The global warming hiatus: It’s critical — but is it real?

(Photo by Christopher Michel)

Billions of dollars, countless Prozac tablets, the fate of our planet – they all revolve around a simple issue: whether Earth stopped warming the past 18 years.

Atmospheric carbon dioxide now stands at 400 parts per million (PPM). It was just 280 before the Industrial Revolution. Since trapped gas bubbles show that CO2 and temperature historically march hand in hand, fossil fuel-burning is worrisome. Indeed, global surface temperature has climbed 1.7 degrees Fahrenheit in the past 125 years. With carbon dioxide likely reaching 500 PPM by century’s end, Earth may change significantly. We must switch over to non-carbon energy. But how quickly must we do this?

Some fear the worst. A close friend hopes that his children don’t have kids because our planet is screwed. Many adolescents are downright depressed over what they see as a hopeless future. On the other hand, some scientists believe that carbon dioxide only has a strong heat-trapping effect during its first 50 PPM of increase; after that, its climate-changing ability diminishes. If that’s true, and CO2’s consequences are not linear, future warming might be minimal.

There’s also the issue of feedback loops. Nature is complex, and many areas are poorly understood. A famous example of a positive feedback is when increased CO2 melts some floating sea ice, revealing dark ocean that absorbs more solar energy than the ice. This is positive feedback because the initial impetus causes a boosted final effect. Another example is when melting Arctic permafrost releases trapped methane.

But what about negative feedback effects? What if a little extra temperature causes added evaporation and greater cloud cover, which then reflects away more sunlight and inhibits surface warming? Even additional haze might do the job. Perhaps Gaia might come up with many such protections against our atmospheric carbon. In any case, no one knows which will dominate: the positive or the negative loops. If the latter, then the net global effect could be quite manageable – or at least something to which we could readily adapt.

While there’s no question that human fossil fuel-burning is greatly raising the carbon dioxide levels, and also no question that Earth has warmed a little over the last century, the future is far from certain.

With all that as background, it’s obviously vital that we know the global temperatures each year. We need to know what is really happening. So land and sea temperatures are continuously sampled. Doing so, climatologists have discovered that something strange has been afoot since the record-hot El Niño year of 1998. Since then, temperatures have been flat or nearly so. While 2005, 2010 and 2014 were “hottest-ever” years, they were only a few hundredths above previous records: tiny bumps on that flat plateau.

When that global-warming pause had endured for ten years, then 12, then 15, it increasingly threw climatologists for a loop. No models had predicted it. Many left-leaning publications scarcely mentioned the warming pause, knowing that climate-deniers would seize on it as “proof” against climate change. Finally, in late 2013, it could no longer be officially ignored. The International Panel on Climate Change acknowledged the existence of the pause, and renamed it a “hiatus” from global warming. Since then, at least 50 papers have appeared in the scientific literature, trying to explain where the missing heat went.

All these disparate guesses did little to make onlookers (like myself) feel confident that anyone really had a handle on what was happening. Finally, a paper released on May 28 by researchers at the National Oceanic and Atmospheric Administration (NOAA) readjusted the past temperature data to make the warming hiatus disappear. Unfortunately, the study’s readjusted data conflict with many other climate measurements, including data taken by satellites and from thousands of ARGO buoys built specifically to measure sea temperature.

That NOAA team simply added 0.12 degrees Celsius to each of those thousands of buoys’ readings, to make them better match the warmer temperatures taken by ships (mostly in their engine-inlet water readings). The buoys tend to get cooler temperature readings than the ships, likely because ships’ engines warm the water.

The readjustment was a bit strange, because the ships’ temperatures had always been regarded as less reliable. Moreover, the new upward-adjusted temps contradict those from infrared sensing satellites. In short, the NOAA team didn’t use any new measurements. They simply changed the lowest existing ones and tweaked them all upward. Since they did that to all buoys, and since several thousand new buoys have been added to the oceans since 2004, their adjustment created an upward-pointing global temperature graph. The hiatus was gone.

Carbon-haters breathed a sigh of relief. The New York Times ran a front-page story: “NOAA Analysis Shows that Temperature Hiatus Never Existed.”

But many are uncomfortable with the revision. Not surprisingly, the Republicans in the House have called for an investigation and subpoenaed the records of NOAA to see whether the revision amounted to “cooking the books” to get the graph plot they want. As anti-science as the House nut-jobs are, many of us do want to know if the revision was kosher. A lot is riding on that graph.

Naturally, we should phase out carbon anyway. The issue is: How dramatically must we rush to do it? Some would impose a carbon tax that would make commuters pay an extra buck a gallon. Others would fight anything that hurts the working class. Though my instinct is that our planet will do just fine when all is said and done, I still bought an eco-car (the buttery XLE Camry Hybrid) and just purchased solar panels.

Can’t hurt, right?


Want to know more? To read Bob’s previous “Night Sky” columns, visit our Almanac Weekly website at

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