Burning carbon emits carbon-dioxide and other greenhouse gasses into the atmosphere. Greenhouse gases then trap heat in the atmosphere, preventing it from escaping out into space. This effect is responsible for global warming. Since the late 18th Century, burning carbon has fueled the Industrial Revolution. In the 1980s and 1990s, the surface temperature of the Earth rose by 1.2 degrees. This rise then caused substantial melting of the polar ice caps and extreme weather events.
How much worse, then, would be the effects of the spread of industrialization into the non-Western world in the 21st Century? This has greatly increased the burning of carbon. Between 2000 and 2010, 110 billion tons of carbon dioxide were released into the atmosphere. This amounts to an estimated one-fourth of all the greenhouse gases ever emitted. At this rate, the volume of carbon dioxide concentrations in the atmosphere compared to pre-industrial times will double by 2050. In 2007 the UN’s Intergovernmental Panel on Climate Change (IPCC) predicted that such a doubling could lead to a temperature rise of 5.4 degrees, with increases each decade of 0.2 degrees Celsius per decade. (Which I think, but I’m a dumb American, works out to be 0.36 degrees Fahrenheit.) So, the temperature of the Earth should be rising even faster than before.
It isn’t. Since 1998 the surface temperature of the Earth has risen by 0.2 degrees. However, this is much less of a rise than climate scientists had projected by extrapolating the temperature increases that were recorded in the 1980s and 1990s. (I think that we should be about 0.5 degrees warmer, but see my earlier disclaimer.) “Baby, Baby, where did the heat go?”
Some climate change skeptics love this: “There is no problem with global warming. It stopped in 1998.” OK, but why did it stop? Will it restart? Another stripe of skeptics take issue with the accuracy of the models used to estimate the effects of greenhouse gas emissions. They argue that the climate is not as sensitive to increases in greenhouse gases as many models assume. We have more time to adapt and at a lower cost than “alarmists” predict.
Climate scientists offer a number of possible explanations for the “missing heat.”
The deep seas absorbed the extra heat, the way they did the “Titanic.” While surface sea temperatures have remained stable, temperatures below 2,300 feet have been rising since 2000.
The rhythms in the heat radiated by the Sun are responsible. The highs and lows of this rhythm are called solar maximums and solar minimums. One solar maximum ended in 2000 and we are in the midst of a solar minimum.
The pollution emitted by major carbon-burners like China actually reflects away some of the Sun’s heat before it becomes trapped in the atmosphere. (You can see how this answer would alarm proponents of responding to climate change. “The real problem with air pollution is that we don’t have enough of it.”)
Climate scientists have also scaled-back their predictions from a possible 5.4 degree rise in surface temperatures to projections between 1.6 and 3.6 degrees. These less-warm decades will then be followed by the roof falling in. The sun will move toward the next solar maximum; the heat trapped in the deep sea will rise toward the surface to boost temperatures; and the “pollution umbrella” will go back to trapping heat in the atmosphere. We’ll fry like eggs. Or perhaps just get poached. Depends on which scientists you believe.
“The missing heat,” The Week, 30 August 2013, p. 11.
Judith Curry, “The Global Warming Statistical Meltdown,” Wall Street Journal, 10 October 2014.