A group of climate scientists have found that the ‘pause’ in global warming is real, and have challenged National Oceanic and Atmospheric Administration’s (NOAA) conclusion that global warming has not slowed down in the 2000’s.

John Fyfe, study lead author and a climate scientist at Environment and Climate Change, Canada said that the slowdown has taken place and it is shown in the updated data sheet. When the NOAA study was released last summer, Gerald Meehl, a climate scientist at NOAA said that there was no slowdown in global warming. The NOAA study, lead by Tom Karl, director of NOAA’s National Centers for Environmental Information, have compared the warming during the past 15 years with the temperature trends between 1950 and 1998.

“As scientists, we must go where evidence takes us, we can’t allow our worries about climate contrarians and how they might seek to misrepresent our work to dictate what we do and do not publish,” said study co-author Michael Mann.

Rather than Karl’s comparison of temperature data over 10- and 15-year stretches, scientists are studying the rise and fall in global temperatures with the natural fluctuations in the climate system. Fyfe said that decadal variability played out recently, when warming slowed to 0.11 degrees Celsius per decade between 2001 and 2010, and the rate was 0.17 degrees C per decade, 15 years prior. Fyfe and his team believe that the Pacific Decadal Oscillation (PDO), a natural variance in the climate system that switches between positive, negative and neutral phases, explained the recent slowdown. Global warming slows and Pacific cools, when PDO is on the negative side.

Fyfe added that PDO was neutral between 1971 and 2000. Another possibility of the slowdown is that the world might not be as sensitive to greenhouse gases as measured by the models. The models might not be perfect or are overly sensitive, said Fyfe. The study has been published in the journal Nature Climate Change.