious deficiencies. One expert wrote: “The statistical methodology … [has] no scientific basis whatsoever.” Another emphasized that the forecasts seemed “unintuitively large.”
Roger Pielke Jr. calls it a scandal. Incorrect figures have been known for over a year, yet they continue to shape climate policy and financial decisions. Weinkle criticizes that “Nature” has “turned into a doormat.” This is how science loses credibility.
Criticism ignored, economic damage risked
Just a few weeks after publication, Christof Schötz of the Technical University of Munich presented a detailed critique. He made it clear that the results “do not provide the robust empirical evidence required for climate policy.” Nevertheless, Nature suppressed the analysis for months.
Other researchers from Princeton and the Bank Policy Institute responded. Gregory Hopper describes his unsuccessful attempts to submit comments. Rosen described the PIK study as “completely scientifically invalid.” It has since become clear that while the criticism was suppressed, the NGFS continued to use the data. This resulted in massive economic and political damage.
New methods, same weaknesses
Under pressure, the PIK researchers published a new version. In this “preprint,” they claimed their core findings remained intact. However, they had to swap methods to produce similar results. For Pielke, this is “a tacit admission… that the original analysis is no longer valid.”
Hopper is even more critical of the new version. “The revised climate damage model is even more flawed,” he explains. The statistical problems persist. This demonstrates that science is serving politics here rather than providing objective results.
Dangerous intertwining of research and politics
The PIK study reveals a web of science, politics, and financial institutions. Ben Caldecott of the Oxford Sustainable Finance Group described in the Financial Times how banks influence research: “They have done so by attempting to alter or … prevent research findings before publication in order to protect their products and services.”
Confidence in independent science continues to collapse. A climate study that is methodologically weak nevertheless shapes climate policy and financial decisions. This poses risks and economic damage for companies and citizens. In the end, the PIK researchers admitted: “The authors and PIK welcome and appreciate the feedback … and accept responsibility for the shortcomings.” But this admission comes too late. The consequences for the economy and climate policy have long been a reality.