Contrary to a recent opinion piece in The Oregonian,
global warming is indeed still happening.
Gordon J. Fulks asserts that "honest data show no unusual warming in the latter half of the 20th century and none at all for the past 15 years, despite a slow increase in carbon dioxide"
("The dishonesty of climate change arguments," Commentary, July 20). But in fact, the Earth's surface has warmed by a significant 1.2 degrees Fahrenheit since 1950, and the continental U.S. by an average 3.2 degrees. By now a host of evidence shows this is primarily caused by the buildup of greenhouse gases -- especially carbon dioxide -- in the Earth's atmosphere. Our planet's greenhouse effect is increasing.
During this time the Earth's oceans have warmed strongly too, and, tellingly, the upper region of the atmosphere, called the stratosphere, has cooled, as greenhouse theory predicts. And the current increase in atmospheric carbon dioxide is anything but "slow"; it is, in fact, higher than at any time in human history and roughly 100 times faster than when the Earth left its last ice age.
Data on global surface temperatures finds warming in the past 15 years (by about 0.2 degrees F), but with a statistical significance of about 65 percent rather than the usual 95 percent standard. That's because, when the mathematics is done properly, it shows that 15 years is almost always too short a time interval to make meaningful
conclusions about climate.
Temperature is sticky, correlated to itself; a warm year is more likely to follow a warm year, and the same for cold years. Individual years are independent data points.
Climate scientists rarely draw conclusions for intervals less than 30 years. Yet climate-change contrarians are forever finding short-term cooling trends amid the long-term warming trend
The present short-term warming rate is indeed lower than it was in the 1990s. But scientists have never expected that surface warming would increase steadily year after year, since it fluctuates because of El Ninos and La Ninas and other natural cycles in the ocean.
The current "pause" of surface temperatures comes at a time when the large 1998 El Nino pushed temperatures upward and two recent La Ninas helped cool the surface, combining to give the appearance of a 15-year hiatus.
So looking only at short-term surface temperature trends is misleading. The real questions we must answer are these: Is the Earth still subject to a planetary energy imbalance? Is more energy entering the planet than is leaving?
The surest way to answer these questions is to stick thermometers in the massive ocean, where more than 90 percent of the extra, trapped energy goes. National Oceanic and Atmospheric Administration data shows that in the past 15 years, the top half of the worldwide ocean has gained heat about 90 percent faster than in the prior such period; the top fourth, about 40 percent faster. The ocean is a thermal reservoir, and its vast storage of heat can influence the atmosphere for decades.
As long as this planetary energy imbalance exists -- and it is getting stronger every year -- climate will change. While climate models cannot yet account for every fluctuation, and complicating factors such as man-made aerosols and clouds give rise to uncertainties, knowledge of the greenhouse effect is solid.
The Earth's glaciers, ice caps and sea ice continue to melt, sea levels continue to rise and the oceans continue to acidify.
Global warming is a long-term problem that is really just getting started. Your carbon emissions in this hour alone will ultimately trap a Hiroshima bomb's worth of heat, and about 25 percent of the carbon dioxide emitted will remain in the atmosphere for more than 10,000 years, altering the climate the entire time.
Climate contrarians are desperate to establish an alternative narrative, even if it is false. They have a quick, easy and wrong answer for every major finding of climate science, and they believe that repeating falsehoods can deny the facts.
Dismissing or avoiding the climate problem benefits no one but fossil fuel interests and those willing to do their dirty work.
David Appell is a science writer who lives in Salem. He holds a doctorate in physics from the State University of New York at Stony Brook.
