A group of prominent climate scientists has challenged the National Oceanic and Atmospheric Administration (NOAA)’s conclusion that global warming has not slowed in the 2000s. Global warming hiatus has been discussed in the past as well. The new study talks about Global Warming Hiatus
Study’s lead author John Fyfe, a climate scientist at Environment and Climate Change Canada, said that the conclusion made by the NOAA is not correct. The slowdown has taken place and can be seen in the newly updated data set.
The disagreement highlights the biggest climate difference of the past decades. Gerald Meehl, a climate scientist at the National Center for Atmospheric Research, said that when the NOAA study was released last summer, there was a perception that no slowdown came in warming.
Study’s co-author Michael Mann, a climatologist at Pennsylvania State University, said, “As scientists, we must go where the 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allow our worries about climate contrarians and how they might seek to misrepresent our work to dictate what we do and do not publish”.
In the NOAA study, the researchers led by Tom Karl, director of NOAA’s National Centers for Environmental Information, have compared warming over the past 15 years with the long-term temperature trend between 1950 and 1998.
The new study researchers have affirmed that NOAA’s comparison was somewhat arbitrary. Fyfe and his colleagues have affirmed that the Pacific Decadal Oscillation (PDO), a natural variance in the climate system, explains the recent slowdown. When the PDO moves to the negative side, the Pacific cools and global warming slows.
Fyfe said that the only time that the PDO was neutral was between 1971 and 2000. Another explanation for the slowdown could be the world is not as sensitive to greenhouse gases as the models think so. Fyfe said that the models might be are not perfect and might be overly sensitive.
Overall, there is compelling evidence that there has been a temporary slowdown in observed global surface warming, especially when examined relative to our expectations, which can be explained by a combination of factors. Research into the nature and causes of this event has triggered an improved understanding of observational biases, radiative forcing, and internal variability.
A Stanford University study published in September 2015 has denied any chance of global warming hiatus. The study team added, “An apparent lull in the recent rate of global warming that has been widely accepted as fact is actually an artifact arising from faulty statistical methods.” “Our results clearly show that, in terms of the statistics of the long-term global temperature data, there never was a hiatus, a pause or a slowdown in global warming,” said Noah Diffenbaugh, a climate scientist in the School of Earth, Energy & Environmental Sciences, and a co-author of the Stanford University study.