In a move that has sent shockwaves through the global scientific community, the Trump administration has abruptly terminated U.S. involvement in pivotal United Nations climate change assessments, most notably the Intergovernmental Panel on Climate Change (IPCC) (1, 2). This decision prevents federal scientists from contributing to the IPCC’s upcoming seventh global climate assessment, scheduled for 2029.
Domestic Impact on the Scientific Community
Within the United States, the policy shift has led to a climate of uncertainty among federal scientists. Reports indicate that federal employees are increasingly cautious, engaging in a form of self-censorship, avoiding discussions on topics like climate change due to fear of repercussions (3). NOAA scientists are even refusing to link climate change to weather disturbances (4).
Reactions from the Global Community
The decision has prompted responses from various stakeholders. European Union and United Kingdom officials have expressed concerns that the U.S. withdrawal could delay the next global climate assessment, emphasizing the importance of timely contributions to inform the 2028 Paris Agreement “stocktake” (5). Climate-Vulnerable Nations, particularly developing countries most affected by climate change, warn that politicizing science undermines global efforts to address environmental challenges.
Critical Resources
The U.S. National Government has critical resources utilized by the report. These included the NOAA Geophysical Fluid Dynamics Laboratory GFDL CM6 Model, which contributed five key climate models (CM4, ESM4, ESM2M, OM4, and AM4) to the IPCC Sixth Assessment Report (AR6) through the Coupled Model Intercomparison Project Phase 6 (CMIP6) framework.
The NASA Goddard Institute for Space Studies (GISS-E2.2), a cornerstone of AR6's temperature projections, contributed multiple configurations of its climate model to the Coupled Model Intercomparison Project Phase 6 (CMIP6), which underpins the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6). Among these, the GISS-E2.1 and GISS-E2.2 models were significant. The GISS-E2.1 model, for instance, demonstrated notable improvements in simulating modern climatology compared to its predecessors, particularly in the Southern Ocean regions (6).
This does not include the myriad of satelites, gauges and data sets utlized, and there is no indications of how each of these might be effected by the ban. There is also argument that continued retreat from global science endevors along with funding cuts are hampering American competitiveness (7)
Climatic and Environmental Implications
The Trump administration’s decision to withdraw U.S. participation from the Intergovernmental Panel on Climate Change (IPCC) comes at a time when the planet is experiencing unprecedented climatic upheaval. In 2024, global temperatures surpassed the critical threshold of 1.5°C above pre-industrial levels for the first time (yoy), marking it as the hottest year on record. This alarming rise has been linked to a surge in climate-related disasters worldwide (7).
The human toll of these climatic shifts is profound. In 2024, the United States faced 27 distinct weather and climate disasters, each causing damages exceeding $1 billion. Collectively, these events resulted in approximately $182.7 billion in losses and claimed at least 568 lives (8).
The acceleration of glacier melt is another stark indicator of climate change’s impact. Since the year 2000, over 7 trillion tons of ice have been lost globally, contributing nearly 2 centimeters to sea-level rise. This rapid melting threatens coastal communities with increased flooding and erosion (9).
Recent discoveries have unveiled significant methane emissions in Antarctica, intensifying concerns about the stability of methane hydrates and their potential impact on global warming. A team of Spanish scientists, led by geologists Ricardo León and Roger Urgeles, reported observing massive methane columns up to 700 meters tall and 70 meters wide emerging from the Antarctic seabed. These findings suggest that warming ocean temperatures and geological processes may be destabilizing methane hydrates—ice-like structures trapping methane beneath the seafloor. The release of this potent greenhouse gas could accelerate climate change, underscoring the urgent need for comprehensive research and monitoring in the region (10).
The withdrawal of U.S. scientists from the IPCC process not only diminishes the quality of global climate assessments but also undermines efforts to address these escalating crises. As climate change intensifies, the absence of U.S. expertise in international discussions hampers the development of effective, coordinated strategies to mitigate its impacts.
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