Climate deniers lose key talking point as satellites show temperatures hit all-time highs
February was the warmest month in the satellite record of atmospheric temperatures, according to new data. This is just the first domino to fall during what will likely prove to be the warmest, or one of the warmest, months on record as more data trickles in on conditions during February.
The satellite data deals a setback to climate deniers that frequently cite the satellite record of atmospheric temperatures as evidence that human-caused global warming either doesn't exist or is far smaller than scientists claim.
A prominent proponent of this view is Texas Sen. Ted Cruz, who won three primaries on Tuesday night, bolstering his bid to challenge Donald Trump for the Republican presidential nomination.
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At a Senate subcommittee hearing on Dec. 8, 2015, Cruz said:
"According to the satellite data, there has been no significant global warming for the past 18 years. Those are the data. The global warming alarmists don't like this data. They are inconvenient to their narrative, but facts and evidence matters."
Roy Spencer, one of the creators of the satellite data, told the Washington Post on Tuesday that the data shows global warming is taking place, but it is not as steep a temperature increase as surface-based thermometers indicate.
According to Spencer's data, the planet had a global average temperature that was 0.83 degrees Celsius, or 1.5 degrees Fahrenheit, above average during the month of February, a likely result of a record strong El Niño event plus global warming.
That reading was a significant boost above the 0.3 degrees Celsius anomaly from satellite-based temperatures in January, which also set a record.
“I’ve always cautioned fellow skeptics that it’s dangerous to claim no warming,” Spencer told the Post. “There has been warming. The question is how much warming there’s been and how does that compare to what’s expected and what’s predicted.”
Another satellite data set, from Remote Sensing Systems, also shows a huge jump in temperature anomalies from January to February.
Kevin Trenberth, a senior climate scientist at the National Center for Atmospheric Research in Boulder, Colo., told Mashable that El Niño likely accounted for about 0.15 degrees Celsius of the 2015 warming at the surface, and that it has a delayed influence on the atmosphere, which likely explains the February spike, which Trenberth said "was expected."
Indeed, those who are invested in the satellite data are blaming the spike solely on El Niño, but that argument misses the full picture of what's going on, according to Trenberth and many other climate researchers.
What's also happening is that the oceans have been heating up to record highs as they absorb the majority of the added heat from human-caused global warming.
"The increase in ocean heat content is relentless and provides the memory of global climate change and Earth's energy imbalance," Trenberth said in an email to Mashable.
In addition, although there are spikes and dips associated with El Niño events and other shorter term sources of climate variability, each temperature spike has jumped off of a higher floor, like a person jumping up and down on an upwardly moving escalator. This is an indication of global warming.
"Just as with the general temperature trend, isolating any of the three ENSO states shows that each state is getting warmer. In other words, La Niñas are getting warmer, El Niños are getting warmer, La Nadas are getting warmer," said Deke Arndt, the director of the climate analysis branch at the National Oceanic and Atmospheric Administration's (NOAA) National Center for Environmental Information, in an email to Mashable.
"Compared to history, the ENSO spike is becoming less and less significant and the accumulation of long-term warming becomes more and more dominant," he said, using the acronym for El Niño-Southern Oscillation, of which El Niño is a part.
"Reheating that old escalator analogy - after a while, your elevation off the floor becomes more about how long you've been on the escalator and less about how high you can jump," he said.
Each of the official temperature monitoring agencies around the world -- including NASA and the NOAA -- use surface-based temperatures to determine both monthly temperature records and long-term climate trends.
This is in part because the surface record is far longer, dating back to 1880 instead of the nearly 40-year satellite history, and also because we live on the surface, not in the lower atmosphere, so temperatures used to track climate change should reflect that. (Strictly speaking, satellites don't measure surface temperatures in the same sense that your home thermometer does, instead they measure atmospheric heat.)
Some scientists and politicians, such as Cruz, think that satellite-data is more accurate in part because surface weather stations can be subject to biases such as the urban heat island effect, which causes urban areas to be warmer than surrounding regions.
However, those effects have been corrected for in the surface record, and satellite data is subject to its own biases as well, namely due to slight shifts in satellite orbits over time.
Although the agencies have not yet reported their official data, computer model tracking of global temperatures, which is becoming increasingly sophisticated but is not yet an official source of temperature information, does show a record warm month for the globe, after factoring in data from a host of sources, from buoys to satellite observations and weather stations on land.
Based on the computer model analysis, it's obvious that the Arctic, in particular, saw far above average temperatures during February, as did parts of Asia, North America, Europe and nearly all of Africa.
It's also clear that February was significantly milder than January, which itself was the most unusually mild month on record, according to NASA, assuming these results hold up.
In the Arctic, winter temperatures averaged 10 to 20 degrees Fahrenheit above average in some areas, leading sea ice to record lows in January and very likely in February as well. This sets the region up for a potentially record low sea ice minimum in September, at the end of the melt season, though that is far from certain.
The U.K. Meteorological Service reported on Wednesday that preliminary data shows the region had its mildest winter on record since such data began in 1910.
Alaska saw one of its mildest and least snowy winters on record this year as well.
In the coming days, global climate agencies including the Japan Meteorological Agency, NOAA, NASA and the UK's Hadley Center will weigh in on just how unusually mild February was in the context of what is an era of more rapid global warming.
However, even if the month did set a record -- which the computer model data doesn't prove yet -- this is just one arbitrarily defined 29-day period.
What matters to climate scientists are long-term trends over the course of several decades.
The 12-month running mean means more than the monthly average, for example, and the 30-year trends are even more significant for what they tell scientists.
The long-term data, be it 12-month running means, 5-year means, or better yet, 30-year trends, also shows stark increases in global average surface temperatures, which scientists have concluded is largely attributable to human-caused greenhouse gas emissions from the burning of fossil fuels.
At this point, if you want to argue -- as Sen. Cruz does -- that climate change isn't occurring, you're increasingly out of friendly data to turn to.
Andrew Freedman is Mashable's Senior Editor for Science and Special Projects. Prior to working at Mashable, Freedman was a Senior Science writer for Climate Central. He has also worked as a reporter for Congressional Quarterly and Greenwire/E&E Daily. His writing has also appeared in the Washington Post, online at The Weather Channel, and washingtonpost.com, where he wrote a weekly climate science column for the "Capital Weather Gang" blog. He has provided commentary on climate science and policy for Sky News, CBC Radio, NPR, Al Jazeera, Sirius XM Radio, PBS NewsHour, and other national and international outlets. He holds a Masters in Climate and Society from Columbia University, and a Masters in Law and Diplomacy from The Fletcher School at Tufts University.
