The Trump administration is eroding vital climate data

AMERICAN SCIENTISTS have historically been leaders in the collection and analysis of data on climate change. The longest-running observations of carbon-dioxide concentrations in the atmosphere, for example, are collected at the Mauna Loa observatory in Hawaii. The National Snow and Ice Data Centre at the University of Colorado, Boulder, for its part, holds unique databases on the annual ebb and flow of sea ice at both poles. America also owns 58% of the roughly 4,000 Argo floats which drift at depth across the world’s oceans, gauging their health before popping up to the surface every ten days or so to broadcast their data home.

These projects, and many more like them, are now under threat. Donald Trump’s administration is decommissioning long-standing databases; deleting key reports and analyses; and firing or reassigning the staff who have unique expertise in making sense of the data. Such actions will make climate modelling harder. But the harm done will be felt not just by the world’s climate scientists. American citizens and businesses will suffer, too.

Good data are an essential part of validating the results of climate models. If a model can accurately simulate what has been observed in the real world, this gives scientists confidence in its projections of the future. Continuous climate data also show how global warming is affecting the world. Information about dead vegetation accumulating in fire-prone regions can be combined with temperature and rainfall numbers to predict a heightened risk of fires. Without it, such events are harder to predict and, therefore, more dangerous.

A number of databases and key reports have already been shut down or deleted. Under America’s Greenhouse Gas Reporting Programme, industries provide data on how much they emit each year; the numbers are published in an annual inventory and submitted to the UN. Last year’s tally was not released, however. The Environmental Protection Agency has proposed eliminating or suspending all reporting requirements for all industries—until 2034 for some, permanently for others. “If finalised as proposed,” the federal pollution regulator writes, “no industries would need to submit reports with 2025 data.”

The National Climate Assessments have also been removed from government servers. Legally mandated to be published every four years, these gather vast amounts of data to paint a granular picture of America’s vulnerabilities in the face of climate change. The information is vital for cities, states and businesses to assess their own risks, plan investments and build resilience. It offers information about the impacts that are causing the most harm, says Rachel Cleetus of the Union of Concerned Scientists, an American non-profit which advocates for science-based policy, including everything from power outages to fires, sea-level rise and heatwaves. The next climate assessment is due in 2027 but the government has terminated the contract with the group that produces it.

Several other national information troves have been discontinued. The Billion-Dollar Weather and Climate Disasters database, for example, which records natural disasters going back to 1980 that have caused at least $1bn in damages, was retired by the National Oceanographic and Atmospheric Administration (NOAA) in 2025. This database not only shows that the costliest climate-related disasters are becoming more frequent and more costly, but also provides hazard maps with future risk projections.

The National Environmental Satellite, Data and Information Service, a branch of NOAA, maintains an online list of dozens of climate data sets and information sites that have been discontinued in the past year—far more than normal. It includes databases documenting marine heatwaves over coral reefs, the properties of cloud cover and more.

“It’s really important to recognise that, first and foremost, this is harmful to people in the United States,” stresses Dr Cleetus. The repercussions will also be felt farther afield. Researchers outside America are wary of how the termination of data collection there will affect their work. The Argo floats, for instance, have built the best evidence there is of how the oceans’ heat content is increasing—an important trend because the oceans have absorbed more than 90% of the extra heat trapped in Earth’s system by greenhouse gases. Rising ocean heat content is the most direct evidence of global warming.

There have been no signs as yet that America will withdraw funding from the project, but international partners and users are increasingly concerned. Officials involved in compiling India’s monsoon forecast have warned that losing the Argo data would significantly affect its accuracy. The loss of the American researchers most experienced in handling these may also prove problematic.

Some steps can be taken to mitigate the damage. Adam Smith, the researcher who previously ran the Billion-Dollar Weather and Climate Disasters project for NOAA, has been hired by Climate Central, a climate non-profit, to run the data set from there. Europe’s Copernicus Climate Change Service has calculated that the loss of American data will have only a small impact on their forecasts. “We are resilient,” says the centre’s director, Carlos Buontempo. But preparing for an uncertain future has become an even harder task. ■