What Global Warming "Hiatus"? New Research Shows Temperature Keeps Rising Without Pause

One more straw is slipping from the climate deniers grasp. According to a new study published online yesterday in the journal Science, another denier gambit on why global warming is not really happening has just vanished. New research shows there actually was no slowdown in the warming trend in the last 15 years.

New analysis of surface temperatures by National Oceanic and Atmospheric Administration's (NOAA) National Climatic Data Center scientists has shown that recent global temperature trends are actually significantly higher than reported two years ago in the most recent IPCC report.

The IPCC report reflected earlier analyses of surface temperature measurements that appeared to have found a slowdown since 1998 from the previous decades' rate of average surface temperature warming. It is important to note here that the earlier analyses found that the world was still continuing to heat up, although at an apparently slower pace. Nevertheless, many climate deniers wrongly claimed that global warming had "stopped." They seized on this argument with a death grip, perhaps because so many of their other "hoax" claims have simply melted away.

The new NOAA study incorporates recent improvements in deriving temperature trends from various measurement records, along with additional years of global data (including a record-warm 2014). Upon re-examination of the data, the researchers found no discernible change in the rate of surface warming from the second half of the 20th century to the first 15 years of the 21st century. The new data include more extensive and improved surface air temperature observations taken at thousands of weather observing stations over land, and for ocean sea surface temperature there are new observations from commercial ships and drifting surface buoys. In addition, the researchers also found that incomplete measurement coverage over the Arctic, which has been warming twice as fast as the rest of the planet, had led to underestimating recent (since 1997) global warming data and trends.

The authors further observe that 1998 was a particularly hot El Nino year, which skews any analysis beginning with that year. Look instead at the period 2000-2014, warming was occurring at an even faster rate than the average for the second half of the 20th century. Bottom line, as stated at the end of their paper:

"Indeed, based on our new analysis, the IPCC's (1) statement of two years ago - that the global surface temperature "has shown a much smaller increasing linear trend over the past 15 years than over the past 30 to 60 years" - is no longer valid."

While it is essential to get accurate annual temperature measurements and correct biases between different types of measurement techniques what remains key is the longer term trend that these short term measurements make up. In any climate systems there will always be short term ups and downs that occur naturally such as La Nina and El Nino events, increased aerosols, solar activity, i.e., the line is not a nice smooth upward slope along every point. But if you look over the long term the upward warming trend over the last hundred years remains incontrovertible.

Climate deniers will likely cry foul once again over this new study claiming scientists can't make up their minds. In fact, the scientific process is taking its normal and predicted course. Scientists make observations and analyze data, not once but many times over both to confirm, or not confirm, previous measurements as well as to update older analyses with new data and more sophisticated measurement and analytical techniques. It is in this way through the scientific process we are able to most accurately understand and describe the natural phenomena that are occurring around us.

About the Authors

Antonia Herzog

Deputy Director, Climate & Clean Air program

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