NOAA says there’s no global warming hiatus.
Greenhouse gases heating the world faster than ever
Staff Report
FRISCO — After carefully analyzing the best global temperature data available, including more readings from ocean buoys and the Arctic, federal climate scientists concluded that there has been no slowdown in the rate of global warming the past 15 years.
“Adding in the last two years of global surface temperature data and other improvements in the quality of the observed record provide evidence that contradict the notion of a hiatus in recent global warming trends,” said Thomas R. Karl, with the National Oceanic and Atmospheric Administration.
“Our new analysis suggests that the apparent hiatus may have been largely the result of limitations in past datasets, and that the rate of warming over the first 15 years of this century has, in fact, been as fast or faster than that seen over the last half of the 20th century,” Karl said.
The study, published in the journal Science, was done by a team of scientists with NOAA’s National Centers for Environmental Information using the latest global surface temperature data.
The idea of a global warming slowdown spread widely and was even formally acknowledged in the most recent IPCCC climate assessment report. But NOAA scientists said they’ve improved their calculations since then. The new numbers also use improved versions of both sea surface temperature and land surface air temperature datasets.
In a press release, NOAA explained the improvements:
Prior to the mid-1970s, ships were the predominant way to measure sea surface temperatures, and since then buoys have been used in increasing numbers. Compared to ships, buoys provide measurements of significantly greater accuracy.
“In regards to sea surface temperature, scientists have shown that across the board, data collected from buoys are cooler than ship-based data,” said Dr. Thomas C. Peterson, principal scientist at NOAA’s National Centers for Environmental Information and one of the study’s authors.
“In order to accurately compare ship measurements and buoy measurements over the long-term, they need to be compatible. Scientists have developed a method to correct the difference between ship and buoy measurements, and we are using this in our trend analysis,” Peterson said.
In addition, more detailed information has been obtained regarding each ship’s observation method. This information was also used to provide improved corrections for changes in the mix of observing methods.
The study also shows that lack of data from some regions led scientists to underestimate the true global temperature change previously reported in the 2013 IPCC report.
Integrating dozens of data sets has improved spatial coverage over many areas, including the Arctic, where temperatures have been rapidly increasing in recent decades.
For example, the release of the International Surface Temperature Initiative databank, integrated with NOAA’s Global Historical Climatology Network-Daily dataset and forty additional historical data sources, has more than doubled the number of weather stations available for analysis.
Adding the data from 2013 and 2014, with 2014 being the warmest year on record, has had a notable impact on the temperature assessment.
