The new climate deniers are the liberals who, despite their obsession with climate change, have managed to miss the biggest story in climate science: there hasn’t been any global warming for about a decade and a half.
“Over the past 15 years air temperatures at the Earth’s surface have been flat while greenhouse-gas emissions have continued to soar,” The Economist magazine writes. “The world added roughly 100 billion tons of carbon to the atmosphere between 2000 and 2010. That is about a quarter of all the CO2 put there by humanity since 1750.” Yet, no more warming.
The Economist has been decidedly alarmist on global warming through the years, so it deserves credit for pausing to consider why the warming trend it expected to continue has mysteriously stalled out.
The deniers feel no such compunction. They speak as if it is still the late 1990s, when measurements of global temperature had been rising for two decades. In his State of the Union address, President Barack Obama said that “we can choose to believe in the overwhelming judgment of science and act before it’s too late.” But he didn’t mention the latest trend in global warming.
This doesn’t mean the Earth didn’t get hotter in the 20th century, or that carbon emissions don’t tend to create a warmer planet, or that warming won’t necessarily begin again. It does mean that we know less about the fantastically complex global climate system than global-warming alarmists have been willing to admit.
Why the stall in warming? According to The Economist, maybe we’ve overestimated the warming impact of clouds. Or maybe some clouds cool instead of warm the planet. Or maybe the oceans are absorbing heat from the atmosphere. Although the surface temperature of the oceans hasn’t been rising, perhaps the warming is happening deep down. Former NASA environmental scientist James Hansen, who has been warning about global warming for years, thinks new coal-fired plants in China and India, releasing so-called aerosols into the atmosphere that act to suppress warming, may be partly responsible for the stasis in temperatures.
Hansen writes that knowing more about the effect of aerosols on the climate “requires accurate knowledge of changes in aerosol amount, size distribution, absorption and vertical distribution on a global basis – as well as simultaneous data on changes in cloud properties to allow inference of the indirect aerosol forcing via induced cloud changes.” Is that all? He ruefully notes that the launch of a satellite with a sensor to measure all of this failed, with no follow-up mission planned.
Hey, but don’t worry. The science is all “settled.”
What is beginning to seem more likely is that the “sensitivity” of the global climate to carbon emissions has been overestimated. If so, the deniers will be the last to admit it.