A contentious claim that global warming paused at the turn of the century has been challenged by a new independent analysis, which found that the apparent slowdown was a measurement artifact. The study, led by researchers at the University of California, Berkeley, and the nonprofit Berkeley Earth, validates a controversial 2015 paper by the National Oceanic and Atmospheric Administration (NOAA) that had been a flashpoint in climate debates.
The NOAA research, published in the journal Science, argued that the so-called “global warming hiatus” between 1998 and 2012 never actually occurred. Instead, it said, older ship-based temperature readings ran warmer than modern instruments, creating a false impression of reduced warming. After correcting for this “cold bias,” NOAA estimated ocean temperatures rose 0.12 degrees Celsius (0.22 degrees Fahrenheit) per decade since 2000 — nearly double the earlier estimate of 0.07 degrees Celsius (0.13 degrees Fahrenheit).
Now, a team from UC Berkeley and Berkeley Earth has independently tested those findings, publishing their results in Science Advances. Rather than combining data from multiple instrument types, the researchers analyzed each source separately — satellites, robotic floats, and ocean buoys — to avoid subjective adjustments. Each dataset, taken on its own, aligned with NOAA’s revised warming rates.
“Our results mean that essentially NOAA got it right, that they were not cooking the books,” said lead author Zeke Hausfather, a graduate student in UC Berkeley’s Energy and Resources Group.
Why the Hiatus Debate Matters
The hiatus has been a recurring talking point for climate skeptics, who have used it to argue that global warming has slowed or stopped. Even a hint of flawed data can muddy public understanding and delay policy responses, scientists say. This independent confirmation helps close a perceived gap in the evidence for human-caused climate change.
“In the grand scheme of things, the main implication of our study is on the hiatus, which many people have focused on, claiming that global warming has slowed greatly or even stopped,” Hausfather said. “Based on our analysis, a good portion of that apparent slowdown in warming was due to biases in the ship records.”
The findings carry a sobering implication: the planet’s oceans are absorbing heat at a steady pace, with no reprieve. While the study reinforces the reality of continued warming, it also comes at a time when political and social responses to climate change remain uneven. Meanwhile, efforts to expand clean energy alternatives continue across governments, organizations, and individual initiatives, though the latest data suggests the urgency remains high.
